Polymerization Of Styrene Research Articles

Superacid-Assisted Degradation of Polystyrene

We report the degradation pathway of polystyrene in a low-temperature environment by superacid. Polystyrene is a thermoplastic resin widely used in packaging, disposable products, and structural materials. However, economically viable upcycling of polystyrene has yet to be established because of the high cost of chemical recycling and the low value of products. To understand the degradation pathway of polystyrene and establish competitive upcycling practices, we investigated the transformation of normal and deuterated polystyrene chains into small compounds by triflic acid at 20 °C. The degradation study of deuterated polystyrene showed the high stability of the hydrogens at the α carbons of polymerized styrene against triflic acid, which suggests the known β-scission degradation pathway of polystyrene by α-proton abstraction is unlikely. Rather, the polystyrene degradation proceeds through three distinct stages: (i) intrachain cross-linking that forms polymer nanoparticles and simultaneous transformation of polymerized styrene to indan units, (ii) degradation of the polymer nanoparticles into small molecular weight compounds, and (iii) formation of polycyclic aromatic hydrocarbons. The stepwise degradation pathway of polystyrene we report may enable the design of efficient and profitable upcycling processes for end-of-life polystyrene products in low-temperature environments.

Morphological and Mechanical Characterization of Friction Stir Welded Zones in Acrylonitrile Butadiene Styrene (ABS) Polymer

Morphological and Mechanical Characterization of Friction Stir Welded Zones in Acrylonitrile Butadiene Styrene (ABS) Polymer

Structured nonlinear process modeling using neural networks and application to economic optimization

This paper presents a model identification approach to develop structured dynamic models that utilize both the available first principles knowledge and neural networks (NNs) estimated from data. The NNs in the dynamic model are used to approximate some complex unknown functions that may be challenging to model in applications using the available first principles knowledge. The parameters in the NNs are estimated by solving a multistep ahead prediction error minimization problem. The efficacy of the modeling approach is demonstrated via case studies with an illustrative chemical reactor and an industrially relevant styrene polymerization process. In the latter example, we use NNs to approximate unknown reaction kinetics and polymer moment functions in the structured model. The economic performances of the structured models are analyzed by solving a steady-state optimization problem. First, we elucidate that to obtain a good steady-state economic performance using the structured models, the training data collected from the plant should contain sufficient steady-state information. In the styrene polymerization example, we examine the economic performances of two structured models with different NN parameterization choices. We show that a structured model that utilizes the most possible physical information about the process provides a median loss of 6.4% compared to the optimal performance of the true plant across a range of steady-state problems. We emphasize in the case studies that physical insight about the process is critical to obtain good economic performance using the structured models.

Functionalization of dielectric BaTiO3 and semiconducting ZnO nanoparticles on rGO layers and their polymer composites: Applications in EMI shielding

Due to the continuous need for electronic devices across various industries, electromagnetic interference (EMI) is a significant problem in contemporary civilization. Materials with properties like lightweight, ease of processing, non-corrosiveness, design flexibility, and compatibility with existing technologies are in the spotlight to handle this problem. In this article, we have synthesized rGO-BaTiO3 by surface hydroxylation of dielectric BaTiO3 with graphene oxide (GO), and rGO-ZnO by in-situ reduction with GO and zinc nitrate. Phase purity, functional group analysis and morphological properties are studied by using PXRD, FTIR, SEM-EDX, and TEM. Polymer composites are prepared using acrylonitrile butadiene styrene (ABS) polymer with nanofillers rGO-BaTiO3 and rGO-ZnO with multiwall carbon nanotube (MWCNT). Total Shielding Effectiveness (SET) was measured by varying the weight ratio and thickness of the shield. The rGO-BaTiO3 composite with 10 wt% for 3 mm thickness shows a SET of 40.5 dB in X-band and maximum SET obtained is 59.8 dB at 11.8 GHz. In the case of rGO-ZnO composites shows 45.1 dB and maximum SET observed is 57.9 dB at 9.6 GHz. The data results obtained are envisaged to prove their potential in electronic appliances, electromagnetic countermeasures, and stealth materials.

The Effect of Divinylbenzene on the Structure and Properties of Polyethylene Films with Related Radiation Chemical Grafted Polystyrene and Sulfocationite Membranes.

