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A material capable of curing due to UV irradiation based on an alkyd oligomer and oligoorganosilsesquioxanes (OOSs) with functional thiol groups was obtained. Using microinterferometry, it was shown that the alkyd oligomer and OOS are completely compatible (mutually soluble). The resulting alkyd‐siloxane composition was cured under the action of UV irradiation due to reaction between double bonds of alkyd oligomer and thiol‐groups of silsesquioxane oligomer. The curing reaction takes 5 min with formation of coating, containing 99% of gel fraction, which is in 30 times faster in comparison with the classical method of alkyd curing in the presence of siccatives. The hydrophobicity of alkyd‐siloxane coatings also increases and varies depending on the content of OOS. The introduction of 50% OOS into the alkyd oligomer makes it possible to increase the water contact angle by 10° relative to the coating based on pure alkyd. A similar dependence is observed when studying the thermal stability of coatings. Thus, even with the introduction of 10% OOS into alkyd oligomer, the temperature at which a loss of 50% of mass occurs increases by 24°C relative to coatings based on a pure alkyd oligomer. [ABSTRACT FROM AUTHOR]

A new type polymeric adsorbent, poly(allylphenol‐co‐hydroxyethyl methacrylate‐co‐vinyl imidazole) (PAHV), is synthesized in this study. 2‐Hydroxyethyl methacrylate is used as complementary monomers along with 1‐vinyl imidazole and allylphenol monomers. The photopolymerization method is preferred as a synthesis method and benzophenone is used as the photoinitiator. The effectiveness of the PAHV against bacterial species such as Escherichia coli and Staphylococcus aureus is investigated by the Clinical and Laboratory Standards Institute (CLSI) disk diffusion method. The inhibition areas of PA1H1V3 and PA1H1V1 derivatives against E. coli and S. aureus are measured as 25 mm ± 0.25 mm and 7 mm ± 0.1 mm; 20 mm ± 0.25 mm, and 5 mm ± 0.1 mm, respectively. Sorption efficiencies (%) at pH = 6 (selected optimum pH) for 100 μg/L Cd and Cr of the PA1H1V1, PA1H3V1, and PA1H1V3 derivatives are found to be 69.0 ± 2.7 and 58.3 ± 6.7, 66.8 ± 6.2 and 75.8 ± 5.5, and 97.2 ± 3.7 and 97.7 ± 3.2 (n = 3), respectively. Adsorption studies revealed that the PA1H1V3 polymer can be used as an alternative for the sorption of cadmium and chromium. The pseudo‐second‐order model and Langmuir isotherm model fits for both adsorption processes. The adsorption capacities obtained from the Langmuir isotherm model for chromium and cadmium sorption are 52.63 and 68.49 μg g−1, respectively. [ABSTRACT FROM AUTHOR]

Direct ink write deposition facilitates line‐by‐line extrusion of inks spanning wide viscoelastic ranges. Following deposition, post processing technologies permit tuning of the extrudate's material property characteristics—ultraviolet (UV) irradiation, facilitating the photopolymerization of UV‐reactive catalyst solutions, permits targeted modification of the extrudate's microstructure and in situ tuning of extrudate macrostructure. This report analyzes the morphological, rheological, and microstructural property relationships governing the printability, and processivity, of extruded UV‐curable resin inks for delineation of sufficiency and optimization of ink printability utilizing direct ink write technologies. A design‐of‐experiments approach is implemented to quantify significance regarding an extrudate's dimensional response to extrusion parameter variation and in situ processing parameters, identifying proportionally of nozzle velocity, nozzle height, and UV irradiation exposure with extrudate aspect ratio, reflected by respective maximum extrudate aspect ratio increases of 158% and 109%, regarding 121 and 123K resin inks. Finally, the relationship between extrudate morphology and microstructure variation was assessed via dielectric cure monitoring, whereby an extrudate's ion viscosity was calculated in relation to its rheological modulus, reflecting the relationship between an extrudate's morphology, rheological response, and printability, regarding its microstructural variation. [ABSTRACT FROM AUTHOR]

A water‐soluble mixture of a novel diallylammonium salt photoinitiator based on 2‐hydroxy‐1‐[4‐(2‐hydroxyethoxy) phenyl]‐2‐methyl‐1‐propanone (Irgacure 2959 or I2959) and diallylammonium tosylate has been prepared. It shows excellent water‐solubility of 6.8 wt% in water, much greater than the solubility of I2959 (<2 wt%). It has a strong absorbance at 269 nm (ε ~ 15731) in methanol. It exhibits 15.6 times higher migration stability than I2959 due to its monomeric nature. Its photoinitiating efficiency of 2‐hydroxyethylmethacrylate (HEMA) and poly(ethylene glycol) diacrylate (PEGDA, Mn = 575 D) was found to be similar to I2959. PEGDA hydrogels prepared using the synthesized photoinitiator (PI) were found to have highly porous structures (15.44 μm) compared with those using I2959. PEGDA film prepared using this PI has demonstrated antibacterial properties against gram‐negative Pseudomonas aeruginosa (ATCC 15442) and gram‐positive Staphylococcus aureus (ATCC 23235) bacterial species. [ABSTRACT FROM AUTHOR]

Photocurable acrylates and vinyl esters are among the most commonly used resins in cured‐in‐place‐pipe (CIPP) rehabilitation technology, as they impart excellent thermomechanical properties in composite pipes. In the quest for achieving a higher energy efficiency of the photo‐curing process in CIPP, the frontal polymerization technique is a viable alternative that requires a lower irradiation dosage coupled with exceptionally high curing speeds and depths. Herein, for the first time, we report the application of frontal polymerization in the rehabilitation of underground pipes using a newly developed frontally curable epoxy‐based resin (Trelleborg Self‐Curing*). The neat resin is characterized for degree of cure, glass transition temperature, and mechanical properties via FTIR, DMA, and tensile tests, respectively. In a comprehensive way, the properties are benchmarked against commercially available acrylate (Trelleborg Light Cure*) and vinyl ester (Trelleborg Rapid Cure*) resins to evaluate their applicability for CIPP. The results show a higher glass transition temperature and final monomer conversion for the frontally cured resin, which cures significantly faster than the reference resins under the same irradiation conditions. In proof‐of‐concept trials, the newly developed resin successfully cures polymeric liners in a PVC host pipe with 100% water tightness and without losing its structural integrity. Results from ring stiffness tests for cured composite pipes additionally show that liners cured with Trelleborg Self‐Curing* resin pass the minimum required Young's modulus for non‐pressure drainage pipes as per ASTM F1216. Thus, frontally curable epoxy‐based resins are a promising and competitive alternative to acrylates and vinyl esters in CIPP. [ABSTRACT FROM AUTHOR]

