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Clean water is essential to our health, community and economy, but also its availability remains a major challenge even today. Graphene oxide membranes have shown significant promise in addressing this problem. A great deal of research has been conducted and is still being done to produce a stable graphene oxide membrane with high permeability and rejection rate. In this study, a highly stable GO membrane was fabricated using a simple vacuum filtration technique by the addition of TRIS and PEG. This is the first paper to discuss the potential for this combination to remove dyes and how it can result in the formation of a stable membrane. The membranes were characterised in detail using various characterisation techniques such as XRD, XPS, AFM, etc., and their ability in dye removal was investigated using UV–Vis spectroscopy. The stability of the developed membranes was tested using ultrasonication, and it was found that the membranes could remove the organic dyes (MB and CR) even at high concentration of dye (20 ppm) and with rejection percentage of 95% for both dyes. Furthermore, the membranes showed good water permeability with a value of 183 Lm−2h−1bar −1 emphasising its high potential for water purification. [ABSTRACT FROM AUTHOR]

Polyethylene (PE), including high‐density polyethylene (HDPE) and low‐density polyethylene (LDPE), makes up a significant part of post‐consumer plastics in municipal solid waste, presenting challenges for traditional recycling methods due to a wide range of melt flow properties and poor interfacial adhesion between the different resin, which often leads to low quality products (downcycling). In this study, a method is proposed to modify the molecular structure of post‐consumer PE (rHDPE and rLDPE) and their blends by using a straightforward organic peroxide crosslinking technique with 1 phr of dicumyl peroxide (DCP). Different rHDPE/rLDPE blend weight ratios (0/100, 20/80, 40/60, 50/50, 60/40, 80/20, and 100/0) were prepared using a combination of co‐rotating twin‐screw extrusion and pulverization. The final parts were produced via rotomolding where both the forming and crosslinking processes occurred concurrently. Subsequently, the materials were characterized in terms of chemical, thermal, and mechanical properties. It was found that the tensile strength (228%), tensile modulus (345%), flexural strength (145%), and flexural modulus (251%) increased by crosslinking the 80% wt. rHDPE (x‐rHDPE). Conversely, the gel content increased by 17%, thermal resistance by 37.2%, and the impact strength by 93% with 80% wt. rLDPE (x‐rLDPE). It can be concluded that a balance between the properties occurs as the addition of DCP improved both the interfacial adhesion and melt properties of rHDPE/rLDPE blends. This innovative approach represents a simple and straightforward method to upcycle mixed plastics (PE) streams, especially for rotomolding applications. It also offers promising avenues for sustainable waste management and material reuse. [ABSTRACT FROM AUTHOR]

Shape memory polymers typically utilize the glass transition or melting temperature to switch from one shape to another. The goal of this work is to check if the α‐relaxation, which is attributed to the migration of chains through lamellar crystals, can be utilized as novel switch for any crosslinkable semi‐crystalline thermoplastic. Using cross‐linked low‐density polyethylene (x‐LDPE) as an example, it is shown that the α‐relaxation is indeed suitable as switch, when the polymer is crystallized under strain to an intermediate shape. It is demonstrated that post‐stretching at a temperature between the α‐relaxation and the melting temperature, followed by subsequent cooling to room‐temperature switches x‐LDPE from the intermediate to a temporary shape and that reheating to this temperature initiates the retraction back to the intermediate shape. Switching between intermediate and temporary shapes is shown to be accompanied by a reversible change in morphology. [ABSTRACT FROM AUTHOR]

Miniaturization and lightweight of power systems urgently ask for polymer dielectrics with high discharged energy density at 150°C. Herein, a molecular design strategy is built to prepare new crosslinkable polyetherimide films (PEIDx, x is the molar ratio of dianhydride to amines) through simultaneously improving the polarization degree and reducing the residual polarization. Thermal, mechanical, and dielectric properties of PEIDx improve as x increases. PEID0.92 shows the best integrated performances, especially its discharged energy density (5.46 J cm−3, at 10 Hz and 454 MV m−1) is higher than those of reported polymer dielectrics with discharged energy storage at 150°C, and its charge–discharge efficiency is 80.14%. The outstanding energy storage performance of PEID0.92 is attributed to its unique molecular structure. Specifically, the use of nonplanar and low‐alkaline aliphatic cyclic diamine effectively improves the polarization degree of macromolecules; while the crosslinking of alkynyl groups limits the macromolecular movement, thus ensuring high heat resistance and low residual polarization. [ABSTRACT FROM AUTHOR]

In this study, three polycarboxylic acids with varying numbers of carboxyl groups were employed to crosslink polyvinyl alcohol (PVA): malonic acid as a diacid (MA), citric acid as a triacid (CA), and 1,2,3,4-butane tetracarboxylic acid as a tetraacid (BTCA). The crosslinking abilities of these acids were compared using physical, chemical, mechanical, morphological, thermal, and swelling measurements to assess their impact on the physicochemical properties of the resulting films. Based on the degree of crosslinking, mechanical strength, and thermal stability, tetra acid demonstrated superior crosslinking performance compared to di and tri acids. The highest strength was observed in the tetra acid crosslinked film, which exhibited a 127% increase over neat PVA. Regarding thermal stability, the decomposition temperature followed the order of tetraacid (450 °C) > triacid (378 °C) > diacid (350 °C). However, in terms of swelling behavior, triacid-crosslinked film, i.e., P-CA, exhibited the highest swelling. Further, the tetra acid-crosslinked film exhibited the lowest crystallinity and a higher contact angle (104.9°) than diacid and triacid crosslinked films. Additionally, the crosslinked films displayed enhanced elasticity compared to pure PVA, with the elasticity order being diacid > triacid > tetraacid, possibly due to differences in available crosslinking sites among the crosslinkers. [ABSTRACT FROM AUTHOR]

The current study aims to develop a cutting-edge methodology to enhance compatibility between natural fiber and polymeric matrix in bio-composites. To achieve this, an innovative approach for grafting an azide functional group (Az) onto the surface of polypropylene (PP) was successfully developed and confirmed. The Az group contributed to enhancing the interfacial interaction between the polymer matrix and the bio-filler through chemical crosslinking. Crosslinking is achieved through an innovative and efficient chemical process known as click chemistry. In particular, a click reaction is established between the functionalized PP with an azide group and functionalized natural filler with an alkyne group. The effectiveness of the proposed technique is verified using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Thermo-Gravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). The resulting bio-composite exhibits higher mechanical properties, better thermal stability, and improved biocompatibility compared to conventional materials. Specifically, the maximum tensile strength was achieved at 10% DPP loading, showing a 22% increase over the base material (DPP/PP) and a 7% increase over neat PP. A more significant enhancement was observed in Young's modulus results across all samples. Therefore, the established method is beneficial for polymer modification, promoting the production of high-performance bio-composite materials. [ABSTRACT FROM AUTHOR]

For thermosetting resins the degree of cross-linking plays a crucial role in the dielectric properties of the resin. In our previous works we confirmed this by simulating the relationship between the dielectric properties of poly(2-(4-benzocyclobutenyl)-divinylbenzene (DVB-S-BCB)) and the degree of cross-linking. In our research described here, we constructed a novel random copolymer with all-hydrocarbon structure based on poly(DVB-S-BCB) by introducing styrene (St) as the second polymerization monomer, thus controlling the number of cross-linking sites in the polymer. The effect of changes in St monomer content (number of cross-linking points) in the polymer chains, i.e. DVB-S-BCB and St, on the dielectric properties of the cured resins was investigated by molecular dynamics simulations. The simulation results showed that increasing the St monomer content in the copolymer, decreasing the cross-linking points, led to an increase in the dielectric constant of the cured resin, in addition to which the copolymer exhibited excellent thermo-mechanical properties. We also tested resin samples prepared by the experimental method and compared them with the simulated data, confirming the reliability of the results within acceptable error limits. [ABSTRACT FROM AUTHOR]

