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Endo-norbornene derivatives are much cheaper and more accessible. However, it is difficult to prepare endo-polynorbornenes with ultra-high molecular weight (UHMW) by ring opening metathesis polymerization (ROMP) owing to the low activity. The molecular weight of poly(endo-NB-2OH)n could only reach to 309.1 kg mol−1 for 24 h via ROMP. While, UHMW poly(endo-NB-2OH)m was prepared by combining ROMP and acyclic metathesis reaction in much shorter time. The effects of residual monomer, amount of H2SO4, concentration, temperature and reaction time were investigated in depth. The UHMW P(endo-NB-2OH)m (Mn=2645.5 kg mol−1, PDI = 1.74) could be obtained at 80 °C for 5 min with H2SO4/G3 as 10/1 and concentration of 0.1 M. Moreover, UHMW P(endo-NBI-OH)m(Mn=1114.2 kg mol−1, PDI = 1.95) was also successfully prepared by this method. However, the H2SO4/G3 should increase to 30/1, and reacted for 45 min owing to the steric resistance of the cyclic dicarboximide. For P(exo-NBI-OH)n with lower activity, reaction time should prolong to 3 h to obtain UHMW P(exo-NBI-OH)m(Mn=1716.7 kg mol−1, PDI = 1.93). Finally, UHMW P(endo-NB-2alkyne)m, P(endo-NBI-alkyne)m, and P(exo-NBI-alkyne)m were successfully prepared via post-modification. Acyclic metathesis reaction is a robust and universal reaction to prepare other functional UHMW polynorbornenes, especially for the UHMW endo-polynorbornenes, which could not be prepared by ROMP efficiently. [ABSTRACT FROM AUTHOR]

A new aluminum complex (NSO)AlMe2 featuring a hydrogen bond donor on the ligand backbone has been synthesized via the reaction of AlMe3 with 1-((2-(isopropylamino)phenyl)thio)propan-2-ol (NSO-H) and spectroscopically characterized. In the complex, the aluminum atom is in a distorted tetrahedral coordination sphere determined by the anionic oxygen and neutral nitrogen atoms of the ligand and by the two carbon atoms of the alkyl groups. After proper activation, the complex (NSO)AlMe2 was able to promote the ring-opening polymerization of L-, rac-lactide, ε-caprolactone and rac-β-butyrolactone. The polymerization of rac-lactide was faster than that of L-lactide: in a toluene solution at 80 °C, the high monomer conversion of 100 equivalents was achieved in 1.5 h, reaching a turnover frequency of 63 molLA·molAl–1·h–1. The experimental molecular weights of the obtained polymers were close to those calculated, assuming the growth of one polymer chain for one added alcohol equivalent and the polydispersity indexes were monomodal and narrow. The kinetic investigation of the polymerization led to the determination of the apparent propagation constants and the Gibbs free energies of activation for the reaction; the terminal groups of the polymers were also identified. The complex (NSO)AlMe2 was active in harsh conditions such as at a very low concentration or in the melt using technical-grade rac-lactide. A relatively high level of activity was observed in the ring-opening polymerization of ε-caprolactone and rac-β-butyrolactone. DFT calculations were performed and revealed the central role of the NH function of the coordinated ligand. Acting as a hydrogen bond donor, it docks the monomer in the proximity of the metal center and activates it toward the nucleophilic attack of the growing polymer chain. [ABSTRACT FROM AUTHOR]

Smart microgels have gained much attention because of their wide range of applications in the field of biomedical, environmental, nanotechnological and catalysis sciences. Most of the applications of microgels are strongly affected by their morphology, size and size distribution. Various methodologies have been adopted to obtain polymer microgel particles. Droplet microfluidic techniques have been widely reported for the fabrication of highly monodisperse microgel particles to be used for various applications. Monodisperse microgel particles of required size and morphology can be achieved via droplet microfluidic techniques by simple polymerization of monomers in the presence of suitable crosslinker or by gelation of high molecular weight polymers. This report gives recent research progress in fabrication, characterization, properties and applications of microgel particles synthesized by microfluidic methods. [ABSTRACT FROM AUTHOR]

A new design policy to synthesize nanogel molecules having desired dimensions under unperturbed state is proposed. Miniemulsion copolymerization of vinyl and divinyl monomers, both conventional free‐radical polymerization and ideal living polymerization, is used to illustrate the method. For the network formation dynamics, the newly proposed model that takes into account the size and structure dependence of cross‐linking/cyclization reactions is employed. The master curve relationship that indicates the maximum average dimensions for randomly cross‐linked networks is used as a guideline and the network dimension is controlled by the magnitude of network maturity index NMI, which is the average number of cycle rank per primary chain. By appropriately sizing the NMI, it is possible to synthesize network polymers with dimensions equal to or greater than the maximum dimensions achievable with a homogeneous, randomly cross‐linked network polymer of the same cycle rank and molecular weight. The current strategy of designing and controlling 3D size is applicable regardless of the reaction mechanism of network formation and will also be applied to the synthesis of macro‐gels. [ABSTRACT FROM AUTHOR]

Polyamide plays a pivotal role in engineering thermoplastics. Constrained by the harsh conditions and arduous procedures for its industrial synthesis, developing facile synthesis of polyamides is still challengeable and holds profound significance. Herein, we successfully utilized water as one of the monomers to synthesize functional polyamides under ambient conditions. A powerful multicomponent polymerization of water, isocyanides, and chlorooximes was established in phosphate‐buffered saline. Soluble and thermally stable polyamides with high weight‐average molecular weights (up to 53 900) were obtained in excellent yields (up to 95 %). The polymerization exhibits unique polymerization‐induced emission characteristics, successfully converting non‐emissive monomers into unconventional emissive polymers. Notably, the resultant polyamides could undergo effective post‐modification via the hydroxyl‐yne click reaction. By incorporating various functional groups into the polyamide, its emission color could be fine‐tuned from blue to green and to red. Remarkably, the refractive index (n) of the polyamide at 589 nm could be increased from 1.6173 to 1.7227 and the Δn could be unprecedentedly as high as 0.1054 for non‐heavy atom‐containing polymers after post‐modification, and its micron‐thick films exhibited excellent transparency in the visible region. Thus, this work not only establishes a powerful polymerization toward novel polyamides but also opens up an avenue for their versatile functionalization. [ABSTRACT FROM AUTHOR]

The stereoregularity of poly(lactide) (PLA) plays a significant role in its physicochemical properties. In recent years, various metallic and nonmetallic catalysts have been developed. Organic catalysts, in particular, have garnered attention due to their potential use in biomedical applications, making them safer options. This study presents the design of a cost‐effective thiourea‐based racemic organocatalyst [(rac‐TU)Me] and its effective utilization in ring‐opening polymerization (ROP) of lactide. Using the catalyst and optimized base (N,N‐dimethylcyclohexylamine), ROP in dichloromethane achieved 98% monomer conversion and controlled molecular weights in 48 h. The polylactides obtained using this catalyst exhibited moderate tacticity, with a Pm value ranging from 0.71 to 0.78. The bulk structure of synthesized poly(lactic acid) (PLAs) is extensively studied using DSC, FTIR, and WAXS. The DSC analysis indicated stereoregular PLAs synthesized from rac‐lactide exhibited a higher melting transition than isotactic PLAs. Furthermore, the FTIR and WAXS studies revealed characteristic peaks and patterns typically associated with stereocomplex PLAs. These analytical results confirm the stereocomplex bulk structures of these PLAs synthesized using this organic catalyst [(rac‐TU)Me]. [ABSTRACT FROM AUTHOR]

