Search

The photoATRP of methyl acrylate (MA) is investigated using riboflavin (RF) and CuBr2/Me6TREN as a dual catalyst system under green LED irradiation (λ ≈ 525 nm). Both RF and CuBr2/Me6TREN enhanced oxygen tolerance, enabling effective ATRP in the presence of residual oxygen. High molar mass polymers (up to Mn ≈ 129 000 g·mol−1) with low dispersity (Đ ≤ 1.16) are prepared, and chain‐end fidelity is confirmed through successful chain extension. The molecular masses of the obtained polymer increased linearly with conversion and showed high initiation efficiency. Mechanistic studies by laser flash photolysis reveal that the predominant activator generation mechanism is reductive quenching of RF by Me6TREN (83%, under [CuBr2]/[Me6TREN] = 1/3 condition), supported by polymerization kinetics and thermodynamic calculations. [ABSTRACT FROM AUTHOR]

Hydroxy-functionalized polyacrylate rubber particles (ACR-OH) were synthesized with micrcrcrosslinked poly-butyl acrylate (PBA) as a rubber core and methyl methacrylate-hydroxyethyl acrylate copolymer (HEA) as a shell through seed emulsion polymerization. ACR-OH was mixed with triglycidyl isocyanurate (TGIC) and then added into polybutylene terylene phthalate (PBT). Owing to the reactions occurring between the hydroxyl groups on the surface of ACR particles and epoxy groups in TGIC and between the epoxy groups in TGIC and hydroxyl end-group of PBT in the melt blending process, the modified PBT (PBT/TGIC/ACR-OH) gained the good compatibility between ACR and PBT. The effect of the addition of ACR-OH and TGIC on the impact strength and tensile strength of the modified PBT were investigated. The results indicated that the addition of ACR-OH effectively improved the toughness of PBT due to good compatibility. When the addition amounts of ACR-OH and TGIC were 20 and 2 phr, respectively, the impact strength of the modified PBT reached 20. 45 kJ/m², which was 8. 4 times as high as that of pure PBT (2. 43 kJ/m²). Moreover, with the help of multi-functional TGIC, the modified PBT exhibited both good toughness and good strength at addition amounts of ACR-OH and TGIC of 8 and 2 phr, respectively. Its impact strength and tensile strength reached 10. 87 kJ/m² and 42. 1 MPa, respectively. [ABSTRACT FROM AUTHOR]

Substrate-controlled divergent reactions of between salicylaldehydes and acrylates have been developed. By using methyl acrylate as the substrate with salicylaldehydes, a domino reaction was established, delivering coumarins with good yield (up to 81% yields) and high chemoselectivity under mild conditions. Whereas the methyl acrylate was changed to tert-butyl acrylate or iso-propyl acrylate, the classical Morita − Baylis − Hillman adducts were produced in good yields (up to 75% yields) under near exclusivity under the otherwise identical reaction conditions, without any other competitive products. Additionally, the synthetic utility of the present methodology was further demonstrated by synthetic transformation. The structure of the typical product was unambiguously established by single crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Many stimuli‐responsive materials harness the reversible association of supramolecular binding motifs to enable advanced functionalities such as self‐healing, switchable adhesion, or mechanical adaptation. Despite extensive research into the structure–property relationships of these materials, direct correlations between molecular‐level changes in supramolecular binding and macroscopic material behaviors have mostly remained elusive. Here, we show that this challenge can be overcome with supramolecular binding motifs featuring integrated binding indicators. We demonstrate this using a novel motif that combines a hydrogen‐bonding ureido‐4‐pyrimidinone (UPy) with two strategically placed pyrene fluorophores. Dimerization of this motif promotes pyrene excimer formation, facilitating the straightforward optical quantification of supramolecular assembly under various conditions. We exploit the new motif as a supramolecular cross‐linker in poly(methyl acrylate)s to probe the extent of (dis)assembly as a function of cross‐linker content, processing history, and applied stimuli. We demonstrate that the stimuli‐induced dissociation of hydrogen‐bonding linkages strongly depends on the initial cross‐link density, which also dictates whether the force‐induced dissociation in polymer films correlates with the applied stress or strain. Thus, beyond introducing a robust tool for the in situ study of dynamic (dis)assembly mechanisms in supramolecular systems, our findings provide new insights into the mechanoresponsive behavior of such materials. [ABSTRACT FROM AUTHOR]

The aim of the work is to study the effect of the acid comonomer content and forming conditions on the dyeability of gel fibers based on copolymers of acrylonitrile (AN), methyl acrylate (MA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS). For this purpose, model copolymers AN, MA and AMPS were synthesized with an acid comonomer content in the monomer mixture from 0 to 2 % (wt.) by changing the proportion of MA. It has been established that the actual content of the acidic monomer in the fiber-forming copolymer is higher than expected based on the composition of the initial monomer mixture. Analysis of the dyeability of model samples of polyacrylonitrile fibers formed from synthesized copolymers by the dimethylformamide method with varying technological regimes showed that the amount of dye selected from the dye bath by the gel structure of the fibers is proportional to the content of the acid comonomer in the fiber-forming copolymer. The most significant decrease in the whiteness index (lightness) of the finished fibers is observed with an increase in the AMPS content in the copolymer from 0 to 0.7 % (wt.). Microscopy of model fibers was carried out. Based on the experimental data obtained in the course of the work, it was suggested that in order to achieve an acceptable intensity of dyeing and ensure a soft handle of polyacrylonitrile fibers, the optimal content of acid comonomer during the synthesis of fiber-forming copolymers based on AN, MA and AMPS should be in the range of 0.9 up to 1.3 % (of the mass of monomers in the reaction mixture).

The adsorption of oligomeric peroxide of sebacic acid on aerosols was studied. The parameters of the adsorption process were found. The effect of aerosil on the polymerization of styrene (ST), methyl acrylate (MA), butyl acrylate (BA), methyl methacrylate (MMA) and butyl methacrylate (BMA) was studied. The initiators used were oligomeric sebacic acid peroxide (OPSA), benzoyl peroxide (BP), lauryl peroxide (PL) and didecanoyl diperoxy adipinate (DP). The mineral filler increases the polymerization rate of MMA, BMA, MA, BA initiated by OPSA. Under the same conditions, the polymerization rate of ST decreases with an increase in the aerosil content in the polymerization system. BP practically does not affect the polymerization rate of vinyl monomers in the presence of aerosil. The reaction of thermal decomposition of OPSA, DP, PL and BP in styrene in the presence of aerosol was studied. An increase in the content of aerosil leads to an increase in the effective decomposition constant of OPSA, DP, PL. in the case of BP, aerosil has practically no effect on the decomposition rate. [ABSTRACT FROM AUTHOR]

Methyl acrylate has a wide range of uses, but the production process usually produces aqueous by-products. In this study, four commonly used alcohols (1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were selected as extractants to explore the liquid–liquid extraction behavior of water + methyl acrylate + extractants. Through the analysis of partition coefficient (D) and separation coefficient (S), it is found that the data of all systems are greater than 1, indicating that all four alkyl alcohols can well separate methyl acrylate from aqueous solution, and 1-octanol is the best. In addition, the consistency between the binary interaction parameters of regression and tie-line data was tested using Matlab tools, proving that the obtained parameters have good consistency. [ABSTRACT FROM AUTHOR]

