Polymerization Of Styrene Research Articles

Study of the Recoil Impulse of Gaseous Products of IR Laser Ablation of Polystyrene and Polystyrene/Carbon Nanotubes Composite Obtained by Radiation Polymerization of Styrene

Study of the Recoil Impulse of Gaseous Products of IR Laser Ablation of Polystyrene and Polystyrene/Carbon Nanotubes Composite Obtained by Radiation Polymerization of Styrene

Insight into thermo-mechanical enhancement of polymer nanocomposites coated microsand proppants for hydraulic fracturing

The present work reports the fabrication of ultra-high strength microsand proppants (100 mesh) through a polymer nanocomposite dual coating approach and gives insight into their thermo-mechanical reinforcements. The dual coating can be of 3D-cross-linked poly(styrene-methyl methacrylate)/divinylbenzene) (PS-PMMA/DVB) porous network and thermally cross-linked epoxy with graphene nanosheets. The inner layer of PS-PMMA/DVB was prepared using bulk polymerization of styrene (S) and methyl methacrylate (MMA) at 70 °C with a free radical initiator azobisisobutyronitrile (AIBN). The outer layer was prepared by mixing epoxy resin, a cross-linker, and commercial graphene (CG) followed by thermally curing the mixture. The dual-coated microsand proppants exhibited enhanced mechanical characteristics of elastic modulus (E) as high as 7.78 GPa, hardness (H) of 0.35 GPa, and fracture toughness (Kc) of 3.19 MPa m1/2 along with largely improved thermal properties. Moreover, the dual-coated microsand proppants exhibit a very high-stress resistance up to 14000 psi, and to the best of our knowledge, this is the highest stress resistance value attained for the modified sand-based proppants so far.

Influence of Gamma-Irradiation on Mechanical and Structural Characteristics of ABS Plastic Based on High-Molecular-Weight Technical Acrylonitrile–Butadiene–Styrene Polymer

Influence of Gamma-Irradiation on Mechanical and Structural Characteristics of ABS Plastic Based on High-Molecular-Weight Technical Acrylonitrile–Butadiene–Styrene Polymer

Research on Dynamic Mechanical Properties of Different Silane Coupling Agent In-situ Modified SSBR/Silica Composites

Hydroxyl density of silica surface will reduce and the compatibility of silica with rubber matrix will be improved through the modification of silica by silane coupling agent (SCAs). The silica-silica and silica-rubber interaction of silica filled solution polymerized styrene butadiene rubber (SSBR) in-situ modified by silane coupling agent TESPT and Si747 are studied by Dynamic Mechanical Analyzer (DMA). The effect of different types and loading amounts of SCAs on the dynamic mechanical properties of silica filled SSBR is investigated. The results show that the novel silane coupling agent Si747 has a more apparent effect on lessening the silica network than that of silane coupling agent TESPT, Hysteresis factor (tanδ) measured by DMA reduces, and the heat-built improves. It could also be found that Si747 modified composites have the lowest apparent activation energy, which is used to characterize the filler-rubber interaction, indicating the lowest temperature dependence.

Study on Performance and Mechanism of SBR and Bio-Oil Recycled SBS Modified Asphalt

With the continuous development of road construction and maintenance, SBS(Styrene-butadiene-styrene)-modified asphalt is widely used. However, there is no mature method for restoring aged SBS-modified asphalt. This study proposes the use of SBR(polymerized styrene butadiene rubber) and bio-oil for the restoration of aged SBS. In this study, five kinds of recycled asphalt were prepared by adding 5% bio-oil, 10% bio-oil, 6% SBR, 6% SBR + 5% bio-oil, and 6% SBR + 10% bio-oil to long-term aged SBS-modified asphalt. Softening point, penetration, and rotational viscosity experiments were tested to evaluate the conventional properties. Rheological tests revealed the performance of asphalt. Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM) tests were tested to demonstrate the microscopic characteristics of asphalt. Conventional tests investigated that aged asphalt viscosity will increase. Bio-oil could well recycle the asphalt viscosity. SBR could also soften aged asphalt, but its modification effect is limited compared with bio-oil. Rheological tests presented that the SBR and bio-oil have little impact on the temperature sensitivity of SBS-modified asphalt. SBR and bio-oil could decrease the asphalt stiffness. However, SBR and bio-oil could ameliorate the anti-cracking behavior of aged asphalt. The microscopic tests exhibited that SBR and bio-oil could decrease the asphaltene and colloid. Meanwhile, bio-oil could supplement alcohols and ethers at wave number 1000 cm-1-1270 cm-1. Alcohols and ethers are hard to oxidize, something which has a beneficial role in the anti-aged of recycled asphalt.