Sulfur‐containing polymers with unique structures and fascinating properties have attracted much attention recently, the efficient and economic synthetic approaches for various sulfur‐containing polymers have rapidly developed. Herein, the multicomponent reaction of elemental sulfur, isocyanide, and alcohol was designed at mild condition in the presence of NaOH, and the corresponding NaOH‐assisted multicomponent polymerization of elemental sulfur, diisocyanides, and diols were developed at room temperature or 40 °C in air, to produce poly(O‐thiocarbamate)s with well‐defined structures, high molecular weights (Mws up to 32 500 g/mol) and high yields (up to 99 %). The facilely available monomers, mild condition, and high efficiency of this MCP enabled scale‐up synthesis of poly(O‐thiocarbamate)s, and 7.33 g polymer was obtained in 98 % yield. These functional poly(O‐thiocarbamate)s could enrich Au3+ from aqueous solution with high enrichment capacity (983 mg⋅Au3+/g) and high efficiency (>99.77 %) in 1 min, demonstrating superior gold enrichment performance and their potential industrial and economic values. [ABSTRACT FROM AUTHOR]

In the realm of biological macromolecules, entities such as nucleic acids and proteins are distinguished by their homochirality, consistently defined chain lengths, and integral sequence‐dependent functionalities. Historically, these refined attributes have eluded traditional synthetic polymers, which often exhibit wide variabilities in chain lengths, limited batch‐to‐batch reproducibility, and stochastic monomer arrangements. Bridging this divide represents a pivotal challenge within the domain of polymer science – a challenge that the burgeoning discipline of precision polymer chemistry is poised to address. Recent advancements have yielded precision polymers that boast prescribed monomer sequences and narrow molecular weight distributions, heralding a new era for developing model systems to decipher structure‐property correlations within functional polymers, analogous to those within biological matrices. This review discusses the innovative liquid‐phase and solid‐phase synthesis techniques for creating precision polymers and the advanced characterization tools essential for dissecting their structure and properties. We highlight potential applications in self‐assembly, catalysis, data storage, imaging, and therapy, and provide insights into the future challenges and directions of precision polymers. [ABSTRACT FROM AUTHOR]

Recently, the important role of sterically bulky aromatic substituents at the axial position of the metal center for synthesizing high‐performance catalysts were recognized. In this study, a series of α‐diimine nickel complexes with bulky N‐ortho‐aryl substituents were designed and synthesized. The as‐synthesized nickel complexes showed high activities (up to 2.3×107 g ⋅ mol−1 ⋅ h−1) and superior thermostability, giving access to moderately branched polyethylenes (35–86/1000 C) with high molecular weights (up to 197.5×104 g ⋅ mol−1). The polyethylene materials generated by these nickel complexes at 80 °C exhibited outstanding tensile mechanical. In addition, these nickel complexes could also catalyze the copolymerization of ethylene and polar monomer with modest activity (such as undecenoic acid, 10‐undecen‐1‐ol and 6‐chlorohex‐1‐ene), yielding functionalized polyolefin with adjustable molecular weights (6.8–222.9×104 g ⋅ mol−1) and incorporation ratios (0.2–4.3 mol %). [ABSTRACT FROM AUTHOR]

TBRT and ATRP are orthogonal initiation chemistries used in vinyl polymerisations. Here, we present the first combination of these techniques to readily create high molecular weight branched polyester macroinitiators capable of forming star copolymers from a range of methacrylate monomers. [ABSTRACT FROM AUTHOR]

Recent progress regarding the copolymerization of norbornene with various polar α‐olefins catalyzed by nickel and palladium catalysts is reviewed here with special attention paid to the diverse catalyst frameworks, polar monomer scopes as well as polymer microstructures. Both the influences of steric effect and electron property of ligand substituents and the type of polar monomers on the catalytic behaviors (activity, stability, polarity tolerance, etc.) and the polymer microstructures (molecular weight and distribution, comonomer contents, etc.) have been summarized. The introduction of noncyclic‐olefins, such as polar vinyl monomers, polar higher α‐olefins, and polar styrenes, into rigid cyclic‐based polynorbornene chain resulted in significant modifications on the polarity, compatibility, thermostability, processibility, transparency, and many other properties of the material, which has also been discussed in the review. The contents of this review have been classified according to the type of polar monomers involved in the norbornene copolymerization, and each section included nickel and palladium catalysts bearing different ligand structures, which will be meaningful for the development of new types of catalysts and new families of norbornene‐based cyclic olefin copolymer materials in the future. [ABSTRACT FROM AUTHOR]

Visible light‐induced polymerization, as a promising and green strategy, is showing great potential in preparing value‐added polymers. Herein, a visible light photoredox catalysis method is reported to afford a library of polyamide with high yields (up to 99%) and high molecular weights (Mws) (up to 71 000 g mol−1). Dithioacids and diamines as the monomers, and 9‐mesityl‐10‐methylacridinium tetrafluoroborate (Mes‐Acr‐MeBF4) as the organic photoredox catalyst give the polyamides with structural diversity in air under mild conditions without extra metal, base, or additives. [ABSTRACT FROM AUTHOR]

Olefin coordination copolymerization with polar monomers is an important topic both in academia and industry. During copolymerization, polar monomers will seriously reduce the polymerization activity and the molecular weight of the copolymer, making it difficult to balance the two and the polar monomer incorporation at the same time. In this study, a metallocene catalyst, Ph2C(Cp)(Flu)ZrCl2, is used for the copolymerization of ethylene with 4‐penten‐1‐ol. The incorporation of 4‐penten‐1‐ol can be effectively increased by the introduction of the steric phenol as the third component (TC). Depending on the cocatalyst, the activity or molecular weight can be improved. It is believed that the promotion effect may work by the interaction of the steric phenol with the catalyst or cocatalyst. It is also suggested that in this system, polymerization is terminated by deactivation‐chain transfer mechanism rather than β‐X elimination due to back‐biting. [ABSTRACT FROM AUTHOR]

