Polystyrene-based Composites Research Articles

Constructing highly thermally conductive polystyrene-based composites by introducing multi-walled carbon nanotubes into melamine foam-supported boron nitride network

High-density 3D thermally conductive nanofiller network plays a vital role in the fabrication of polymer-based composites with high thermal conductivity (TC) for thermal management systems. In this work, highly thermally conductive polystyrene (PS)-based composites were prepared by introducing boron nitride nanosheets-coated melamine foam (MF@BNNSs) and carboxylated multi-walled carbon nanotubes (MWCNT–COOH). In this unique structure, MF@BNNSs can provide a 3D thermally conductive network, while MWCNT–COOH is embedded into the MF@BNNSs skeleton to improve the network-density. Specifically, the TC of PS/MWCNT/MF@BNNSs composite with 0.6 wt% MWCNT–COOH loading reaches 5.33 W /m· K, about 4.4-fold as high as that of the PS/MF@BNNSs. Moreover, the PS/MWCNT/MF@BNNSs composite exhibits effective heat dissipation capacity after assembling the power LED chip. Due to the isolation effect of MF@BNNSs skeleton, the PS/MWCNT/MF@BNNSs maintain electrical insulation properties. Consequently, the design of the thermal conductive network based on MF@BNNSs and MWCNT–COOH offered a substantial potential avenue for the preparation of polymer-based composites with high TC and insulating properties.

Hybrid Polymer Composites Based on Polystyrene (PS) Used in the Melted and Extruded Manufacturing Technology.

As part of the work, innovative hybrid polymer composites dedicated to rapid prototyping, especially for 3D printing with the melted and extruded manufacturing (MEM) technique, were developed. For this purpose, the influence of modified fillers, such as alumina-modified silica, bentonite modified with quaternary ammonium salt, and lignin/silicon dioxide hybrid filler, on the functional properties of polystyrene-based composites was investigated. The introduced additives were selected to improve the processing properties of polystyrene (PS), in particular its thermal stability, while maintaining good mechanical properties. In the first part of the work, using the proprietary technological line, filaments from unfilled PS and its composites were obtained, which contain modified fillers in the amount of 1.5% to 3.0% by weight. Samples for testing functional properties were obtained by 3D printing in MEM technology and injection technique. The rheological properties-mass melt flow rate (MFR), viscosity, and mechanical properties-are presented in the further part of the work. The size and the respective dispersion in the polystyrene polymer matrix of the fillers used were determined by scanning electron microscopy with energy dispersion spectroscopy (SEM/EDS). The correct dispersion of additives in PS was also confirmed by wide-angle X-ray analysis (WAXS). A significant improvement in the thermal stability of the obtained composites after the introduction of fillers into the polymer matrix was confirmed on the basis of thermogravimetric analysis (TGA). The remaining tests of physicochemical properties, differential scanning calorimetry (DSC), and infrared spectroscopy with Fourier transform (FT-IR) allowed us to state no significant changes in relation to polystyrene. The obtained test results allowed us to conclude that the amount and type of fillers used in the PS polymer matrix significantly affect the performance properties of the tested hybrid composites. The composites obtained as part of the work can be successfully used in rapid prototyping technologies, especially for the production of details originally designed from PS, which are required to have higher thermal stability than is guaranteed only by the polymer matrix.

Correction to: Graphene oxide dispersion state in polystyrene-based composites below percolation threshold via linear melt rheology

Correction to: Graphene oxide dispersion state in polystyrene-based composites below percolation threshold via linear melt rheology

Achieving Superior Energy Storage Properties of All-Organic Dielectric Polystyrene-Based Composites by Blending Rod–Coil Block Copolymers