3D printing is the technology of choice for the rapid production of objects with complex morphologies and controlled physical and chemical properties. 3D printing by photopolymerization is of great interest because of its ability to access very small scales and its high resolution. In the case of recent 3D printers, the preferred wavelength for light irradiation is 405 nm since it is a safe and energy‐economical irradiation. For 3D printing to be effective, it is therefore necessary to develop easily accessible, stable and highly efficient photoinitiating systems at the 405 nm wavelength. Beside, with the increasing use of photoinitiators, it is essential to develop structures with low cytotoxicity. Hence, the development of new photoinitiators is currently of major interest. To this end, the photochemical properties (triplet energy, bond dissociation energy, cleavage reaction enthalpy, and absorption properties) of several molecules have been calculated by molecular modeling and the most promising compounds have been synthesized. In this paper, four phosphine oxides photoinitiators (ADPO‐1, CPO‐2, CPO‐3, and FPO‐1) are synthesized and characterized. Subsequently, their absorption properties are measured and their efficiencies in photopolymerization under LED irradiation at 405 nm are evaluated. It is important to note that these structures have never been reported in 3D printing. Markedly, among the obtained photoinitiators, two of them show better efficiency than the commercially available and widely used phenylbis(2,4,6‐trimethylbenzoyl)phosphine oxide (BAPO) in photopolymerization (i.e., (Rp/[M0]) x100 values are 6.94, 12.95, and 4.93 s−1 for CPO‐2, ADPO‐1, and BAPO; with [M0] the initial acrylate function concentration). Furthermore, one of the synthesized photoinitiators is successfully used in 3D printing of thermoplastics for potential recycling ability. Finally, one of the obtained structures shows a lower cytotoxicity than the benchmark structure diphenyl(2,4,6‐trimethylbenzoyl)phosphine oxide (TPO). [ABSTRACT FROM AUTHOR]

Microcapsules encapsulating functional components have been widely applied in smart coating, but there was little literature about the relationship between the dispersion of embedded microcapsules and the coating performances. In this work, a series of microcapsules with different shell chemical structures were prepared via photo‐polymerization, and the relationship between the microcapsule shell component, the dispersion state in coating system and the coating properties were systematically investigated. The dispersion of microcapsule was investigated by measuring rheological behavior and SEM images. The dispersion of the microcapsules was closely correlated with the similarity between the chemical structure of the microcapsule shell and the coating matrix, and higher structural similarity facilitated a more uniform dispersion state of microcapsules in the coating matrix. The dispersion state of the microcapsules directly affected the physical properties and anticorrosion performance of the coating. The uniform dispersion of microcapsules could minimize the negative impact on the composite coating performance, whereas the agglomerated microcapsules destroyed the compactness of the composite coating, thus heavily impairing the basic properties and anti‐corrosion performance. [ABSTRACT FROM AUTHOR]

The development of new photoreactive resins to obtain smart coatings and enhance the self‐healing (SH) properties of photoreactive resins has attracted great interest in the past few years, and the investigation of the relationship between phase structure and smart properties is necessary. Herein, four types of urethane acrylate resins with built‐in DA structures with different hard segment structures, and a slight change in the length of the polyol soft segment were prepared. The hard segments were made of hexamethylene diisocyanate (HDI) with a linear structure and isophorone diisocyanate (IPDI) with an alicyclic structure, and the soft segments consisted of polyethylene glycols (PEG 400 and PEG 1000, respectively). The obtained resins were used to prepare polymer films that were cured using UV radiation. The coatings obtained in this way were tested for the influence of the polymer chain architecture on the kinetics of photopolymerization, the properties of the cured coatings, as well as the thermal characteristics and thermoreversibility performance of the cured coatings and their SH ability. [ABSTRACT FROM AUTHOR]

The aim of this study is to synthesize two eugenol‐derived halogenated monomers and to evaluate their properties as antibacterial and antifungal agents in the formulation of dental composite resins. The 4‐allyl‐2‐methoxyphenyl (2‐chloroethyl) carbonate (ECl) and 4‐allyl‐2‐methoxyphenyl 2,2,3,3,4,4,4‐heptafluorobutanoate (EF) monomers have halogens, chlorine or fluorine bonded in their structure, whose antibacterial activity is known. The characterization of ECl and EF monomers was made by Fourier transform infrared and 1H and 13C NMR. dental resin composites are formulated by mixing the BisGMA/TEGDMA, photoinitiator system, inorganic filler, and the ECl or EF monomer, respectively. The antimicrobial and antifungal activity of the experimental resins is determined using the strains of Staphylococcus aureus and Candida albicans. After copolymerization, DCRs with ECl or EF monomers significantly stop antibacterial growth and show excellent antifungal effect. The best results in the antibacterial test are using 0.5 or 3 wt% of the ECl monomer, while for the EF monomer is 5 wt%. On the other hand, the most adequate concentration of ECl and EF monomers in the antifungal activity is 0.5 wt%. The above demonstrates the ability of ECl and EF monomers to prevent antibacterial and antifungal growth in a dental composite resin, which would extend the useful life of a dental restoration. [ABSTRACT FROM AUTHOR]

The cycloaliphatic epoxy compounds have been widely used as the monomers in cationic photopolymerization and the fluorine‐modified organosilicon materials combine the merits of both organosilicon and organofluorine. In this work, three trifluoromethyl organosilicon cycloaliphatic epoxy monomers with different chain length (CE‐FSin, n = 3, 6, 9) were designed and prepared by using a facile two‐step synthesis and very competitive raw materials. CE‐FSin showed good ability to cationically photopolymerize. The final conversion of the alicyclic epoxy group of CE‐FSin systems reached up to 84.0% under the irradiation for 900 s. The addition of CE‐FSin enhanced the surface water repellency, heat resistance, elongation at break and glass transition temperature (Tg) of the cured film because of the presence of organosilicon chain and trifluoromethyl group of CE‐FSin. The cured film of CE‐FSi3‐0.5% had the largest water contact angle (105.0°), while the cured film of CE‐FSi9‐0.5% had tensile strength of 0.49 MPa and elongation at break of 68.51% that was three folds as that of the blank control. The addition of CE‐FSin had no obvious influences on the adhesion forces of the cured films, but decreased the pencil hardness. [ABSTRACT FROM AUTHOR]

Photosensitive resins are the research and development foundation of photopolymerization 3D printed products. We have found that cyclic trimethylolpropane formal acrylate (CTFA) and 2‐phenoxy ethyl acrylate (PHEA) resins are suitable for UV‐curable 3D printing consumables. Their photopolymers exhibit excellent shape memory characteristics at shape change temperature, shape recovery speed, shape extension limit, and shape maintenance ability. Moreover, we have analyzed the internal and external factors affecting these shape memory characteristics through several tests, including multi‐scale structure observation, thermal analysis, and mechanical tests. Furthermore, the complex hollow model design and multiple heat transfer media are adopted to expand the concept of additive manufacturing, and improve the practicability of 4D printing intelligent products. [ABSTRACT FROM AUTHOR]

Considering the current efforts for to develop new antimicrobial polymers from renewable resources suitable for application in environmentally friendly light‐based technologies, novel dual‐cured photopolymers of vanillin alcohol diglycidyl ether and glycerol dimethacrylate are developed. The kinetics of the sequential and simultaneous dual‐curing processes, combining free radical and cationic photopolymerizations, is investigated by real‐time photorheometry. Comparison of dual‐curing systems with different ratios of biobased epoxy and acrylate monomers revealed that the increase in the acrylate content increases the photocuring rate and improves the mechanical performance (Young's modulus increases from 76.64 to 190.71 MPa) and thermal stability (the 10% weight loss increases from 227 to 274°C) of the polymers, while the increase in the vanillin epoxy content results in better antimicrobial activity. Developed photopolymers create unfavorable conditions for the growth of microorganisms and reduce their population by up to 0% in 24 h. The excellent antibacterial and antifungal activity of new photopolymers allows them to be considered as biobased alternatives to petroleum‐based antimicrobial coatings, films, or optical 3D printed objects. [ABSTRACT FROM AUTHOR]

