Polymerization Of Styrene Research Articles

Effect of filler loading on the frictional, thermal and mechanical properties of ABS/boron nitride (h-BN) nanocomposites

The effect of hexagonal boron nitride (h-BN) nanoparticles in acrylonitrile butadiene styrene (ABS) polymer matrix is investigated. ABS/h-BN nanocomposites were prepared with h-BN content ranging from 0.5 to 5 wt% and their frictional, thermal and mechanical properties were evaluated. XRD analysis showed that the 'd' spacing in h-BN stacks increased in the ABS nanocomposite due to the interpenetration of ABS polymer chains. The tensile properties and thermal stability of ABS matrix showed better improvement with 0.5 wt% addition of h-BN nanoparticles. The tensile fracture mechanism in ABS/h-BN nanocomposites was predicted using tensile fracture surface analysis. Coats-Redfern approach was applied to support the thermal stability analysis results. Significant enhancement (28 %) in frictional property of ABS was observed in the nanocomposite with h-BN. Wettability and flame retardancy of the ABS/h-BN nanocomposites were also investigated.

Comparison of mechanical properties of bagasse fiber reinforced styrenic polymer composites

Comparison of mechanical properties of bagasse fiber reinforced styrenic polymer composites

Cancer Cell-Selective Inhibition of Migration by Styrenic Catiomer Emulsions.

Cancer metastasis remains the most formidable cause of mortality and morbidity in cancer patients. Developing an effective and economical method toward cancer antimetastatic strategy demands immediate attention in anticancer therapy. Herein, we followed a cost-effective greener method for preparing a small family of amphiphilic catiomers with varied styrene content (45, 63, and 83%), which revealed the unique potential of promoting normal cell migration while retarding cancer metastasis. The styrenic polymers formed micellar self-assembly in aqueous phase and exhibited a cationic charge. Polymers were quite nontoxic up to 200 μg/mL concentration toward human embryonic kidney cell HEK293 as well as human, triple negative breast cancer cell MDAMB-231, mouse melanoma cell B16F10, and human oral squamous carcinoma cell FaDu. Confocal imaging and fluorescence activated cell sorting (FACS) showed effective incorporation of polymers within cells. Interestingly, the polymer-treated HEK293 cells underwent prominent wound healing in scratch assay. However, the as-synthesized polymer-treated cancer cells resisted migration as analyzed from the scratch assay. A mechanistic study using immunoblotting assay established upregulation of migratory proteins vimentin and TGF-β and downregulation of E-cadherin in normal HEK293 cells. Remarkably, this trend was completely reversed in cancer cell MDAMB-231. This study describes the extraordinary potential of styrenic catiomers as wound healers for normal cells while inhibiting cancer metastasis.

Bioderived Thiol-Ene Emulsion Polymerization for Hybrid Latex Particles.

The thiol-ene emulsion polymerization of three dienes synthesized from bioderived compounds, and subsequent preparation of core-shell polymer latexes, is reported. Levoglucosan (LGA), levogucosenone (LGO) and isosorbide were first modified with 4-pentenoic acid to install polymerizable groups. These monomers were used along with a dithiol to prepare poly(thioether) particles via ab initio emulsion polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant. The structure of the diene significantly influenced the size of the resulting polymer latex particles. Given their low glass transition temperature, the LGA-derived poly(thioether) particles were used as a seed for the seeded emulsion polymerization of either styrene or methyl methacrylate. Core-shell latex particles with a high Tg core and a low Tg bioderived shell were formed, as verified by electron microscopy and in agreement with theoretical predictions of the equilibrium particle morphology based on the interfacial tensions of each particle phase.