Dispersion Mechanism of Styrene–Butadiene Rubber Powder Modified by Itaconic Acid and Its Toughening Effect on Oil Well Cement

Styrene-butadiene rubber (SBR) has been extensively applied to enhance the toughness of hardened cement. The instability of existing liquid latex leads to difficulties in storage and transportation, and even performance regression. Thus, the well-dispersed carboxylated butylbenzene (SISBR) latex powders were fabricated through the seed emulsion polymerization of liquid polybutadiene (LPB), styrene (St), itaconic acid (IA), and sodium p-styrenesulfonate (SSS) to overcome the difficulties. The dispersion performance of latex powders with various IA amounts was quantitatively evaluated using particle size distribution, zeta potential, and ultraviolet-visible spectrophotometry. Results showed that the carboxylic ionic (COO-) from IA enhanced the dispersing abilities of SISBR latex powders, which ensured the uniform distribution in water. Based on this, the influence of latex powder on cement was assessed mainly by fluidity, isothermal heat flow calorimetry, X-ray diffraction (XRD), and triaxial mechanical testing. Results showed the fluidity and dispersion performance of cement were improved with more IA in latex, while the hydration of cement was retarded due to excessive adsorption of carboxyl (-COOH) groups in IA. Triaxial mechanical testing showed that cement with SISBR-3 (latex containing 3% IA) exhibited the minimal elastic modulus of 3.16 GPa, which was lower than that of plain cement (8.34 GPa).

Digital image correlation to reveal mechanical anisotropy in 3D printing of polymers

ABSTRACT In this work, we propose to study the mechanical anisotropy inferred in printed acrylonitrile butadiene styrene polymer using fused deposition modelling by combining digital image correlation and mechanical testing. Tensile specimens are printed utilising different design orientations and raster angles. Monitoring of deformed samples is performed and strain fields are derived for each configuration. The results show that a heterogeneous strain field develops leading to a more significant strain localisation for samples printed with the dimensions mainly aligned with the building direction. An optimal printing angle allowing the filament to be crossed at −45°/+45° shows the best behaviour even with a larger elongation at fracture compared to the raw material. The digital image correlation based on optical imaging indicates, however, scaling limits to reveal the effect of the filament orientation on strain localisation.

Thermal and Thermal-Oxidative Molecular Degradation of Polystyrene and Acrylonitrile Butadiene Styrene during 3D Printing Starting from Filaments and Pellets

An important polymer processing technique is additive manufacturing (AM), which enables shape-free design of complex final parts with limited waste during the development change, at least if the impact of molecular degradation reactions is minimized. In the present work, polystyrene (PS) and acrylonitrile butadiene styrene (ABS) polymer have been processed via: (i) fused filament fabrication (FFF), separately accounting for the prior single screw extrusion (SSE) filament production; and (ii) pellet-based additive manufacturing (PBAM), which are two important AM techniques. The influence of printing temperature, layer thickness, printing velocity, and printing technique on the degradation of both polymeric materials is studied by means of thermogravimetric analysis (TGA), size exclusion chromatography (SEC), small amplitude oscillatory shearing tests (SAOS), Fourier-transform infrared spectroscopy (FTIR), and yellowness index (YI) measurements. For ABS, SSE-FF leads to more fission (higher mechanical loading) whereas PBAM results in more cross-linking (more thermal loading). For PS, fission is always dominant and this more evident under FFF conditions. ABS also exhibits yellowing upon processing, indicating thermo-oxidative degradation although below the FTIR sensitivity limit. The selected PBAM conditions with PS are already delivering printed specimens with good mechanical properties and lower degradation. For ABS, a further PBAM optimization is still desired compared to the FFF countercase, taking into account layer-by-layer adhesion.