The ordered structure of biological tissues is a precondition for the development of high performance in these tissues. Hydrogels with anisotropic structures provide a good starting point for studying their biomimetic applications. In this work, a hydrogel that mimics the endogenous anisotropic structure of heart tissue was reported. The gel consists of acrylamide (AM) and 2‐Acrylamide‐2‐methylpro panesulfonic acid (AMPS) as gel monomers, α‐ketoglutaric acid as photoinitiator, and modified magnetic nanoparticles (Fe3O4‐RS) as crosslinking agent. Thus, AM, AMPS and Fe3O4‐Rs was called AAF for short. In the system, the orientation of Fe3O4‐Rs was arranged by an external magnetic field. Under ultraviolet (UV) irradiation, the precursor solution was polymerized in situ to form an AAF hydrogel. The structure, pore distribution, rheological properties, mechanical performance, swelling property, and biocompatibility of the prepared anisotropic AAF hydrogel were studied in this paper. Results showed that the mechanical performance of the AAF hydrogels was remarkably enhanced in comparison with the isotropic ones. The tensile strength of AAF hydrogel could reached 184 kPa in the direction of the parallel Orientation of Fe3O4‐Rs, and 80 kPa in the direction of the vertical Orientation of Fe3O4‐Rs under 25% strain (no magnetic field was applied during all test). Moreover, the anisotropic tensile ratio of AAF hydrogel also reached 2.3. The strength and modulus of anisotropic hydrogels were similar to cardiac tissue (anisotropic tensile ratio was 2.5), which has great potential for application in cardiac tissue engineering. [ABSTRACT FROM AUTHOR]

In this study, the waste Si sawdust (WSS) obtained from the silicon wafer sawing process was applied in polymer composite for anticorrosion application for the first time. The WSS powder was processed through a beads‐milling (BM) procedure using Zr beads. Subsequently, WSS‐based polystyrene (PS) composite coatings were prepared by photo‐polymerization of styrene monomers in the presence of a specific amount of WSS powder with UV radiation. The as‐prepared WSS‐based PS composite coatings were subsequently investigated and characterized by a series of tests. Anticorrosion performance of sample‐coated cold‐rolled steel (CRS) electrodes were investigated by a series of electrochemical corrosion measurements (e.g., Tafel, Nyquist, and Bode plots) in saline conditions. Gas permeability analysis (GPA) study of these membranes were also determined to support the anticorrosion data of coatings. It should be noted that the WSS‐based PS composite coatings were all found to exhibit better corrosion resistance than that of neat PS. Moreover, the composite coating with higher loading of WSS was found to show better anticorrosion performance than of lower loading of WSS. This may be attributed to the dispersion of WSS particles in PS can effectively prolong the diffusion path of corrosive factors, as evidenced by the corresponding GPA results. [ABSTRACT FROM AUTHOR]

UV‐curing 3D printing technology is one of the additive manufacturing techniques with the best printing accuracy and efficiency, but its advance is being challenged by the high curing shrinkage, poor mechanical strength and low toughness of photosensitive resin. Herein, rod‐shaped calcium carbonate modified by γ‐mercaptopropyl triethoxysilane (RCa‐Si) is used to improve the 3D printing resin. After compositing with RCa‐Si, the photopolymerization conversion of resin is slightly decreased, but it is still possible to 3D print accurate samples with a warpage of 1.0%. By adjusting the grafting ratio of thiols and the content of resultant RCa‐Si, the maximum elastic modulus of 3D printed samples is increased from 990 to 1420 MPa, tensile strength is enhanced from 35 to 63 MPa, and impact strength is also increased from 2.1 to 4.6 kJ/m2, owing to its anchoring effect between printing layers. Moreover, the thermal decomposition temperature of 3D printed sample containing 1.0 wt% of RCa1‐Si1 is increased to 325°C, and its Vicat softening point temperature is also increased to 193°C. Therefore, the comprehensive properties of 3D printing resin can be greatly improved by modified rod‐shaped calcium carbonate with thiols, guaranteeing the future large‐scale applications. [ABSTRACT FROM AUTHOR]

Polyelectrolyte hydrogel used for supercapacitors have the roles of both electrolyte and separator, the morphology and the strength of gel polyelectrolyte (GPE) are the keys for ionic transport properties therein. Here, the P(NVP‐co‐SPE)/polyvinyl alcohol (PVA) IPN hydrogel was prepared by photopolymerization and thermal polymerization, respectively. The influences of preparation method on morphology, mechanical strength and electrochemical performances were studied. Photopolymerized IPN GPE (UV‐GPE) exhibits a special regular microphase separation structure, and therefore has outstanding strength‐toughness and better electrochemical performance. The tensile strength and the toughness increased intensively from the 6.2 MPa and 3.4 MJ m−3 of thermal polymerized IPN GPE (TH‐GPE) to 28.5 MPa and 24.9 MJ m−3, respectively. The maximum swelling ratio of UV‐GPE is increased from 327% of TH‐GPE to 630%. The ionic conductivity of UV‐GPE increased from 4.29 × 10−2 S/cm of TH‐GPE to 5.82 × 10−2 S/cm. UV‐GPE has higher response current and specific capacitance. It also has the obviously better charge–discharge symmetry and cycling stability, and the capacity retention rate is still 92.3% after 1000 cycles. Thus, it brings out the fast, eco‐economic photopolymerization method is an effective way to prepare high‐performance polyelectrolyte hydrogel. [ABSTRACT FROM AUTHOR]

Hydrogels are hydrophilic crosslinked polymer networks that can absorb large amounts of water. They are used as biomaterials in numerous tissue engineering applications. Considering environmental awareness, the synthesis of biomaterials from renewable resources through green fabrication methods is essential. This study produces thermoresponsive hydrogels from a castor oil‐based monomer, acrylated methyl ricinoleate, and poly(ethylene glycol) via an environmentally friendly synthesis method. A photopolymerization technique is used with a very short reaction time. Characterization of the hydrogels is performed using thermogravimetric analysis, scanning electron microscopy, and Fourier‐transform infrared spectroscopy. Swelling and deswelling profiles are subsequently analyzed. A maximum equilibrium swelling degree of 271% is reached within 30 min. In vitro cytotoxicity assays of the hydrogels and the degradation products are performed to evaluate the biocompatibility. The hydrogels are biocompatible because the cell survival of all hydrogel samples and degradation products is greater than 100% and 85%, respectively. Consequently, the thermoresponsive hydrogels made from renewable raw materials in a green process offer interesting platforms for building biomaterials such as actuators for lab‐on‐a‐chip devices, microfluidics, drug delivery systems, preclinical drug screening models, and regenerative medicine. [ABSTRACT FROM AUTHOR]

A facile strategy is developed to fabricate a two‐layer grafted polymer coatings on silicon wafers, specifically soft crosslinked polythioether as middle damping layer and stiff poly(methyl methacrylate) (PMMA) as top protecting layer. At first, a highly crosslinked polythioether layer was constructed on the surface of the silicon wafer with tunable thickness and smooth morphology with trimethylolpropane tris(2‐mercaptoacetate) and pentaerythritol triallyl ether as monomers and 4‐(N,N‐diphenyl‐amino)benzaldehyde as an organocatalyst. The Young's modulus of the grafted crosslinked polythioether layer is about 300–400 MPa and the roughness is about 11.3 nm measured by atomic force microscope. There are about 9000 ea reactive –SH in a cuboid cell with 1 nm2 base area and 7–14 μm height in the grafted crosslinked polythiolether layer. Then, a flatten PMMA coating layer with Young's modulus as high as ~2.4 GPa was grafted from/onto the surface of the crosslinked polythiolether with surface –SH groups as initiating or chain transfer sites. [ABSTRACT FROM AUTHOR]