Molecular weight distribution (MWD) is a key characterization parameter of polymers and has crucial impact on the properties of polymers. The MWD regulation of polypeptoids, an attractive class of biomaterials, has not been reported so far. This study designed and synthesized the photolabile dormant initiator, 2-nitro-4,5-dimethoxybenzylcyclohexylaminecarbamate, for the ring-opening polymerization of N-butyl-N-carboxyanhydride (BuN-NCA). Upon the ultraviolet (UV) light irradiation (360 nm), the photolabile dormant initiator could release the active cyclohexylamine. The release amount was well controlled by manipulating the duration of the applied radiation. The release amount of cyclohexylamine was increased as the time of UV irradiation increased from 1 h to 4 h, resulting in the Mn decrease of the polypeptoid (from 9.6×10³ to 4.6×10³). The release rate of cyclohexylamine was controlled by the intervals of the applied UV irradiation. The early released cyclohexylamine initiated the monomer to form longer chains while the lately released cyclohexylamine initiated the monomer to form shorter chains. Thus, the MWDs of polypeptoids were well regulated in situ. This study provides the possibility to tune the Mn and MWD of polypeptoids in a more precise manner, and also lays the foundation for the investigation of the relationship between the MWD and the properties of polypeptoids. [ABSTRACT FROM AUTHOR]

Ring opening metathesis polymerization (ROMP) is widely used to prepare functional materials with various topological structures. However, it is difficult to prepare polymers with ultra‐high molecular weight (UHMW) directly. We found a new method to prepare UHMW polymers by combining ROMP and acyclic metathesis reaction. First, monomer NB‐2OH was polymerized by ROMP with different feed ratio of NB‐2OH/G3, and obtained well‐defined polymers P(NB‐2OH)n (n = 50, 200, and 463). Then acyclic metathesis reaction was used to synthesize UHMW polymers. The results indicated that polymer P(NB‐2OH)z with higher molecular weight (Mw = 6067.3 kg mol−1) and narrower distribution (PDI = 1.58) could be obtained at 80°C for 5 min, when P(NB‐2OH)463 was used as raw material with H2SO4/G3 = 10/1. Compared with polymer P(NB‐2OH)1990 (Mw = 5343.1 kg mol−1, PDI = 1.61) prepared by ROMP directly, the new method tremendously shortens reaction time, lowers the requirement for the purity of monomer and produces UHMW polymers with narrower distribution. The compositions of prepared polymers were also confirmed clearly by post‐modification and 1H NMR characterization. [ABSTRACT FROM AUTHOR]

Anionic ring opening polymerization of ε‐caprolactam (CL) results in the formation of high molecular weight polyamide 6 (PA6) within a few minutes. The monomer conversion rate is an important characterization parameter for polymerization process as well as the end products. This paper used PA6 films with different polymerization degrees as research object for the first time, and systematically compared the performance of four methods for measuring CL conversion rate. The analytical methods were solvent extraction (methanol, ethanol, or water), vacuum removal, thermogravimetric analysis (TGA), and absorbance ratio respectively. For all PA6 products, solvent extraction based on methanol/water and vacuum removal were effective methods for determine their conversion rates. And TGA was only applicable for samples with high degree of polymerization. The CL conversion rate obtained by solvent extraction based on ethanol and absorbance ratio was slightly higher than the real value, especially the latter. Moreover, a new method was discovered and validated during the research process, namely atmospheric devolatilization. The methodology and results in this study can be employed for guiding the production and application of polymers, especially the reactive processing of PA6. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) have gained interest recently due to their biodegradability and versatility. In particular, the chemical compositions of medium‐chain‐length (mcl)‐PHAs are highly diverse, comprising different monomers containing 6–14 carbon atoms. This review summarizes different feedstocks and fermentation strategies to enhance mcl‐PHA production and briefly discusses the downstream processing. This review also provides comprehensive details on analytical tools for determining the composition and properties of mcl‐PHA. Moreover, this study provides novel information by statistically analyzing the data collected from several reports on mcl‐PHA to determine the optimal fermentation parameters (specific growth rate, PHA productivity, and PHA yield from various structurally related and unrelated substrates), mcl‐PHA composition, molecular weight (MW), and thermal and mechanical properties, in addition to other relevant statistical values. The analysis revealed that the median PHA productivity observed in the fed‐batch feeding strategy was 0.4 g L−1 h−1, which is eight times higher than that obtained from batch feeding (0.05 g L−1 h−1). Furthermore, 3‐hydroxyoctanoate and ‐decanoate were the primary monomers incorporated into mcl‐PHA. The investigation also determined the median glass transition temperature (−43°C) and melting temperature (47°C), which indicated that mcl‐PHA is a flexible amorphous polymer at room temperature with a median MW of 104 kDa. However, information on the monomer composition or heterogeneity and the associated physical and mechanical data of mcl‐PHAs is inadequate. Based on their mechanical values, the mcl‐PHAs can be classified as semi‐crystalline polymers (median crystallinity 23%) with rubber‐like properties and a median elongation at break of 385%. However, due to the limited mechanical data available for mcl‐PHAs with known monomer composition, identifying suitable processing tools and applications to develop mcl‐PHAs further is challenging. [ABSTRACT FROM AUTHOR]

Stockmayer's formula for the weight average of cross‐linked primary chains is extended to the z‐average degree of polymerization DPz$DP_z$. This average is a function of the weight‐ and z‐average degree of polymerization λw and λz of the primary chain distribution and the branching density α: DPz=λz(1+α)3−λw2α2(3+α)(1−α(λw−1))2(1+α)$DP_z= \frac{\lambda _z(1+\alpha)^3-\lambda _w^2\alpha ^2(3+\alpha)}{(1-\alpha (\lambda _w-1))^2(1+\alpha)}$. Higher averages of branched polymers from monomers of type Af$A_f$ and BAf−1$BA_{f-1}$ with functionalities f ⩾ 2 are discussed. [ABSTRACT FROM AUTHOR]

This study introduces an efficient strategy for synthesizing polyhydroxyurethane-based multicomponent hydrogels with enhanced rheological properties. In a single-step process, 3D materials composed of Polymer 1 (PHU) and Polymer 2 (PVA or gelatin) were produced. Polymer 1, a crosslinked polyhydroxyurethane (PHU), grew within a colloidal solution of Polymer 2, forming an interconnected network. The synthesis of Polymer 1 utilized a Non-Isocyanate Polyurethane (NIPU) methodology based on the aminolysis of bis(cyclic carbonate) (bisCC) monomers derived from 1-thioglycerol and 1,2-dithioglycerol (monomers A and E, respectively). This method, applied for the first time in Semi-Interpenetrating Network (SIPN) formation, demonstrated exceptional orthogonality since the functional groups in Polymer 2 do not interfere with Polymer 1 formation. Optimizing PHU formation involved a 20-trial methodology, identifying influential variables such as polymer concentration, temperature, solvent (an aprotic and a protic solvent), and the organo-catalyst used [a thiourea derivative (TU) and 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU)]. The highest molecular weights were achieved under near-bulk polymerization conditions using TU-protic and DBU-aprotic as catalyst–solvent combinations. Monomer E-based PHU exhibited higher M w ¯ than monomer A-based PHU (34.1 kDa and 16.4 kDa, respectively). Applying the enhanced methodology to prepare 10 multicomponent hydrogels using PVA or gelatin as the polymer scaffold revealed superior rheological properties in PVA-based hydrogels, exhibiting solid-like gel behavior. Incorporating monomer E enhanced mechanical properties and elasticity (with loss tangent values of 0.09 and 0.14). SEM images unveiled distinct microstructures, including a sponge-like pattern in certain PVA-based hydrogels when monomer A was chosen, indicating the formation of highly superporous interpenetrated materials. In summary, this innovative approach presents a versatile methodology for obtaining advanced hydrogel-based systems with potential applications in various biomedical fields. [ABSTRACT FROM AUTHOR]