With the excessive consumption of natural resources and the miniaturization trends of advanced electronic products and equipment, there is an urgent need to improve the energy density and efficiency of polymeric dielectrics. In this paper, we explore the effect of rod–coil block copolymer polystyrene-b-poly[bis(4-cyanophenyl) 2-vinylterephthalate] (denoted as PS-b-PBCN) on the dielectric behavior and energy storage properties of PS-based blend films. The dipolar glass rigid polymer PBCN can have a columnar nematic phase, a high glass-transition temperature of 156 °C, a high relative permittivity (εr) of 14, and a low band gap of ≈3.44 eV; however, it has poor film-forming properties. Linear dielectric PS possesses low cost, and good film-forming and insulation properties, with a low εr value of 2.5. Two types of PS-b-PBCN block copolymers (PS158-b-PBCN78 and PS158-b-PBCN16), including a coil PS block and an electronically polarized rod PBCN block, are fabricated via reversible addition–fragmentation chain transfer polymerization polymerization. The PBCN/PS- and PS-b-PBCN/PS-blended films are synthesized by solution casting. The experimental results indicate that the εr and breakdown strength of the blend films improve with an increasing mass content of homopolymer PBCN or block copolymer PS-b-PBCN. A maximum εr value of 5.8 at 1 kHz is obtained in the 30 wt % PS158-b-PBCN78/PS blend film owing to the good compatibility and high loading of the polar polymer PBCN. Moreover, a low dielectric loss of 0.018 is found. A discharged energy density of 2.16 J/cm3 with a high efficiency of 90% at 295 MV/m is achieved because PBCN can immobilize free electrons and restrict the long-distance migration of charges. This work provides an idea for the fabrication of all-organic PS-based dielectrics with a high energy storage performance by introducing rod–coil block copolymers.

Effects of graphene oxide and reduced graphene oxide on thermal and mechanical properties of expanded polystyrene-based composites

Effects of graphene oxide and reduced graphene oxide on thermal and mechanical properties of expanded polystyrene-based composites

Graphene oxide dispersion state in polystyrene-based composites below percolation threshold via linear melt rheology

In this work, the relation between the morphological structure and the linear viscoelasticity of graphene oxide (GO)-based polystyrene nanocomposites below percolation threshold was investigated. The rheological properties were observed to change upon addition of GO-2D particles at filler content below mechanical percolation threshold (0.06–0.3 %vol). In particular, the nanocomposite systems showed a delayed long-range relaxation dynamic regardless particle concentration, when compared to the neat polystyrene matrix. Moreover, little shift with regard to higher relaxation times of the full relaxation spectra of PS-GO nanocomposite was observed. This is attributed to the presence of attractive-kind interfacial interaction between polymer chains and GO-2D particles via π-π binding of benzyl rings, which strongly depends on GO sheets dispersion and exfoliation state. In light of these observations, oscillatory shear rheology measurements were used as an indirect tool to establish how exfoliated GO-2D particles were homogeneously dispersed in a low-polar polymer matrix.

Allyl and Benzyl Modified Aramid Nanofibers as an Enhancement in Polystyrene-Based Composites.

Aramid nanofibers (ANFs) represent the most promising nanoscale building blocks for high-performance nanocomposites. But their applications are mostly limited to those polymers containing –OH or –NH2 groups that can interact with ANFs through hydrogen bonding or others. In this paper, allyl and benzyl modified ANFs were successfully fabricated using a metallization method followed by functionalization with allyl and benzyl bromide. A series of modified aramid nanomaterials (ANMs) with different degrees of modification were prepared and their morphologies studied. The modified ANFs were added to polystyrene (PS) films as reinforcements. The mechanical properties of the resulting composite PS films including Young's modulus, toughness and yield strength were dramatically improved compared to those of pure PS film. These new types of reinforcement additives for non-polar polymer materials are presented in this paper.

Fire reaction properties of polystyrene-based composites using hollow silica as synergistic agent

Hollow silica microsphere (h-SiO2) has been widely applied in the field of thermal insulation, catalyst supports and drug storage/delivery containers. In this research, h-SiO2 has been innovatively used as synergistic agent to enhance the flame retardancy of intumescent flame-retardant polystyrene. The synergistic effects of h-SiO2 on intumescent flame-retardant polystyrene have been studied by limiting oxygen index (LOI), UL-94 test and cone calorimeter test (CCT). When 0.5 mass% h-SiO2 was substituted for the intumescent flame-retardant additive, the LOI of polystyrene composite (PS/IFR/Si0.5) increased by 5 units and the composite preserved the V-0 rating. Manipulation of parameters from CCT indicated that the peak heat release rate was reduced by 27% for the PS/IFR/Si0.5 composite, whereas the total heat release decreased by 14.5% and the ratio of residue increased by 85.6% (from 13.2 to 24.5%) compared to those of the composite without h-SiO2. The synergistic effects of h-SiO2 on intumescent flame-retardant polystyrene are attributed to physical and chemical processes in the condensed phase. The morphologies of charred layer after CCT proved that h-SiO2 induced compact charred layer with enhanced thermal and gas barrier effect, which in turn protected the inner matrix from combustion and decreased specific extinction area by 24.2%.