In the present work, the effect of divinylbenzene (DVB) on the kinetics of post-radiation chemical graft polymerization styrene (St) on polyethylene (PE) film and its structural and morphological features were investigated. It has been found that the dependence of the degree of polystyrene (PS) grafting on the DVB concentration in the solution is extreme. An increase in the rate of graft polymerization at low concentrations of DVB in the solution is associated with a decrease in the mobility of the growing chains of PS. A decrease in the rate of graft polymerization at high concentrations of DVB is associated with a decrease in the rate of diffusion of St and iron(II) ions in the cross-linked network structure of macromolecules of graft PS. A comparative analysis of the IR transmission and multiple attenuated total internal reflection spectra of the films with graft PS shows that graft polymerization of St in the presence of DVB leads to the enrichment of the film surface layers in PS. These results have been confirmed by the data on the distribution of sulfur in these films after sulfonation. The micrographs of the surface of the grafted films show the formation of cross-linked local microphases of PS with fixed interfaces.

Dl-Methionine-Mediated Reversible Deactivation Radical Polymerization of Styrene and Methyl Methacrylate.

Reversible deactivation radical polymerization (RDRP) is a facile and highly efficient technique for the synthesis of well-defined polymer with precise structure. dl-Methionine (Met) as a RDRP control agent is described and assessed for RDRP of styrene (St) and methyl methacrylate (MMA) with AIBN as radical initiator at 75°C, which enables excellent control of this polymerization. The addition of dl-Methionine significantly decreased the dispersity (Đ) of the polymers for both monomers and first-order linear kinetic plots of polymethyl methacrylate (PMMA) are observed in DMSO. Considering the heat resistance of dl-Methionine, kinetic studies indicate that polymerization develops at a faster rate at higher reaction temperature (100°C) with the same dl-Methionine content. Well-defined polymethyl methacrylate-block-polystyrene (PMMA-block-PSt) is successfully achieved by the chain extension reaction that demonstrates the high end fidelities of this polymerization approach. The system allows the use of dl-Methionine, a rich source and easily synthesized agent, to mediate RDRP strategy.

Compensatory method for the synthesis of chelating polymeric ligands based on styrene and 5-methyl-5-hexene-2,4-dione as a way to increase the efficiency of macroinitiators of the b-diketonate type

Polymeric chelating ligands based on styrene and unsaturated -diketone 5-methyl-5-hexene-2,4-dione (MHD) were prepared by radical copolymerization initiated by benzoyl peroxide in benzene solution at the volume ratios of monomers styrene:MHD=1:30 and 1:10. In this case, -diketone was added to the system by conventional (simultaneous) and compensatory (equal portions at conversions of 0, 5, and 10%) methods. The resulting products were studied by IR and 1H NMR spectroscopies. It has been shown that macrochelates obtained on the basis of such ligands differ in their structure and as a consequence in their macroinitiating ability in the grafting of vinyl monomers. Polymeric ligands synthesized at the ratio of 1:10, regardless of the preparation method, form mixed-ligand complexes in the subsequent complexation reaction with cobalt(II) acetate, which exhibit weak activity in styrene grafting and are not effective in the case of methyl methacrylate. The use of a small amount of MHD (1:30) in combination with the compensatory synthesis method leads to the predominant formation of intramolecular complexes of the -diketonate type, which are more active macroinitiators in the graft polymerization of styrene and methyl methacrylate than those obtained by the traditional simultaneous method of adding MHD.

Interactions of alumina and polystyrene nanoparticles with the innate immune system of Galleria mellonella

Nowadays, particularly metallic, and polymeric nanoparticles (NPs) are widely produced and used in many fields. Due to the increase in both their usage and diversity, their release and accumulation in the environment are also accelerating. Therefore, their interactions with cells, especially immune cells, and their health risks are not fully understood. The impacts of metallic alumina (Al) NPs and polystyrene (PS) NPs obtained after the polymerization of carcinogenic styrene on living organisms have not yet been elucidated. Galleria mellonella larvae can biodegrade plastics. While biodegradation and solving the waste problem have attracted much attention, the interactions of this distinctive property of G. mellonella larvae in the immune system and ecosystem are not yet completely understood. Al and PS NPs were applied to G. mellonella separately. Al NPs were purchased and PS NPs were prepared from PS by single-emulsion technique and characterized. Then LC50 values of these NPs on G. mellonella were determined. The interactions of these NPs with encapsulation, melanization, and phenoloxidase activity, which express innate immune responses in G. mellonella larvae, were revealed. NP exposure resulted in suppression of the immune response, probably because it affects the functions of hemocytes such as enzymatic activation, hemocyte division, and populations. In this context, our data suggest that Al and PS NPs induce toxic impacts and negatively alter the physiological status of G. mellonella. It is also shown that G. mellonella has the potential to be an impactful alternative model for biosafety and nanotoxicology studies.