Turbo-Grignard Reagent Mediated Polymerization of Styrene under Mild Conditions Capable of Low Đ and Reactive Hydrogen Compatibility

Turbo-Grignard Reagent Mediated Polymerization of Styrene under Mild Conditions Capable of Low <i>Đ</i> and Reactive Hydrogen Compatibility

High-throughput generation of uniform droplets from parallel microchannel droplet generators and the preparation of polystyrene microsphere material

To prepare uniform polystyrene particles with ten microns of diameter, a parallel scaling-up strategy for the capillary-assembled stepwise microchannel was developed, which created uniform droplets with high-throughput and formed a large amount of emulsion templates for the polymerization of styrene and cross-linker. The microchannel droplet generator was robust for the flow rate deviation of the continuous phase in the jetting flow, and droplet generation frequency up to 2.8 × 104 Hz was achieved with only four parallel droplet generators, which were much more efficient than the parallelly scaled microfluidic devices working in dripping flow. 32–52 μm average diameter droplets with 4.5%–8.4% diameter variation coefficients were successfully prepared from the microchannel device fabricated by low-cost 3D-print method, and the droplets were subsequently turned to solid particles via a two-step polymerization in the platform. The polystyrene particles were further reduced to 16.9–23.5 μm with 5.0%–8.6% diameter variation coefficients due to the accompanying emulsion polymerization, and the working capacity of the platform reached hundred milligrams of particles per hour.

Evaluation of Acrylonitrile Butadiene Styrene (ABS) polymer reinforced with Bi and TiO2 nanopowders for gamma and neutron shielding

Abstract 3D printer technology has recently become easily reachable technology and are used to create simple or complex structures with high-quality. Its superior advantages could also be useful on the production of effective radiation shielding materials. On this purpose, the presented work studies the gamma and neutron shielding effectiveness of Acrylonitrile Butadiene Styrene (ABS) sample, a 3D printing material, reinforced with Bi and TiO2 nanopowders at various gamma and neutron energies. The gamma shielding properties were evaluated using experimental (High Purity Germanium detector system), theoretical (WinXCOM computer program) and simulation techniques (GEANT4 and FLUKA) in a wide gamma energy region ranging from 59.5 to 1332.5 keV. The investigation on neutron attenuation capabilities of the printed composites were performed with help of simulation and theoretical approaches for various sample thickness and neutron energies. The half value layer of ABS-Bi10 sample is found to be as 4.9565 cm, which is much smaller than some commercial polymers: polyvinylidenechloride, polyamide, polyacrylonitrile, polyphenylenesulfide, and unsaturated polyester. With the usage of 3D printing technology, significant enhancements in neutron and gamma shielding were reported.

Comprehensive Performance Evaluation of Asphalt Mortar Based on Multi-Index Weighted Decision Model

Abstract Aggregate is the key factor to ensure the performance of asphalt mixture. In order to analyze the impact of limestone, basalt, diabase, and steel slag on the road performance of asphalt mortar, with the ratio of mineral powder to asphalt in asphalt mortar being the same as the asphalt concrete (AC)-13 Styrene Butadiene Styrene (SBS) polymer–modified asphalt mixture, the four types of asphalt mortar specimens with different aggregates were designed and molded. The high-temperature performance, low-temperature performance, water stability, and fatigue performance tests were carried out to obtain the performance parameters of asphalt mortar. The multi-index weighted decision model was used to quantitatively evaluate the influence of the four types of aggregate on the comprehensive pavement performance of asphalt mortar. Results indicated that basalt asphalt mortar had the best high-temperature performance, steel slag asphalt mortar had the best low-temperature crack resistance and fatigue performance, and limestone asphalt mortar had the best water stability. Moreover, basalt asphalt mortar had the best comprehensive pavement performance. Finally, the optimized basalt asphalt mortar and steel slag asphalt mortar were applied to the engineering field, and both met the requirement.

Designing and Fabrication of Polymer Based Injection Molding Die Using 3D Printing

Abstract: The purpose of this study is to design and fabricate the injection molding die with help of designing software and fabricating it with the help fused deposition modelling based 3d printing machine. Emphasis on designing of the injection die is given on the size and shape of the specimen to be molded and on giving a proper shrinkage allowance to the injection molding die for getting the desired dimension of the specimen molded in the injection molding die. Draft analysis of the injection die was carried out on the designed injection die for easy separation of the specimen and the polymer based injection die. Acrylonitrile butadiene styrene (ABS) polymer based filament is used in the fabrication of the injection die using Fused Deposition Modelling (FDM) working principle based 3d printer. The nozzle temperature requirement of the ABS based filament is 250 degree Celsius and the bed temperature required for printing ABS is around 90 degree Celsius which is recommended by the company which manufactures the used ABS based filament. The time consumption in manufacturing of the die is recorded and then compared to the time taken in manufacturing metal based die. This study concludes the optimum value of shrinkage allowance and proper draft analysis and time taken in the manufacturing of the die in the recommended parameters for the printing of the die.