Combine calculation and experiment to study the undesired polymerization of styrene for screening of effective inhibitors

Regarding undeniable formation of the undesired polymer (UP) in the styrene purification process, it is of vital importance to inhibit its production. To address the mentioned issue, effects of injecting antipolymers (e.g., stable nitroxide radicals (i.e., SNRs) and antioxidants (e.g., alkylhydroxylamines (AHA)) on the controlling the UP formation have been studied through density functional theory (DFT) calculations as well as experimental method in this study. In fact, electrophilicity and growth percentage were evaluated by DFT calculations and experimental approach, correspondingly. Accordingly, it was revealed that the best antipolymers in terms of inhibiting performance were 4‑hydroxy-2,2,6,6-tetramethyl piperidine 1-Oxyl (4‑hydroxy-TEMPO) and 4-oxo-2,2,6,6-tetramethylpiperidine 1-Oxyl (4-oxo-TEMPO), and from the antioxidants, N-Ethyl-N-phenyl hydroxylamine (EPHA) and N-Benzyl-N-phenyl hydroxylamine (BPHA) exhibited the best performance. In addition, the growth percentage of 18.70, 20.55, 24.85 and 46.8, were obtained for the EPHA, BPHA, 4‑hydroxy-TEMPO, and 4-oxo-TEMPO after 4 hrs of operation, correspondingly. Besides, the synergetic effects of the used inhibitors were determined experimentally. Among the evaluated inhibitors, EPHA/4‑hydroxy-TEMPO demonstrated the best synergetic effects over the control of UP formation. Finally, the blend of 4‑hydroxy-TEMPO (40 wt.%) and EPHA (60 wt.%) was obtained to be the optimum (best) inhibitor with 7.2 % polymer growth after 4 hrs of operation.

Could Olympic Gels of Polystyrene be Produced by ARGET ATRP From Bifunctional Initiators?

The kinetics of gelation in the Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) of styrene, using a bifunctional initiator and no crosslinking agents are investigated. By applying the method of moments, we develop a system of differential equations that accounts for the formation of polymer rings. The kinetic rate constants of this model are optimized on the experimentally determined kinetics, varying the reaction temperature and ethanol fraction. Subsequently, we explore how variations in the amounts of catalyst, initiator, and reducing agents affect the simulated equilibria of ARGET ATRP, the emergence of gelation, and the swelling properties of the resulting networks. These findings suggest that favoring ring formation enhances the gelation phenomenon, supporting the hypothesis that the networks formed under the reported reaction conditions are olympic gels.

Functionalized Polyisobutylene and Polyisobutylene‐Based Block Copolymers by Mechanistic Transformation from Cationic to Radical Process

AbstractThe strategy for the preparation of polyisobutylene‐based block copolymers via mechanistic transformation from cationic to radical polymerization is reported. This strategy involves the synthesis of 2‐bromo‐2‐methylpropanoyl‐terminated difunctional polyisobutylene macroinitiator (BiBB‐PIB‐BiBB) via consecutive cationic polymerization, in situ preparation of hydroxyl‐terminated polyisobutylene and its acylation by 2‐bromo‐2‐methylpropanoyl bromide. The Mn2(CO)10−triggered photo‐induced radical polymerization of styrene in bulk using this macroinitiator leads to the formation of multiblock copolymer, while predominantly triblock copolymer is generated during the polymerization of methyl methacrylate. The possibility to functionalize the polyisobutylene by pyrene via photo‐induced radical addition of 1‐bromomethyl pyrene in the presence of Mn2(CO)10 is also demonstrated in this work.

Increased stability of polymer dispersions obtained by heterophase radical polymerization of styrene and MMA in the presence of water-insoluble organosilicon macromeres

It is shown that during the copolymerization of methyl methacrylate with the surfactant comonomer α,ω-dipropylmethacrylatep olidimethylsiloxane with the number of repeating dimethylsiloxane units n = 20 (DPMPDMS), strong interfacial adsorption layers are formed on the surface of polymer–monomer particles formed from microdrops, ensuring the stability of particles to various types of influences.