Facile preparation of isocyanate-functionalized poly(styrene-co-maleimide-co-maleic anhydride) particle and its application as a versatile support for nano-sized TiO2 photocatalyst

Polymer-supported catalysts have attracted intensive research attentions due to easy handling, facile separation and outstanding recycling performance. Herein, a simple, efficient and universal strategy was developed to fabricate isocyanate-functionalized polymer microspheres bearing highly reactive surface isocyanate groups, which could serve as a versatile support for the immobilization of photocatalyst. Firstly, self-stabilized precipitation polymerization of maleimide, maleic anhydride and styrene was performed in the presence of divinyl benzene (crosslinker) to prepare imide-functionalized poly(styrene-co-maleimide-co-maleic anhydride) (PSMM) microspheres. By simply adjusting the solvent composition and monomer feed ratio, monodisperse PSMM particles with diameter in the range of 0.52–1.01 μm were successfully obtained, which were further modified with hexamethylene diisocyanate (HDI). As a proof-of-concept, TiO2 nanoparticles were readily and covalently bound to the surface of HDI-functionalized PSMM (PSMM-HDI) particles through reaction with isocyanate groups, leading to the formation of PSMM-HDI supported TiO2 (PSMM-HDI@TiO2). Furthermore, anhydride groups on the surface of PSMM was hydrolyzed to endow PSMM-HDI@TiO2 with better dispersibility and adsorption performance. The degradation of methylene blue under UV-light was performed to evaluate the photocatalytic performance of the resultant PSMM-HDI@TiO2. Compared with pristine TiO2, the PSMM-HDI@TiO2 exhibited not only higher degradation efficiency, but also facile separation and better reusability.

Synthesis of Ion-Exchange Catalysts by Introduction of Fluorinated Ponytails into Novel Mesoporous Polymers.

A novel synthetic procedure for the functionalisation of styrenic cross-linked polymers with perfluorinated acyl chains has been reported. The effective significant grafting of the fluorinated moieties is supported by {1H}-13C and {19F}-13C NMR characterisations. This kind of polymer appears promising as catalytic support for a variety of reactions requiring a highly lipophilic catalyst. Indeed, the improved lipophilicity of the materials resulted in enhanced catalytic properties of the corresponding sulfonic materials in the reaction of esterification of a solution in a vegetable oil of stearic acid with methanol.

Engineering properties of SBS and crumb-rubber modified bitumen – a design of experiment approach

Purpose Cracking, deformation and rutting are the most prevalent types of pavement distress, and these deformations and flow characteristics greatly distress the pavement features while also limiting its use. In India, on the other hand, more than 300 million scrap tyres are generated each year, and their disposal has become a severe environmental issue. Furthermore, the scrap generated by the used tyre must be disposed of properly. Hence, this study presents the experimental investigations of bitumen incorporating with Crumb rubber as main additive along with SBS polymer, to enhance the engineering property. Design/methodology/approach Crumb rubber (CR) was used as an additive along with styrene–butadiene–styrene (SBS) polymer to enrich the engineering qualities of the bitumen to reduce the disposal problem of scrap tyres and reduce the risk of environmental pollution. Because SBS polymer is expensive, response surface methodology modelling's central composite design (CCD) was used to optimise the number of tests. CCD modelling's input factors (process variables) were the inclusion rates of SBS and CR, which ranged from 2% to 5% and 4% to 10%, respectively, by total weight. Furthermore, the influence of SBS polymer and CR on the characteristics of modified bitumen was prioritised. Findings The addition of SBS and CR enhanced the bitumen's penetration resistance at service temperatures. Furthermore, increasing the SBS and CR concentration affected the flow characteristics of the modified bitumen and enhanced its viscosity. The addition of SBS and CR as bitumen modifiers increased penetration resistance by 24.06%. The Dynamic Shear Rheometer test demonstrated that the complex modulus of virgin bitumen increases with increasing SBS and CR content, which is consistent with the shifting softening point trend. The dosing rate of up to 3.5% SBS and 11% CR considerably contributed to the creation of polymer link networks, which increased the complex modulus of the bitumen by 16.5%. The CCD model's analysis of variance and Pareto bar chart demonstrated that the dose of CR is significant in improving the engineering features of the virgin bitumen rather than the SBS. Originality/value The utilisation of CR as a bitumen modifier may solve the problem of waste tyre disposal while also lowering the risk of environmental damage. Furthermore, because the presence of CR increased the engineering properties, particularly the complex modulus of virgin bitumen, the use of CR in combination with SBS polymer can be an efficient and cost-effective strategy to improving bitumen qualities.