We report the copolymerization synthesis of novel poly(allylisothiocyanate‐co‐hydroxyethylmethacrylate‐co‐vinylimidazole) (PAHV) adsorbents for potential applications in the heavy metal removals. In the present study, the copolymerization reaction was introduced by photopolymerization using benzophenone as the photoinitiator. The chemical structure in the PAHV adsorbents was monitored and evaluated by Fourier transform infrared spectroscopy, 1H‐nuclear magnetic resonance, andX‐ray photoelectron spectroscopy measurements. Surface analysis and molecular weight distribution of PAHV adsorbents were performed by scanning electron microscopy and gel permeation chromatography analysis, respectively. The adsorption method, which is one of the most effective techniques, was used for the elimination of heavy metal ions from aqueous solutions in this study. In order to understand the adsorption capacity and removal efficiency of heavy metal ions by PAHV, the effects of pH value and monomer ratio in the adsorbents were investigated. Inductively coupled plasma mass spectrometry device was used for these analyses. The optimum pH values for adsorption capacity and removal efficiency of heavy metal ions have been 6–8. The removal efficiency of heavy metal ions by the various PAHV adsorbents decreased in the order: Cd2+ > Pb2+ > Co3+ > Cr3+ > Ni2+ > Cu2+. [ABSTRACT FROM AUTHOR]

Filling hexagonal boron nitride (h‐BN) is a hot topic in the research of improving the thermal conductivity of polymer composites. Conversely, its difficulty in dispersing and forming a three‐dimensional thermal network has become a major problem. This article uses liquid resin can effectively help the filler to be evenly dispersed and construct a multi‐layer connection network through 3D printing technology, which improves the thermal conductivity of polymer effectively. With the addition of 30 wt% h‐BN, the thermal conductivity of the epoxy acrylate (EA) composite reaches 1.60 Wm−1 K−1, which is 6.8 times that of pure epoxy acrylic resin. Our work provides a new idea for improving the thermal conductivity of photocured polymers. [ABSTRACT FROM AUTHOR]

The route via the cross‐linking of hyperbranched prepolymers has potential advantage to construct low dielectric constant (low‐k) resins owing to the enhanced molecular free volume in hyperbranched structure. However, it is still a challenge to prepare hyperbranched resins with good film‐forming property and low‐k. In this paper, two hyperbranched polycarbosilanes with reactive benzocyclobutene groups were synthesized via hydrosilylation reaction to avoid the generation of SiO bonds for enabling the low polarity of chemical bonds. The spacing groups including phenyl or ethylene were incorporated into the hyperbranched structures, and the effect of the spacing groups on the physicochemical properties of hyperbranched polycarbosilane derived resins were investigated. The phenyl groups were found to effectively decrease the dielectric constant (k), while endowing the resins with good film forming ability and thermostability. The UV/thermally cured phenyl group resin owing to dual crosslinked structure, the patterns would not be deformed significantly during thermally cured process. Both hyperbranched polycarbosilane derived resins could be potential photoresists. [ABSTRACT FROM AUTHOR]

Transferable shadow cure is presented as an improved method of shadow cure. In this new method, active centers are formed in one space, and active‐center‐containing monomer is then moved to another space where the bulk of the polymerization proceeds. This transference enables inclusion of pigments and fillers, layering in thick systems, and polymerization in complex geometries. Kinetic analysis of shadow‐cure samples shows conversions consistently ~15% less than comparable light‐cure samples. In addition, shadow‐cure films have a higher Tg and crosslink density than light‐cure films, likely driven by annealing that occurs during the first dynamic mechanical analyzer temperature ramp sequence. A central‐composite design explored the effect of sample depth, effective irradiance, exposure area, and exposure time on conversion and the weight percent of the light‐cure section. The model predicts both responses are maximized by increasing effective irradiance and exposure time and decreasing sample depth, which is consistent with classical photopolymerization kinetics. [ABSTRACT FROM AUTHOR]

Epoxy resins have been an inspiration in adhesives and coatings, however, uneven photopolymerization kinetics result in wrinkled surface and filler segregation, causing aesthetic and mechanical damage. Hence a control over curing kinetics is required not only to dodge filler segregation but also to control composite surface smoothness. In this study, photochemical modification of carbon black with mercaptopropyltrimethoxysilane, has resulted in unique silanol dendrites exterior on carbon black. Kinetic investigation confirmed that Ea for cationic polymerization of modified CB composite is three folds less in comparison to neat matrix, and two folds less in comparison to unmodified CB composite. Silanol dendrites have contributed on epoxy curing kinetics, through activated monomer mechanism. Samples have been characterized through XPS, FTIR, SEM, TGA, DSC, Raman, and EDX. [ABSTRACT FROM AUTHOR]

Host matrices play an important role in the volume holographic gratings formation of photopolymers. In this study, a series of fluorinated epoxy resin (FTGE) with low refractive index (1.44–1.46) are synthesized and characterized by nuclear magnetic resonance spectra (1H NMR, 19F NMR) and fourier transform infrared spectra (FTIR). Fluorinated epoxy‐amine cross‐linked matrices are formed at room temperature and their thermal polymerization properties are investigated through real‐time FTIR and thermogravimetric analyses (TGA). Using the fluorinated epoxy‐amine as host matrices, holographic photopolymers are fabricated. The influence of different kinds (Prop‐FTGE, Buta‐FTGE, and Penta‐FTGE) and weight ratios (0%, 8%, 16%, and 23%) of FTGEs on holographic performances of the photopolymers are explored. The results show that the sample with 23% Prop‐FTGE has the most excellent holographic optical characteristics. 0.5 mm thick sample with 23% Prop‐FTGE reaches 91% diffraction efficiency within 80 mJ/cm2 exposure dosage, and gets a 2000 lp/mm Bragg volume grating with 0.24° angular selectivity. Meanwhile, under a single pulse exposure mode (150–200 ps pulse width, 25 mJ/cm2 exposure dosage), a grating with 4.4% diffraction efficiency is obtained, which proves the ultrafast response and recording capability of the sample. [ABSTRACT FROM AUTHOR]

Digital light processing 3D printing has been rapidly evolving conventional manufacturing industry with the most meticulous resolution and strongest layer‐to‐layer adhesion among all additive manufacturing techniques. In this study, to improve poor polymer thermal stability and dielectric properties from prevailing methyl methacrylate‐based resin, tri‐functional trimethylolpropane tri‐acrylate (TMPTA) is introduced to form a stable polymer network. Meanwhile, monomers carrying non‐polar, bulky adamantane are added to eradicate poly‐TMPTA's notorious high cracking and warping tendency. Test results showed both high 1‐adamantyl methacrylate and 1, 3‐adamantyl di‐acrylate (ADDA) additions can print crack‐free samples. However, only ADDA addition keeps low CTE (82.86 ppm/oC, 200 ~ 260°C) and cuts down Df (0.02, 10 GHz). TMPTA polymer network modifications of both additions are explored. By contrast, poly‐MMA exhibits much higher CTE (323.44 ppm/oC) and Df (0.035). A 3D‐printed curvilinear circuit board from above resin formulation with electroplated copper circuits successfully passes lead‐free level reflow without deformation. [ABSTRACT FROM AUTHOR]