Synthesis, Structural Analysis, and Polymerization Activity of Noncyclopentadienyl Constrained Geometry Complex [Me2Si(Ph2C)(tBuN)]ZrCl2(thf)

ABSTRACTConstrained geometry complexes (CGCs) are homogeneous olefin polymerization catalysts that have been improved because of their considerably high activity and their copolymerization abilities for ethylene with α‐olefins. The ancillary ligands in CGCs comprise bridged 6π‐electron moieties (e.g., cyclopentadienyl (Cp) and fluorenyl) and amide donors. In this study, we investigated the effect of changing the 6π‐electron moieties to a diphenylmethyl moiety (Ph2C) on the polymerization activity of [Me2Si(Ph2C)(tBuN)]ZrCl2(thf) (thf = tetrahydrofuran). We synthesized [Me2Si(Ph2C)(tBuN)]ZrCl2(thf) and characterized it via 1H nuclear magnetic resonance analysis and single‐crystal X‐ray crystallography. Ethylene polymerization at 2 MPa using a catalyst of the [Me2Si(Ph2C)(tBuN)]ZrCl2(thf) and modified methylaluminoxane (MMAO) as a cocatalyst yielded a linear polyethylene (PE) with a high melting point (124°C–134°C); moreover, the polymerization activity of the catalyst was found to be up to 445 g (PE) mmol (Zr)−1 h−1. The polymerization of styrene using the zirconium complex and MAOs did not proceed, but the polymerization of 1,3‐butadiene produced a small amount of polybutadiene with ~60% cis‐1,4‐structure. These results indicate that non‐Cp‐type CGCs, which can be defined as metal complexes bearing an ancillary ligand in which non‐Cp moieties (benzyl moiety in this study) and an amido group are bridged by an organic linker, can become a new family of homogeneous olefin polymerization catalysts.

Synthesis of ZnO/Poly(Styrene‐co‐Methacrylic Acid) Hybrid Polymer Particles for Enhanced UV‐Visible Photodegradation of Methylene Blue

AbstractIn this study, a series of submicron‐sized functional polymer particles poly(Sty‐co‐MAA) with variable methacrylic acid (MAA) content were prepared by soap‐free emulsion polymerization of styrene (Sty), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA). The number‐average diameters of polymer particles (Dn) were in the range of 0.11 to 0.19 μm. A decrease in particle size was observed with increasing the molar ratio of MAA comonomer in the recipe. ZnO/poly(Sty‐co‐MAA) hybrid polymer particles were prepared by seeded emulsion copolymerization in presence of zinc oxide nanoparticles (ZnO NPs) as seed particles synthesized using Citrus lemon aqueous leaf extract. Scanning electron microscopy (SEM), transmission electron microsphere (TEM), X‐Ray Diffraction (XRD), and Fourier transformed infra‐red (FT‐IR) analysis were performed to characterize polymer particles. The crystalline size of ZnO NPs and ZnO/poly(Sty‐co‐MAA) hybrid polymer particles calculated from XRD analysis were 20.75 and 29.85 nm, respectively. These hybrid polymer particles were applied as photocatalyst in the photodegradation of methylene blue (MB) dye under UV irradiation, which showed high catalytic activity with degradation efficiency of 85.70 % at room temperature compared to bare ZnO NPs.

Studies on the Termination Behavior of Styrenic Free‐Radicals

AbstractIn order to provide more evidence to understand the termination mechanism in styrene free‐radical polymerization, (1‐bromoethyl) benzene and polystyrene with bromide end group (PSt‐Br) synthesized by atom transfer radical polymerization (ATRP) were used as the model compound and model polymer to study the termination behavior of styrenic radical by atom transfer radical coupling (ATRC), and then the NMR chemical shifts of the head‐to‐head enchainment from coupling termination were obtained. SEC and different NMR measurement methods were used to analyze and characterize the products. It is confirmed that there is no bimolecular disproportionation termination between styrenic free radicals, but only coupling termination to form the head‐to‐head enchainment. The proton and carbon chemical shifts of the head‐to‐head enchainment from coupling termination for (1‐bromoethyl) benzene are 2.7–2.86 ppm and ~47.3 ppm. As for the polystyrene through ATRC from PSt‐Br, the corresponding chemical shifts are 2.61–3.29 ppm and ~46.4 ppm, respectively, they are almost the same as the data in our previous paper (~3.05 ppm, ~46.6 ppm) for polystyrene initiated by BPO, proving that the chain termination in free‐radical polymerization of styrene initiated by BPO occurs through primary termination between chain radical and primary radical rather than bimolecular termination between chain radicals.