Polymerization of styrene in lyotropic liquid crystal lamellar (Lα) phase via gamma and electron beam irradiation

Radiation induced polymerization in forming polystyrene of lyotropic liquid crystal lamellar (Lα) phase based on an Aerosol® OT (AOT)/sodium dodecyl sulfate (SDS), styrene, and deionized water ternary system has been investigated. Formed Lα phase, affirmed via polarized light microscope (PLM) through the visualization of a multi-layered structure with Maltese cross pattern, were irradiated in inducing polymerization at three different dose rates of gamma (γ) and an electron beam (EB) radiation. The phase behavior of pure Lα phase via rheology measurement deduced that the gamma irradiation dose of 7.2 kGy at a rate of 3.78 kGy/h had the most prominent effect on the elasticity and viscosity properties with respect to the sample storage modulus (G') and loss modulus (G") value. Whereby it was illustrated via scanning electron microscopy (SEM) micrographs that the phase structure copied upon polymerization had a layered phase morphology, templated as the Lα phase layered structure. The final yielded product was affirmed as polystyrene based on molecular conformation via Fourier transform infrared spectroscopy (FTIR) characterization. This study elucidates that styrene in a ternary system of Lα phase liquid crystal can undergo polymerization using gamma and electron beam radiation to produce polystyrene-template Lα phase structure that can be utilized as a layered structure with advantageous properties.

Enhancing silica dispersion and interfacial interaction in styrene butadiene/silica rubber composites by using epoxidized styrene butadiene rubber as interfacial compatibilizer

AbstractIt is usually desired but often challenging to improve the wet traction, and reduce the abrasion and rolling resistance simultaneously in tread rubber, which is referred to as “magic triangle” in tire industry. To fulfill this goal, the filler dispersion and interfacial interaction required to be improved, as they are two essential factors to concurrently govern the ultimate properties of rubber composites. Herein, we synthesized the epoxidized solution polymerized styrene butadiene rubber (ESSBR) with different epoxy level, and used them as interfacial compatibilizer to promote the silica dispersion and silica/rubber interfacial interaction. The epoxy of ESSBR would react with silanol on silica surface and co‐crosslink with SSBR simultaneously, therefore build a strong bridge between rubber matrix and filler. By incorporation of 20 phr of ESSBR‐15% (15% of double bonds on main chain was epoxidized), the wet grip was improved by 40%, and DIN abrasion and rolling resistance were reduced by 38% and 21%, respectively with hardly sacrifice the mechanical properties. We envisage that this study provides an approach for the fabrication of rubber composites with improved silica dispersion and strengthened interfacial interaction.

Emulsion polymerized styrene acrylic/nanocellulose composite coating to improve the strength and hydrophobicity of kraft paper