Topological gels possess structures that are cross‐linked only via physical constraints; ideally, no attractive intermolecular interactions act between their components, which yields interesting physical properties. However, most reported previous topological gels were synthesized based on supramolecular interlocked structures such as polyrotaxane, for which attractive intermolecular interactions are essential. Here, we synthesize a water‐soluble "molecular net" (MN) with a large molecular weight and three‐dimensional network structure using poly(ethylene glycol). When a water‐soluble monomer (N‐isopropylacrylamide) is polymerized in the presence of the MNs, the extending polymer chains penetrates the MNs to form an ideal topological MN gel with no specific attractive interactions between its components. The MN gels show unique physical properties as well a significantly high degree of swelling and high extensibility due to slipping of the physical cross‐linking. We postulate this method to yield a new paradigm in gel science with unprecedented physical properties. [ABSTRACT FROM AUTHOR]

The incorporation of BN units in organic scaffolds by isoelectronic/isosteric substitution of selected CC couples has emerged as an efficient tool to produce new materials with useful properties and functions. The knowledge about BN‐doped inorganic–organic hybrid polymers, however, is still rather scarce. This is especially true for linear or cyclolinear macromolecules that feature longer inorganic chains. Herein, we introduce 1,2,5‐azadiborolane as a polymer building block for the first time. An attempt to apply it for the synthesis of a cyclolinear poly(iminoborane) resulted after only two B−N coupling events in the formation of a molecular compound comprising a chain of three nitrogen and two boron atoms – as confirmed by single‐crystal X‐ray diffractometry. In combination with a p‐phenylene diamine‐based co‐monomer, we accomplished to incorporate the 1,2,5‐azadiborolane into a hybrid polymer of considerable molecular weight that features a B2N3 chain. We additionally synthesized a small molecular model compound for the polymer and characterized it crystallographically as well. Comparison of the UV‐vis spectra of the monomer, the oligomer, and the polymer revealed systematic red‐shifts of the longest‐wavelength absorption band with increasing number of BN units in the chain. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis of fully renewable polycarbonates (PCs) starting from cellulose‐based platform molecules levoglucosenone (LGO) and 2,5‐bis(hydroxymethyl)furan (BHMF). These unique bio‐based PCs are obtained through the reaction of a citronellol‐containing triol (Triol‐citro) derived from LGO, with a dimethyl carbonate derivative of BHMF (BHMF‐DC). Solvent‐free polymerizations are targeted to minimize waste generation and promote an eco‐friendly approach with a favorable environmental factor (E‐factor). The choice of metal catalyst during polymerization significantly influences the polymer properties, resulting in high molecular weight (up to 755 kDa) when Na2CO3 is employed as an inexpensive catalyst. Characterization using nuclear magnetic resonance confirms the successful incorporation of the furan ring and the retention of the terminal double bond of the citronellol pendant chain. Furthermore, under UV irradiation, the presence of both citronellol and furanic moieties induces singular structural changes, triggering the formation of three distinct structures within the polymer network, a phenomenon herein occurs for the first time in this type of polymer. These findings pave the way to new functional materials prepared from renewable monomers with tunable properties. [ABSTRACT FROM AUTHOR]

The 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers are mimetic to phospholipids, being widely used as biocompatible polymers. In our previous study, MPC polymer hydrogels proved more effective for optical tissue clearing compared to acrylamide (AAm) polymer hydrogels. In the present study, 2-acryloyloxyethyl phosphorylcholine (APC) was synthesized and employed to create hydrogels for a comparative analysis with methacrylic MPC-based hydrogels. APC, an acrylic monomer, was copolymerized with AAm in a similar reactivity. In contrast, MPC, as a methacrylic monomer, demonstrated higher copolymerization reactivity than AAm, leading to a spontaneously delayed two-step polymerization behavior. This suggests that the polymer sequences and network structures became heterogeneous when both methacrylic and acrylic monomers, as well as crosslinkers, were present in the copolymerization system. The molecular weight of the APC polymers was considerably smaller than that of the MPC polymers due to the formation of mid-chain radicals and subsequent β-scission during polymerization. The swelling ratios in water and strain sweep profiles of hydrogels prepared using acrylic and methacrylic compounds differed from those of hydrogels prepared using only acrylic compounds. This implies that copolymerization reactivity influences the polymer network structures and crosslinking density in addition to the copolymer composition. APC-based hydrogels are effective for the optical clearing of tumor tissues and are applicable to both passive and electrophoretic methods. [ABSTRACT FROM AUTHOR]

Herein, we report the hybrid copolymerization of methyl methacrylate (MMA) and e-caprolactone (CL). 2D metal-organic frameworks, ZIF-L as a robust polymerization catalyst, can catalyze this hybrid copolymerization. Though these monomers differ from each other in structure and activity, different characterization techniques (1H-NMR, 13CNMR, GPC, DSC, fractional precipitation techniques) confirm that they form biodegradable block copolymer PMMA-b-PCL with high molecular weight (1190 kg/mol). Also, PXRD and SEM results of the recovered ZIF-L reveal that the catalyst ZIF-L is remarkably stable even after a long-time polymerization reaction with no significant loss in activity. [ABSTRACT FROM AUTHOR]

The production of CO2-containing polymers is still very demanding in terms of controlling the synthesis of products with pre-defined CO2 content and molecular weight. An elegant way of synthesising these polymers is via CO2-containing building blocks, such as cyclic ethylene carbonate (cEC), via catalytic ring-opening polymerisation. However, to date, the mechanism of this reaction and control parameters have not been elucidated. In this work, using DFT-metadynamics simulations for exploiting the potential of the polymerisation process, we aim to shed more light on the mechanisms of the interaction between catalysts (in particular, the catalysts K3VO4, K3PO4, and Na2SnO3) and the cEC monomer in the propagation step of the polymeric chain and the occurring CO2 release. Confirming the simulation results via subsequent kinetics measurements indicates that, depending on the catalyst's characteristics, it can be attached reversibly to the polymeric chain during polymerisation, resulting in a defined lifetime of the activated polymer chain. The second anionic oxygen of the catalyst can promote the catalyst's transfer to another electrophilic cEC monomer, terminating the growth of the first chain and initiating the propagation of the new polymer chain. This transfer reaction is an essential step in controlling the molecular weight of the products. [ABSTRACT FROM AUTHOR]

