Papers by Keyword: Polystyrene

Abstract: In this paper, the selected properties of lightweight composites based on the different kinds of binder and recycled waste plastics aggregate were studied. Plastic waste e.g. foamed polystyrene, polypropylene, polyurethane foam or ethyl vinyl acetate (EVA) as an aggregate in these composites was used. Cement CEM II B/S 32.5 R and an organic-based adhesive with the business name Conipur 360 were used as a binder. The cement composites consisted of constant water to cement ratio 0.50 and dose of cement 175 kg/m³. Mixtures of adhesive composites were prepared with constant dose of adhesive 100 kg/m³. The kind of recycled waste aggregate was only changed. The physical properties, such as bulk density, compressive strength and thermo-technical properties were verified. The application of organic-based adhesive resulted in a significant decreasing values of the bulk density (100 kg/m³ - 230 kg/m³) and the thermal conductivity coefficient (0.0511 W/m.K - 0.0686 W/m.K) of lightweight composites. The negative impact of this type of binder resulted to a decreasing value of the compressive strength (0.15 MPa - 0.32 MPa). Use of cement binder caused to an increasing of bulk density (290 kg/m³ - 375 kg/m³) and worsening of the thermal conductivity coefficient of these composites (0.0660 W/m.K - 0.0799 W/m.K). The compressive strength values of cement composites ranged from 0.24 MPa to 0.50 MPa.

Abstract: Micro-porous hydrophilic membranes were successfully fabricated using polystyrene waste by phase inversion casting. Four concentrations (20, 25, 30, and 35 wt%) of recycled high-impact polystyrene (HIPS-R) in N, N-dimethyl formamide (DMF) solution were employed to prepare the membranes. The effect of polystyrene concentration on the characteristics of the different membranes was thoroughly studied. Based on the Fourier transform infrared spectroscopy (FTIR) results, the chemical composition of HIPS-R was analogous to that of pure high-impact polystyrene HIPS raw material of the previous studies. Also, field-emission scanning electron microscopy (FESEM) was employed to study the morphology and porosity of the prepared membranes. The membranes cross-section showed a sponge structure with longitudinal macro voids. The solid walls around these voids have a sponge-like structure, especially for high concentration polystyrene membranes. Furthermore, the number of pores into the membrane surface decreased with the increase of polystyrene concentration. The membranes surface pores size was ranged from 150 nm to 550 nm with the different used concentrations. Water contact angle (CA) of the prepared membrane's surface were measured. All the measured CA of the prepared membranes, except the 35 wt% showed CA of 91^o, showed a hydrophilic behavior. Thus, the results suggest effective membranes could be obtained using recycled polystyrene. And then, solve the polymer waste accumulation problem in parallel with help in drinking water crisis solution.

Abstract: Polystyrene is a type of plastic that is widely used in daily life. It is applied for decoration, food packaging, and electronic packaging process. However, the use of polystyrene has become a problem for the environments because its properties are difficult to be degraded by nature. Pyrolysis method can be regarded as one of the environmentally friendly methods for recycling polystyrene waste. This research aims to investigate the effect of bentonite and natural zeolite catalyst on the pyrolysis of polystyrene. The experiment was carried out in a batch process. The pyrolysis process consists of a cylindrical reactor with electrical heater, a condenser, and a liquid product container. About 100 grams of polystyrene material was pyrolysis per batch. Catalysts used in the variation of 0%, 10%, 15%, 20%, and 25% of polystyrene. The liquid product was collected in 60 minutes and weighed. The composition of the liquid product was determined by gas chromatography. Polystyrene pyrolysis utilizes bentonite and natural zeolite as the catalyst. It produces benzene, toluene, ethylbenzene, styrene, and isopropyl benzene as the liquid product, and polystyrene residue as a solid product. Among the catalyst studied, bentonite is found to be the most efficient and increase the styrene selectivity (30.28 wt%) significantly at a reaction temperature of 400°C in comparison to the natural zeolite catalyst.

Abstract: This experiment was conducted to investigate thermal and mechanical properties of the biodegradable composites based on Poly (lactic acid) (PLA) incorporated with cellulose-graft-polystyrene (cellulose-g-PS) at 1, 3, 5 and 10 wt%. The modification of cellulose filler was confirmed by the T_d shifting of thermogravimetric analysis (TGA) thermogram from 334 to 348 °C and characteristic peaks corresponding to the styrene benzylic ring obtained from fourier-transform infrared spectroscopy (FTIR) analysis. The slight improvement of PLA properties with addition of 1 wt% of cellulose-g-PS composite probably was due to the good interaction and compatibility between filler and the matrix of polymer.