AbstractA kind of highly dispersed ZrO2 modified Cs/SiO2-based catalyst was prepared via ligand–assisted impregnation strategy. The catalyst was then used to the aldol condensation reaction of methyl acetate (MAc) with formaldehyde (FA) to produce methyl acrylate (MA). The effect of highly dispersed ZrO2 promotion on Cs/SiO2 catalyst selectivity and activity was studied as well. Various techniques such as XRD, FT-IR, TEM, XPS, NH3-TPD, CO2-TPD, N2 physical adsorption, and solid-state MAS NMR were used to characterize the structural features, Cs species states, and acid–base properties of these catalysts. The use of Zr(acac)4 as a zirconium source for modifying Cs/SiO2 could be considered optimal for ligand-assisted impregnation. By modifying the highly dispersed ZrO2, more Cs–O–Si species and a suitable balance of acid–base sites were formed in the Zr–Cs/SiO2 catalyst. As a result, the catalyst showed significant improvements in selectivity and yield of MA under optimized reaction conditions. This study is beneficial for the development and optimization of catalysts for aldol condensation and provides a reference for future industrial applications.

An efficient method is developed to prepare copolymer of Poly(styrene-co-methylacrylate) using silver nanoparticle decorated reduced graphene oxide (Ag-rGO) under photocatalytic conditions using blue LED as light source. We have successfully utilised the prepared poly(styrene-co-methylacrylate) copolymer-based Ag-rGO nanocomposite (Ag-rGO/(P(S-co-MA) as a filler for reinforcing epoxy composite. Better dispersibility of the hybrid nanocomposite in diglycidyl ether of bisphenol A (DGEBA) over Ag-rGO helped in enhancing the mechanical properties of epoxy. The synthesis of P(S-co-MA)-Ag-rGO was confirmed using various characterization techniques like 1H NMR, 13C-NMR, FTIR etc. The particle size distribution and surface morphology were investigated using Field emission scanning electron microscopy (FE-SEM). The mechanical properties of P(S-co-MA)-Ag-rGO based epoxy composites showed a significant 104% of improvement in fracture toughness when compared to neat epoxy. Antibacterial performance and thermal characteristic of the fabricated epoxy composites also were investigated. [ABSTRACT FROM AUTHOR]

Despite their industrial ubiquity, polyolefin‐polyacrylate block copolymers are challenging to synthesize due to the distinct polymerization pathways necessary for respective blocks. This study utilizes MILRad, metal–organic insertion light‐initiated radical polymerization, to synthesize polyolefin‐b‐poly(methyl acrylate) copolymer by combining palladium‐catalyzed insertion–coordination polymerization and atom transfer radical polymerization (ATRP). Brookhart‐type Pd complexes used for the living polymerization of olefins are homolytically cleaved by blue‐light irradiation, generating polyolefin‐based macroradicals, which are trapped with functional nitroxide derivatives forming ATRP macroinitiators. ATRP in the presence of Cu(0), that is, supplemental activators and reducing agents , is used to polymerize methyl acrylate. An increase in the functionalization efficiency of up to 71% is demonstrated in this study by modifying the light source and optimizing the radical trapping condition. Regardless of the radical trapping efficiency, essentially quantitative chain extension of polyolefin‐Br macroinitiator with acrylates is consistently demonstrated, indicating successful second block formation. [ABSTRACT FROM AUTHOR]

The present work proposes to investigate the effect of an ultrahigh molecular weight silicone rubber (UHMW-SR) and two ethylene methyl acrylate copolymers (EMA) with different methyl acrylate (MA) content on the mechanical and fire performance of a fireproof acrylonitrile butadiene styrene copolymer (ABS) composite, with an optimum amount of ammonium polyphosphate (APP) and aluminum diethyl phosphinate (AlPi). ABS formulations with a global flame retardant weight content of 20 wt.% (ABS P) were melt-compounded, with and without EMA and UHMW-SR, in a Brabender mixer. During this batch process, ABS P formulations with UHMW-SR and/or EMA registered lower torque values than those of ABS P. By means of scanning electron microscopy (SEM), it was possible to observe that all ABS composites exhibited a homogenous structure without phase separation or particle agglomeration. Slightly improved interfacial interaction between the well-dispersed flame-retardant particles in the presence of EMA and/or UHMW-SR was also noticed. Furthermore, synergies in mechanical properties by adding both EMA and UHMW-SR into ABS P were ascertained. An enhancement of molecular mobility that contributed to the softening of ABS P was observed under dynamic mechanical thermal analysis (DMTA). An improvement of its flexibility, ductility and toughness were also registered under three-point-bending trials, and even more remarkable synergies were noticed in Charpy notched impact strength. Particularly, a 212% increase was achieved when 5 wt.% of EMA with 29 wt.% of MA and 2 wt.% of UHMW-SR in ABS P (ABS E29 S P) were added. Thermogravimetric analysis (TGA) showed that the presence of EMA copolymers in ABS P formulations did not interfere with its thermal decomposition, whereas UHMW-SR presence decreased its thermal stability at the beginning of the decomposition. Although the addition of EMA or UHMW-SR, as well as the combination of both in ABS P increased the pHRR in cone calorimetry, UL 94 V-0 classification was maintained for all flame-retarded ABS composites. In addition, through SEM analysis of cone calorimetry sample residue, a more cohesive surface char layer, with Si-O-C network formation confirmed by Fourier transform infrared (FTIR), was shown in ABS P formulations with UHMW-SR. [ABSTRACT FROM AUTHOR]

It has been shown that there exist conditions under which thermosensitive copolymers of N-vinylpyrrolidone with methyl acrylate form hydrophobic–hydrophilic associations, which are unstable dynamic meshes, the bonds in which are continuously broken and created again, and the nature of the formation of such meshes depends significantly on the proportion of the hydrophobic component in the copolymer. It is shown that the interaction of the above copolymers with polyacrylic acid results in the formation of not only classical interpolymer complexes, but also hydrophilic interpolymer associates, which also represent unstable networks existing in a dynamic mode. In such meshes, the molecules of the above copolymers serve as a kind of cross-agent connecting the polyacid molecules. There are also conditions under which such meshes acquire a complex structure, since unstable bonds between macromolecular tangles of both the same and different types take part in their formation. It is shown that the transition from the formation of interpolymer complexes to the formation of hydrophilic interpolymer associates can occur, among other things, due to changes in the acidity or concentration of low-molecular salt in solution. [ABSTRACT FROM AUTHOR]