Correntropy based Elman neural network for dynamic data reconciliation with gross errors

BackgroundMeasurement information in chemical processes is inevitably corrupted. Dynamic data reconciliation is an effective method to improve the quality of noisy measurement data. However, except for random errors, possibly gross errors are usually present in the measurement data, which may result in the deterioration and even failure of process control and optimization. MethodsConsidering the problem that dynamic mathematical models of some complex and unknown processes are difficult or impossible to be obtained, this paper combines the neural network with the correntropy estimator to design a robust dynamic data reconciliation scheme for unknown dynamic systems corrupted by both random and gross errors. The correntropy estimator is taken as a new objective function to form the robust Elman neural network (ENN). Furthermore, the processes of weight learning and parameter optimization are designed and described in detail based on the correntropy estimator. FindingsThe performance of the proposed robust ENN is demonstrated through its application on the free radical polymerization of styrene. With mixed gross errors, the mean squared error decreases more than 14-fold and falls below one ten-thousandth. Comparisons with other approaches show that the proposed method can effectively suppress the influence of gross errors and greatly improve the dynamic behavior of systems.

Dual-Dynamic Chemistries-Based Fast-Reprocessing and High-Performance Covalent Adaptable Networks.

Covalent adaptable networks (CANs) possess multiple functions including reprocessing (or recyclability), self-healing, welding, shape shifting, 3D printing, etc., due to the network rearrangement from dynamic bonds, and favorable performance from their cross-linked feature, and they are supposed to be as sustainable alternatives to thermosets. However, the thermal and mechanical properties, and stability of CANs are often sacrificed for rapid network rearrangement. In this paper, fast-reprocessing CANs with high performance are facilely constructed by in situ polymerization and dynamic cross-linking of styrene (St), maleic anhydride (MA), and acetal diol (BHAD). The rigid and hydrophobic polymer backbone endow the materials with high glass transition temperatures, mechanical performance, and water resistance. Besides, carboxylic group-catalyzed dual dynamic ester and acetal-based networks exhibit faster stress relaxation and realize extrusion reprocessing. This work provides an ingenious and simple strategy of construction of CANs combining rapid network rearrangement and excellent comprehensive performance, which is beneficial for the application of CANs.

Synthesis of Well‐Defined Block Copolymers of Hyperbranched Polyamide and Polystyrene and Their Micelle‐to‐Vesicle Transformation in Organic Solvents

AbstractWell‐defined block copolymers consisting of hyperbranched polyamide (HBPA) and polystyrene (PSt) are synthesized, and their self‐assembled structures in solutions are investigated. Atom transfer radical polymerization (ATRP) of styrene initiated from an HBPA macroinitiator, prepared by the chain‐growth condensation polymerization of an AB2 monomer, followed by introduction of an ATRP initiator unit at the focal point, gives the desired block copolymers, PSt‐b‐HBPAs, with well‐defined molecular weight and narrow molecular weight distribution. The block copolymer (PSt/HBPA = 84/16) undergoes self‐assembly in toluene to form spherical micelles (≈10–20 nm), but upon addition of methanol to the toluene solution (toluene/methanol = 0.97/0.03), the morphology changes to vesicles. Further addition of methanol (toluene/methanol = 0.90/0.10) leads to an increase in vesicle size (200–300 nm) and the morphology further transforms from vesicles to large aggregates (&gt;100 nm) at toluene/methanol = 0.80/0.20. In the case of PSt‐b‐HBPA with shorter PSt segments (PSt/HBPA = 76/24 and 60/40), spherical micelles are formed in toluene, but the micelle morphology remains unchanged when 10 wt% methanol is added, though large aggregates (&gt;100 nm) are still formed in toluene/methanol = 0.80/0.20. Interestingly, the morphological transformations of linear/hyperbranched block copolymers are different from those of their double linear block copolymer counterparts.