Production of waste polystyrene-based composites and evaluation as corrosion inhibitor for rebar coating

Corrosion is one of the most effective structural damages in rebar reinforced structural elements. Different methods are applied to protect concrete structures from corrosion. In this study, in order to prevent rebar corrosion, it has aimed to coating recycled polystyrene based composite materials and to examine them with electrical methods. The matrix element in the composites has obtained by dissolving the waste polystyrene foam material in benzine. Carbon, carbon fiber and standard sand were used as additives. Rebar reinforced cylinder concrete specimens, which completed their 28-day age in the curing pool, were subjected to accelerating corrosion by applying 70 Volt voltage in 3% NaCl water solution for 48 hours. Anode-cathode and four-probe conductivity measurement tests were performed to determine the corrosion condition of the samples. Splitting tensile test has been performed on the same samples. According to the results, it was found that although the Splitting tensile strength of coated rebar reinforced concrete samples did not change significantly compared to the control sample, all the coatings were advantageous in terms of corrosion prevention. It was also has found that there was good adherence between most rebar and concrete, as understood in the splitting tensile test.

Modification of POSS hybrids by ionic liquid simultaneously prolonging time to ignition and improving flame retardancy for polystyrene

Polystyrene (PS) with great flame retardancy has been achieved by addition of polyhedral oligomeric silsesquioxane (POSS). However, the POSS/PS composite showed easy-ignition behavior leading to fire hazard exposed. Aiming to prolong time to ignition (TTI) and improve flame retardancy simultaneously, using non-flammable modifier to decorate POSS is a facile method. Here, two kinds of POSS hybrids (POSS-ILs), denoted as POSS-EVIM and POSS-VIPSP, were synthesized by free radical copolymerization between vinyl POSS and two kinds of ionic liquid, commercial [EVIm]BF4 and Bronsted ionic liquid, respectively. The polystyrene-based composites (POSS-ILs/PS) were prepared by incorporated POSS-ILs into polystyrene. The results of thermal gravimetric analysis test evidenced that both POSS-ILs increased char yield and decreased decomposed rate of composites. Compared with neat PS, the TTI of POSS-ILs/PS was prolonged by 26 s and 21 s, and meanwhile, the fire hazard was decreased due to reduction of peak value of heat release rate (PHRR) and smoke release rate (PSPR) in cone calorimeter test. Scanning electron microscope observed compact residue of POSS-EVIM/PS and honeycombed residual morphology of POSS-VIPSP/PS, and additionally, both of these residual char possessed higher degree of graphitization than that of PS and POSS/PS in Raman spectrum, suggesting good physical barrier for matrix from heat and oxygen. Besides, the flexural strength of both POSS-ILs/PS composites were increased compared with neat PS. Taking the results above mentioned, POSS modified by ionic liquid can be a decent candidate to prolong time to ignition, simultaneously improve fire safety and mechanical properties for polymeric materials.

Quantitative evaluation of carbon nanomaterial releases during electric heating wire cutting and sawing machine cutting of expanded polystyrene-based composites using thermal carbon analysis

Field measurements were conducted at a facility where expanded polystyrene-based carbon nanomaterial composites, namely, carbon nanotube and carbon black composites, were cut with an electric heating wire cutter or a circular sawing machine. The aerosol particles released during the cutting of the composites were measured using real-time aerosol monitoring, gravimetric analysis, thermal carbon analysis, and scanning electron microscopic observations. This study had two major goals: (1) to quantitatively evaluate the concentrations of airborne carbon nanomaterials during the cutting of their composites; (2) to evaluate the capability of thermal carbon analysis to quantify airborne carbon nanomaterials in the presence of expanded polystyrene-derived particles. The results of thermal carbon analysis showed that the concentrations of elemental carbon (an indicator of carbon nanomaterials) for all the respirable dust samples in both cutting processes were less than the limit of detection (∼2 µg/m3), which is nearly equivalent to or lower than the occupational exposure limits for carbon nanotubes (1 to 50 µg/m3). For total dust, which includes particles larger than respirable size, although the elemental carbon concentrations during heating wire cutting were low (<3 µg/m3), those during sawing machine cutting were up to 58 µg/m3. In scanning electron microscopic observations, micron-sized particles composed of or including carbon nanotubes were detected only in aerosol particles collected during the sawing machine cutting. Therefore, heating wire cutting is considered preferable. This study demonstrated that thermal carbon analysis can quantify airborne carbon nanomaterials in the presence of expanded polystyrene-derived particles.