A new biomass-based carboxymethyl inulin modified chitosan material was designed and synthesized as an adsorbent for the Cu (II) removal from aqueous solutions, in which carboxymethyl inulin (CMI) with specific degree of substitution (DS) was prepared by optimal three steps alkalization-etherification processes, and then moderately crosslinked with chitosan by DMTMM. The structure and morphology of CMI-CS were characterized using fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), brunauer–emmett–teller (BET) and thermogravimetric analysis (TGA) analyses. The effects of CMI dosage, adsorption time, adsorption temperature, pH and initial Cu (II) concentration on the adsorption capability of CMI-CS to Cu (II) were investigated. The adsorption capacity of the adsorbent for Cu (II) was 49.4 mg/g under the conditions of CMI and CS mass ratio 3:2, pH 6, and adsorption time for 90 min. Its adsorption kinetics fitted the pseudo-second-order model, and adsorption isotherms followed by the Freundlich and the Temkin models well. XPS, FTIR, and SEM were used to explore the adsorption mechanism. The results demonstrated chemisorption and physisorption coexist in the adsorption process. The nitrogen-containing groups and oxygen-containing functional groups of CMI-CS adsorbent participated in the adsorption of Cu (II) through electrostatic interaction and chelation. Based on the above traits, the biomass-based adsorbent shows promising application in wastewater treatment. [ABSTRACT FROM AUTHOR]

As a type of cellulose ether, cyanoethyl cellulose (CEC) is considered to be a promising candidate for polymer dielectrics due to its sustainable nature and high dielectric constant induced by the cyano groups. However, the relatively high conduction loss of CEC arising from the charge motion across the polymer degrades its dielectric properties. In this work, we designed and synthesized an all‐organic polymer composite of CEC/itaconic anhydride (ITA) to improve dielectric properties. The CEC matrix was graft functionalized by ITA via an esterification reaction between the anhydride groups of ITA and hydroxyl groups of CEC. Meanwhile, crosslinking structure was also established in the composite by the generation of diester. Significantly improved dielectric constant (εr), elevated breakdown strength (Eb), restrained dielectric loss (tan δ) and decreased conductivity (σ) were observed in the composites compared with unmodified CEC. The εr increased from 17 for pure CEC to 32 for CEC/ITA at 1 kHz, and Eb also soared from 145 MV m−1 for CEC to 226 MV m−1 for the composite. The tan δ reduced from 0.24 for pure CEC to about 0.05 for the composite at 100 Hz. This should be attributed to the molecule trapping centers arising from the high electron affinity ITA and the formation of crosslinked networks as well as hydrogen bonding, which impeded the electric conduction. It also provided additional advantages of better dielectric properties for the CEC/ITA composites than pure CEC at high temperatures, which may offer inspiration for the design and preparation of bio‐based dielectrics for high temperatures. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Molecular hybrid materials based on widely available polymers crosslinked with an inorganic species have received increasing interest for their unique property sets outside of the usual range of commodity plastics and/or nanocomposites. Here, we provide a mini‐review on molecular hybrids based on metal oxide hydrates—compounds that readily react with, for example, hydroxylated polymers to form inorganic:organic materials systems with many desirable features and properties. Focusing on titanium oxide hydrates, we discuss here that such molecular hybrids can exhibit a broad refractive index range in addition to an increased glass transition temperature, mechanical stiffness and swelling resistance in comparison to the neat polymer, which illustrates that such hybrid systems offer a new, low‐cost, robust and versatile functional materials platform with great promise for, for example, solution‐processed photonics, catalysts and antimicrobial coatings. Generally, our mini‐review seeks to provide a concise and accessible overview of titanium oxide hydrate:polymer hybrid systems, focusing on their unique properties and processability as well as their broad and largely untapped potential as functional materials. © 2024 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPE) obtained from polyesters are viable alternatives to polyethylene oxide‐based materials, especially for room‐temperature applications. In SPEs, the ion conduction is dependent on the polymer segmental mobility and is thus facilitated by low glass transition temperature (Tg). Here, the study synthesizes an ester‐funtionalized polysiloxane‐based polymer electrolyte with an exceptionally low Tg of −76 °C, resulting in a high ionic conductivity of 2.6 × 10−5 S cm−1 at room temperature and a lithium transference number of 0.72. However, the low Tg and consequently low mechanical stability require reinforcement to promote the formation of stable lithium‐electrolyte interfaces in lithium plating stripping experiments and stable battery cycling in lithium‐metal batteries (LMBs). For this, the SPE is incorporated into a network structure to yield a semi‐interpenetrating network electrolyte (SPE20‐SIPN) which results in significantly improved storage modulus by three orders of magnitude and ionic conductivity is maintained upon crosslinking. The SPE20‐SIPN exhibits stable cycling for up to 50 cycles with fluctuation (voltage noise) in some of the cells. A combination of crosslinking and nanoparticle addition (SPE20‐N10‐SIPN) overcomes the voltage noise and results in high coulombic efficiencies and high capacity retention above 80% for 200 cycles in solvent‐free, all‐solid‐state LMBs at 30 °C. [ABSTRACT FROM AUTHOR]

Although there are many studies on CO2 adsorption via PEI‐modified carbon particles, metal–organic frameworks, zeolitic imidazolate frameworks, and silica‐based porous structures, only a limited number of studies on solely cross‐linked PEI‐based structures. Here, the CO2 adsorption capacities of PEI‐based microgels and cryogels were investigated. The effects of various parameters influencing the CO2 adsorption capacity of PEI‐based structures, for example, crosslinker types, PEI types (branched [bPEI] or linear [lPEI]), adsorbent types (microgel or cryogel), chemical‐modification including their complexes were examined. NaOH‐treated glycerol diglycidyl ether (GDE) crosslinked lPEI microgels exhibited higher CO2 adsorption capacity among other microgels with 0.094 ± 0.006 mmol CO2/g at 900 mm Hg, 25°C with 2‐ and 7.5‐fold increase upon pentaethylenehexamine (PEHA) modification and Ba(II) metal ion complexing, respectively. The CO2 adsorption capacity of bPEI and lPEI‐based cryogels were compared and found that lPEI‐GDE cryogels had higher adsorption capacity than bPEI‐GDE cryogels with 0.188 ± 0.01 mmol CO2/g at 900 mm Hg and 25°C. The reuse studies revealed that NaOH‐treated GDE crosslinked bPEI and lPEI microgels and cryogels showed promising potential, for example, after 10‐times repeated use >50% CO2 adsorption capacity was retained. The results affirmed that PEI‐based microgels and cryogels are encouraging materials for CO2 capture and reuse applications. [ABSTRACT FROM AUTHOR]