Photocuring resins have emerged as cutting‐edge technology in coatings, adhesives, composites, additive manufacturing, and so forth. In the present work, different bisphenol, namely A, F, and S, were used to synthesize low molecular weight epoxy resin, which was further reacted with acrylic acid monomer to form bisphenol‐based epoxy acrylate (BEA). The BEA resins were formulated using reactive diluents, trimethylolpropane triacrylate, and hexanediol diacrylate in the ratio of 0–40 wt% at the increment of 10 wt% alongside a fixed quantity photoinitiator. These resins were then cast into dumbbell‐shaped specimens by irradiating them under ultraviolet (UV) light. The structural elucidation of BEA resins was performed using Fourier transform infrared, nuclear magnetic resonance, and UV–Vis spectroscopy. The formulated resins were also studied for their rheological properties. Further, the UV cured specimens were evaluated for mechanical, thermal, contact angle, and extent of curing. These outcomes were utilized for establishing the structure–property relationship based on the functionality, reactivity, and molecular structure of synthesized BEA resins, which controllers the design architecture and cross‐linking density of UV‐cured specimens. [ABSTRACT FROM AUTHOR]

In this work, we designed a new D‐π‐A‐π‐D LED photoinitiator BBFC with high molar excitation coefficient and photoinitiation efficiency based on the principle of inhibition of photoisomerization. Via introduction of benzene ring on the BFC, which we have reported before, the absorption wavelength, molar excitation coefficient and photoinitiation efficiency of BBFC were greatly improved. The characterization and theoretical calculation proved BBFC has no photoisomerization, for the change of the configuration of BBFC requiring high energy due to the steric effect. BBFC has higher initiation efficiency than that of commercial photoinitiator ITX with little content under air condition. This might have potential to design new D‐π‐A‐π‐D molecules with high‐photoinitiation efficiency and contribute the field of photo polymerization. [ABSTRACT FROM AUTHOR]

In this research, a 3D printing technique was employed for processing biobased composites of polyacrylated epoxidized soybean oil (AESO) with modified ethyl cellulose macromonomer (ECM). In this 3D printing process, objects are built in a layer‐by‐layer fashion by depositing formulated liquid solutions on a platform and rapidly transformed into a solid film cured by UV light. The sustainable materials consisting of ECM and AESO biopolymer were examined for their physical and thermal properties. Samples with different ECM and AESO weight ratios were prepared. Tensile test results showed the ECM‐AESO composites had higher strength and stiffness than AESO alone. Their tensile strengths with ECM weight contents from 30 wt.% to 5 wt.% are between 11.5 MPa and 5.9 MPa and Young's moduli are between 167 MPa and 56 MPa, compared to AESO polymer itself with 4.3 MPa and 27.4 MPa, respectively. Further, the glass transition temperatures of all ECM‐AESO composites were increased from 57.4 to 82.2°C, compared to AESO polymer itself with 47.1°C. Thermal properties of the ECM‐AESO composites are stable up to 325°C. These materials may be of great environmental interest because these composites consist of high amounts of agricultural resources. [ABSTRACT FROM AUTHOR]

In this work, we aimed to prepare a simple and an efficient adsorbent for the removal of toxic, cationic dye; malachite green (MG). We reviewed many previous studies and designed our adsorbent based on the rationale that (1) acidic groups containing monomers which are capable of making hydrogen bonds (or electrostatic interactions) with MG are very effective in adsorption and (2) π‐π stacking enhances the adsorption capacity. We first synthesized an imidazole‐acrylate adduct and used it for the preparation of photocured hydrogels. The imidazole‐acrylate adduct was characterized by H NMR and FTIR spectroscopy. The effect of experimental conditions on the MG adsorption properties of the hydrogels such as the effect of pH, time and MG concentration were also investigated. Under the optimum conditions (pH = 6 and 220 min contact time) at room temperature, the maximum adsorption capacity was found as high as 714.28 mg/g. The results showed that the adsorption process of the optimum hydrogel, which can be used 4 times without a significant loss in its adsorption capacity, fits the Langmuir isotherm model. The hydrogel adsorbent displayed good selectivity and reusability. [ABSTRACT FROM AUTHOR]

Stereolithography is a 3D‐printing process that is rapidly shifting from being an expensive and limited technology to an affordable, precise, and fast method of mass production. However, most of the current resins are petroleum‐based, which makes them toxic, non‐degradable and with poor biocompatibility. In this study, a standard petroleum‐based resin containing urethane acrylate and acrylic monomers was combined with epoxy‐acrylate soybean oil (EASO), aiming to reduce its impact on the environment. Ratios varying from 10 to 50 wt% of EASO were incorporated into the commercial resin while maintaining the viscosity low, between 0.27 and 1.06 Pa s. The printed samples showed good quality and complete integration between the layers. The addition of 50 wt% of EASO increased the samples elongation at break by 108% (from 2.3% to 4.8%) and decreased the contact angle by 26.4% (from 72 to 53°). Moreover, the mixture showed good thermal and swelling stability and tensile strength in the range of other commercial cured systems. The addition of EASO may significantly contribute to the exploitation of greener materials, which well matches today's circular economy concept. [ABSTRACT FROM AUTHOR]

The inclusion of the metal free semiconductor graphitic carbon nitride (g‐CN) into polymer systems brings a variety of new options, for instance as a heterogeneous photoredox polymer initiator. In this context, we present here the decoration of the inner surface of poly(styrene‐co‐divinylbenzene) beads with organomodified g‐CN via one pot suspension photopolymerization. The resulting beads are varied by changing reaction parameters, such as, crosslinking ratio, presence of porogens, and mechanical agitation. The photocatalytic activity of so‐formed beads was tested by aqueous rhodamine B dye photodegradation experiments. Additionally, dye adsorption/desorption properties were examined in aqueous as well as in organic solvents. Photoinduced surface modification with vinylsulfonic acid and 4‐vinyl pyridine is introduced. Overall, metal‐free semiconductor g‐CN donates photoactivity to polymer networks that can be employed for dye photodegradation and acid–base catalyst transformation through facile photoinduced surface modifications. [ABSTRACT FROM AUTHOR]

Nowadays water scarcity represents a threat for human and living beings. Therefore, to satisfy the demands of people for clean and safe water, new technologies for wastewater treatment have been developed. Thus, photocatalysis has emerged as a green chemical approach for such treatment. In this context, new polyoxometalate (POM)/polymer composites with relevant photocatalytic properties have been developed via an easy and cheap photopolymerization process upon mild visible light irradiation at 405 nm. This fruitful association between POM and polymer allowed the obtention of shaped materials facile to collect and reuse at the end of the photocatalytic treatment avoiding then the usual time‐consuming regeneration methods. The prepared photocomposites displayed excellent photocatalytic performance for the removal of bisphenol‐A from water under different sources of irradiation. Hence, 100%, 88%, and 50% of this model compound were decomposed by the phosphomolybdic composite under just 90 min of UV lamp, solar and LED@375 nm irradiations, respectively. The effectiveness of these developed photocatalysts towards the degradation of other organic compounds, as well as the degradation mechanism based on the generation of highly reactive chemicals such as •OH radicals promoting the degradation were already reported. Bisphenol‐A degradation pathway and the identification of the photoproducts were discussed using mass spectroscopy technique. Therefore, this paper highlighted the photocatalytic efficiency of the new manufactured materials for the photodegradation of the bisphenol‐A, thus expanding their application fields, under different sources of irradiation and under pure solar irradiation which make their applications more interesting and less energy consuming. [ABSTRACT FROM AUTHOR]