Polystyrene-Based Composites with Aluminosilicate Inclusions of Different Shapes

Samples of composites based on polystyrene with addition of halloysite nanotubes, mica, and montmorillonite aluminosilicates are obtained and the influence of these fillers on viscoelastic, mechanical, and structural properties of composites is studied. It is shown that an addition of up to 5% of mica can increase the rigidity of composites along with maintaining their strength at the level of pure polystyrene and without considerable embrittlement of samples. The addition of halloysite nanotubes and montmorillonite also increases the material stiffness but reduces its strength and elasticity. A significant (up to 50%) increase in the bending elasticity modulus of the composite was achieved by addition of 15% of halloysite nanotubes or 5% of mica.

Bentonite filler effect on structure and properties of polystyrene-based composites

The current research focuses on the preparation and characterization of polystyrene/bentonite composite materials with improved physicochemical properties and biological activity. Bentonite particles were immobilized into the polystyrene matrix by mechanical dispersion, and composite films were obtained. New data on the structure and properties of polystyrene/bentonite composites were discovered using SEM, optical microscopy, XRD, IR and UV spectrometry, tensile and microbiological testing. The effect of the filling agent on morphology and crystal structure composites was revealed. Insertion of bentonite into polystyrene resulted in an increase in interplanar layer distance in clay. It was found that the adsorption kinetics of methylene blue by pure polymer and the polystyrene/bentonite composite films was controlled by the pseudo-first-order kinetic equation. Isotherms were in good agreement with Langmuir model. For a composite with 5 wt% filler content, the maximum monolayer adsorption capacity was ten times greater than in the unmodified polymer. It was concluded that the modification of polystyrene with bentonite resulted in development of new adsorption-active centers. The strengthening testing results showed that insertion of bentonite (5 wt%) into the polystyrene matrix resulted in improved tensile strength. In addition, the polystyrene/bentonite composite films showed an antifungal effect against Candida albicans.

Polystyrene-based composites and nanocomposites with reduced brominated-flame retardant

Polystyrene was melt blended with a halogen-based flame retardant (FR), hexabromocyclododecane, and a non-halogenated FR, triphenyl phosphate (TPP), in a twin-screw extruder. An organically modified montmorillonite (Cloisite 15A) was used to prepare FR polystyrene nanocomposites. The flammability properties and thermal stability of FR polystyrene composites and nanocomposites were investigated. X-ray diffraction analysis showed that the exfoliation structure of organically modified montmorillonite in polystyrene nanocomposites may be achieved by melt-compounding in a twin-screw extruder. Furthermore, a good dispersion of FRs and nanoparticles of organically modified montmorillonite was observed by energy dispersive X-ray analysis. Thermogravimetric analysis demonstrated that the thermal stability of FR nanocomposites enhanced in the presence of clay nanoparticles and antioxidant. The aim of this study was to reduce the FR level, especially in the brominated FRs. The good results obtained by the limiting oxygen index test showed high-performance flammability properties in the composites containing hexabromocyclododecane and TPP, resulted from the synergy effects between these two FRs. However, in spite of producing high thermal performance polystyrene nanocomposites and dispersing clay nanoparticles efficiently into the polystyrene matrix, the flame retardancy properties were deteriorated in the presence of clay nanoparticles. Therefore, the organically modified clay (Cloisite 15A) was not a good synergic compound to improve the flame retardancy of polystyrene nanocomposites.