Multi-objective optimization and prediction of surface roughness and printing time in FFF printed ABS polymer

In this study, fused filament fabrication (FFF) printing parameters were optimized to improve the surface quality and reduce the printing time of Acrylonitrile Butadiene Styrene (ABS) polymer using the Analysis of Variance (ANOVA), it is a statistical analysis tool. A multi-objective optimization technique was employed to predict the optimum process parameter values using particle swarm optimization (PSO) and response surface methodology (RSM) techniques. Printing time and surface roughness were analyzed as a function of layer thickness, printing speed and nozzle temperature. A central composite design was preferred by employing the RSM method, and experiments were carried out as per the design of experiments (DoE). To understand the relationship between the identified input parameters and the output responses, several mathematical models were developed. After validating the accuracy of the developed regression model, these models were then coupled with PSO and RSM to predict the optimum parameter values. Moreover, the weighted aggregated sum product assessment (WASPAS) ranking method was employed to compare the RSM and PSO to identify the best optimization technique. WASPAS ranking method shows PSO has finer optimal values [printing speed of 125.6 mm/sec, nozzle temperature of 221 °C and layer thickness of 0.29 mm] than the RSM method. The optimum values were compared with the experimental results. Predicted parameter values through the PSO method showed high surface quality for the type of the surfaces, i.e., the surface roughness value of flat upper and down surfaces is approximately 3.92 µm, and this value for the other surfaces is lower, which is approximately 1.78 µm, at a minimum printing time of 24 min.

Influence of Carbon Dioxide on the Glass Transition of Styrenic and Vinyl Pyridine Polymers: Comparison of Calorimetric, Creep, and Rheological Experiments

The glass transition of amorphous polymers determines the mobility of polymer chains and the time scale of relaxation processes. The glass transition temperature is reduced by the presence of low molecular weight molecules, e.g., dissolved gases or organic solvents. The quantitative knowledge of reduction of the glass transition temperature caused by the addition of carbon dioxide in a polymer melt is highly relevant for foam extrusion. However, measurement of the reduction of glass transition temperature caused by gas loading has to be performed under elevated pressure which implies high experimental efforts. In this work, we discuss and compare three methods for determination of the influence of carbon dioxide on thermal properties of amorphous polymers, i.e., calorimetric measurements, creep tests, and rheological experiments. The advantages and disadvantages of these methods are elucidated. Furthermore, the influence of molecular structure of the styrenic and vinylpyridine polymers on the glass transition temperature is discussed. Polystyrene generally shows the highest reduction of glass transition temperature. Poly(2-vinylpyridine) and poly(4-vinylpyridine) show a slightly less pronounced behaviour in comparison to polystyrene because of the lower polarity of polystyrene. Poly(α-methyl styrene) is associated with a different dependence of glass transition temperature on gas loading in calorimetric and rheological experiments.

Graphene's effect on the mechanism of radical polymerization with in situ graphene composites

Polymerizing a monomer in the presence of graphene/graphite is a common approach to making composites. However, the role played by the graphitic carbon in the polymerization is often poorly understood or neglected. Specifically, the polymer formed at the interface between the graphite and filler is expected to be most affected by the presence of the filler and can have an outsized effect on the composite properties. Herein we study the impact of pristine graphene on the polymerization of styrene during the synthesis of styrene/graphene nanocomposites. Although there is reason to expect that pristine graphene will interact with radicals, the difficulty of suspending graphene in solution has meant that experimental investigations have been limited to graphene nanoplatelets produced from microcrystalline graphite. However, microcrystalline graphite is fundamentally different than flake graphite, possessing more defects and sheets of limited lateral dimension. We overcome this challenge and study graphene obtained from natural flake graphite using interfacial exfoliation and graphene trapping. We find that graphene plays an active role in radical polymerization, acting as a chain transfer agent. At high graphite/graphene loading, it reversibly couples growing chains, lowering the value of the dispersity (Ð) relative to controls without graphene by nearly an order of magnitude.

Initiating and Cross-Linking Properties of Urea-Formaldehyde Oligomers with Peroxide Groups

The initiating properties of urea-formaldehyde oligomers with peroxide groups have been studied. For comparison, the initiating activity has been examined for the polymerization of styrene by the peroxide oligomer based on the epoxy oligomer Epidian-5 and tert-butyl hydroperoxide. The cross-linking properties of the urea-formaldehyde oligomers with peroxide groups have been investigated using unsaturated oligoesters as a model. The chemistry of the formation of the substances with a cross-linked structure has been studied using IR spectroscopy.