The concentration of harmful metal ions is growing globally, which raises the risk to both human and ecological health. The use of "adsorption" technique has been found to be very effective, for the removal of toxic metal ions. Among other things, hydrogels as an adsorbent work effectively for the removal of toxic metal ions and other aquatic pollutants. The newly designed potato starch‐xanthate (SX) based hydrogel (SX‐modified hydrogel) has been synthesized using a mixture of acrylamide (AAm) and acrylic acid (AA) monomers, with the help of free‐radical graft copolymerization technique. The synthesized SX‐modified hydrogel has been characterized by several analytical techniques, namely, UV–visible (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric (TG) analysis, point of zero charge (ΔpHPZC) analysis, x‐ray diffraction (XRD) analysis, and scanning electron microscope (SEM) analysis. The main objective of the current work is to remove the Cu2+ and Co2+ ions from wastewater using SX‐modified hydrogel as well as to study the swelling and water retention properties of the SX‐modified hydrogel. The swelling ratio of SX‐modified hydrogel has been found to be 312.31, 374.01, and 410.20 g/g at optimum pH 10, temperature 35°C, time 675 min in gray wastewater, tap water, and distilled water, respectively. The maximum percentage removal of Cu2+ and Co2+ ions by SX‐modified hydrogel has been found as 97.7% and 94.2%, respectively, at optimum conditions. The Langmuir isotherm model fits best with the experimental data, with maximum adsorption capacity of 515.46 mg/g for Cu2+ and 483.09 mg/g for Co2+ ions, respectively. The kinetic studies suggest that the adsorption process is governed by the second order kinetic model with rate constant of 2.06 × 10−4 g/(mg min) for Cu2+ and 1.79 × 10−4 g/(mg min) for Co2+ ions, respectively. The negative ΔG values suggest the adsorption process is spontaneous in nature. In addition, the positive ΔH values support the adsorption process is endothermic in nature. The SX‐modified hydrogel showed a remarkable desorption efficiency with 96.7% for Cu2+ and 92.5% for Co2+ ions and reusability for four consecutive adsorption–desorption cycles. It can be concluded that the SX‐modified hydrogel has showed an effective, economical, easy, low energy consuming, and significant potential in the treatment of wastewater containing heavy metal ions. [ABSTRACT FROM AUTHOR]

In the process of curing or service, epoxy resin is prone to crack damage due to complex stress, resulting in material performance degradation and other catastrophic accidents. Self‐healing microcapsules offer an effective strategy to address the aforementioned issues and enhance the long‐term durability of materials. However, traditional microcapsules face challenges in achieving non‐contact repair, as the healing agent requires high temperature or other extreme conditions to achieve curing, which necessitates the artificial provision of these conditions. Moreover, such extreme conditions may accelerate equipment aging or negatively impact the matrix material. To address these issues, this paper reports a photosensitive microcapsule that can achieve healing by natural light for non‐contact self‐healing of insulating composites. In particular, SiO2 nanoparticles are incorporated into the shell of the microcapsules to construct a UV shielding layer, effectively preventing premature curing and failure of the untriggered microcapsules. Experimental results indicate that the proposed photosensitive microcapsule@SiO2 exhibits excellent thermal stability, remaining intact at temperatures up to 200°C. With a healing agent content of approximately 77.5%, the photosensitive microcapsule@SiO2 ensures effective repair. Furthermore, when cross‐linked with epoxy resin, it has minimal negative impact on the epoxy matrix, with a slight improvement in mechanical properties. The composites demonstrate outstanding self‐healing performance in response to mechanical scratch damage. Without the need for any artificial stimuli, the healing process can be easily activated by natural light, facilitating intelligent, contactless, and autonomous self‐healing. [ABSTRACT FROM AUTHOR]

This research intends to create biodegradable packaging films using solution casting method. The films are composed of guar gum, carboxymethylcellulose, and blends of these materials with citric acid as a crosslinking agent. The concentration of citric acid ranges from 10 to 30% (w w−1). This study performs a curing treatment at 140°C for 30 min on the dried films containing the crosslinking additive to promote the esterification between the polymeric matrix and the crosslinking agent. The thin films have a smooth, homogeneous, and transparent aspect. Although the crosslinking reaction – evidenced by FTIR spectra – does not affect the thickness of the material, it causes a slight color variation making the samples assume a yellowish shade. Moreover, the crosslinking process enhances the water resistance, decreases the crystallinity index, and improves the water vapor barrier and thermal resistance of the films. The SEM images reveal the excess of unreacted crosslinking agent accumulated on the samples; these particles work as a plasticizer, affecting the morphology of the films as well as their water resistance, crystallinity, and thermal resistance. [ABSTRACT FROM AUTHOR]

The advent of flexible electronics has prompted the development of functional fibers with superior mechanical and electrical properties. MXenes, a novel family of 2D functional materials, have a variety of potential applications in flexible electronics. Herein, wet‐spinning is employed to continuously assemble Ti3C2Tx MXene liquid crystals into macroscopic fibers. Meanwhile, Zn2+ is introduced into the fiber to eliminate the electrostatic repulsion between the MXene nanosheets and enhance interlayer interactions and sheet alignment. The as‐obtained MXene fibers have strong mechanical strength (150.7 MPa), high electrical conductivity (3637.9 S cm−1), and good flexibility that facilitates weaving and knotting, making them suitable for fabric‐like flexible devices. The sound pressure sensors are woven from MXene fibers, which feature quick response time (286 ms) and recovery time (642 ms), ultra‐high sensitivity (280.2 kPa−1), and a low detection limit (0.1 Pa). Sound detection and recording are achieved using this sensor. MXene fibers as wearable thermal management devices are also demonstrated, exhibiting fast Joule thermal responses and good cycling stability. [ABSTRACT FROM AUTHOR]

Irreversible deformation of paper is a challenge for both printer operation and product quality, particularly in inkjet printing with water-based inks. Here we are investigating permanent paper curl, which is the residual curl of paper after drying of the ink (i.e., it is not the immediate paper curl due to wetting). The key aim of this work was to test the hypothesis that permanent paper curl is created by partial opening and rearrangement of the fibre–fibre bonds in the wetted paper layer. In order to test this hypothesis, we produced paper with crosslinked fibre–fibre bonds that do not open in the presence of water. Polyamideamine epichlorohydrin (PAE) and 1,2,3,4-butanetetracarboxylic acid were used as crosslinking agents and properties of the treated paper samples were analysed. Both agents led to significantly improved wet strength of the papers, furthermore we indeed found that the permanent curl of crosslinked papers was strongly reduced. Other curl related mechanisms like differences in fibre swelling, paper hydroexpansion and liquid penetration were not able to explain the reduction in curl. The finding that the creation of fibre–fibre bonds unaffected by water prevents permanent curl of paper after wetting and redrying leads to the conclusion that the mechanism for creating permanent paper curl after wetting is related to the partial opening and rearrangement of fibre–fibre bonds in the wetted paper. Possible pathways to apply these findings to paper production are discussed, for example switchable or temporary wet strength agents. [ABSTRACT FROM AUTHOR]

In this survey, the different weight ratios of polybenzimidazole (PBI)/polyvinyl alcohol (PVA) blend polymer membranes were produced using the solution‐casting method. The crosslinking agents of phosphoric acid (PA) and glutaraldehyde (GA) were studied separately to prevent the PVA water solubility in the PBI/PVA blend membrane structure. The GA crosslinking (24 h) successfully prevented membrane solubility, reducing it to below 1%. The chemically crosslinked blend membrane (Cr‐PBI/PVA‐9:1) has the highest proton conductivity result which is 0.209 S cm−1 at 80°C and it has excellent oxidative stability since the membrane only lost 4% of its weight in a Fenton agent after 96 h. The Cr‐PBI/PVA‐9:1 also has higher proton conductivity than the commercial PBI membrane (0.122 S cm−1 at 80°C). The glass transition temperature of the synthesized Cr‐PBI/PVA‐9:1 blend membrane is greater than the synthesized PBI membrane (390°C). The current density and power density measured at 0.6 V for the synthesized Cr‐PBI/PVA‐9:1 membrane were found to be 504 mA cm−2and 251 mW cm−2. This work sheds light on the potential use of PVA in PEMFC applications by mixing PVA with a high‐temperature polymer like PBI and crosslinking the membrane with a prepared GA crosslinking agent. [ABSTRACT FROM AUTHOR]