Upcycling of waste acrylonitrile butadiene styrene as N-doped carbocatalyst for peroxymonosulfate-induced degradation by solvothermal process

Advanced upcycling of post-consumer waste plastics into functional carbocatalyst has emerged rapidly as a strategy for simultaneously achieving waste plastics disposal and alternative catalysts fabrication. In this study, this type of magnetic N-doped carbocatalyst hybrid was fabricated by a facile solvothermal impregnation of metallic nitrates into waste acrylonitrile butadiene styrene polymer. The key point of the process was that solvothermal impregnation remarkably enhanced a homogeneous metal dispersion and graphitic N structure was stably introduced into carbocatalyst due to N heteroatoms in inherent structure of waste plastics. It was found that carbocatalyst with predominant encapsulation of magnetic CoFe2O4, Fe0.64Ni0.36 and CoFe possessed excellent catalytic performance to activate peroxymonosulfate with substantial degradation of 98.3% synthetic azo contaminant. Mechanism study indicated that graphitic N and metal species exhibited strong synergistic effects for peroxymonosulfate activation to generate SO4·−, ·OH and 1O2. This system achieves a dual-pathway degradation and electron transfer from azo contaminant to peroxymonosulfate to dominate degradation of azo contaminant, providing a new insight into magnetic carbocatalyst confinement from plastic scrap for peroxymonosulfate activation and its versatile application in wastewater reclamation.

Improved Interfacial Electron Dynamics with Block Poly(4-vinylpyridine)-Poly(styrene) Polymers for Efficient and Long-Lasting Dye-Sensitized Solar Cells.

Dye-sensitized solar cells (DSSCs) have recently entered the market for indoor photovoltaics. Fast electron injection from dye to titania, the lifetime of the excited dye, and the suppression of back electron recombination at the photoanode/electrolyte interface are crucial for a high photocurrent conversion efficiency (PCE). This study presents block copolymers of poly(4-vinylpyridine) and poly(styrene)-P4VP67-b-PSt x(x=23;61) as efficient accelerators of electron injection from dye to titania with extended lifetime excited states and long-lasting back electron recombination suppression. P4VP67-b-PSt23 and P4VP67-b-PSt61 rendered devices with PCEs of 10.0 and 9.8%, respectively, under AM 1.5G light; PCEs of 19.4 and 16.4% under 1000 lx LED light were attained. Copolymers provided a stable PCE with the two most popular I3 -/3I- electrolytes based on ACN and 3-methoxypropionitrile solvents; PCE history was tracked in the dark and under 1000 h of continuous light soaking with passive load according to ISOS-D1 and ISOS-L2 aging protocols, respectively. The impact of the polymer molecular structure on electron recombination, charge injection, dye anchoring, light absorption, photocurrent generation, and PCE and the long-term history of photovoltaic metrics are discussed.

Determining the Kinetic and Thermodynamic Parameters of Anionic Polymerization of Styrene Using Linear Free‐Energy Relationship

Determining the Kinetic and Thermodynamic Parameters of Anionic Polymerization of Styrene Using Linear Free‐Energy Relationship

Thermoplastic Vulcanizates with an Integration of High Wear-Resistant and Anti-Slip Properties Based on Styrene Ethylene Propylene Styrene Block Copolymer/Styrene Ethylene Butylene Styrene Block Copolymer/Solution-Polymerization Styrene-Butadiene Rubber.