With advancements in architectural coatings, the demand for antimicrobial coatings in this sector has increased significantly. The COVID-19 pandemic has also been a primary force behind the increased demand for and production of antimicrobial coatings. Typically, antimicrobial coatings are used to resist and decolonize microbial attacks such as biofilm formation, fungal contamination, and black mold formation. In this study, we synthesized a water-based antimicrobial polymer nanocomposite, I-P(MMA/BA), by blending an iodine complex with a poly (methyl methacrylate-butyl acrylate) latex with the aid of polyol and polyvinylpyrrolidone. Antimicrobial efficacy was evaluated in two habitats, namely planktonic and biofilm. Biomass studies indicated that iodinated latex nanocomposites and films show excellent antibacterial and antibiofilm activities. About 85–97% of biofilm formation was reduced by covering 15–30% of the area with iodinated latex film. The contact angle measurement of the iodinated latex-coated surface provides evidence of good hydrophobicity, which prevents stagnation of water over the surface. The developed dual-functional water-based iodinated nanocomposite displays great potential for inhibiting biofilm formation on surfaces when employed as a binder in paints. [ABSTRACT FROM AUTHOR]

Inspired by the drawstring structure in daily life, here we report the development of a drawstring‐mimetic supramolecular complex at the molecular scale. This complex consists of a rigid figure‐of‐eight macrocyclic host molecule and a flexible linear guest molecule which could interact through three‐point non‐covalent binding to form a highly selective and efficient host‐guest assembly. The complex not only resembles the drawstring structure, but also mimics the properties of a drawstring with regard to deformations under external forces. The supramolecular drawstring can be utilized as an interlocked crosslinker for poly(methyl acrylate), and the corresponding polymer samples exhibit comprehensive enhancement of macroscopic mechanical performance including stiffness, strength, and toughness. [ABSTRACT FROM AUTHOR]

Inspired by mussel chemistry, we presented a facile and eco‐friendly method to synthesize silver nanoparticles (AgNPs) using dopamine as a reductant and stabilizer. The synthesized AgNPs as an antibacterial agent and photothermal filler were further introduced to random copolymers of methyl methacrylate and butyl acrylate (MMA‐co‐BA) via latex mixing. The morphology and structure of the formed AgNPs were confirmed by transmission electron microscopy (TEM), UV–Vis spectrum, and x‐ray powder diffraction (XRD). The results showed that the synthesized AgNPs were spherical in the size of 5–30 nm with the characteristic crystalline structure of AgNPs. Mechanical properties of MMA‐co‐BA were significantly enhanced by the introduction of AgNPs. The MMA‐co‐BA/Ag nanocomposite films showed antibacterial activity against E. coli and S. aureus. Moreover, the scratches on the MMA‐co‐BA/Ag nanocomposite film can be healed under infrared light irradiation, which indicated that AgNPs enhanced the self‐healing ability of the MMA‐co‐BA. This work offers a viable avenue for developing antibacterial activity and self‐healing multifunctional coatings. Highlights: Silver nanoparticles modified by dopamine are introduced to acrylic copolymer.Acrylic copolymer/Ag nanocomposites exhibit antibacterial activity.Acrylic copolymer/Ag nanocomposites have photothermal performance.Acrylic copolymer/Ag nanocomposites have self‐healing ability. [ABSTRACT FROM AUTHOR]

Tailoring the hydrophobicity of supramolecular assembly building blocks enables the fabrication of well‐defined functional materials. However, the selection of building blocks used in the assembly of metal–phenolic networks (MPNs), an emerging supramolecular assembly platform for particle engineering, has been essentially limited to hydrophilic molecules. Herein, we synthesized and applied biscatechol‐functionalized hydrophobic polymers (poly(methyl acrylate) (PMA) and poly(butyl acrylate) (PBA)) as building blocks to engineer MPN particle systems (particles and capsules). Our method allowed control over the shell thickness (e.g. between 10 and 21 nm), stiffness (e.g. from 10 to 126 mN m−1), and permeability (e.g. 28–72 % capsules were permeable to 500 kDa fluorescein isothiocyanate‐dextran) of the MPN capsules by selection of the hydrophobic polymer building blocks (PMA or PBA) and by controlling the polymer concentration in the MPN assembly solution (0.25–2.0 mM) without additional/engineered assembly processes. Molecular dynamics simulations provided insights into the structural states of the hydrophobic building blocks during assembly and mechanism of film formation. Furthermore, the hydrophobic MPNs facilitated the preparation of fluorescent‐labeled and bioactive capsules through postfunctionalization and also particle–cell association engineering by controlling the hydrophobicity of the building blocks. Engineering MPN particle systems via building block hydrophobicity is expected to expand their use. [ABSTRACT FROM AUTHOR]

Polymer composites with high dielectric constant and minimal dielectric losses have wide ranging prospects for advanced applications in the flexible electronics and electrical industry. In this study, we used the advantages of carbonaceous hybrid nanofillers to develop a flexible dielectric material. Herein, a set of hybrid nanocomposites were successfully fabricated by incorporating the Ti3C2Tx (MXene) and MWCNTs (multi‐walled carbon nanotubes) hybrid mixture as the conductive moiety into the poly(ethylene‐co‐methyl acrylate) (EMA)/ethylene‐octene co‐polymer (EOC) binary blend as the matrices using solution mixing technique followed by compression molding. As prepared, EMA/EOC/Ti3C2Tx/MWCNTs hybrid composites have been characterized by FTIR (Fourier transform infrared) spectroscopy, XRD (X‐ray diffraction), TGA (thermogravimetric analysis), FESEM (field emission scanning electron microscopy), and DSC (differential scanning calorimetry). We studied the effects of Ti3C2Tx and MWCNTs contents in the hybrid composites on the thermal, dielectric, and electrical properties. Among all the 15 wt% hybrid mixture containing 2 wt% MWCNTs loaded composite has the highest dielectric constant (ℇr = 122.21) and the lowest dissipation loss (tan δ = 0.030) at 100 Hz. The present studies recommend the EMA/EOC/Ti3C2Tx/MWCNTs hybrid composites can be used in smart and flexible electronic storage material. Highlights: EMA‐EOC blend composites with hybrid Ti3C2Tx/MWCNTs were processed.2.5 wt% MWCNTs loaded hybrid composite shows excellent thermal stability.Composite with 2 wt% MWCNTs has ℇ' = 122.21 and tanδ = 0.03 at 100 Hz.2.5 wt% MWCNTs composite has electrical conductivity of 3.26 × 10−8 Ω−1 m−1.This composite can be used in smart and flexible electronic storage material. [ABSTRACT FROM AUTHOR]

In inkjet 3D printing, material selection plays a crucial role in shaping both printing performance and material characteristics. Achieving the desired properties relies on precisely formulated compositions. In this context, ultraviolet (UV) curable polymers require specific viscosities, typically ranging from 3700 to 5700 mPa·s, to function effectively in 3D printing's material jetting technique, preventing complications during material dispensing. This study formulates UV‐curable polymers by blending four distinct monomers: Genomer 4247 Aliphatic Urethane Dimethacrylate, 1,10‐Decanediol Dimethacrylate, Isobornyl Acrylate, and Methyl Acrylate, within a controlled dark room environment at room temperature to prevent undesired crosslinking reactions during mixing. The selection of these monomers and their compositions is meticulous, considering their capacity to achieve specified viscosities and enhance overall material performance. This formulation process yields a wide range of UV‐curable polymer viscosities. The study employs comprehensive methodologies, including rheometry, Fourier transform infrared analysis, Soxhlet extraction, thermal analysis, and tensile testing, for rigorous evaluation of viscosity, curing efficiency, thermal characteristics, and mechanical performance. Notably, mechanical and chemical performance exhibits marginal differences within the viscosity range, attributed to UV‐curable polymer crosslinking, consistently exceeding 99% for all samples. However, the polymer composed of 98% v/v oligomer and methyl acrylate (MA) demonstrates notably better thermal and mechanical properties due to its 99.91% gel content crosslinking. Remarkable polymer fabrication thus occurs within the desired viscosity range. [ABSTRACT FROM AUTHOR]