The construction of poly‐dioxolane (PDOL) solid‐state electrolytes by in situ polymerization is an effective way to achieve high performance lithium‐metal batteries. However, the poor electrochemical stability and safety issues of linear PDOL limit their further application. In this work, a multifunctional crosslinker has been introduced to construct a flame retardant crosslinked quasi solid‐state electrolyte (FCDOL). Due to the synergistic effect of the crosslinked network, the prepared FCDOL achieves excellent room temperature ionic conductivity (0.72 mS cm−1), high Li+ transference number (0.655), wide electrochemical stabilization window (4.8 V vs Li/Li+), and impressive performance when matched with lithium metal anodes (>4000 h plating/stripping) and high‐voltage cathodes, and the corresponding pouch cells can withstand abusive tests such as bending and cutting, encouraging that in situ polymerization of SPEs provides new insights into high‐energy density and high‐safety solid‐state batteries. [ABSTRACT FROM AUTHOR]

The present study aims to improve the mechanical strength of hydrogels via a simplified method, involving the creation of a nanocomposite hydrogel using polyvinyl alcohol (PVA) incorporated with un‐modified multiwalled carbon nanotubes (um‐MWCNTs). Departing from conventional freezing–thawing cycles, our research employs a facile approach, in which high‐shear mixing along with solvent exchange with deionized water was utilized. Morphological analysis unveiled a compact and dense microstructure within the nanocomposite hydrogel in correlation with MWCNT concentration. Attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR) elucidated the chemical structure of PVA/um‐MWCNTs hydrogel nanocomposite. Rheological studies on the viscoelastic properties indicated the formation of more "solid‐like" structure in the developed hydrogel nanocomposite. Broadband dielectric spectroscopy revealed alterations in dielectric properties of the fabricated PVA/um‐MWCNTs hydrogel nanocomposite corresponding to MWCNTs content in the PVA matrix. This comprehensive investigation highlights the impact of minimal MWCNTs concentration on the rheology, mechanical, and dielectric properties of developed PVA/um‐MWCNTs hydrogel nanocomposite. [ABSTRACT FROM AUTHOR]

To solve the severe coal dust pollution and dust hazards in underground coal mines, this study utilized graft copolymerization modification technology and compound technology to develop a mining composite consolidation dust suppressant. On this basis, analysis of its consolidation wettability and dust suppression mechanism was conducted through characterization tests and molecular dynamics simulation methods. The results show that polyacrylamide (PAM) had been successfully grafted onto the soybean protein isolate (SPI) molecule, and form a SPI‐PAM complex. After the dust suppressant acted on the coal dust surface, it utilized its wealthy hydrophilic groups, for the adsorption of water molecules and the positive amide group for binding to produce a large area of agglomeration of coal dust particles at the interface, exhibiting good wetting and consolidation into a shell. At the same time, molecular dynamic simulation verified that the diffusivity of water molecules in the dust suppressant‐coal system was 0.30Å2/ps, decreased by 43.3%, and the interaction energy with coal molecules was −200.27 kcal/mol, absolute value increased by 41.35%, which made the dust suppressant molecules more easily adsorb and agglomerate on the surface, demonstrated an excellent solidification and dust suppression effect. [ABSTRACT FROM AUTHOR]

Carbon fibers (CFs) are experiencing a growing demand owing to their low specific weight, exceptional mechanical properties, superior temperature, and corrosion resistance, however, their sustainability and energy consumption during manufacturing is still a challenge. Therefore, reclamation of waste CFs and their reformatting has gained significant attention. Herein, we synthesized a chemically degradable vitrimer matrix by curing bisphenol‐A diglycidyl ether (BADGE) with 2‐aminophenyl disulfide (2‐AFD) and further utilized the matrix for the development of CF reinforced composites (CFRCs) through vacuum‐assisted resin infusion molding (VARIM) process. The obtained vitrimeric system and its composites show excellent mechanical, self‐adhering, shape‐memory, and reprocessing properties. Meanwhile, the developed CFRP vitrimer composites can be rapidly dissolved in thiol solvent (1‐octanethiol), resulting in the efficient recycling of CFs. X‐ray diffraction, scanning electron microscopy, and Raman spectroscopy validate that the chemical structure of the recycled fibers closely resembles the structure of the original CFs. The recycled CFs were further used to prepare second generation composite materials with excellent thermal, dynamic, and mechanical properties for nonstructural applications (e.g., sports, automotive, etc.). Thus, with an effective CF recycling method, this study can assist in preparing reliable, long‐term functional, recyclable, and high‐performance composites. [ABSTRACT FROM AUTHOR]

We present a novel method for synthesizing water‐based non‐conjugated polymer nanoparticles that possess green fluorescence. This synthesis involves the crosslinking of polyethyleneimine (PEI) with glutaraldehyde (GA), followed by in situ polymerization of an acrylic acid‐based monomer. The nanoparticles are formed through self‐assembly driven by in situ electrostatic complexation, resulting in unique photoluminescence properties. This process involves the negatively charged polymer, formed via graft and homo‐polymerization, interacting with the pre‐existing positively charged PEI. The nanoparticles consist solely of heteroatomic bonds like C−O, C−N, C=O, and C=N. The restriction of vibrational and rotational relaxation of these bonds within the nanoscale poly‐ionic complex enhances their photoluminescence properties. For example, glutaraldehyde‐crosslinked polyethyleneimine/poly(methacrylic acid) (gPEI/PMAA) nanoparticles produced by this method demonstrate outstanding properties including a narrow size distribution with an average diameter of 35 nm, excitation‐dependent fluorescence with a green emission peak at 527 nm when excited at 480 nm, and a high quantum yield of up to 23.6 % (±1.2 %). The green fluorescence property of the nanoparticles can be used in the generation of white LED light through incorporating them with silicone and coating them onto a blue light LED chip. This study represents a significant improvement in the fluorescence properties of PEI‐based materials and opens up new possibilities for their applications in various fields. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the biomechanical and tomographic outcomes of keratoconus patients up to four years after corneal crosslinking (CXL). Methods: In this longitudinal retrospective-prospective single-center case series, the preoperative tomographic and biomechanical results from 200 keratoconus eyes of 161 patients undergoing CXL were compared to follow-up examinations at three-months, six-months, one-year, two-years, three-years, and four-years after CXL. Primary outcomes included the Corvis Biomechanical Factor (CBiF) and five biomechanical response parameters obtained from the Corvis ST. Tomographically, the Belin-Ambrósio deviation index (BAD-D) and the maximal keratometry (Kmax) measured by the Pentacam were analyzed. Additionally, Corvis E-staging, the thinnest corneal thickness (TCT), and the best-corrected visual acuity (BCVA) were obtained. Primary outcomes were compared using a paired t-test. Results: The CBiF decreased significantly at the six-month (p < 0.001) and one-year (p < 0.001) follow-ups when compared to preoperative values. E-staging behaved accordingly to the CBiF. Within the two- to four-year follow-ups, the biomechanical outcomes showed no significant differences when compared to preoperative. Tomographically, the BAD-D increased significantly during the first year after CXL with a maximum at six-months (p < 0.001), while Kmax decreased significantly (p < 0.001) and continuously up to four years after CXL. The TCT was lower at all postoperative follow-up visits compared to preoperative, and the BCVA improved. Conclusion: In the first year after CXL, there was a temporary progression in both the biomechanical CBiF and E-staging, as well as in the tomographic analysis. CXL contributes to the stabilization of both the tomographic and biomechanical properties of the cornea up to four years postoperatively. Key message: What is known: • While corneal crosslinking (CXL) is an effective procedure for halting disease progression in keratoconus patients, biomechanical in vivo measurements following CXL have shown conflicting results. What is new: • Biomechanical and tomographic severity indices CBiF, E-staging, and BAD-D show a temporary worsening within the first year after CXL. • Post-CXL biomechanical stabilization can be observed up to four years postoperatively when analyzing the corneal response parameters and severity indices. • Due to corneal thinning following standard protocol CXL, thickness-dependent parameters may not be optimal for the biomechanical and tomographic evaluation after CXL. [ABSTRACT FROM AUTHOR]