Improving the mechanical and water repelling property of kraft paper will extend its use for packaging application. In this work, we developed a cellulose nanofiber (CNF)-based colloidal polymer nanocomposite that was used as coating for improving those properties of kraft paper. In this case, the polymer latex was obtained by the mini-emulsion copolymerization of styrene (St), 2-ethyl hexyl acrylate (EHA) initiated by ammonium persulfate. The CNFs were incorporated into the styrene-acrylic copolymer matrix by the in-situ polymerization and ex-situ mixing process keeping the CNF concentration up to 1.0 wt%. All the latexes showed particle size below 100 nm and excellent colloidal stability (Zeta potential > −32 mV) for several months. The nanocomposite films showed improved mechanical properties (tensile strength upto 7.8 MPa, elongation upto 1096 %) than the pristine copolymer. The in-situ prepared nanocomposite at 1.0 wt% CNF showed the highest storage modulus. The latex-coated kraft paper showed improved tensile index (31.0–45.1 Nm/g) compared to the uncoated paper (20.3 Nm/g) and also high hydrophobicity (water contact angle ∼120°) for the ex-situ prepared nanocomposites. The results are quite promising to develop paper-based packaging materials using nanocellulose in combination with synthetic polymers.

Synthesis and electrical characterization of poly[(linoleic acid)‐g‐(styrene)‐g‐(ε‐caprolactone)] graft copolymers as gate insulator for OFET devices

AbstractThis study reports a one‐pot process used to synthesize poly[(linoleic acid)‐g‐(styrene)‐g‐(ε‐caprolactone)] (PLina‐g‐PSt‐g‐PCL) graft copolymers. The process was carried out by combining the atom transfer radical polymerization of styrene with the ring‐opening polymerization of ε‐caprolactone from polymeric linoleic acid having hydroxyl groups and bromine groups in the main chain. The characterization of the products was achieved using proton nuclear magnetic resonance, size‐exclusion chromatography, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry techniques. Subsequently, an organic field effect transistor (OFET) was fabricated with PLina‐g‐PSt‐g‐PCL graft copolymers as the insulator layer. Poly(3‐hexylthiophene) (P3HT) was used as the active layer and prepatterned OFET substrates were used as the welding/discharge electrodes. To measure capacitance, an ITO/P3HT/PLina‐g‐PSt‐g‐PCL/Al structure was prepared using the same method. To obtain output and transfer current–voltage characteristics, electrical characterizations of OFET devices were conducted in darkness and an atmosphere of air. From a capacitance–frequency plot, the key characteristics of the devices, including the threshold voltage (VTh), field effect mobility, and current on/off ratio (Ion/off), were derived. The fundamental electrical parameters in the fabricated OFET devices based on styrene concentration were thoroughly examined. It was observed that the produced PLina‐g‐PSt‐g‐PCL OFETs display positive device characteristics such as low VTh, exceptional mobility, and Ion/off values. © 2023 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

Experimentation and Numerical Modeling of Peak Temperature in the Weld Joint during Rotary Friction Welding of Dissimilar Plastic Rods.

Rotary friction welding (RFW) could result in lower welding temperature, energy consumption, or environmental effects as compared with fusion welding processes. RFW is a green manufacturing technology with little environmental pollution in the field of joining methods. Thus, RFW is widely employed to manufacture green products. In general, the welding quality of welded parts, such as tensile strength, bending strength, and surface hardness is affected by the peak temperature in the weld joint during the RFW of dissimilar plastic rods. However, hitherto little is known about the domain knowledge of RFW of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) polymer rods. To prevent random efforts and energy consumption, a green method to predict the peak temperature in the weld joint of dissimilar RFW of ABS and PC rods was proposed. The main objective of this work is to investigate the peak temperature in the weld joint during the RFW using COMSOL multiphysics software for establishing an empirical technical database of RFW of dissimilar polymer rods under different rotational speeds. The main findings include that the peak temperature affecting the mechanical properties of RFW of PC and ABS can be determined by the simulation model proposed in this work. The average error of predicting the peak temperature using COMSOL software for five different rotational speeds is about 15 °C. The mesh element count of 875,688 is the optimal number of meshes for predicting peak temperature in the weld joint. The bending strength of the welded part (y) using peak welding temperature (x) can be predicted by the equation of y = -0.019 x2 + 5.081x - 200.75 with a correlation coefficient of 0.8857. The average shore A surface hardness, impact energy, and bending strength of the welded parts were found to be increased with increasing the rotational speed of RFW.