Glycerol is produced in large quantities as a co‐product in the manufacturing of biodiesel and has received relatively little attention as a substrate for carbon−carbon bond‐forming reactions. In this work, the photocatalyzed reaction between glycerol and electron‐deficient olefins is investigated to regioselectively insert an alkyl group at C2 in the triol. The results show that the transformation is highly dependent on the nature of the photocatalyst and the olefin. In the presence of an iridium catalyst and quinuclidine, glycerol can be coupled at C2 with sterically unhindered acrylates. In the presence of tetrabutylammonium decatungstate, glycerol can be reacted with fumaronitrile, N‐methyl maleimide, methyl acrylate and itaconic anhydride where the latter two substrates require the additional presence of potassium persulfate as an oxidant. These findings give rise to several new carbon−carbon bond‐forming reactions with glycerol that allow the triol to be converted into more elaborate structures. [ABSTRACT FROM AUTHOR]

The copolymerization of methyl acrylate (MA) and glycidyl methacrylate (GMA) with 1-hexene was carried out using activator regenerator by electron transfer atom transfer radical polymerization (ARGET ATRP) employing Cu(0)/CuBr2 as a catalyst, pentamethyl diethylenetriamine (PM DETA) as a ligand, and ethyl 2-bromoisopropionate (EBriP) as the initiator, all at a reaction temperature of 70°C. This process resulted in the production of viscous and transparent copolymers, namely poly (methyl acrylate-co-1-hexene) or PMH and poly (glycidyl methacrylate-co- 1-hexene) or PGMH. For the MA/1-Hex copolymer, conversion rates ranged from a maximum of 31 wt% to a minimum of 12 wt%, while the GMA/1-hexene copolymer exhibited conversion rates ranging from a maximum of 42 wt% to a minimum of 12 wt%. It was observed that increasing the amount of 1-hexene during the synthesis led to a higher incorporation of 1-hexene content in both the MA and GMA polymer backbones, with a maximum of 15 wt% and 18 wt% of 1-hexene being incorporated into PMH and PGMH, respectively. The incorporation of 1-hexene was confirmed through Nuclear Magnetic Resonance (NMR) studies, including 1H, 13C, and DEPT 135 studies. Additionally, the copolymer PMH and PGMH exhibited monomodal molecular weight distribution curves when evaluated using the size exclusion chromatography (SEC) high-performance liquid chromatography (HPLC) technique, with polydispersity values in the range of 1.19-1.37 and 1.07-1.11, respectively. These findings indicate that the copolymerization process was well-controlled and followed a radical polymerization mechanism.

Polyacrylonitrile (PAN) copolymers are important precursors for the preparation of high-performance PAN-based carbon fibers. In this study, different ratios of P(AN-co-AMPS) and P(AN-co-MA-co-AMPS) were prepared by solution polymerization. The compositional structure, thermal, and crystallization properties of P(AN-co-AMPS) and P(AN-co-MA-co-AMPS) were characterized. The results show that an increase in the AMPS feeding ratio is beneficial for improving the thermal stability and crystallization ability of the PAN copolymer; however, it also reduces the molecular weight of the copolymer and increases the cyclization exothermic peak temperature, which is not conducive to the preparation of high-performance carbon fibers. This problem is avoided in P(AN-co-MA-co-AMPS), which maintains its high thermal stability and crystallization properties when appropriate amounts of MA and AMPS are introduced, and P(AN-co-MA-co-AMPS) has smoother cyclization exothermic rates, lower onset exothermic temperatures and lower peak exothermic temperatures. The structural changes of PAN, P(AN-co-MA), and P(AN-co-MA-co-AMPS) during thermal stabilization were investigated in detail using Fourier-transform infrared spectroscopy and it was found that P(AN-co-MAco-AMPS) formed more stable structures at lower temperatures. Furthermore, when the AN:MA:AMPS mass ratio is 97.5:1.5:1, P(AN-co-MA-co-AMPS) has the best overall performance. Our results suggest that the P(AN-co-MA-co-AMPS) has potential as a precursor for carbon fibers. [ABSTRACT FROM AUTHOR]

Concrete is vital for the development of modern buildings. However, they suffer from the high viscosity problem in their application process due to the use of a low water–cement ratio in order to maintain their high strength. Developing PCEs with the presence of ester functional groups in their molecular structure is one of the most effective measures to improve the flowability of concrete. Here, three PCEs with different alkyl densities of acrylic acid ester: PCE-M, PCE-E, and PCE-B were designed to explore their viscosity-reducing effect on the performance of cement and concrete. The structures of the three PCEs were characterized via Fourier transform infrared (FTIR) spectra, proton nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). Their properties were also determined via zeta potential, surface tension, and rheological experiments. It was found that PCE-M had the best performance, with the lowest surface tension, highest zeta potential, and therefore highest charge density on the cement particles, lowest viscosity, and highest flowability of cement paste, and exhibited the best performance of concrete in terms of workability. The best performance of PCE-M in reducing the viscosity of cement and concrete can be ascribed to the smallest amount of water-repellent alkyl groups, enhancing the electrostatic repulsion and reducing the viscosity, thereby boosting the dispersion and stabilization of cement pastes and concrete. This study shed lights on designing other PCEs with high viscosity-reducing effects via an ester group control. [ABSTRACT FROM AUTHOR]

Improving water-based polymer's properties using silicon compounds is strongly noticed nowadays. A novel siloxane-based crosslink agent was synthesized using oligomeric polydimethylsiloxane (PDMS) hydroxyl-terminated. The crosslinker was used for emulsion copolymerization of methyl methacrylate (MMA), butyl acrylate (BA), and acrylic acid (AA). Incorporation of the crosslinker in the structure of the copolymer increased the average latex particle size (from about 165 to 207 nm) and as a result, the viscosity of the latexes was dramatically decreased (from 212 cP to 83 cP). The crosslink density of the latexes, meanwhile, was raised (from about 7–60%). Electrostatic stability of the latexes was improved in the presence of the crosslinker (zeta potential from − 31.7 mV to -49.5 mV and the average mobility of the latexes particles from − 2.4 μm/s/V/cm to -3.8 μm/s/V/cm). The crosslinking agent affected both the initial decomposition temperature and residual weight fraction of the copolymer (from 353 to 406 °C and from about 0.5 w% to 12.4 w% respectively). A morphological study of the latexes was carried out using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The addition of the crosslinker, led to a decrease in the contact angle (from 70 to 39 degrees) of the latexes film formed. [ABSTRACT FROM AUTHOR]