Hydrogels have been used in the clinic since the late 1980s with broad applications in drug delivery, cosmetics, tissue regeneration, among many other areas. The past three decades have witnessed rapid advances in the fields of polymer chemistry, crosslinking approaches, and hydrogel fabrication methods, which have collectively brought many new hydrogel products, either injectable or non‐injectable, to clinical studies. In an article published in 2020 entitled "Hydrogels in the clinic", we reviewed the clinical landscape and translational challenges of injectable hydrogels. Here, we provide an update on the advances in the field and also extend the scope to include non‐injectable hydrogels. We highlight recently approved hydrogel products, provide an update on the clinical trials of injectable hydrogels, and discuss active clinical trials of topically applied and implantable hydrogels. [ABSTRACT FROM AUTHOR]

Current families of reversible photochemical reactions present challenges for light‐controlled polymers of either photostationary states, which are common in photoinduced cycloaddition/cycloreversion reactions, or exclusively intramolecular bond changes, which characterize most photochromic units. In response to these challenges, here the concept of "proximal photocleavage" is presented, which combines photochemical crosslinking with a photocleavable linker, enabling a one‐time bond formation/cleavage sequence. Proximal photocleavage methacrylate monomers comprising, in series along the pendant of the methacrylate, a coumarin unit for crosslinking and either a phenacyl or ortho‐nitrobenzyl photocleavable group for decrosslinking are reported. The photophysical properties of these monomers and their statistical copolymers with methyl methacrylate are described, and wavelength selective crosslinking and de‐crosslinking of thin polymer films are demonstrated. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) composites reinforced with sepiolite and crosslinked with phenolic resin were prepared. Effects of compatibilizer types and contents, namely 3-aminopropyl triethoxysilane (APTES) or epoxidized NR (ENR50), on curing, tensile, strain-induced crystallization, and stress relaxation were investigated. Compared to APTES, ENR50 provided a greater compatibilizing effect in the NR composites. The ENR50 introduced strong physical and chemical interactions between sepiolite and NR, while only physical interaction was present in the APTES compatibilized composites. Stronger interaction between rubber and sepiolite improved filler dispersion, swelling resistance, and tensile strength; and delayed stress relaxation of the composite. Increased addition of ENR50 improved the modulus and tensile strength, and the greatest tensile strength was achieved at 2 phr ENR50 with a 15% improvement over composite without compatibilizer. In the case of APTES, 2 phr level enhanced tensile strength, but a further increase in APTES content degraded tensile, swelling resistance, and stress relaxation responses, due to its plasticizing effect. Moreover, ENR50 enhanced the strain-induced crystallization and delayed stress relaxation of the composites more than APTES. Weaker interaction between rubber and filler in APTES filled composites was due to having only hydrogen bonds formed between rubber and filler, in addition to crosslinks. [ABSTRACT FROM AUTHOR]

The well-known "click chemistry" reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at various extents (i.e., 10, 20, and 40%) with fluorogenic ferulic acid (FA) residue bonding propargyl groups were used in the CuAAC reaction with novel azido-terminated crosslinking agents Tri(Ethylene Glycol) Ethyl Resorcinol Acrylate (TEGERA) and Hexa(Ethylene Glycol) Ethyl Resorcinol Acrylate (HEGERA). The resulting HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL materials were characterized from the point of view of their structure by performing NMR studies. Moreover, the swelling behavior and rheological features were assessed employing TGA and DSC analysis to evaluate the potential gel-like properties of the resulting crosslinked materials. Despite the 3D crosslinked structure, HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL frameworks showed adequate swelling performance, the required shear thinning behavior, and coefficient of friction values close to those of the main commercial HA solutions used as viscosupplements (i.e., 0.20 at 10 mm/s). Furthermore, the presence of a crosslinked structure guaranteed a longer residence time. Indeed, HA(270)-FA-TEGERA-CL-40 and HA(270)-FA-HEGERA-CL-40 after 48 h showed a four times greater enzymatic resistance than the commercial viscosupplements. Based on the promising obtained results, the crosslinked materials are proposed for their potential applicability as novel viscosupplements. [ABSTRACT FROM AUTHOR]

The main weakness of non-silicone hydrogel contact lenses is their low oxygen permeability (Dk). Hence, we have tried to optimize their Dk using various concentrations and lengths of the poly (ethylene glycol) dimethacrylate crosslinker in a mixture of N,N-Dimethylacrylamide and Cyclohexyl methacrylate monomers. After synthesizing the different contact lenses, we evaluated their chemical, optical, and mechanical properties. The resultant non-silicone hydrogel contact lenses presented similar high water contents (75.69–80.60%) and adequate optical (e.g., a transmittance ranging from 85.91% to 99.91% and a refractive index between 1.3630 and 1.3740) and elongation at break (178.95–356.05%) characteristics for clinical applications. Conversely, they presented high contact angles (81.00–100.00°) and a low Young's modulus (0.066–0.167 MPa). Regarding the impact of the crosslinking modifications, the water content, contact angle, refractive index, transmittance, and Young's modulus of the synthesized lenses were slightly affected by crosslinker conditions. In contrast, the elongation at break (178.95–356.05%) and, more importantly, the oxygen permeability, which reached values of up to 73.90 Fatt units, were considerably impacted by the crosslinker conditions. To our knowledge, this study demonstrates for the first time that, in addition to water, other usual hydrogel components, like crosslinkers, can modulate the Dk of non-silicone contact lenses. It also provides a simple and scalable method to fabricate more permeable non-silicone lenses. [ABSTRACT FROM AUTHOR]

In this study, a novel bio-based acrylic monomer derived from cardanol was synthesized and used in order to prepare acrylic copolymers that can be applied as thermoplastic polymers alone initially and then curable with the help of some driers to get a crosslink network similar to thermosetting polymers with their hydrophobic long alkyl chains having double bonds in their chemical structure. The synthesized polymers have the ability to be used in the paint or varnish formulations with or without paint driers. The synthesized monomers and polymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Thermal properties of the polymers and obtained coatings therefrom were studied by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The varnish's thermal and coating characteristics, such as its adhesion, gloss, hardness, salt spray resistance, and touch and hard drying times, were examined and analyzed. The results showed that the bio-based cardanol moieties improved the coatings' resistance to chemicals and saltwater exposure as well as their thermal and mechanical characteristics through the incorporation aromatic and long linear alkyl chains. The block copolymers with cardanol units were used both on its own to produce thermoplastic polymeric films and in conjunction with driers to get thermoset crosslinking networks. The contact angle of thermoset polymeric films with driers measured as 77° but in case of thermoplastic blank polymer, it was 61°. Furthermore, the Tg of blank polymer was 13.37 °C, but with the addition of 10% cardanol units and a small amount of driers, the Tg was increased to 53.12 °C. [ABSTRACT FROM AUTHOR]