Medium-chain-length polyhydroxyalkanoates (mcl-PHA) are biobased materials with promising properties for environmentally friendly applications. Due to high production costs, which are related to the cost of the carbon sources combined with conversion insufficiencies, currently only small quantities are produced. This results in a lack of reliable data on properties and application potential for the variety of polymers from different types of production strains. This study investigated the potential for the production of mcl-PHA from volatile fatty acids (VFA) at a larger scale, given their potential as low-cost and sustainable raw material within a carboxylate-platform based biorefinery. Pseudomonas citronellolis (DSMZ 50332) was chosen as the production strain, and acetic acid was selected as the main carbon and energy source. Nitrogen was limited to trigger polymer production, and a fed-batch process using a pH-stat feeding regime with concentrated acid was established. We report successful production, extraction, and characterization of mcl PHA, obtaining a total of 1.76 kg from two 500-litre scale fermentations. The produced polymer was identified as a copolymer of 3-hydroxydecanoate (60.7%), 3-hydroxyoctanoate (37.3%), and 3-hydroxyhexanoate (2.0%) with a weight average molecular weight (M w) of 536 kDa. NMR analysis indicates the presence of unsaturated side chains, which may offer additional possibilities for modification. The results confirm that there is a potential to produce significant amounts of mcl-PHA with interesting rubber-like properties from waste-derived VFA. • Successful pilot scale production and extraction of significant quantity of mcl-PHA. • Pseudomonas citronellolis can produce a small fraction of unsaturated monomers from acetic acid. • Oxygen limitation is present only during the exponential growth phase. • Pure acid can be successfully used in a pH-stat setup. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis, isolation and polymerisation activity of two new zinc compounds based on a 2,6-diisopropylphenyl (Dipp) β-diiminate (NacNac) ligand framework with zinc also ligated by an amidate (2-pyridonate or 6-methyl-2-pyridonate) unit. The compounds crystallised as either monomeric (6-Me-2-pyridonate derivative) or dimeric (2-pyridonate) species, although both were found to be monomeric in solution via1H DOSY NMR spectroscopy, which was supported by DFT calculations. These observations suggest that both complexes initiate ring-opening polymerisation (ROP) through a single-site monometallic mechanism. High molecular weight poly ε-caprolactone (PCL) was achieved via exogenous initiator-free ROP conditions with both catalysts. An increase in the 2-pyridonate initiator steric bulk (6-Me- vs. 6-H-) resulted in an improved catalytic activity, facilitating complete monomer conversion within 1 h at 60 °C. Pyridonate end-groups were observed by MALDI-ToF mass spectrometry, contrasting with previous observations for DippNacNac-Zn acetate complexes (where no acetate end groups are observed), instead this more closely resembles the reactivity of DippNacNac-Zn alkoxide complexes in ROP (where RO end groups are observed). Additional major signals in the MALDI-ToF spectra were consistent with cyclic PCL species, which are attributed to back-biting ring-closing termination steps occuring in a process facilitated by the pyridonate unit being an effective leaving group. To the best of our knowledge, these complexes represent the first examples of pyridonate, and indeed amidate, initated ROP. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of isotactic poly(lactic acid) (P(rac-LAA)) using a ring-opening deacetonation polymerization of racemic lactide (rac-TDO). The authors used homosalen-Al catalysts to achieve high stereoselectivity in the polymerization process. The resulting P(rac-LAA) had a number-average molecular weight (Mn) of 6,100, a polydispersity index (PDI) of 2.20, and a melting temperature (Tm) of 156 °C. However, there were still some challenges to overcome, such as broad polydispersity, low molecular weight, and low Tm. Overall, this study demonstrates the potential of rac-TDO as a monomer for the synthesis of highly isotactic P(rac-LAA). [Extracted from the article]

Novel method of obtaining functional acrylic resins (FARs) containing carboxyl- and benzophenone groups (in-chain functionalization) and terminal Br atoms was verified. Acrylic oligomers were prepared by a solution-free, UV-initiated telomerization process of basic monomer (n-butyl acrylate) and functional monomers (acrylic acid and 4-acrylooxybenzophenone) in the presence of radical photoinitiator and different amount of tetrabromomethane (CBr4) as telogen. The effect of telogen content on UV-telomerization kinetics as well as physicochemical and thermal (Tg) properties of FARs was investigated. A telogen content higher than 5 wt. parts does not affect the UV-telomerization rate (photo-DSC), the molecular weights of telomers (GPC), or their glass transition temperature (DSC), but it significantly increases the conversion of monomers (up to 88%) and lowers the viscosity of FARs (approx. 6 Pa·s). NMR studies confirmed the inclusion of CBr4 in the structure of functional acrylic telomers. [ABSTRACT FROM AUTHOR]

Trioxane (TOX), which is usually produced from formaldehyde catalyzed by acid-catalysts, is an important polymerizing monomer to produce high-performance plastics polyoxymethylene polymers (POMs). In order to reduce the separation cost and increase the catalytic activity, hierarchical Beta zeolites with different pore size were synthesized by PDDA and used for TOX produce from formaldehyde in this work. Hierarchical Beta zeolites' average pore size increased with the increasing of PDDAs' molecular weight. Compare to conventional Beta zeolite, it exhibited a higher catalytic performance with 95.13% selectivity and 2118 g/kg/h space–time yield of TOX due to its excellent diffusion performance from extra mesopore. The HCHO conversion and space–time yield of TOX increase first and then decrease with the pore size increasing. Further research showed that the decrease of catalytic activity is mainly due to the increase of extra-framework Al percent. This work illustrates the influence of both pore size and extra-framework Al content in hierarchical Beta zeolites for TOX produce from formaldehyde reaction. [ABSTRACT FROM AUTHOR]

In this study, a modified torque rheometer is used to investigate the volatilization behavior of monomer and oligomers in polyamide-6 (PA6) melt under dynamic film–forming conditions with negative pressure. The surface renewal model is employed to simulate the volatilization behavior. The effects of actual processing factors and simulation results on the volatilization behavior of monomer and oligomer are analyzed comparatively. It is found that the monomer and oligomers removal rate increase continuously with increasing temperature, residence time, and rotational speed. And, the cyclic dimer, which is extremely harmful to spinning, can be removed. It is found that the removal of monomer and oligomers continued to increase with increasing temperature, residence time, and spinning speed. Moreover, cyclic dimers, which are extremely harmful to spinning, are also removed. Additionally, it is discovered that the polycondensation reaction of PA6 results in an increase in the molecular weight and viscosity at lower temperatures (250 °C), while a higher temperature (270 °C) and shear rate (150 r/min) cause a reduction in viscosity and molecular weight. [ABSTRACT FROM AUTHOR]