In this study, for the first time, we investigate cobalt-mediated radical block copolymerization of vinyl acetate (VAc) and methyl acrylate (MA) in a packed column system in the presence of cobalt(II) acetylacetonate (Co (acac)2) as a controlling agent. This copolymerization system has the capability to remove the residual catalyst and separate copolymers with different molecular weights, simultaneous to polymerization. Synthesis of high-purity poly (vinyl acetate)-b-poly(methyl acrylate-co-vinyl acctate) (PVAc-b-P(MA-co-VAc)) copolymers were successfully performed by initiating the radical copolymerization of MA and VAc from PVAc-Co (acac)2 macroinitiator in the packed column with silica gel particles. Copolymerization reaction proceeds via a controlled characteristic with first-order kinetics with respect to monomers, predetermined molecular weight, and relatively narrow molecular weight distribution. GPC, 1HNMR, and DSC analyses demonstrated that the PVAc-b-P(MA-co-VAc) was formed with a blocky structure. Based on the analyses, it was found that the VAc content in the block copolymer progressively increased with increasing conversion in the constant VAc initial ratio, indicating that the second block copolymer had a gradient sequence distribution. Moreover, the VAc and MA reactivity ratios in the packed column with silica gel particles were calculated using the extended Kelen–Tudos method to be rMA = 4.98 and rVAc = 0.62, respectively. [ABSTRACT FROM AUTHOR]

The copolymerization of methyl acrylate (MA) and glycidyl methacrylate (GMA) with 1-hexene was carried out using activator regenerator by electron transfer atom transfer radical polymerization (ARGET ATRP) employing Cu(0)/CuBr2 as a catalyst, pentamethyl diethylenetriamine (PMDETA) as a ligand, and ethyl 2-bromoisopropionate (EBriP) as the initiator, all at a reaction temperature of 70°C. This process resulted in the production of viscous and transparent copolymers, namely poly (methyl acrylate-co-1-hexene) or PMH and poly (glycidyl methacrylateco-1-hexene) or PGMH. For the MA/1-Hex copolymer, conversion rates ranged from a maximum of 31 wt.% to a minimum of 12 wt.%, while the GMA/1-hexene copolymer exhibited conversion rates ranging from a maximum of 42 wt.% to a minimum of 12 wt.%. It was observed that increasing the amount of 1-hexene during the synthesis led to a higher incorporation of 1-hexene content in both the MA and GMA polymer backbones, with a maximum of 15 wt.% and 18 wt.% of 1-hexene being incorporated into PMH and PGMH, respectively. The incorporation of 1-hexene was confirmed through Nuclear Magnetic Resonance (NMR) studies, including 1H, 13C, and DEPT 135 studies. Additionally, the copolymer PMH and PGMH exhibited monomodal molecular weight distribution curves when evaluated using the size exclusion chromatography (SEC) high-performance liquid chromatography (HPLC) technique, with polydispersity values in the range of 1.19-1.37 and 1.07-1.11, respectively. These findings indicate that the copolymerization process was well-controlled and followed a radical polymerization mechanism. [ABSTRACT FROM AUTHOR]

Photoswitchable fluorescent polymers (PFPs) are emerging as a class of promising systems for photowritable pattern, optical anti‐counterfeiting, and information encryption. They typically use harmful UV light as the stimulus, which often leads to inevitable photobleaching and poor reversibility. To address this issue, visible‐light‐driven PFPs by copolymerization of novel negative photochromic spiropyran monomer and methyl acrylate are developed. The obtained copolymers display bright red fluorescence, which can be reversibly turned off by visible light irradiation. Many appealing features are observed in this system, including fast photo‐responsibility, prominent photo‐reversibility and photostability, simple preparation process, and processability. Their applications in photorewritable patterns, optical anti‐counterfeiting, and information encryption are also demonstrated. [ABSTRACT FROM AUTHOR]

Click reactions on poly[(methyl acrylate)‐co‐(5‐azido‐1‐pentene)], synthesized by radical polymerization of methyl acrylate and 1‐bromo‐5‐pentene, and converted into the click‐ready azido form by nucleophilic substitution with sodium azide, were studied. Propargyl benzoate and propargyl acetate were clicked onto the polymeric substrate, with the latter known to be a poor click reactant. The impact of solvents (dimethyl formamide (DMF) and tetrahydrofuran (THF)), catalytic systems (CuSO4/Na ascorbate, [Cu(BPMEN)(ClO4)2]/Na ascorbate, bromotris(triphenylphosphine) copper(I) ([CuBr(PPh3)3])) and the addition of chelating nitrogenous bases (triethylamine (TEA), diisopropylethylamine, N,N,N′,N″,N″‐pentamethyldiethylenetriamine) on the degree of conversion was analyzed. Only reactions catalyzed with [CuBr(PPh3)3] led to high or complete conversions in both solvents. Reactions catalyzed with the pre‐catalyst complexes CuSO4⋅5H2O and [(CuBPMEN)(ClO4)2], which require the in situ reduction of Cu(II) to Cu(I) by sodium ascorbate, yielded incomplete conversions in both solvents. Adding chelating nitrogenous bases, with TEA being the most effective, yielded complete conversions for propargyl benzoate with all three catalytic systems in DMF. Adding TEA to reactions of propargyl acetate in DMF increased conversion by 17.9% for CuSO4⋅5H2O/Na ascorbate and 29.6% for [(CuBPMEN)(ClO4)2]/Na ascorbate. The addition of chelating bases was more effective in DMF than in THF, which was also the less suited solvent in reactions without chelating bases. The results show that click reactions with propargyl reagents that cannot increase the nucleophilicity of the vinylidene‐like β‐carbon through electron conjugation yield lower conversions. The effectiveness of catalytic systems that undergo in situ reductions can be enhanced by nitrogenous chelating bases that stabilize the Cu(I) stage. © 2023 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

This study presents the correlation of thermal, morphological and melt rheological properties of poly(ethylene oxide)/poly(methyl acrylate) (PEO/PMA) blends and PEO/poly(n‐butyl methacrylate) (PEO/PnBMA) blends. The miscibility and correlation of these properties were assessed through thermal analysis such as glass transition temperature (Tg) and apparent melting temperature (Tm), morphological study and melt rheological analysis of the blends. The results show that PEO/PMA blends are miscible as suggested by the number of Tg values that follow the Fox equation and the development of homogeneous mixtures in the molten state (T = 80 °C). On the other hand, PEO/PnBMA blends are immiscible as shown by the constancy of the Tg values of PEO throughout the blend compositions. The immiscibility was confirmed by optical microscopy which shows the matrix‐droplet and co‐continuous morphologies (i.e. heterogeneous mixtures) in the PEO/PnBMA blends at T = 80 °C. Melt rheological properties of the immiscible PEO/PnBMA blends are affected by the blend compositions and show significant deviation from Maxwell behaviour. Conversely, the rheological properties of the miscible PEO/PMA blends show close to Maxwell behaviour. Hence, the correlation of thermal, morphological and melt rheological studies is discussed for both miscible and immiscible PEO/polyacrylate blends. © 2023 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Fluorinated polymers are receiving more and more attention worldwide due to their unique chemical properties, and modified fluorinated polymers with different topologies are persued for enriching and enhancing their performance in a variety of application fields. In this work, main-chain-type semifluorinated graft copolymers are produced steadily in continuous tube reactors via photocontrolled step transfer-addition and radical-termination (START) polymerization and Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-RDRP) at room temperature for the first time. Specifically, semifluorinated alternating copolymer (AB)nB is prepared by START polymerization of 1,6-diiodoperfluorohexane (A) and 1,7-octadiene (B) in the first quartz pipeline under irradiation with purple LED light at 20 °C. The (AB)nB with periodic C-I bonds is then flowed into the second copper pipeline directly and acts as the macroinitiators for Cu(0)-RDRP of methyl acrylate (MA) to obtain corresponding graft copolymer (AB)nB-g-PMA. This work provides a new strategy for continuous synthesis of fluorinated graft copolymer materials. [ABSTRACT FROM AUTHOR]