In this study, biocompatible and biodegradable superabsorbent polymers (SAPs) were prepared from carboxymethyl cellulose (CMC) using citric acid as a crosslinking agent, utilizing a high-concentration CMC paste and a short annealing process. The effects of CMC molecular weight, annealing temperature and time, and crosslinker concentration on the absorption properties in saline solution were evaluated. In addition, the effects of mixing CMC SAPs with different molecular weights were explored to optimize performance. The results showed that CMC molecular weight significantly affected absorption properties, with medium molecular weight (395 kDa) exhibiting the best overall performance. The content of the crosslinking agent and annealing conditions were also critical—higher crosslinking improved absorption under load but reduced free swell absorption and retention. In addition, the absorption properties could be optimized by appropriately mixing the CMC SAPs with different molecular weights, indicating complementary interactions that enhance performance beyond the individual contributions of each SAPs. These findings can contribute to the development of environmentally friendly, high-performance superabsorbent materials for personal care products as a sustainable alternative to conventional petroleum-derived SAPs. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs), as a kind of zero‐dimensional nanomaterials, have been widely synthesized by bottom‐up methods from various precursors. However, the formation mechanism is still unclear and controversial, which also brings difficulty to the regulation of structures and properties. Only some tentative formation processes were postulated by analyzing the products obtained at different reaction times and temperatures. Here, the effect of crosslinking on the formation of carbonized polymer dots (CPDs) is explored. Crosslinking‐induced nucleation and carbonization (CINC) is proposed as the driving force for the formation of CPDs. Under hydrothermal synthesis, the precursors are initiated to polymerize and crosslink. The crosslinking brings higher hydrophobicity to generate the hydrophilic/hydrophobic microphase separation, which promotes dehydration and carbonization resulting in the formation of CPDs. Based on the principle of CINC, the influence factors of size are also revealed. Moreover, the dissipative particle dynamics (DPD) simulation is employed to support this formation mechanism. This concept of CINC will bring light to the formation process of CPDs, as well as facilitate the regulation of CPDs' size and photoluminescence. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) was crosslinked with a homologous series of four different dicarboxylic acids, HOOC(CH2) n‐2COOH (n = 2 to 5) viz. oxalic acid (OA; C2), malonic acid (MA; C3), succinic acid (SA; C4) and glutaric acid (GA; C5) containing odd and even number of carbon atoms. The characterization and assessment of synthesized crosslinked films were done using ATR‐FTIR, XRD, SEM, AFM, DSC, rheology, percent swelling and sessile drop contact angle. The odd‐even effect of dicarboxylic acids was observed to significantly influence the physicochemical properties of PVA when employed as a crosslinker. PVA films crosslinked using dicarboxylic acids containing an even number of carbon atoms, displayed translucency, roughness, and an irregular matrix. In contrast, films incorporating an odd number of carbon atoms were transparent, homogenous, and densely packed. Furthermore, films containing even acids exhibited relatively lower crystallinity, lower melting temperature (Tm) and displayed an unexpected irregular trend in swelling as crosslinker concentration increased compared to films containing dicarboxylic acids with an odd number of carbon atoms which exhibits a consistent swelling with increasing crosslinker concentration. These results are attributed to the difference in the solubility and crystal structures of the odd‐even series of dicarboxylic acids. [ABSTRACT FROM AUTHOR]

Background: Wound healing represents a complex biological process, critically important in clinical practice due to its direct implication in a patient's recovery and quality of life. Conservative wound management frequently falls short in providing an ideal environment for the optimal tissue regeneration, often resulting in extended healing periods and elevated risk of infection and other complications. The emerging biomaterials, particularly hydrogels, have shown substantial promise in addressing these challenges by offering properties such as biocompatibility, biodegradability, and the ability to cure wound environment. Recent advancements have highlighted the therapeutic potential of integrating cell-derived conditioned medium (CM) into hydrogel matrices. Cell-derived CM represents a rich array of bioactive molecules, demonstrating significant efficacy in modulating cellular activities crucial for wound healing, including cellular proliferation, migration, and angiogenesis. Methods: The methodology of this review adheres to the standards set by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The review includes a selection of studies published within the last five years, focusing on in vivo experiments involving various types of skin injuries treated with topically applied hydrogels loaded with CM (H-CM). The search strategy refers to the PICO framework and includes the assessment of study quality by CAMARADES tool. Results: The systematic review represents a detailed evaluation of H-CM dressings wound healing efficiency based on the experimental results of cell-based assays and animal wound models. The study targets to reveal wound healing capacity of H-CM dressings, and provides a comparative data analysis, limitations of methods and discussions of H-CM role in advancing the wound healing therapy. Conclusions: The data presented demonstrate that H-CM is a promising material for advanced wound healing and regenerative medicine. These dressings possess proved in vitro/in vivo efficacy that highlights their strong clinical potential and paves the way to further investigations of H-CM formulations within clinical trials. [ABSTRACT FROM AUTHOR]

Keratoconus (KC) is a corneal thinning dystrophy that leads to visual impairment. While the cause of KC remains poorly understood, changes in sex hormone levels have been correlated with KC development. This study investigated circulating gonadotropin-releasing hormone (GnRH) in control and KC subjects to determine if this master hormone regulator is linked to the KC pathology. Plasma and saliva were collected from KC subjects (n = 227 and n = 274, respectively) and non-KC controls (n = 58 and n = 101, respectively), in concert with patient demographics and clinical features. GnRH levels in both plasma and saliva were significantly lower in KC subjects compared to controls. This finding was retained in plasma when subjects were stratified based on age, sex, and KC severity. Control and KC corneal fibroblasts (HKCs) stimulated with recombinant GnRH protein in vitro revealed significantly increased luteinizing hormone receptor by HKCs and reduced expression of α-smooth muscle actin with treatment suggesting that GnRH may modulate hormonal and fibrotic responses in the KC corneal stroma. Further studies are needed to reveal the role of the hypothalamic–pituitary–gonadal axis in the onset and progression of KC and to explore this pathway as a novel therapeutic target. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are getting attention as renewable alternatives to petroleum-based plastics due to their environmental benefits. However, improving their physical properties remains challenging. In this work, biodegradable biopolymers (PVA-PCD) were fabricated by chemically crosslinking petroleum-based polyvinyl alcohol (PVA) with biomass-derived cardanol-based polyols (PCD). Biopolymers were characterized using various techniques, including Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and swelling tests. Cardanol, the raw material, was converted into polyols via epoxidation followed by hydroxylation. FT-IR analysis confirmed that PVA-PCD biopolymers were crosslinked between the hydroxyl groups of PVA and PCD and the aldehydes of crosslinker glutaraldehyde (GLU), accompanied by the formation of acetal groups with ether bridges. XRD showed that the crystallinity of crosslinked polymers decreased, indicating that crosslinking occurs disorderly. TGA exhibited that GLU significantly improved the thermal stabilities of PVA and PCD-PVA polymers, as evidenced by increased decomposition temperatures. On the other hand, the effect of PVA/PCD ratios was minor on biopolymers' thermal stabilities. Swelling tests revealed that increased crosslinking density decreased the swelling ratio, suggesting that PVA-PCD biopolymers become more hydrophobic with high brittleness, high strength, and low swelling capacity. In summary, this study demonstrates that PVA-PCD biopolymers fabricated from biomass-derived materials have potential for various applications, such as biodegradable materials and sustainable packaging. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive block copolymer nanoparticles (NPs) have received close attention in recent years owing to their tremendous application potential in smart materials. Azobenzene‐containing NPs are widely studied due to the advantages of light as a stimulus and fast reversible trans–cis isomerization of azobenzene chromophores. However, the inefficient preparation process and difficult reversible transformation of morphologies limit their development. Herein it is demonstrated that the light‐triggered reversible swelling behavior of wormlike NPs with high azobenzene content could be realized via confined deformation. These worms are prepared in large quantities via polymerization‐induced self‐assembly based on the copolymerization of 11‐(4‐(4‐butylphenylazo)phenoxy)undecyl methacrylate (MAAz) and N‐(methacryloxy)succinimide (NMAS) monomers. Upon UV/visible light irradiation, the reversible deformation of worms is achieved when the feed molar ratio of NMAS/MAAz is relatively high or via crosslinking using diamines, which leads to the reduction of the photoisomerization efficiency. The diameter variation of the worms is influenced by the amount and types of crosslinkers. Moreover, the scalability of this strategy is further proved by the fabrication of photo‐ and reductant‐responsive crosslinked worms. It is expected that this study not only provides a new route to affording reversible photoresponsive NPs but also offers a unique insight into the reversible photodeformation mechanism of azobenzene‐containing NPs. [ABSTRACT FROM AUTHOR]