Abstract: In this study, the cellulose nanofiber (CNF) was prepared using carrot slag discarded from industrial carrot juice. The FTIR results of the carrot fiber show that the impurities such as lignin have been removed after alkali and acid neutralization treatment. In addition, it was confirmed that the carrot nanofiber was successfully prepared by the 2,2,6,6-tetramethylpiperidine (TEMPO) radical oxidation method. Subsequently, the obtained nanofiber was surface modified by styrene suspension polymerization and silane coupling agent, respectively. The results of water contact angle analysis show that the hydrophobicity of the modified nanofibers was improved. Moreover, a set of nanocomposite films were prepared by incorporating carrot nanofiber into sodium alginate (SA) and polystyrene (PS), respectively by using solution casting method. The obtained results showed that the TEMPO radical oxidized nanofiber containing film had the best transmittance in SA nanocomposite series. On the other hand, styrene suspension polymerization modified nanofiber containing one exhibited the best transparency in PS nanocomposite series.

Abstract: Thermoplastic vulcanizates or TPVs is a type of materials exhibiting excellent properties between thermoplastic and elastomer by combining the characteristics of vulcanized rubber with the processing properties of thermoplastics. This research aims to study the effect of thermal aging on the morphology and mechanical properties of thermoplastic vulcanizates (TPVs) based on a mixture of natural rubber (NR) and polystyrene (PS). TPVs samples were prepared using the internal mixer at a mass ratio of NR/PS 70/30, 50/50, 30/70 and 0/100. Tensile properties and impact strength showed that when the amount of NR increased tends of impact strength and elongation at break increased but tends of tensile strength decreased. On the other hand, tends of tensile strength for thermal aging at 70°C for 3 days increased when the amount of PS increase. The blending ratio of NR / PS at 70/30 is the best. It gave a worthy increase from 19.94 MPa to be 25.56 MPa (28.18%).

Abstract: In this paper some sandwich bars made from classical materials (polystyrene core, glass fiber) but combined in order to obtain an original material, are made. For these new sandwich bars, some dynamic parameters are studied, such as: damping factors per unit mass and length, eigen frequency.

Abstract: Supercritical fluids (SCFs) process can be considered as an emerging ”clean“ technology for the production of small-size particles (e.g. micron-size). Microsphere is a material in micron scale which has been widely used as adsorbent, catalyst support, and drug delivery system. For advanced application, those materials are formulated in the form of porous microspheres. There are several methods that can be used using SCFs. One of them is Solution Enhanced Dispersion by Supercritical Fluids (SEDS). This method is considered to be suitable in obtaining the porous microsphere polystyrene. In this study, polystyrene was first dissolved into toluene (polystyrene solution) at different concentrations (i.e. 3, 5, 7, 9, 11, 13, 15 wt%) and then blown/sprayed together with supercritical carbon dioxide (CO₂) through co-axial nozzle with two differents annulus diameter (i.e. 3.6 mm and 4.6 mm). Co-axial nozzle consists of two concentric pipes, inner pipe and annulus. Inner pipe for polystyrene solution flow and annulus for supercritical carbon dioxide flow. The expansion of these two of fluid was done both in atmospheric condition and in pressurized precipitator (40 bar). The resulted microsphere was analyzed by using SEM (Scanning Electron Microscope) to determine morphology and average diameter of the microsphere. The SEM analysis results showe that the smaller the initial concentration of solution used, the resulted microspheres tend to be smaller and less fibrils formed. Additionally, in the pressurized precipitator, the formed microspheres size was smaller and size distribution more narrow than that of atmospheric condition. Moreover, the use of smaller annulus diameter in co-axial nozzle produced smaller microsphere size and the size distribution was more uniform.

Abstract: Polystyrene is commercial polymer of extensive use in industrial scale due to great physical and chemical properties and low cost. Lifespan of polymer materials can be changed by incorporation of additions to polymeric matrix.The present study aimed to evaluate the influence of crystal violet dye in polystyrene matrices when irradiated by visible radiation. The samples were studied in the form of films, in which solution of crystal violet (5.0x10^-4mol.L^-1) was added to the PS solution (8% w / w). The films were irradiated with commercial lamp for 150 hours and analyzed with UV-Vis and FTIR. The results showed that the dye degraded at a rate of 16%, however the FTIR analysis revealed that polystyrene did not degrade under the conditions studied, since no formation of carbonyl compounds was observed.

Abstract: Extruded polystyrene (XPS) is a material with applications in the building industry, where it is typically used as thermal insulation. Fracture experiments in the three-point bending configuration were conducted on XPS beam specimens with an initial stress concentrator made before testing. The nominal dimensions of the beams were 40 × 40 × 160 mm. The depth of the initial edge notch on the bottom side of the specimen was approximately 1/3 of specimen height. The span length was 120 mm. Load vs. displacement diagrams were recorded during fracture tests, and subsequently the modulus of elasticity (E), effective fracture toughness (K_Ice) and specific fracture energy (G_F) of the XPS were determined. The mean values obtained for the mechanical fracture parameters and coefficients of variation (number of specimens) were the following: E = 10.7 MPa, 9.2 % (7); K_Ice = 0.0547 MPa∙m^1/2, 16.7 % (3); G_F = 183.2 J∙m^–2, 34.3 % (3).