The effect of titanium dioxide (TiO2) on the thermal properties, morphology, intermolecular interactions, and dielectric response of poly(ethylene oxide)/poly(methyl acrylate) (PEO/PMA) polymer electrolytes was studied. These properties were elucidated based on the empirical point of view through systematic sample characterization using differential scanning calorimetry (DSC), polarized optical microscopy (POM), Fourier-transform infrared (FTIR) spectroscopy and impedance spectroscopy (IS). Without TiO2, lithium perchlorate preferably dissolves in the PEO phase rather than in the PMA phase. When TiO2 is added into PEO/PMA/salt systems, TiO2 shows weak interactions either with PEO or PMA phase. The addition of TiO2 changes the morphology of PEO/PMA systems with or without salt from a homogeneous mixture to a heterogeneous mixture displayed by the presence of two Tgs and through the morphological study. The conductivity of both PEO/PMA with and without salt systems remains constant upon the addition of TiO2. Hence, the presented data here have shown that TiO2 provides only a minor effect on the properties of PEO/PMA with and without salt systems. Indirectly, it shows by adding TiO2 under this experimental study may not bring a significant contribution to the improvement of polymer electrolytes. [ABSTRACT FROM AUTHOR]

We have prepared a ligand library based on a ferrocenyl aziridinyl methanol core unit (simply called FAM) having a phenyl group, a cyclohexyl group, and a naphthyl group to be used in 1,3‐dipolar cycloaddition (1,3‐DC) reactions for the synthesis of chiral pyrrolidines. These chiral ligands were used with AgOAc in 1,3‐DC reactions taking place between the aryl‐substituted azomethine ylides and N‐methylmaleimide as the dipolarophile. In each case, the expected aryl‐substituted pyrrolidines were obtained in good to excellent yields with acceptable enantioselectivities favoring only the endo product. The chiral catalyst system CFAM4–AgOAc was also used in 1,3‐DC reaction with different dipolarophiles such as dimethyl maleate, tert‐butyl acrylate, methyl acrylate, trans‐chalcone, and vinyl sulfone. In each case, the cycloadducts were obtained in acceptable yields albeit with low ee. Fortunately, it was possible to increase the ee up to >99% upon crystallization. [ABSTRACT FROM AUTHOR]

Terpolymers of acrylonitrile with acrylic acid and alkyl acrylates, including methyl-, butyl-, 2-ethylhexyl-, and lauryl acrylates, were synthesized using the reversible addition–fragmentation chain transfer method. In this study, the focus was on the investigation of the impact of different monomer addition methods (continuous and batch) on both the rheological behavior of the spinning solutions and the mechanical properties of the resulting fibers. Our findings revealed that the method of monomer addition, leading either to non-uniform copolymers or to a uniform distribution, significantly influences the rheological properties of the concentrated solutions, surpassing the influence of the alkyl-acrylate nature alone. To determine the optimal spinning regime, we examined the morphology and mechanical properties at different stages of fiber spinning, considering spin-bond and orientation drawings. The fiber properties were found to be influenced by both the nature and introducing method of the alkyl-acrylate comonomer. Remarkably, the copolymer with methyl acrylate demonstrates the maximum drawing ratios and fiber tensile strength, reaching 1 GPa. Moreover, we discovered that continuous monomer addition allows for reaching the higher drawing ratios and superior fiber strength compared to the batch method. [ABSTRACT FROM AUTHOR]

Attaining nanocomposites having high mechanical and electrical properties simultaneously via carbon based nanomaterials remains exciting as carbon nanomaterial have a pattern of formation of random dispersive networks in polymeric nanocomposites. Here, polycarbonate/ethylene methyl acrylate blend (PC/EMA) nanocomposites were fabricated using graphene to explore their effect on electrical, mechanical, and electromagnetic interference (EMI) shielding properties. The mechanical properties of the nanocomposites are improved by enhancing the graphene content. EMI shielding properties of graphene based composites were calculated in X band. The fabricated PC/EMA-graphene nanocomposites showed an EMI shielding of -51 dB for 15 phr graphene loading. Thus, the excellent EMI shielding performance and sensitive response combination make the nanocomposites promising material for many potential applications in next-generation electronics. [ABSTRACT FROM AUTHOR]

Mixed 18% solutions of cellulose and PAN terpolymer containing methyl acrylate and methylsulfonate comonomers in N-methylmorpholine-N-oxide have been obtained over the entire range of compositions. All the obtained systems based on cellulose and PAN are biphasic, and the morphological features of the emulsions change from highly dispersed isotropic to fibrillar depending on the phase composition and the intensity of the deformation effect. At high shear stresses that emerge during preparation of the solutions in an extruder, all emulsions are characterized by the same microheterogeneous morphology, which is transformed into fibrillar by deformation. An IR spectroscopic study has established that in the preparation process, specific interactions occur between the functional groups of macromolecules of the cocomponents, leading to the formation of PAN/cellulose associates, which undergo hydrophobic repulsion along the interfaces. It is this process that initiates the fibrillation of the cellulose solution phase in the presence of a PAN solution during deformation. The rheological behavior of mixed solutions over the entire range of concentrations in continuous and dynamic modes at temperatures of 110–130°C is a direct consequence of the phase composition and morphological transformations occurring during deformation. Emulsion compositions characterized by viscoelastic properties that make it possible to successfully form composite fibers have been chosen. [ABSTRACT FROM AUTHOR]

Copper methoxide compound IPrCuOMe was unexpectedly formed in a reaction of IPrCuPPh2 with methyl acrylate. The alkoxide product was identified from the reaction mixture spectroscopically and structurally characterized. This C–O bond cleavage reaction likely depends on nucleophilicity of the Cu–P bond of IPrCuPPh2. [ABSTRACT FROM AUTHOR]