Polyethers and polythioethers have a long and storied history dating back to the start of polymer science as a distinct field. As such, these materials have been utilized in a wide range of commercial applications and fundamental studies. The breadth of their material properties and the contexts in which they are applied is ultimately owed to their diverse monomer pre-cursors, epoxides and thiiranes, respectively. The facile polymerization of these monomers, both historically and contemporaneously, across academia and industry, has occurred through the use of Earth-abundant metals as catalysts and/or initiators. Despite this, polymerization methods for these monomers are underutilized compared to other monomer classes like cyclic olefins, vinyls, and (meth)acrylates. We feel a focused review that clearly outlines the benefits and shortcomings of extant synthetic methods for poly(thio)ethers along with their proposed mechanisms and quirks will help facilitate the utilization of these methods and by extension the unique polymer materials they create. Therefore, this Feature Article briefly describes the applications of poly(thio)ethers before discussing the feature-set of each poly(thio)ether synthetic method and qualitatively scoring them on relevant metrics (e.g., ease-of-use, molecular weight control, etc.) to help would-be poly(thio)ether-makers find an appropriate synthetic approach. The article is concluded with a look ahead at the future of poly(thio)ether synthesis with Earth-abundant metals. [ABSTRACT FROM AUTHOR]

Using a highly active supported permethylindenyl-phenoxy (PHENI*) titanium catalyst, high molecular weight ethylene–propylene (EPM) and ethylene–propylene–diene (EPDM) elastomers are prepared using slurry-phase catalysis. Final copolymer composition was found to reflect the monomer feed ratio in a linear fashion, to access a continuum of material properties with a single catalyst. Post-polymerisation crosslinking of EPDM was also demonstrated in a model sulfur vulcanisation system. [ABSTRACT FROM AUTHOR]

Lig-FC is a network depolymerization mechanism for the rapid primary devolatilization of mineral-free lignins that has already been validated with test data on 16 lignin samples. This paper expands the validation with an additional 13 lignins, including cases that applied different lignin preparations to the same feedstock. The validations reported here cover 27 mineral-free lignins for temperatures to 1150 °C, heating rates from 30 to 8000 °C/s, contact times after heatup to 90 s, and pressures from vacuum to 0.13 MPa. Lig-FC accurately depicts the impacts of lignin quality, heating rate, temperature, contact time, and pressure on the major products and oils' molecular weight distributions (MWDs). All raw lignins contain abundant oil precursors that are released as oils via flash distillation as soon as a flow of noncondensables carries them into the free stream. Consequently, lignin MWD is an essential aspect of lignin constitution because it determines the inventory of inherent volatile chains subject to unhindered flash distillation. Lighter lignin MWDs have larger inherent inventories and therefore produce more oils than heavier MWDs at the onset of devolatilization. Oil yields diminish and char yields increase for progressively heavier MWDs and heavier mean monomer weights and for lignins with relatively less H and more O compared to C. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: α‐Poly(L‐lysine) (α‐PLL) is a water‐soluble cationic biopolymer containing the monomeric unit α‐L‐lysine, which not only possesses excellent intrinsic properties but also can be modified via facile reactions between the side amine groups and many other functional moieties. Ring‐opening polymerization (ROP) is the most prevalently used technique for the synthesis of PLL‐based polypeptides, which involves initial conversion of the ε‐primary amine‐protected α‐L‐lysine to the L‐lysine NCA monomer. However, obtaining N‐carboxyanhydrides (NCAs) in high purity has been a formidable challenge for over 50 years, let alone the large‐scale synthesis. Herein, we show an unprecedented scale‐up synthesis of L‐Cbz‐LysNCA monomer and its polymers, generating linear α‐poly(L‐lysine) with molecular weight (MW) up to 13.4 kDa. This easy operated scale‐up strategy will lay the foundations for the industrial preparation of L‐Cbz‐LysNCA and its polymers, and further extend the realm of existing applications, offering a paradigm for scale‐up synthesis of other polypeptides. [ABSTRACT FROM AUTHOR]

This paper presents examples of separation on monolithic columns prepared by two different methods: copolymerization and post-modification. In the first method, monoliths were prepared from styrene, divinylbenzene, and heterocyclic nitrogen-containing monomers. In the second, a styrene/divinylbenzene/4-vinylbenzyl chloride copolymer was obtained and in situ modified with 1-methylimidazole. It has been shown that monolithic columns are capable of separating macromolecules and low-molecular compounds. A comparison was made between a styrene/divinylbenzene/1-vinylimidazole copolymer column and a ProSwift™ RP-3U monolithic column. It has been established that a monolithic column based on 1-vinylimidazole is capable of separating proteins and low molecular weight test substances. However, the ProSwift™ RP-3U column is only capable of separating proteins. Separation examples are given: a test mixture of proteins, natural milk proteins, carbohydrates and drugs on a column with a sorbent based on styrene/divinylbenzene. A modified column was used to study the content of salicylic acid in medicinal preparations containing acetylsalicylic acid. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: α‐Poly(L‐lysine) (α‐PLL) is a water‐soluble cationic biopolymer containing the monomeric unit α‐L‐lysine, which not only possesses excellent intrinsic properties but also can be modified via facile reactions between the side amine groups and many other functional moieties. Ring‐opening polymerization (ROP) is the most prevalently used technique for the synthesis of PLL‐based polypeptides, which involves initial conversion of the ε‐primary amine‐protected α‐L‐lysine to the L‐lysine NCA monomer. However, obtaining N‐carboxyanhydrides (NCAs) in high purity has been a formidable challenge for over 50 years, let alone the large‐scale synthesis. Herein, we show an unprecedented scale‐up synthesis of L‐Cbz‐LysNCA monomer and its polymers, generating linear α‐poly(L‐lysine) with molecular weight (MW) up to 13.4 kDa. This easy operated scale‐up strategy will lay the foundations for the industrial preparation of L‐Cbz‐LysNCA and its polymers, and further extend the realm of existing applications, offering a paradigm for scale‐up synthesis of other polypeptides. [ABSTRACT FROM AUTHOR]

Organic polymer cathodes with flexible backbones and structural diversity have attracted extensive attention in rechargeable aqueous zinc-ion batteries (ZIBs). However, the precursor monomers have limited active sites and large molecular weight, leading to the obtained polymers having limited capacities. Here, we synthesized a novel polymer cathode poly(2,3-disulfide-1,4-benzoquinone) (PSBQ) based on 1,4-benzoquinone and lithium sulfide using the solvothermal method. The PSBQ cathode displays a high discharge capacity of 216.5 mA h g−1 with a capacity retention of 85.2% after 200 cycles at 1 A g−1. The assembled flexible Zn‖PSBQ battery exhibits capacity retention of 90% after 90° and 180° bending. The superior performance is contributed by the polymerization and the flexible molecular backbone of PSBQ as well as the enhanced reactivity and stability of the Zn anode enabled by the 3.0 M ZnSO4 electrolyte. This work provides a novel strategy for designing high-capacity polymer cathodes in aqueous ZIBs. [ABSTRACT FROM AUTHOR]