Hydrogels can form physically or chemically interactions with tissues and are widely used in the design of bioadhesive material. Polydopamine (PDA)/polyacrylamide (PAM)‐based adhesion hydrogels have emerged as one of the hydrogel adhesive materials with great potential for development. However, this type of hydrogel has low mechanical and adhesion properties, which has certain limitations in practical applications. Herein, inspired by the mussel adhesion mechanism, we introduced PDA into PAM/3‐aminophenylboronic acid grafted sodium alginate (SA‐PBA) double network system prepared a series of adhesive hydrogels, PDA was crosslinked by dynamic boronic ester bonds with SA‐PBA. The experimental results established that the hydrogels have favorable adhesive, anti‐fatigue, stretchable, and self‐healing properties. Cytocompatibility assay and in vitro hemolysis assay also indicated that the multifunctional hydrogel has excellent cytocompatibility and hemocompatibility. [ABSTRACT FROM AUTHOR]

The network structure and reactivity of suitable restoration agent consisting of silane coupling agents (SCAs) of the brittle walls of a cultural heritage site located underground in a desert area in Egypt were investigated using 1H pulsed nuclear magnetic resonance (pulse NMR). It should possess both high coagulation strength and ductility to ensure that it can withstand an earthquake; it should also contain ethoxy rather than methoxy groups, which generate toxic methanol. The solidification rate for the SCA or oligomer with ethoxy groups was lower than those with methoxy groups; however, the final polycondensates showed the same relaxation time (hardness). The difference spectrum was developed newly to analyze the network structure combined higher strength and ductility. The distribution of crosslinking degree of such polycondensates was narrow, and the amount of lower crosslinking degree was small. On the other hand, the distribution was wide in the polycondensates with ductility but lower strength. From the compression tests of model sand solidified with the restoration agent for both methoxy and ethoxy types showed the superior properties combined higher strength and ductility. The pulse NMR experiment was useful for estimating the solidification rate and the network structure. [ABSTRACT FROM AUTHOR]

Soft matrices with tuned properties are part of the vast landscape of innovative materials for the restoration of works of art. "Twin chain" polymer networks (TC‐PNs) based on polyvinyl alcohol have proven unique as scaffolds for Cultural Heritage cleaning. They enable optimum adaptability, adhesion, porosity, and connectivity at both micro‐ and nano‐scale resulting in superior time/space‐controlled cleaning operations. In this work, TC‐PNs properties are tuned through a mild crosslinking of the poly(vinyl alcohol) (PVA)‐porogen polymer by using sebacic, adipic, or succinic acid. The modified porogens have different structural features imparting a different phase behavior to TC‐PVAs mixtures in aqueous solution, i.e., in pre‐gel systems used to form gels through a liquid–liquid phase separation. The macro‐, micro‐, and nanoscale features of the final gels are characterized by Confocal Laser Scanning Microscopy, Small Angle X‐ray Scattering, Rheology and are related to their cleaning performances. The study shows that the gels cleaning capacity is related to their tortuosity, that can be tailored at the nanoscale. Counterintuitively gels with higher tortuosity show better performances as evidenced by the cleaning of mockups and paintings from Jean Helion, Jackson Pollock, and Tancredi Parmeggiani at Peggy Guggenheim Collection in Venice. [ABSTRACT FROM AUTHOR]

Starch is considered an ideal alternative to petroleum‐based plastics. However, the application of thermoplastic starch (TPS), which produced from cassava starch plasticized with glycerol, is limited by its hydrophilic, poor mechanical properties, and inadequate processability. In this study, dialdehyde starch (DAS) is used as crosslinker to modify TPS/poly(vinyl alcohol) (PVA), and DAS crosslinked cassava starch/PVA blends are fabricated by melt mixing method. Studies on the molecular structure of DAS crosslinked cassava starch/PVA blend indicate that the addition of DAS enhances the intermolecular interactions between cassava starch and PVA, resulting in the formation of a dense internal structure. The plasticizing torque and equilibrium torque of crosslinked cassava starch/PVA blends are increased and the tensile strength reaches 3.60 MPa, an improvement of 186% compared with TPS. Additionally, the water contact angle increases from 87.8° to 119.6° after modification. Compared with other crosslinkers, DAS has obvious advantages, making the DAS crosslinked cassava starch/PVA blend a biodegradable material with excellent properties and promising application prospects. [ABSTRACT FROM AUTHOR]

The mechanical properties of sclera play an important role in ocular functions, protection, and disease. Modulating the sclera's properties by exogenous crosslinking offers a way to expand the tissue's range of properties for study of the possible influences on the eye's behavior and diseases such as glaucoma and myopia. The focus of this work was to evaluate the effects of genipin crosslinking targeting the porcine perilimbal sclera (PLS) since the stiffness of this tissue was previously found in a number of studies to influence the eye's intraocular pressure (IOP). The work includes experiments on tensile test specimens and whole globes. The specimen tests showed decreased strain-rate dependence and increased relaxation stress due to the cross-linker. Whole globe perfusion experiments demonstrated that eyes treated with genipin in the perilimbal region had increased IOPs compared to the control globes. Migration of the cross-linker from the target tissue to other tissues is a confounding factor in whole globe, biomechanical measurements, with crosslinking. A novel quantitative genipin assay of the trabecular meshwork (TM) was developed to exclude globes where the TM was inadvertently crosslinked. The perfusion study, therefore, suggests that elevated stiffness of the PLS can significantly increase IOP apart from effects of the TM in the porcine eye. These results demonstrate the importance of PLS biomechanics in aqueous outflow regulation and support additional investigations into the distal outflow pathways as a key source of outflow resistance. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis, characterization, and application of four ionic liquids (ILs), three of which are being reported for the first time, with unique thermal properties and diverse anion-cation combinations, specifically in the context of epoxy resin polymerization. 1-3-Didodecylimidazolium dicyanamide (dDDIM DCA), 1-3-Didodecylimidazolium docusate (dDDIM DOSS), 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA), and 1-ethyl-3-methylimidazolium docusate (EMIM DOSS) were used to prepare six different mixtures with the same cation and with varying concentrations of DCA components, which is the main factor of an efficient polymerization, while the other component is intended to modify the properties of the cured resin. Mixtures based on EMIM cation demonstrated increased enthalpy and lower onset polymerization temperatures, indicating more efficient curing processes. The hardness of cured epoxy resins can be adjusted by altering the curing temperature and IL composition, with EMIM DCA and EMIM DOSS mixtures displaying high Shore A hardness, suitable for durable surface applications. In contrast, mixtures with higher dDDIM DCA proportions offered a balance between rigidity and flexibility, ideal for applications requiring both mechanical strength and elasticity. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WPU) often suffers from poor water resistance and mechanical properties due to hydrophilic emulsifiers. To address these issues, this study introduces glycidyl carbamate (GC) as a crosslinker to improve WPU performance. Three types of GC were synthesized using aliphatic, cycloaliphatic, and aromatic isocyanates, respectively. The crosslinked network was established through a reaction between the epoxide group of GC and the carboxylic acid and amine groups of WPU. Among these, the WPU film utilizing aromatic isocyanate-based GC exhibited the highest crosslink density, modulus, hardness, and water resistance, due to the rigidity of the aromatic molecular structure. However, the film displayed excessive brittleness, resulting in reduced tensile strength, along with yellowing typically associated with aromatic compounds. The WPU crosslinked with cycloaliphatic GC demonstrated the next best mechanical properties and water resistance, with a 2.7-fold increase in tensile strength, a 1.5-fold increase in hardness, and a 66% reduction in the water swelling ratio compared to neat WPU. This study presents a novel and effective strategy to enhance the water resistance and mechanical properties of WPU films, making them suitable for advanced coating applications. [ABSTRACT FROM AUTHOR]