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The subject of the study was the structural and morphological features and mechanical properties of polyacrylonitrile fibers obtained by the dimethylformamide method. For this purpose, on the basis of an industrial tercopolymer of acrylonitrile, methyl acrylate, and itaconic acid, fibers were formed on a laboratory bench installation in water-dimethylformamide precipitation baths of various composition using spinnerets with round holes. The spinnability of a concentrated solution of a tercopolymer in dimethylformamide was evaluated. Microscopic examination of the resulted model samples was carried out and the influence of the composition and temperature of the precipitation bath on the uniformity of the structure and the shape of the cross section of the fibers was shown. The influence of the concentration and temperature of the precipitation bath on the deformability of the spinning solution jet and the value of the maximum multiplicity of the plasticization drawing of gel fibers in an aqueous medium at a temperature of 95.5 °С was noted. The physical and mechanical properties of model polyacrylonitrile fibers produced under various conditions were studied, and the influence of the composition and temperature of the precipitation bath on their specific breaking load, elongation at break, performance and shrinkage was determined. The principal possibility of the process of obtaining fibers by the dimethylformamide method based on a fiber-forming tercopolymer of acrylonitrile, methyl acrylate, and itaconic acid was shown. Предметом исследования явились структурно-морфологические особенности и свойства полиакрилонитрильных волокон, полученных по диметилформамидному методу. С этой целью на основе промышленного терсополимера акрилонитрила, метилакрилата, итаконовой кислоты на лабораторной стендовой установке сформованы волокна в различных по составу водно-диметилформамидных осадительных ваннах с использованием фильер с круглыми отверстиями. Оценена прядомость концентрированного раствора терсополимера в диметилформамиде. Проведено микроскопирование полученных модельных образцов и показано влияние состава и температуры осадительной ванны на однородность структуры и форму поперечного сечения волокон. Отмечено влияние концентрации и температуры осадительной ванны на деформируемость струи прядильного раствора и значение максимальной кратности пластификационной вытяжки гель-волокон в водной среде при температуре 95,5 °С. Изучены физико-механические показатели модельных полиакрилонитрильных волокон, полученных в различных условиях, и установлено влияние состава и температуры осадительной ванны на их удельную разрывную нагрузку, удлинение при разрыве, работоспособность и усадку. Показана принципиальная осуществимость процесса получения волокон по диметилформамидному методу на основе волокнообразующего терсополимера акрилонитрила, метилакрилата и итаконовой кислоты.

Polyacrylate-based network materials are widely used in various products owing to their facile synthesis via radical polymerization reactions. In this study, the effects of alkyl ester chains on the toughness of polyacrylate-based network materials were investigated. Polymer networks were fabricated via the radical polymerization of methyl acrylate (MA), ethyl acrylate (EA), and butyl acrylate (BA) in the presence of 1,4-butanediol diacrylate as a crosslinker. Differential scanning calorimetry and rheological measurements revealed that the toughness of MA-based networks drastically increased compared with that of EA- and BA-based networks; the fracture energy of the MA-based network was approximately 10 and 100 times greater than that of EA and BA, respectively. The high fracture energy was attributed to the glass transition temperature of the MA-based network (close to room temperature), resulting in large energy dissipation via viscosity. Our results set a new basis for expanding the applications of polyacrylate-based networks as functional materials. [ABSTRACT FROM AUTHOR]

DMSO, an interesting solvent for copper‐catalyzed living radical polymerization (LRP) mediated by disproportionation, does not exhibit the greatest disproportionation of Cu(I)X into Cu(0) and Cu(II)X2. Under suitable conditions, DMSO provides 100% conversion and absence of termination, facilitating the development of complex‐architecture methodologies by living and immortal polymerizations. The mechanism yielding this level of precision is being investigated. Here we compare Cu(0)‐wire‐catalyzed LRP of methyl acrylate mediated by disproportionating ligands tris(2‐dimethylaminoethyl)amine, Me6‐TREN, tris(2‐aminoethyl)amine, TREN, and Me6‐TREN/TREN = 1/1 in presence of eight disproportionating solvents, some more efficient than DMSO in disproportionation. Unexpectedly, we observed that all solvents increased the rate of polymerization when monomer concentration decreased. This reversed trend from that of conventional LRPs demonstrates catalytic effect for disproportionating solvents. Above a certain concentration, the classic concentration‐rate dependence was observed. The external order of reaction of the apparent rate constant of propagation, kpapp on solvent concentration demonstrated the highest order of reaction for the least disproportionating DMSO. Of all solvents investigated, DMSO has the highest ability to stabilize Cu(0) nanoparticles and therefore, yields the highest activity of Cu(0) nanoparticles rather than their greatest concentration. The implications of the catalytic effect of solvent in this and other reactions were discussed. [ABSTRACT FROM AUTHOR]

A series of siloxane-functionalized vanadium phosphorus oxide (VPO)-TiO2 catalysts were prepared by a wet-solid mechanochemical method and used to catalyze the co-activation reaction of aldehyde condensation with esterification, a novel route to significantly reduce carbon deposition and stably, efficiently, sustainably prepare methyl acrylate and acrylic acid. [ABSTRACT FROM AUTHOR]

Solvents constitute around 80% of the total volume of chemicals used in fine-chemical processes and contribute significantly to their environmental impact and hazard profile. Thus, there is a strong driving force towards the replacement of traditional fossil-based solvents by alternatives that are more benign in terms of their origin, availability, convenience of synthesis, handling, biodegradability and environmental impact. In the class of polar aprotic solvents, the most successful "green" replacement is γ-valerolactone (GVL). Here, we propose the use of a structurally related compound, 5-methyl-1,3-dioxolane-4-one (LA-H,H), as a reaction medium. It is easily prepared from lactic acid and formaldehyde and satisfies the criteria for a green solvent. It is stable under neutral or basic conditions. Despite the presence of a ketal functionality, it even survives mildly acidic conditions. Evaluation of the Kamlet–Taft and Hansen solvent parameters shows that indeed LA-H,H and GVL are closely similar, suggesting that LA-H,H is an effective new green entry in the class of polar aprotic solvents. We have tested its performance in Pd-catalyzed Heck arylation of methyl acrylate and in the Menschutkin reaction of N-methylimidazole with 1-iodobutane. LA-H,H is also the parent of a whole family of potential solvents easily prepared from two green precursors: α-hydroxy carboxylic acids (lactic, mandelic, and α-hydroxyisobutyric acids) and aldehydes/ketones (formaldehyde, acetaldehyde, and acetone); five such variations were briefly examined. Interestingly, LA-H,H has the unusual property of forming a three-phase system when combined with water and hexane, which may allow technological variations that are not possible with the more normal one- and two-phase systems. As a curiosity, a rare four-phase system is achievable combining LA-H,H with octane, water and perfluorodecaline. [ABSTRACT FROM AUTHOR]

The one-pot synthesis of N-substituted α,β-dehydrotyrosyl dipeptides was carried out by the azlactone method. The target dipeptides were obtained in good yields (53–79%). From the latter, 2,3,5-trisubstituted 4-imidazolones were obtained using 1,1,1,3,3,3-hexamethyldisilazane as a dehydrating agent. It was found that in the case of β-alanine-containing peptides, abstraction of the methyl ester of acrylic acid and the formation of 2,5-disubstituted 4-imidazoline were observed. Antiradical and anticholinesterase properties of the synthesized compounds were studied. Docking analysis was carried out for both some dipeptides and imidazole-4-ones. [ABSTRACT FROM AUTHOR]