The application of N‐heterocyclic carbene (NHC) catalysis under highly diluted oxidative condition to the polycondensation of dialdehydes and diols is herein presented as an alternative, atom‐economical synthetic route to macrocyclic oligoesters (MCOs). The disclosed protocol paves the way to the straightforward access to MCOs, starting from commercial dialdehydes, avoiding the use of toxic diacyl chlorides, commonly employed in traditional MCOs synthetic processes. The method is totally metal‐free, takes place in the green Me‐THF solvent and requires the use of a fully recyclable quinone oxidant. The protocol versatility is confirmed by the employment of fossil‐based and bio‐based monomers such as 2,5‐diformylfuran (DFF), 2,5‐bis(hydroxymethyl)furan (BHMF), and isomannide, synthesizing a series of novel and known synthetically relevant macrocyclic oligoesters, fully characterized by NMR and MALDI‐TOF MS analysis, with product yields (51–86 %) comparable to those obtained by traditional synthetic routes. Finally, to emphasize the synthetic relevance of the target macrocycles, an entropically‐driven ring opening polymerization (ED‐ROP) key study has been performed, optimizing the organocatalyzed synthesis of poly(2,5‐furan‐dimethylene 2,5 furandicarboxylate) (PBHMF) with number‐average molecular weight up to 8200 g mol−1 and 66 % isolated yield. [ABSTRACT FROM AUTHOR]

The photo copolymerization of N-ethylmaleimide (NEM) and methyl methacrylate (MMA) in 1,1,1,3,3,3- hexafluoro-2-propanol (HFP) and dichloromethane (DCM) was reported. The polymerization was carried out by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization method using 2-(2-cyanopropyl) dithiobenzoate (CPDB) as the initiation-regulation dual functional agent. The copolymerization behavior of this monomer pair was investigated in detail at different reaction conditions. The structures of the copolymers were characterized by 1H-NMR and MALDI-TOF-MS. Results revealed that fluoroalcohols were quite effective in affording the copolymers with controlled molecular weights and adjustable MMA contents compared with the normal solvent DCM, due to the hydrogen-bonding interaction. When the molar ratio between HFP and monomer was 1∶1, the reaction rate of NEM was similar to that of MMA, and NEM and MMA were written alternately to the polymer chain to form an alternate copolymer with a well-defined sequence structure. [ABSTRACT FROM AUTHOR]

Preparation of chemically recyclable polyesters by ring-opening polymerization (ROP) has made a considerable progress over the past few years. However, this method involves cumbersome synthesis and minimal functional diversity of cyclic monomers. Therefore, it is of great significance to develop novel polymerization methods for direct polymerization of commercially available monomers to prepare recyclable polyesters with versatile functionalities. In present work, we report dehydrogenative copolymerization of commercial α,ω-diols to afford high molecular weight chemically recyclable aliphatic copolyesters (65.7 kg·mol−1) by using commercially available Milstein catalyst precursor. The thermal properties of the obtained copolymers could be finely tuned by simply adjusting the feeding ratio of two monomers. The incorporation of aliphatic or aromatic rings into polyester mainchain via copolymerization of 1,10-decanediol with 1,4-cyclohexanedimethanol and 1,4-benzenedimethanol could significantly improve the thermal properties of the resulting copolymers. More importantly, the obtained copolyesters were able to completely depolymerize back to original diols via hydrogenation by the same catalyst in solvent-free and mild conditions, thus offering a green and cost-effective route toward the preparation of widely used polyesters. [ABSTRACT FROM AUTHOR]

In this work, a rapid polymerization method was combined with thiol-para-fluoro (TPF) "click" post-polymerization modification (PPM) strategy. To this end, a reactive monomer, namely bis((perfluorophenyl)methyl) but-2-ynedioate, was specifically designed and used in the synthesis of polythioether via thiol-Michael addition reaction by using 1,6-hexanedithiol (HDT) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a catalyst, and the reaction proceeded at room temperature for 5 min to give the pristine polythioether P0. This polymer was then used as a platform to perform PPM with various thiol compounds. The PPM reactions showed quantitative efficiency in 4 h with moderate to high yields. All modified polymers were analyzed with 1H, 13C, and 19F NMR analyses, and molecular weights were calculated by using GPC. It is believed that combining such polymerization and PPM reactions can be a very useful tool to obtain polymers having different structures for different purposes. Hence, this work introduces a new type of polymer backbone that can be rapidly prepared and undergo a relatively fast PPM. [ABSTRACT FROM AUTHOR]

The iron‐containing imidazolium‐based ionic liquids (ILs) 1‐n‐butyl‐3‐methylimidazolium heptachlorodiferrate (BMI.Fe2Cl7) and 1‐n‐butyl‐3‐methylimidazolium tetrachloroferrate (BMI.FeCl4) are applied as catalysts in the homogeneous polymerization of n‐butyl vinyl ether. Both solventless conditions as well as using different organic solvents, catalyst concentrations, temperatures, and reaction times are tested to assess the polymerization conditions that lead to the highest molecular weights of poly(n‐butyl vinyl ether). The Lewis acidic IL BMI.Fe2Cl7 proves to be highly efficient, even at low catalyst concentrations. In bulk polymerization, polymers with 142 kg mol−1 are obtained using a 1:10000 molar ratio of catalyst to monomer. In solution polymerization, the monomer consumption is also rapid and the molecular weight of the polymer is related to the catalyst concentration used. These results indicate the potential of this catalyst for industrial applications. In contrast with the acidic IL, the neutral iron‐containing imidazolium‐based IL BMI.FeCl4 does not show any catalytic activity. [ABSTRACT FROM AUTHOR]

Enzymatic one-pot synthesis procedures in a one-step and two-step monomers addition were developed to obtain poly(glycerol adipate) macromers with methacrylate end-functional groups under the presence of 1 and 3 wt% of Candida antarctica lipase B (CALB). Glycerol, divinyl adipate, and vinyl methacrylate were enzymatically reacted (vinyl methacrylate was either present from the beginning in the monomers solution or slowly dropped after 6 h of reaction) in tetrahydrofuran (THF) at 40 °C over 48 h. Macromers with a methacrylate end groups fraction of ≈52% in a simple one-pot one-step procedure were obtained with molecular weights (Mn) of ≈7500–7900 g/mol. The obtained products under the one-pot one-step and two steps synthesis procedures carried out using 1 and 3 wt% of a CALB enzymatic catalyst were profusely characterized by NMR (1H and 13C), MALDI-TOF MS, and SEC. The methacrylate functional macromers obtained with the different procedures and 1 wt% of CALB were combined with an Irgacure® 369 initiator to undergo homopolymerization under UV irradiation for 10 and 30 min, in order to test their potential to obtain amorphous networks within minutes with similar properties to those typically obtained by complex acrylation/methacrylation procedures, which need multiple purification steps and harsh reagents such as acyl chlorides. To the best of our knowledge, this is the first time that it has been demonstrated that the obtention of methacrylate-functional predominantly linear macromers based on poly(glycerol adipate) is able to be UV crosslinked in a simple one-step procedure. [ABSTRACT FROM AUTHOR]

The properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) copolymers with different ratios of monomers synthesized by the wild-type strain Cupriavidus necator B-10646 on sugars, and an industrial sample from Kaneka synthesized by the recombinant strain C. necator NSDG-ΔfadB1 on soybean oil, were studied in a comparative aspect and in relation to poly(3-hydroxybutyrate) P(3HB). The copolymer samples, regardless of the synthesis conditions or the ratio of monomers, had reduced values of crystallinity degree (50–60%) and weight average molecular weight (415–520 kDa), and increased values of polydispersity (2.8–4.3) compared to P(3HB) (70–76%, 720 kDa, and 2.2). The industrial sample had differences in its thermal behavior, including a lower glass transition temperature (−2.4 °C), two peaks in its crystallization and melting regions, a lower melting point (Tmelt) (112/141 °C), and a more pronounced gap between Tmelt and the temperature of thermal degradation (Tdegr). The process, shape, and size of the spherulites formed during the isothermal crystallization of P(3HB) and P(3HB-co-3HHx) were generally similar, but differed in the maximum growth rate of the spherulites during exothermic crystallization, which was 3.5–3.7 μm/min for P(3HB), and 0.06–1.25 for the P(3HB-co-3HHx) samples. The results from studying the thermal properties and the crystallization mechanism of P(3HB-co-3HHx) copolymers are important for improving the technologies for processing polymer products from melts. [ABSTRACT FROM AUTHOR]

Nanoemulsion polymerization is a novel process for the synthesis of specialty‐purpose latexes. In this work, styrene and 1,4‐butadiene polymerization are demonstrated through a nanoemulsion‐based process. Conventional emulsifiers like rosin soap and fatty soaps are used to prepare base emulsions having 2–10 nm particle size through the sonication process. The high surface area and higher number of micelles allow superior mixing of monomers and initiators leading to more efficient and rapid reaction. Additionally, the use of nanoemulsion improves the efficiency and quality of emulsion with higher productivity. These latexes have unique high molecular weight polymers with smaller particle size which is the most desirable criterion for coating applications. Finally, nanoemulsion‐based polymer is compared with conventional macroemulsion‐based product. [ABSTRACT FROM AUTHOR]

For the first time, the effect of the solvent and monomer ratio on molecular weight, chemical structure, and mechanical, thermal, and rheological characteristics of polyphenylene sulfone has been studied. When dimethylsulfoxide (DMSO) is used as a solvent, cross-linking occurs during the processing of the polymer, which is accompanied by an increase in melt viscosity. This fact sets a pressing need for the complete removal of DMSO from the polymer. The best solvent used for the production of PPSU is N,N-dimethylacetamide. This study of the molecular weight characteristics of polymers by gel permeation chromatography showed the stability of the polymers practically does not change with a decrease in molecular weight. The synthesized polymers correspond in tensile modulus to the commercial analog Ultrason-P, while exceeding it in terms of tensile strength and relative elongation at break. Thus, the developed polymers are promising for spinning hollow fiber membranes with a thin selective layer. [ABSTRACT FROM AUTHOR]

Simple Summary: The cyanobacterium Arthrospira platensis contains PHA synthase Class III (PhaCAp), which can produce short chain length (SCL) PHB under nitrogen-depleted conditions. In this study, we cloned a gene encoding PhaC from A. platensis into Escherichia cloni ®10G cells to produce rPhaCAp protein. The Vmax, Km, and kcat values for β-3-hydroxybutyryl coenzyme A (3HB-CoA) of the purified rPhaCAp were investigated. Size-exclusion chromatography revealed that rPhaCAp exists as an active dimer. The overall fold and catalytic triad residues were predicted using the 3D structural model for rPhaCAp. These results are discussed with respect to the dimerization mechanism of PhaCAp, which has not yet been clarified. Polyhydroxybutyrate (PHB) is a biocompatible and biodegradable polymer that has the potential to replace fossil-derived polymers. The enzymes involved in the biosynthesis of PHB are β-ketothiolase (PhaA), acetoacetyl-CoA reductase (PhaB), and PHA synthase (PhaC). PhaC in Arthrospira platensis is the key enzyme for PHB production. In this study, the recombinant E. cloni ®10G cells harboring A. platensis phaC (rPhaCAp) was constructed. The overexpressed and purified rPhaCAp with a predicted molecular mass of 69 kDa exhibited Vmax, Km, and kcat values of 24.5 ± 2 μmol/min/mg, 31.3 ± 2 µM and 412.7 ± 2 1/s, respectively. The catalytically active rPhaCAp was a homodimer. The three-dimensional structural model for the asymmetric PhaCAp homodimer was constructed based on Chromobacterium sp. USM2 PhaC (PhaCCs). The obtained model of PhaCAp revealed that the overall fold of one monomer was in the closed, catalytically inactive conformation whereas the other monomer was in the catalytically active, open conformation. In the active conformation, the catalytic triad residues (Cys151-Asp310-His339) were involved in the binding of substrate 3HB-CoA and the CAP domain of PhaCAp involved in the dimerization. [ABSTRACT FROM AUTHOR]

Achieving the linear polymers with high molecular weight via step-growth polymerization of A2 and B2 monomers is significantly limited by the requirement of strict stoichiometry of two monomers when the reactivity of A and B groups are not changed during the polymerization. Herein, a unique step-growth polymerization based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) with reaction-enhanced reactivity of intermediate (RERI) mechanism was developed for the preparation of mainchain semifluorinated polymers with high molecular weight. The CuAAC polymerization of bis-alkynyl-terminated fluorinated monomers (A2) and 2,2-bis(azidomethyl)propane-1,3-diyl bis(2-methylpropanoate) (BiAz, B2) with RERI effect at different stoichiometric ratio was systematically investigated. The results indicated that the semifluorinated polymers with ultrahigh molecular weight, Mw,MALLS>106 g/mol, could be efficiently synthesized by using excess molar of BiAz monomers. The resultant high-molecular-weight semifluorinated polymers show good thermostability and high hydrophobicity. In addition, the glass transition temperature (Tg) of these mainchain semifluorinated polymers could be tuned conveniently due to the bis-alkynyl-terminated comonomers could be consumed completely when excessive BiAz monomers were used in this this step-growth polymerization. [ABSTRACT FROM AUTHOR]

The influence of trifluoromethanesulfonic (TFSA) superacid on conditions of the synthesis of polybenzimidazoles, such as OPBI and CF3PBI, was studied. It was shown that the polycondensations proceeded smoother and at lower temperatures in the presence of the TFSA in Eaton's Reagent and that polymers of high molecular weights, and readily soluble in organic solvents, were obtained. The effect was more pronounced for CF3PBI, where the low reactivity monomer, 4,4′ (hexafluoroisoproylidene)bis (benzoic acid), was used. CF3PBI was obtained at a moderate temperature of 140 °C with no gel fraction and exhibited an inherent viscosity twice higher than the one obtained by the traditional method. In fact, the addition of TFSA allows the obtention of soluble N-phenyl substituted CF3PBI by direct synthesis, which had not been obtained otherwise. Thus, the use of TFSA is a good media for the synthesis of N-substituted PBIs under relatively mild conditions. [ABSTRACT FROM AUTHOR]