Recycled High Impact Polystyrene Research Articles

New Polymer Composites Made of Recycled Polystyrene with Red Mud and Wind Blade Waste: An Industrial Ecology Case

The development of composites with the waste of industries close to each other would mean an interesting case of industrial symbiosis in search for using less financial and natural resources. This paper presents the development of polymer composites made of three types of waste, produced by industries located in the same region and distant at most 25 km from each other: electronic waste, red mud (obtained during aluminium production), and the waste of wind turbine blades' manufacturing (epoxy resin/glass fibre). Composites were obtained incorporating 5%, 10%, and 15% of industrial waste (red mud and epoxy/fibre) in a matrix of recycled high-impact polystyrene (HIPS) from discarded electronic equipment. Tests were performed to obtain the melt flow index and the composites' water content and study the mechanical properties (tensile and impact) of test specimens produced with the composites by injection moulding (temperature from 200 to 250°C, the injection pressure of 45 MPa, and the injection time of 2.5 s). Results showed that the composites have water content and melt flow index within the specifications for recycled HIPS and are usually more rigid than it, reaching values for Elasticity Modulus up to 34% higher. Therefore, these composites can be applied when materials with more stiffness than HIPS are required.

Reinforcing and toughening blends of recycled acrylonitrile-butadiene-styrene/recycled high-impact polystyrene through ionic crosslinking

With the increasing attention to environmental pollution, the recycling and modification of wasted plastics has attracted more and more attention. In this study, zinc dimethacrylate (ZDMA) was first used to introduce ionic crosslinking into recycled acrylonitrile-butadiene-styrene (rABS)/recycled high-impact polystyrene (rHIPS) blends. On one hand, ZDMA underwent self-polymerization to form poly-ZDMA (PZDMA) particles. On the other hand, ionic crosslinks were formed by grafting with butadiene on the rABS or rHIPS chains of ZDMA. The ionic interaction between Zn2+ and unsaturated carboxylate was used to improve the compatibility between rABS and rHIPS. The enhanced impact strength, tensile strength, storage modulus and loss modulus of the blends were observed. In the case of 4 wt% ZDMA, the notched impact strength was 8.71 kJ/m2, 133% higher than that of blends without ZDMA. Scanning electron microscope (SEM) showed that polybutadiene (PB) had a good dispersion in rABS/rHIPS blends, the interface between rABS and rHIPS was indistinct, suggesting good compatibility. This indicated that the compatibility of rABS/rHIPS blends can be improved by using ion crosslinking.

Validity of using Single Extruder in Wood Plastic Composite from Rice Straw and High Impact Polystyrene Wastes

This work mainly aims to study the validity of using the single extruder in achieving adhesion and compatibility between rice straw fibers and plastic wastes as an attempt for manufacturing wood plastic composite (WPC). A single extruder was used for mixing recycled high impact polystyrene (RHIPS) and Egyptian natural rice straw (RS) after being fibrated mechanically to produce an eco-friendly synthetic wood that can be named as rice straw plastic composite (RSPC). The components have passed through many operations such as drying, extrusion, shredding, etc.). To produce the final product, the flat press technique was used with a hydraulic press. Samples with 60 % mechanically fibrated rice straw (MFRS) ratio were produced. The density test was operated on the samples according to ASTM-D-792 to reveal the density of the composite. The water absorption was determined according to ASTM-D-570. Using the single extruder for blending the two components didn’t achieve high levels of compatibility. However, comparing the results with natural soft, hard wood and medium density fiberboard (MDF) synthetic wood. The prepared RSPC samples exhibited less water absorption and higher density than that of natural and MDF woods.

Water Purification using Recycled Polymeric Microfiltration Membranes

In our previous work, microfiltration membranes were successfully manufactured by non-solvent induced phase separation (NIPS) method using two concentrations (30 and 35 wt%) of recycled high impact polystyrene (HIPS-R). N, Ndimethyl formamide (DMF) was used as solvent and water as a coagulation bath. These membranes were characterized in terms of chemical composition, surface hydrophilicity, surface crosssection morphology, porosity, and pores size distribution. Accordingly, the membrane's surfaces showed a semihydrophilic behavior with contact angles of 81o and 91o for 30 wt% and 35 wt% membranes respectively. In the current study, The prepared membranes were examined for the removal of Humic acid (HA) and Rhodamine B (RhB) dye in a microfiltration process. Filtration experiment showed that pure water flux of 30 wt% membrane was higher than of 35 wt% membrane, also 30 wt% membrane has a higher humic acid and Dye removal efficiency than of 35 wt% membrane. Thus, the results suggest active membranes could be obtained using recycled high-impact polystyrene. And then, solve the polymer waste accumulation problem in parallel with help in drinking water crisis solution.