Coagulative nucleation in the copolymerization of methyl methacrylate–butyl acrylate (MMA-BA) via semicontinuous emulsion heterophase polymerization (SEHP) under monomer-starved conditions in latexes with high solid content (50.0 wt %) and low concentrations of surfactant is reported. The SEHP technique allows the obtention of latex with high colloidal stability and has potential industrial application in polymer synthesis. High instantaneous conversions (>90%) and a high-ratio polymerization rate/addition rate (Rp/Ra) ≥ 0.9 were obtained at low times until the final copolymerization, which confirmed the starved conditions in the systems at the highest surfactant concentrations. The particle size exhibited a linear size increment at conversions between 0 and 40% induced by homogeneous nucleation, a transition region between 40 and 50%, and non-linear behavior at higher conversions by coagulative nucleation. These three behaviors were also observed in the particle surfactant coverage area (Sc), Z-potential, particle coagulation rate (dNp/dt) by the Smoluchowski model, final particle size (Dpz), and number particle (Np) through the reaction. By means of transmission electron microscopy (TEM) images, the onset of coagulation was observed from 50% of conversion until the end of the reaction. In addition, in both processes of copolymerization, tacticity was displayed (mainly syndiotacticity). [ABSTRACT FROM AUTHOR]

Rationale: Synthesis of copolymer is one of the major approaches to establish sophisticated polymers. In copolymer analysis in mass spectrometry (MS), an increase in the number of monomer unit species and/or the polymer molecular weight results in complex mass spectra, and a method is required to solve this problem. Methods: In this study, electrospray ionization‐ion mobility spectrometry‐mass spectrometry was employed to analyze styrene/methyl methacrylate/n‐butyl acrylate (St/MMA/nBA) terpolymers via Kendrick mass defect (KMD) analysis. An expanded Fourier transform‐based noise reduction method for the copolymer was developed to improve the decrease in the signal/noise ratio observed in the higher m/z region. Results: Low‐mass terpolymers (0.7 kDa) were identified by comparing the observed and theoretical results using a two‐dimensional KMD plot. For the 1.5 kDa terpolymer, the signal overlap, of which KMD value was not matched with the theoretical one, was interpreted by the shift from the theoretical value in the KMD plot. For the 3.0 kDa terpolymers, the compositional candidates were determined by the prediction based on the compositional information of low‐mass terpolymers previously analyzed. The 4.5 kDa terpolymer was interpreted after the expanded noise filtering. Conclusions: The terpolymers, whose molecular weight was up to 4.5 kDa, were successfully characterized at a molecular level. The dependency of the St/MMA/nBA composition on molecular weight was observed; that is, the nBA content decreased with an increase in the molecular weight. [ABSTRACT FROM AUTHOR]

A biodegradable silica was fabricated to achieve effective tumor microenvironment responsive drug delivery with low drug leakage (4%, 80 h) and good biosafety. A disulfide bond embedded copolymer composited by methylacrylic acid (MAA) and vinyl trimethoxysilane was utilized for the in situ synthesis of the PMAA hybrid biodegradable silica shell. The biodegradable silica was introduced as a gatekeeper to alter the drug release behavior of the doxorubicin‐loaded in the mesoporous silica microspheres. The fabrication process and glutathione‐responsive degradation of the drug delivery system were carefully studied. In vitro drug release experiments revealed that 65% of the loaded drug could be released after 80 h in simulated tumor environment. The biocompatibility of the carrier and the anti‐cancer efficiency against the HepG2 cancer cell line were studied with the cell counting kit‐8 assay. The method to prepare the biodegradable silica reported in this work might provide new thought to the fabrication of high‐performance drug delivery systems. [ABSTRACT FROM AUTHOR]

We report a versatile mechanophore exhibiting a vividly detectable, light‐regulable multicolor mechanochromism. Such optical features rely on the synergistic coupling of mechanochromic bis‐rhodamine (Rh) and photochromic bisthienylethene (BTE). Poly(methyl acrylate)s incorporating this bis‐mechanophore can be mechanically activated under sonication. The relative distribution of the two distinctly colored and fluorescent Rh ring‐opening products is altered with different magnitudes of applied force. Orthogonal use of the photochromic reaction of the BTE core can strengthen the mechanochromism and gate the mechanofluorescence in polymers. Due to increased conjugation offered by the BTE linker, both force‐ and light‐induced optical signals display high contrast. Combined DFT simulated and experimental results reveal that the three subunits (two Rhs and one BTE) in this chromophore are activated sequentially, thus generating switchable three‐colored forms and gradient optical responses. [ABSTRACT FROM AUTHOR]

Low-pressure (33.33 Pa) plasma polymerized methyl acrylate and vinyl acetate composite thin films with various monomer compositions were deposited onto glass substrates. Under the same plasma conditions, the homopolymer thin films were also prepared. The thickness of the composite films was observed to vary between 117 and 213 nm depending on the monomer ratio. The composite films exhibit a smooth, pinhole-free, and immaculate surface morphology, surpassing that of the homopolymers. The energy dispersive x-ray study shows that the films contain mainly carbon and oxygen with 26.09–37.20 at% and 35.03 − 40.10 at%, respectively. The composite films contain more carbon contents which enhance the film stability. The appearance of some broad absorption bands in the Fourier transform infrared spectroscopy indicates structural changes in the PP films caused by the restructuring or dilapidation of monomer molecules while forming the polymer. The UV–visible spectra analysis reveal that the composite films exhibited a tunable optical band gap by adjusting the monomer ratio. The decrease of methyl acrylate monomer reduces the direct and indirect optical band-gap values of composite films from 3.15 to 3.00 eV and 2.35 to 1.74 eV, respectively. While Urbach energy values increases from 0.33 eV to 0.90 eV. All the films showed good transmittance properties (86 − 96%) in the visible range wavelength (550 − 800 nm). Other optical parameters are also found better in composite films which indicates the aptness of the composite films in various optoelectronic or electronic applications.

The process of suspension polymerization was utilized to create acrylate resin microspheres with mesh numbers of 140–200 μm and particle sizes of 100 μm for implementation in mesh coating technology. The copolymer of methyl methacrylate (MMA) and methyl acrylate (MA) served as the primary polymer, with dibenzoyl peroxide (DBPO) functioning as the initiator, and a mixture of calcium carbonate and deionized water served as the dispersion medium. The surface morphology of the synthesized microspheres was analyzed through Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) to confirm successful synthesis. The optimal reaction conditions for the synthesis of these microspheres were determined to be a dispersant dosage of 30 g of calcium carbonate with a monomer ratio of 4:1, a reaction time of 1 h, an initiator dosage of 1.2 g of BPO, and a reaction temperature of approximately 75–80 C, resulting in microspheres with a regular spherical shape and smooth surface.

A new rotationally hindered diphosphoramidite ligand has been applied to the Rh-catalyzed hydroformylation of various olefins. Good activity as well as excellent regioselectivity toward the formation of linear aldehydes were achieved. Remarkable performances were also observed in the hydroformylation of functionalized olefins, including methyl acrylate, allyl acetate, crotonaldehyde ethylene acetal and styrene. [ABSTRACT FROM AUTHOR]