Cellulose nanocrystal-assisted processing of nanocomposite filaments for fused filament fabrication

This study introduces a scalable processing technique where cellulose nanocrystals (CNCs) are used to integrate pristine multi-walled carbon nanotubes (CNTs) into acrylonitrile butadiene styrene (ABS) polymer without functionalization, solvents, or surfactants. A synergy between the nanomaterials and printed road angle was discovered, with angle ply orientation optimizing mechanical properties and longitudinal orientation improving thermal conductivity. Mechanical properties improved up to 81% in tensile strength and 95% in elastic modulus, while a 102% increase in interlaminar strength was exhibited. The thermal conductivity trend showed an anisotropy between radial and axial directions, where one could be increased while the other was diminished, with as much as 807% increase in the transverse sample. By optimizing print orientation and nanoparticle content, tailored material properties are achievable.

Thermal and tensile properties of 3D printed ABS-glass fibre, ABS-glass fibre-carbon fibre hybrid composites made by novel hybrid manufacturing technique

This study was an attempt to combine fused deposition modelling and hot press moulding technique to fabricate hybrid polymer composites using acrylonitrile butadiene styrene (ABS) polymer, woven glass fibre (GF) and woven carbon fibre (CF). The composite specimens were subjected towere subjected to mechanical and thermal characterization.Tensile strength of GF/ABS and GF/CF/ABS composite were far higher than the virgin ABS. GF/ABS composites displayedimproved thermal resistance by giving a final residue of 42.36%, followed by GF/CF/ABS hybrid composites as per the thermogravimetric analysis. Thermomechanical analysis revealed the coefficient of thermal expansion in the order: ABS > GF/ABS > GF/CF/ABS. The entropy obtained from the DSC curve was of higher value for composites than the ABS. The ABS based composites fabricated from this technique can be applicable to structural parts in the automobiles, aircrafts, shipping vessels, etc.

Effect of UV-C Radiation on 3D Printed ABS-PC Polymers.

During the initial stages of the COVID-19 pandemic, healthcare facilities experienced severe shortages of personal protective equipment (PPE) and other medical supplies. Employing 3D printing to rapidly fabricate functional parts and equipment was one of the emergency solutions used to tackle these shortages. Using ultraviolet light in the UV-C band (wavelengths of 200 nm to 280 nm) might prove useful in sterilizing 3D printed parts, enabling their reusability. Most polymers, however, degrade under UV-C radiation, so it becomes necessary to determine what 3D printing materials can withstand the conditions found during medical equipment sterilization with UV-C. This paper analyzes the effect of accelerated aging through prolonged exposure to UV-C on the mechanical properties of parts 3D printed from a polycarbonate and acrylonitrile butadiene styrene polymer (ABS-PC). Samples 3D printed using a material extrusion process (MEX) went through a 24-h UV-C exposure aging cycle and then were tested versus a control group for changes in tensile strength, compressive strength and some selected material creep characteristics. Testing showed minimal mechanical property degradation following the irradiation procedure, with tensile strength being statistically the same for irradiated parts as those in the control group. Irradiated parts showed small losses in stiffness (5.2%) and compressive strength (6.5%). Scanning electron microscopy (SEM) was employed in order to assess if any changes occurred in the material structure.

Evaluation of Bitumen Modification Using a Fast-Reacting SBS Polymer at a Low Modifier Percentage.

The study presented in this paper investigates the application of asphalt bitumen modification using a fast-reacting SBS polymer at a low modifier percentage. The hypothesis is that a fast-reacting styrene-butadiene-styrene (SBS) polymer that composes only 2% to 3% of the weight of the bitumen modification could extend the life of the pavement surfacing and pavement performance at relatively low input costs, increasing the net present value produced by the pavement during its life cycle. To confirm or refute this hypothesis, two types of road bitumens CA 35/50 and 50/70 were modified with low amounts of fast-reacting SBS polymer with the expectation of attaining properties similar to a 10/40-65 modified bitumen. For each type of unmodified bitumen, bitumen modification and comparative 10/40-65 modified bitumen, the following tests were conducted: needle penetration, softening point-ring and ball test method, and ductility test. The second part of the article focuses on a comparison of asphalt mixtures with different compositions of coarse-grain curves. For each mixture, complex modulus with varying temperatures and fatigue resistances are represented by the Wöhler diagram and compared. Based on in labo testing, the impact of the modification on pavement performance is evaluated. Life cycle changes for each type of modified and unmodified mixtures are quantified as road user costs, and attained benefits are compared with increased construction costs.