Shape memory polymers (SMPs) are polymers which ''remember'' their original shape and can return to it after deformation, if an external stimulus—often an increased temperature – is applied. Some SMPs can be 3D printed, typically by fused deposition modeling (FDM). The most well‐known SMP is poly(lactic acid), which belongs to the most often used materials in FDM 3D printing. There are; however, many more SMPs which can be 3D printed to combine the possibilities to prepare new, sophisticated shapes with the opportunity to restore these shapes after undesirable or intentional deformation. This review gives an overview of several 3D printable SMPs, their mechanical characteristics and their possible applications. [ABSTRACT FROM AUTHOR]

One‐dimensional fillers such as rods and fibers have shown effective mechanical reinforcement in polymer nanocomposites, but their application in vat polymerization‐based 3D printing techniques was hindered due to the rapidly increased viscosity of the resin. In order to improve the fluidity of the composites without sacrificing the mechanical performance, herein we demonstrated that one‐dimensional hydroxyapatite (HAP) whiskers could be surface modified with 3‐(trimethoxysilyl) propyl methacrylate, to decrease the viscosity of the resulting resins and to enhance the interfacial adhesion between the filler and matrix. Rheology results showed that the resin was still fluidic with loading of HAP whiskers up to 20 wt%, with Young's modulus increased by a factor of 98% and the ultimate tensile strength increased by 26%. Successful printing of the resin on a DLP printer was achieved with high resolution and fine surface, and the biocompatibility test showed an increase in cell viability with the addition of HAP whiskers. These results provide a promising approach to develop high‐performance printable resin for orthopedic and related bio‐printing. [ABSTRACT FROM AUTHOR]

Electrospinning has been used to create scaffolds with tunable micro/nano architecture, stiffness, and porosity to mimic native extracellular matrix. This study investigated the effects of electrospinning parameters and hydrogel formulation (solvent and crosslinker type) on the architecture and properties of fibrous poly(ethylene glycol) (PEG) hydrogels formed from a photoclick thiol‐norbornene reaction. Fibrous hydrogels were prepared using hydrogel precursors (four‐arm PEG norbornene and multi‐thiol crosslinker), sacrificial poly(ethylene oxide) (PEO, 400 kDa), and photoinitiator (I2959) in either 2,2‐triflouroethanol (TFE) or water. Three thiol crosslinkers‐ 2,2′‐(ethylenedioxy)diethanethiol (EDT), pentaerythritol tetrakis(3mercaptopropionate) (PTMP), and PEG dithiol (PEGDT)‐ were investigated. Fibrous PEG networks with uniform fibers were produced at applied voltages of 10 or 12 kV for TFE and 16 kV for water. Fiber diameters of electrospun hydrogels were largely affected by the solvent when combined with PEO concentration and ranged from 0.5 to 3.5 mm in dry state. While the effect of crosslinker type on fiber diameter, morphology, and porosity of the fibrous hydrogel was minimal, it did modulate its shear modulus. To this end, this study provides the groundwork for selecting processing parameters to achieve desired properties of fibrous PEG thiol‐norbornene hydrogels for intended tissue engineering applications ranging from neural, cardiovascular to musculoskeletal. [ABSTRACT FROM AUTHOR]

In order to lower the volume shrinkage of the DLP 3D printing photosensitive resins during printing, a thiol‐terminated hyperbranched polymer (T‐HBP) was synthesized and introduced into the bisphenol A epoxy acrylate (EA) based photosensitive resin system. The obtained T‐HBP was characterized by FTIR and 1H NMR spectra, and the grafting rate of sulfhydryl was determined. The mechanical properties of the photosensitive resins were measured by tensile and impact strength measurement. The glass transition temperature of the photosensitive resins was analyzed by DSC and the impact fracture surface was observed by SEM. T‐HBP exhibited a much lower viscosity than its linear counterparts, and the addition of thiol improved the curing speed of the photosensitive resins. When the amount of T‐HBP added was 20 wt%, the shrinkage of the photosensitive resins was reduced by about 45.5% and the impact strength increased by 33.9% compared with the control. The macromolecular spherical structure of T‐HBP effectively reduced the functional group density of the photosensitive resins. In addition, the thiol‐acrylate photopolymerization introduced by T‐HBP further reduced the volume shrinkage of the photosensitive resins. [ABSTRACT FROM AUTHOR]

Hydrogels are polymeric materials widely used in medicine due to their similarity with the biological components of the body. Hydrogels are biocompatible materials that have the potential to promote cell proliferation and tissue support because of their hydrophilic nature, porous structure, and elastic mechanical properties. In this work, we demonstrate the microwave‐assisted synthesis of three molecular weight varieties of poly(ethylene glycol) dimethacrylate (PEGDMA) with different mechanical and thermal properties and the rapid photo of them using 1‐hydroxy‐cyclohexyl‐phenyl‐ketone (Irgacure 184) as UV photoinitiator. The effects of the poly(ethylene glycol) molecular weight and degree of acrylation on swelling, mechanical, and rheological properties of hydrogels were investigated. The biodegradability of the PEGDMA hydrogels, as well as the ability to grow and proliferate cells, was examined for its viability as a scaffold in tissue engineering. Altogether, the biomaterial hydrogel properties open the way for applications in the field of regenerative medicine for functional scaffolds and tissues. [ABSTRACT FROM AUTHOR]

Reduction of friction and wear contributes significantly to energy saving for mechanical system as considerable energy has been consumed in various forms of friction worldwide. In the present study, two kinds of dopamine‐based oil‐soluble polymers were synthesized by atom transfer radical polymerization (DOPA‐BiBB‐pLMA) and photopolymerization (DOPA‐I2959‐pLMA), and modified onto the Ti6Al4V sheet by the "grafting to" method. The characterizations of nuclear magnetic resonance, Fourier transform infrared spectrum, water contact angle, and X‐ray photoelectron spectroscopy confirmed that the polymers were successfully grafted onto the Ti6Al4V surface. Additionally, a series of tribological tests were performed in oil environment using a universal materials tester under different experimental conditions. It was shown that the coefficient of friction using the Ti6Al4V sheets grafted by the dopamine‐based polymers was reduced by 23.5–46.2% compared with bare Ti6Al4V sheet. Furthermore, the wear depth and wear volume were also greatly decreased with the introduction of the dopamine‐based polymers. DOPA‐I2959‐pLMA showed slightly better lubrication enhancement than that of DOPA‐BiBB‐pLMA, which may be attributed to the relatively higher polymerization degree. In summary, a universal "grafting to" surface modification approach was proposed bioinspired by catecholamine chemistry, which remarkably reduced friction and wear of the tribopairs with the introduction of oil‐soluble polymers. [ABSTRACT FROM AUTHOR]