Particle release from single-wall and multiwall carbon nanotubes in polystyrene-based composites during grinding

The aerosol particles released during the grinding of polystyrene (PS)-based composites with well- and poorly dispersed single-wall carbon nanotubes (CNTs) and multiwall CNTs were measured using real-time aerosol measuring instruments. Increases in the concentration of aerosol particles were recorded during the grinding of the samples. However, similar increases were observed even when CNT-free polystyrene was ground. Electron microscopic analysis of the released particles revealed that particles with protruding CNTs were observed for the well-dispersed CNT-PS composites, but free-standing CNTs were not found. On the other hand, particles like agglomerated CNTs were found for the poorly dispersed CNT-PS composites.

The effect of silicon dioxide concentration on thermodynamic properties of polystyrene-based composites

Sol-gel synthesis of a silicon dioxide powder is carried out. The samples of polystyrene/silicon dioxide film composites with different concentrations of the filling agent are obtained. Studies using differential scanning calorimetry show that the dependence of the glass transition temperature of the composite on the composition is nonmonotonic with a minimum at 1 wt % SiO2. It is concluded that there is a plasticizing action of small (less than 1 wt %) amounts of silica and a predominant effect of intermolecular interactions of the filling agent with the polymer at high SiO2 concentrations (more than 1 wt %) are concluded.

Potential release of carbon nanotubes from their composites during grinding

We investigated the particle release caused by the grinding of polystyrene-based composites with and without single-wall carbon nanotubes (CNTs). In the results of real-time aerosol monitoring, considerable increases in the number concentration of nano-sized aerosol particles were observed during the grinding of both CNT-containing and CNT-free polystyrene. When a thermodenuder was used, the number of released nanoparticles was reduced by over 99.9%, indicating that the nanoparticles were presumably volatile particles released by the friction heat produced by grinding the composite. In an electron microscopic analysis of the aerosol particles, micron-sized particles with protruding fibers (probably CNTs) were observed, whereas free-standing CNTs were not observed.

Polymer-inorganic composite with ultradisperse gadolinium particles

The objects of investigation are polystyrene-based composites with ultradisperse particles (including nanoparticles) of metallic Gd and SiO2. The composites prepared by milling starting materials in a barrel mill at room temperature are studied by the ferromagnetic resonance method, transmission electron microscopy (TEM), and reflection X-ray diffraction (RXD). It is found that the magnetic subsystem of the composites is formed by magnetic nanoclusters, Gd crystallites 30 ± 10 nm across, which possess volume and surface magnetic anisotropy and pass into the superparamagnetic state at 210 ± 10 K. It is also found that the Landau-Lifshitz equation with the damping term in the Landau-Lifshitz form provides the best quantitative fit to experimental data for the ferromagnetic resonance of superparamagnetic metal nanoparticles.

Fracture of polystyrene- and molecular silica sol-based nanocomposites during fast compression

Polystyrene-based composites containing hybrid molecular silica sol nanoparticles with a core-shell structure are studied during fast compression. Polystyrene and the related composites are found to fail instantaneously at a certain critical pressure, which is accompanied by the emission of electromagnetic and acoustic waves. The composite composition changes the critical pressure during explosion and the frequency characteristics of the generated electromagnetic and acoustic waves. The charge density transfer mechanism in a composite with a filler concentration higher than 10 wt % is shown to differ from that in composites with a lower filler content.

Ultrasonic properties of polystyrene-based composites

In this study, first the pure polystyrenes (PS) with different molecular weights (350 × 103 and 500 × 103) have been modified by the chemical modification with succinic anhydride (SA), maleic anhydride (MA), and phthalic anhydride (PhA) and then the polystyrene based composites (CPS) prepared by addition of modified polystyrenes (MPS) into pure PS (with the molecular weight of 230 × 103) in weight % ratios of 90 : 10, 80 : 20, and 70 : 30. Ultrasonic measurements were performed on PS/MPS blends of different weight percent of MPSs by use of pulse echo method with 5-MHz frequency at room temperature. Elastic properties namely; longitudinal modulus (L), Young's modulus (E), bulk modulus (K) and shear modulus (G), Poisson's ratio (μ), and acoustic impedance (Z) were calculated from the ultrasonic velocities values measured and densities values obtained experimentally. Atomic force microscopy (AFM) has been used for determining the microstructure of composites. The variations of these parameters with increasing MPSs weight percentage content in PS/MPS from 10 to 30 have been discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012