Environment-friendly polymer blends of poly(lactic acid) (PLA) and itaconic acid (IA), poly(itaconic acid) (PIA), poly(itaconic acid)-co-poly(methyl itaconate) (Cop-IA), and net-poly(itaconic acid)-ν-triethylene glycol dimethacrylate (Net-IA) were performed via melt blending. The compositions studied were 0.1, 1, 3, and 10 wt% of the diverse chemical architectures. The research aims to study and understand the effect of IA and its different architectures on the mechanical, rheological, and thermal properties of PLA. The PLA/IA, PLA/PIA, PLA/Cop-IA, and PLA/Net-IA blends were characterized by dynamic mechanical thermal analysis, rotational rheometer (RR), thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. The complex viscosity, storage module, and loss module for the RR properties were observed in the following order: PLA/Cop-IA, PLA/Net-IA, and PLA/PIA > PLA > PLA/IA. Thermal stability improved with increasing concentrations of Cop-IA and Net-IA. In the same way, the mechanical properties were enhanced. In addition, the micrographs illustrated the formation of fibrillar structures for all blends. The crystallinity degree displayed higher values for the blends that contain Net-IA > Cop-IA than IA > PIA. Therefore, IA and its architectures can influence these studied properties, which have potential applications in disposable food packing. [ABSTRACT FROM AUTHOR]

Increasing of rubber content in isotactic polypropylene/ethylene–propylene rubber (iPP/EPR) alloys can extend the applications of this kind of polyolefin. The EPR content and phase structure of isotactic polypropylene multicomponents have great effect on the viscoelasticity and mechanical properties. iPP/EPR in-reactor alloys with a high EPR content were obtained through the in situ crosslinking of EPR chains with α,ω-diene. The morphological observation results indicate that the crosslinked iPP/EPR in-reactor alloys have a good spherical shape with clean and rough external surfaces. The high EPR content is finely dispersed in the crosslinked iPP/EPR alloys in areas ranging in size from tens of nanometers to several micrometers, which implies that a sufficient crosslinking degree of EPR chains can effectively prevent their aggregation and restrict macro-phase separation. The rheological results show a clear plateau in the terminal region, which reveals an entangled polymer chain network in the crosslinked iPP/EPR alloys. The well-dispersed EPR and the bi-continuous phase structure have a great effect on the mechanical properties of the isotactic polypropylene multicomponent which were assessed. [ABSTRACT FROM AUTHOR]

A novel hybrid of a quercetin-loaded silica-chitosan, modified by crosslinked gelatin-folate was developed in the current study as a pH-sensitive drug delivery system. The entrapment efficiency of quercetin was measured at about 77%. The drug release pattern was investigated in acidic and natural media (pH 5.6 and pH = 7.4) for 96 h. In-vitro drug release from unmodified carriers exhibited a rapid release in the early times (57 and 39% after 24 h in acidic and neutral media), which was followed by a slower release. However, the release behavior was improved after modifying the carrier with a gelatin-folate layer. In addition, a further release rate was observed for the gelatin-modified carrier in an acidic medium (31% after 24 h) compared to a neutral condition (20% after 24 h), confirming pH-sensitive behavior. Furthermore, the cumulative release of quercetin from the crosslinked gelatin-folate modified silica-chitosan carrier followed an approximately slow release, so that 23% and 15% of the drug was released after 24 h in acidic and natural conditions, respectively. The release date was described by the Higuchi model, suggesting that both diffusion and polymer swelling control the release process. The high drug loading, pH-triggered behavior, and controlled release of the developed hybrid drug platform, combined with low toxicity, render this designed carrier applicable in targeted drug delivery. [ABSTRACT FROM AUTHOR]

Organic/inorganic nanocomposites uniquely combine the dual advantages of inorganic nanomaterials and organic polymers. However, poor compatibility between inorganic nanoparticles and polymer matrices always arises as a huge obstacle to be addressed while designing and preparing high performance organic/inorganic nanocomposites. In situ surface grafting of ethylene–vinyl acetate copolymer (EVA) onto nanosilica and partial cross-linking of EVA via dynamic Si–O–C bonds with nanosilica as the core were simultaneously achieved via the transesterification reactions between the inherent Si–OH groups on the surface of nanosilica and the ester groups in EVA. The reactions were conducted thorough a one-step, simple and scalable reactive blending approach. The cross-linking reaction of EVA was evidenced by torque curves, FT-IR spectra and gel fraction testing. Uniform dispersion of silica particles in EVA matrix was observed for resulting EVA/silica nanocomposites due to surface modification of silica. Consequently, tremendous enhancement in mechanical properties of resultant EVA/silica nanocomposites were detected. Compared to the original EVA, the tensile strengths and tensile modulus of the EVA/silica nanocomposites increased by 72.5% and 37.8%, respectively, while the elongation at breaks of the EVA/silica nanocomposites remained as high as that of the original EVA. Additionally, the dynamic nature of Si–O–C cross-linkages enabled partially cross-linked EVA/silica nanocomposites to demonstrate exceptional reprocess ability and recyclability. This was evidenced by the sustained mechanical properties of the EVA/silica nanocomposites, which were still maintained even after undergoing three rounds of reprocessing. [ABSTRACT FROM AUTHOR]

Glutaraldehyde (GTA) crosslinking is commonly used to improve the thermal stability and mechanical strength of collagen casings. The aim of this research was to determine the optimal pH of the crosslinking between GTA and collagen as well as the crosslinking mechanisms. The weakly alkaline environment could facilitate the generation of GTA polymerization through the rapid generation of -C = C-C = O and -N = C-C = C- conjugated structures, and enhance the crosslinking reaction of GTA polymers with collagen amino groups. In the pH range of 8–10, the fibril diameter and d-space value declined significantly in the self-assembled collagen fibril-GTA system. Meanwhile, collagen casing films crosslinked with GTA in weakly alkaline conditions exhibited higher mechanical strength and thermal stability. These results suggest that the crosslinking of collagen casings and GTA can be improved by adjusting the pH. Possible crosslinking mechanisms related to the formation of conjugated long chains have also been proposed. This study could provide guidance on the appropriate use of GTA in the production process of collagen casings. [ABSTRACT FROM AUTHOR]