Distinguished from traditional vulcanized rubber, which is not reusable, thermoplastic elastomer (TPV) is a material that possesses both the excellent resilience of traditional vulcanized rubber and the recyclability of thermoplastic, and TPVs have been widely studied in both academia and industry because of their outstanding green properties. In this study, new thermoplastic elastomers based on solution polymerized styrene butadiene rubber (SSBR) and thermoplastic elastomers (SEPSs/SEBSs) were prepared by the first dynamic vulcanization process. The high slip resistance and abrasion resistance of SSBR are utilized to improve the poor slip resistance of SEPSs/SEBSs, which provides a direction for the recycling of shoe sole materials. In this paper, the effects of different ratios of the rubber/plastic phase (R/P) on the mechanical properties, rheological properties, micro-morphology, wear resistance, and anti-slip properties of SSBR/TPE TPVs are investigated. The results show that the SSBR/TPE TPVs have good mechanical properties. The tensile strength, tear strength, hardness, and resilience of the TPVs decrease slightly with an increasing R/P ratio. Still, TPVs have a tensile strength of 18.1 MPa when the ratio of R/P is 40/100, and this reaches the performance of the vulcanized rubber sole materials commonly used in the market. In addition, combined with microscopic morphology analysis (SEM), it was found that, with the increase in the R/P ratio, the size of the rubber particles gradually increased, forming a stronger crosslinking network, but the rheological properties of TPVs gradually decreased; crosslinking network enhancement led to the increase in the size of the rubber particles, and the increase in the size of rubber particles made the material in the abrasion of rubber particles fall easily, thus increasing its abrasion volume. Through dynamic mechanical analysis and anti-slip tests, when the R/P ratio was 40/100, the tan δ of TPVs at 0 °C was 0.35, which represents an ordinary vulcanized rubber sole material in the market. The viscoelasticity of TPVs increased with the increase in the R/P ratio, which improved the anti-slip performance of TPVs. SSBR/TPE TPVs are expected to be used in footwear and automotive fields due to their excellent abrasion resistance and anti-slip performance.

Predicting glass transition temperature of polymers by combining molecular dynamics simulations and machine learning techniques

Polymeric materials, valued for their cost-effectiveness and ease of processing, play a pivotal role in diverse applications. Among them, solution polymerized styrene butadiene rubber (SSBR) stands out with low rolling and wet skid resistance, ideal for eco-friendly tire. The glass transition temperature (Tg) is an important parameter in determining the performance of SSBR, which is time-consuming to test with conventional experiments. In recent years, machine learning (ML) has emerged as a useful tool in materials science. In this study, all-atom molecular dynamics (AAMD) simulation provided the foundational training data. Subsequently, ML techniques are utilized to efficiently predict SSBR’s Tg based on its content of four key structural components. To address the challenge of limited sample sizes, the innovative integration of Ordinary Kriging (OK) from geostatistics and Nearest Neighbor Interpolation (NNI) was employed to compute label values for interpolation points, which surpasses previous studies relying solely on NNI. Comparative analysis of four ML models (XGBoost, Ridge, LASSO, and SVR) reveals XGBoost’s superior performance in handling this nonlinear problem, with consistently high R2 and low RMSE scores. Through 900 repeated experiments, the model demonstrates robustness, maintaining an average R2 of approximately 0.9703. Ultimately, the novel integrated ML approach (NNI-OK-XGBoost) was proposed. Furthermore, four new combinations of structural unit content were evaluated using both ML predictions and AAMD simulations. The validation confirms the efficiency and accuracy of this method in predicting SSBR’s Tg across varying composition ratios within a specified composition space. This work presents a viable solution for accurately and rapidly predicting the Tg of polymeric materials, particularly in scenarios with limited sample sizes.