A series of linear acrylic copolymers based on Isobornyl acrylate (IBOA) and isobutyl acrylate (IsoBA) were elaborated by radical photopolymerization. In addition, several photochemically crosslinked poly(IBOA‐co‐IsoBA) were prepared by introducing small amounts of 1,6‐hexanedioldiacrylate as crosslinking agent. The evolution of the glass transition temperature was determined experimentally by differential scanning calorimetry as a function of composition for both linear and crosslinked poly(IBOA‐co‐IsoBA), yielding Tg values ranging from (~249) to (~315 K). Theoretical modeling was performed applying Fox, Gordon‐Taylor and Couchman‐Karasz models by simple calculations using experimental data, leading to only fair agreement between theoretical and experimental values, or by applying fitting procedures involving one or two adjustable parameters. Likewise, the Kwei model, known to take into account hydrogen bonding interactions between monomers, could not describe well the evolution of Tg, indicating the existence of other factors influencing Tg. Finally, a thermodynamic approach based on entropy considerations allowed to attribute an explanation of the evolution of Tg. [ABSTRACT FROM AUTHOR]

The emerging need for flexible and wearable electronics has been pushing the edge of the traditional electroless deposition (ELD) technique. With the rapid development of polymer‐assisted ELD (PAELD), its time‐consuming and possess‐complicated procedures have hindered the application of the technique. Here, for purpose of addressing the challenge, the work demonstrates a highly efficient and versatile method, based on the procedure consisting of the customized polyelectrolyte brushes patterns fabrication with the assistance of mask‐free dynamic microprojection lithography and sequential selective ELD (DML‐ELD), for the fabrication of arbitrary electrode on the silicon dioxide/silicon (SiO2/Si) substrate. The resistivity of the patterned copper electrode maintained around 0.062 Ω∙mm at room temperature, indicating the high reproducibility and stability of the method. Furthermore, an interdigital copper electrode fabricated with the DML‐ELD method was coated with a poly(vinyl alcohol) sensing layer, forming a sandwich structure for the ambient humidity detection. The sensitivity of the lab‐made humidity sensor achieves 0.82 pF/%RH (<80%RH) and 19.3 pF/%RH (>80%RH). The work has demonstrated the broad prospect of the proposed DML‐ELD method in the rapid and customized manufacturing of microcircuit fabrication for electronic devices. [ABSTRACT FROM AUTHOR]

Green chemistry and green engineering concepts have been combined to develop novel sustainable polymeric materials. Solvent free photocurable acrylate resins with biorenewable carbon content of 75%–82% suitable for application in DLP 3D printing technology were composed by commercially available bio‐based materials, acrylated epoxidized soybean oil (AESO), isobornyl methacrylate (IBOMA), methacrylic ester (ME), tetrahydrofurfuryl acrylate (THFA), and tetrahydrofurfuryl methacrylate (THFMA). They demonstrated high printing accuracy and good adhesion between layers. The monitoring of photocross‐linking kinetics of high biorenewable content acrylate photoresins by the real‐time photorheometry and analysis of their rheological parameters was carried out. Synthesized polymers exhibited high yield of insoluble fraction and thermal decomposition temperature at the weight loss of 10% above 300°C. Polymers AESO/IBOMA and AESO/THFMA showed the highest values of tensile modulus and tensile strength. Biodegradability of the synthesized polymers AESO/ME, AESO/THFA, and AESO/THFMA was investigated by measuring oxygen consumption in a closed respirometer. Such AESO‐based polymers can be a competitive solution to replace petroleum‐derived polymeric materials in additive manufacturing and reduce the environmental impact. [ABSTRACT FROM AUTHOR]

In present work, the development of macroporous monolithic layers bearing the artificial recognition sites toward L‐phenylalanine has been carried out. The set of macroporous poly(2‐aminoethyl methacrylate‐co‐2‐hydroxyethyl methacrylate‐co‐ethylene glycol dimethacrylate) materials with average pore size ranged in 340–1200 nm was synthesized. The applicability of Hildebrand's and Hansen's theories for the prediction of polymer compatibility with porogenic solvents was evaluated. The dependences of average pore size on theoretically calculated parameters were plotted. The linear trend detected for Hansen's theory has indicated the high suitability of this approach to select appropriate porogens. The synthesized monolithic MIP layers were tested toward the ability to rebind phenylalanine‐derivative in microarray format. The influence of such factors as average pore size of the material, the concentration of template molecule in polymerization mixture, interaction time of analyte with its imprinted sites on binding efficiency were studied. The developed materials demonstrated good analyte rebinding from buffer solution with recognition factors 2.5–3.4 depending on the MIP sample. The comparable rebinding efficiency was also detected when the analysis was carried using complex biological media. The selectivity of phenylalanine binding from the equimolar mixture of structural analogues was 81.9% for free amino acid and 91.2% for labeled one. [ABSTRACT FROM AUTHOR]

An ultraviolet‐assisted electrospinning (UVAES) method was investigated to improve the solvent stability of soluble polyimide (PI) electrospun ultrafine fibrous membranes (UFMs) to assist in the development of fibrous polymeric materials with improved resistance to harsh environmental conditions and to expand the potential applications for such soft filaments. A preimidized soluble negative photosensitive polyimide (PSPI) was synthesized via an one‐step thermal polycondensation from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 1,1′‐bis(4‐amino‐3,5‐dimethylphenyl)‐1‐(3′‐trifluoromethylphenyl)methane (TFMDA). The PI resin was then fabricated into UFMs by both conventional electrospinning (ES) and UVAES with N,N‐dimethylacetamide (DMAc) as the solvent. During spinning, photo crosslinking reaction occurred, accompanied by simultaneous micro‐jets of PI‐UV ultrafine fibers in the UVAES procedure. This created fibers that were thermally stable at higher than 500°C, reflection over 77% of the 457‐nm‐ wavelength light, whiteness index (WI) higher than 83, and enhanced solvent resistance in DMAc. Generally speaking, compared with the PI UFMs fabricated by conventional ES procedure, the PI‐UV UFMs obtained by the newly‐developed UVAES procedure showed much superior solvent resistance, comparable thermal stability, slightly decreased optical reflectance and WI values, and reduced fiber diameters. These properties are of great value to future applications in microelectronics and wearable technology. [ABSTRACT FROM AUTHOR]

The booming of modern electronic devices featuring increasing power and multi‐functionalization demands novel high thermal conductive materials with various functions, such as self‐healing property and high deformability, while traditional polymer‐based or metallic‐based materials could hardly provide. Therefore, we report a high thermal conductive and disulfide‐based self‐healable and reprocessible liquid crystalline elastomer (SHLCE) composite by incorporating graphene nanoplates (GNPs) fillers. The obtained GNPs/SHLCE composites exhibited desired thermal conductivity (5.08 Wm−1 K−1) when the content of GNPs was 20 wt% to the composites. Moreover, the GNPs/SHLCE composites showed intriguing recycled performance (Tensile strength after recycle could maintain over 93% compared with that of original composites). Furthermore, we concluded that the improved thermal conductivity of GNPs/SHLCE composites was beneficial to the thermal induced reprocessible and shelf‐healable systems. [ABSTRACT FROM AUTHOR]

Additive manufacturing, more specifically digital light processing as a form of vat photopolymerization, has attracted great interest and plays an important role in many different applications. However, it becomes complicated when complex parts with overhangs and/or pores are printed, especially if the part has to be transparent. The aim of this study is to improve the dimensional accuracy in z‐direction of highly translucent 3D‐printed parts. Therefore, ORMOCER® resin‐based materials containing different light absorbers are developed to control the penetration depth of incident light and thereby increase the resolution in z‐direction. Penetration tests are conducted and show that, in the presence of light absorbers, the curing depth can be adjusted while maintaining a high translucency of the printed part. Furthermore, a model part is developed to quantify the overpolymerization in z‐direction and the influence of the absorber. Additionally, properties that are important for future applications, for example in the dental sector, such as mechanical properties and biocompatibility, are investigated yielding promising results. Finally, a complex filigree 3D‐grid structure is fabricated applying the resin‐based absorber material. [ABSTRACT FROM AUTHOR]

In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by the coprecipitation of FeCl2˙4H2O and FeCl3˙6H2O and applied as a core for preparation of Janus nanoparticles. Accordingly, freshly modified methacrylated iron oxide nanoparticles were reacted with two functionalized polymers. Acrylated poly(ε‐caprolactone) (PCL) and acrylated poly(2‐hydroxyethyl methacrylate) (PHEMA) were synthesized via ring‐opening and free‐radical polymerization, respectively, and subsequent modification with acryloyl chloride. Acrylated PCL as the hydrophobic part and acrylated PHEMA as the hydrophilic domain were grafted on the surface of methacrylated iron oxide nanoparticles with two morphologies. Pickering emulsion and solution photopolymerization reactions were used to prepare nanoparticles with "Janus" and "mixed" morphologies, respectively. The products were characterized in each step using Fourier‐transform infrared spectroscopy (FT‐IR), Proton nuclear magnetic resonance (1H‐NMR), thermogravimetric analysis (TGA), dynamic light scaterring (DLS), transmission electron microscope (TEM), vibrating‐sample magnetometer (VSM), energy dispersive X‐ray (EDX), and ultraviolet–visible spectroscopy (UV‐Vis). Quercetin and 5‐FU (as two anticancer drugs) were loaded in the mentioned nanoparticles, and the drug loading capacity and encapsulation efficiency (EE) of these nanoparticles were calculated. in vitro release behavior at two pH values (5.8 and 7.4) and at 37°C demonstrated that morphology can affect the release profile. Finally, rat C6 cell viability was determined by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazoliumbromide (MTT) assay for drug‐free and drug‐loaded nanoparticles. [ABSTRACT FROM AUTHOR]

Based on the addition reaction of hydroxyl groups and the isocyanate groups in the bi‐functional monomer acroyloxyethyl isocyanate (AOI), two novel self‐initiating ultraviolet (UV)‐curable acrylate monomers were synthesized from benzoin and 2‐hydroxy‐4′‐(2‐hydroxyethoxy)‐2‐methylpropiophenone (commercial‐available Irgacure® 2959), and the products were denoted as Benzoin‐AOI and 2959‐AOI, respectively. The chemical structures of the products were confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The UV–visible absorption spectrum showed that the self‐initiating acrylates exhibited similar maximum absorption wavelengths to both benzoin (250 nm) and Irgacure® 2959 (270 nm). When the products were continually exposed to a mercury lamp, the maximum absorption peak gradually blue shifted, showing that the products decomposed under the UV radiation. The photo differential scanning calorimetry (Photo‐DSC) analysis showed that the self‐initiating monomers could initiate the polymerization of 1,6‐hexanediol diacrylate (HDDA) as quickly as the original photo‐initiator, and the efficiency of Benzoin‐AOI was slightly lower than that of benzoin, while for 2959‐AOI, the efficiency remained stable after being linked to the AOI moiety. The cytotoxicity assay against fibroblasts cell line L929 showed that 2959‐AOI exhibited lower cytotoxicity at low dosages but higher cytotoxicity at high dosages compared to Irgacure® 2959 after the introduction of the AOI structure. [ABSTRACT FROM AUTHOR]

Three‐dimensional (3D) printing elastomers have received wide attention because of their wide applications in many fields. In this work, we report a urethane acrylate‐based photosensitive resin compound for 3D printing whose cured materials are elastic. This resin consists of bifunctional urethane acrylate (Royji 426 as the main matrix, monofunctional urethane acrylate (Royji 425), and isobornyl methacrylate (IBMA) as the diluents, trimethylolpropane triacrylate (TMPTA) as the crosslinker, phenylbis(2,4,6‐trimethylbenzoyl)‐phosphine oxide (819) and 2‐hydroxy‐2‐methyl propiophenone (1173) as photoinitiators. The results indicate that the mechanical properties of cured materials can be tuned by adjusting the content of different components, but it is also accompanied by the changes in viscosity and volume shrinkage. Real‐time Fourier transform infrared spectroscopy was employed to explore the relationship between the photoinitiators and the rate of initiation, and then found the best photoinitiators formulation. The resultant resin exhibits tensile strength of 7.46 MPa, elongation of 180.6%, viscosity of 978.53 mPa·s at 25°C and the volume shrinkage rate of 4.15%. Some complicated structures can be printed with the photosensitive resin such as C60, hollow ball, wrist strap, and porous lattices. These architectures have excellent dimensional accuracy and can undergo any large deformation without damage. This manifested that this resin can provide a solution for existing 3D printing of elastomers. [ABSTRACT FROM AUTHOR]

Safety requirements and the need of low‐migration UV inks have received increasing attention in the packaging industry. Crucial for the development and design of low‐migration UV inkjet inks for migration‐sensitive applications is the polymerization degree. In this study, curing‐behavior of a black, high purity packaging ink (HPP‐ink) was monitored using ATR‐FTIR spectroscopy. UV irradiation of HPP‐ink led to changes in specific absorption bands of the FTIR spectra due to crosslinking reaction of double bonds. Changes in absorptions bands at 1,408 and 1,321 cm−1 permitted the determination of CC conversion of acrylic and vinyl double bond, independently of one another. In addition, a method was developed which allows the investigation of surface‐cure and deep‐cure behavior, separately. [ABSTRACT FROM AUTHOR]

Owing to its excellent physicochemical properties, poly(ether ether ketone) (PEEK) has been used clinically for medical implants. However, its surface properties should be improved to further enhance its compatibility with a living organism and infection resistance. Here, we examined the surface construction via a combined process, that is, the self‐initiated photoinduced graft polymerization of N,N‐dimethylaminoethyl methacrylate (DMA) on PEEK substrate followed by polymer quaternization using various bromoalkanes (Q‐PDMA‐g‐PEEK). Using a Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, the grafting and quaternarization of poly(DMA) (PDMA) on the PEEK substrate was confirmed. The degree of quaternizations was at least 60% even when the various bromoalkanes were reacted. The Q‐PDMA‐g‐PEEK with 1‐bromooctane (BrC8) (C8‐Q‐PDMA‐g‐PEEK) substrate exhibited the highest ζ‐potential of other Q‐PDMA‐g‐PEEK substrates. However, no significant differences were observed in the degree of quaternization, thickness of the polymer layer, and hydrophilicity of all modified PEEK substrates. In addition, from antibacterial test with Escherichia coli, the C8Q‐PDMA‐g‐PEEK substrate exhibited the highest antibacterial rate (80%) among Q‐PDMA‐g‐PEEK substrates examined. Therefore, we concluded that the surface ζ‐potential is the one an important parameter for manufacturing PEEK substrates with bactericidal properties. [ABSTRACT FROM AUTHOR]