CFD simulation study of thermal runaway inhibition for styrene polymerization by jet mixing

CFD simulation study of thermal runaway inhibition for styrene polymerization by jet mixing

Laboratory Evaluation of Wear Particle Emissions and Suspended Dust in Tire–Asphalt Concrete Pavement Friction

This study aims to evaluate the tire–road-wear particles (TRWPs) and suspended dust generated based on the nominal maximum aggregate size (NMAS) of the polymer-modified stone mastic asphalt (SMA) mixtures indoors. The SMA mixtures containing styrene butadiene styrene (SBS) polymer and the NMASs of 19, 13, 10, 8, and 6 mm were used. Dust was generated from the wear of the tires and the pavement inside the indoor chamber by using the laboratory tire–road-wear particle generation and evaluation tester (LTRWP tester) developed by Korea Expressway Corporation (KEC). In this method, a cylindrical asphalt-mixture specimen rotates in the center, and a load is applied using three tires on the sides of the test specimen. During the test, a digital sensor was used to measure the concentration for each particle size. After the test was completed, the dust was collected and weighed. According to the test results, the generated TRWP emissions were reduced by approximately 0.15 g as the NMAS of the SMA mixture decreased by 1 mm. TRWP emissions decreased by 20% when using the 6 mm SMA mixture compared to the 13 mm SMA mixture. For practical application, a predicted equation of TRWP emissions estimation was developed by using the concentration of suspended dust measured by the digital sensor in the LTRWP tester. LTRWP can be used as an indoor test method to evaluate pavement and tire materials to reduce the amount of dust generated from tire and pavement wear.

High Young's Modulus Li6.4La3Zr1.4Ta0.6O12-Based Solid Electrolyte Interphase Regulating Lithium Deposition for Dendrite-Free Lithium Metal Anode.

Artificial solid electrolyte interphase (SEI) layers have been widely regarded as an effective protection for lithium (Li) metal anodes. In this work, an artificial SEI film consisting of dense Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles and polymerized styrene butadiene rubber is designed, which has good mechanical and chemical stability to effectively prevent Li anode corrosion by the electrolyte. The LLZTO-based SEI film can not only guide Li to uniformly deposit at the interface but also accelerate the electrochemical reaction kinetics due to its high Li+ conductivity. In particular, the high Young's modulus of the LLZTO-based SEI will regulate e- distribution in the continuous Li plating/stripping process and achieve uniform deposition of Li. As a consequence, the Li anode with LLZTO-based SEI (Li@LLZTO) enables symmetric cells to demonstrate a stable overpotential of 25 mV for 600 h at a current density of 1 mA cm-2 for 1 mA h cm-2. The Li@LLZTO||LFP (LiFePO4) full cell exhibits a capacity of 106 mA h g-1 after 800 cycles at 5 C with retention as high as 90%. Our strategy here suggests that the artificial SEI with high Young's modulus effectively inhibits the formation of Li dendrites and provides some guidance for the design of higher performance Li metal batteries.

Synthesis and self-assembly of high grafting density core-shell bottlebrush polymer with amphiphilic side chain

Self-assembly of bottlebrush polymers are widely studied in photonic bandgap materials, biomedical materials and nanomaterial with different structures. In this work, high grafting density bottlebrush polymer with amphiphilic QPDMA[FeCl4]-b-PS side chains grafting on every carbon atom of the backbone are prepared via grafting from approach. The para-isocyanobenzoate monomer modified with chain transfer agent (CTA) is designed and synthesized to prepared polymer backbones with CTA grafting on each atoms. The core-shell bottlebrush block copolymer is prepared by sequential reversible addition-fragmentation chain transfer polymerization of dimethylaminoethyl methacrylate and styrene. The inner core follows quaternization and ion exchange to form water soluble QPDMA[FeCl4] magnetic block. The resulting core-shell bottlebrush magnetic polymer (PCN-g-[QPDMA[FeCl4]-b-PS]) self-assembles into nanowires with magnetic QPDMA[FeCl4] as core and PS as corona in the shell selected solvent dichloromethane, the length of nanowires increases with self-assembly time. While it self-assembles into nanoparticle clusters in core selected aqueous solution. And, the thermal and magnetic properties are affected by the self-assembly morphology. Especially, the as prepared PCN-g-[QPDMA[FeCl4]-b-PS] and the nanoparticles cluster self-assembly are paramagnetic, but the nanowire self-assembly is superparamagnetic.