Recycling of high impact polystyrene and low-density polyethylene plastic wastes in lightweight based concrete for sustainable construction

In recent times, a substantial part of the generated solid waste all over the world are plastic-related waste with wide ranges of serious environmental and public health consequences. This study investigates the beneficial use of recycled high impact polystyrene (HIPS) and low-density polyethylene (LDPE) plastic wastes in cement-based composites for production of high strength lightweight concrete. The HIPS and LDPE plastic wastes were recycled into plastic granules of about 2 mm particle sizes and was used to partially substitute the sand in the concrete mixes at varied percentage levels of 0, 10, 30 and 50% by weight using a mixture proportion of 1:1.5:3 (cement: m-sand: coarse aggregate) at water-cement (w/c) ratio of 0.5 with a target characteristic strength of 30 N/mm2 at 28 days. The material characteristics were defined, and concrete cube samples of size 100 mm were cast and tested in the fresh and hardened state. Test results indicate a decrease in the workability, density and compressive strength as the quantities of the recycled waste plastic granules increases. Implications of these results show the possibility of using recycled plastic granules from both high impact polystyrene and low-density polyethylene plastic wastes at optimum of 10% for producing lightweight-high strength concrete that is closely similar in strength to lightweight concrete produce with conventional materials.

Preparation of polystyrene-b-poly(ethylene/propylene)-b-polystyrene grafted glycidyl methacrylate and its compatibility with recycled polypropylene/recycled high impact polystyrene blends

In this study, polystyrene-b-poly (ethylene/propylene)-b-polystyrene grafted glycidyl methacrylate (SEPS-g-GMA) copolymer was prepared by melt grafting in the mixer. The successful grafting of GMA on the SEPS molecular chain was analyzed by Fourier transform infrared spectroscopy (FT-IR). The grafting ratio of SEPS-g-GMA was measured by acid-base titration, which showed that N-vinylpyrrolidone (NVP) had a positive effect on the increased grafting ratio of SEPS-g-GMA. The recycled polypropylene (R-PP)/recycled high impact polystyrene (R-HIPS) blends were prepared by a melt extrusion, and the effect of SEPS-g-GMA copolymer with different ratios on the compatibility of blends was studied. The epoxy groups in SEPS-g-GMA copolymer were found to have a chemical reaction with the carboxyl groups in the waste materials. When the grafting ratio of SEPS-g-GMA was 2.44%, the notched impact strength and the elongation at break of the R-PP/R-HIPS blends with 10 phr SEPS-g-GMA reached 7.06 kJ/m2 and 34.25%, which were significantly increased by 186.99% and 68.30% compared with that of pure blends, respectively. Moreover, the observed decreased particle size and increased dispersion uniformity improved the compatibility using SEPS-g-GMA. The increased complex viscosity, storage modulus and loss modulus indicated that the chemical reaction between SEPS-g-GMA and R-PP/R-HIPS blends improved the component compatibility among the blends, resulting in the chain entanglement prominently. The presence of SEPS-g-GMA inhibited the degradation and increased the thermal stability of R-PP/R-HIPS blends.

Application of post-consumer recycled high-impact polystyrene in the preparation of phase-inversion membranes for low-pressure membrane processes

In this study, recycled plastic waste was successfully used in preparing low-pressure membranes by phase-inversion method. These membranes are considered as an alternative solution for economical and environmental concerns, namely: water reclamation as well as polymer recycling and reuse. Post-consumer recycled high-impact polystyrene and virgin commercial high-impact polystyrene were separately used to prepare membranes, which were thereafter compared in terms of their respective characteristics and performance. N,N-dimethylacetamide and deionised water were used as a solvent and coagulant, respectively. Membranes were characterised by microscopic observations, contact angle measurements, thermogravimetric analysis, and filtration experiments. The recycled polymeric membranes presented similar thermal properties as the membranes made from commercial high-impact polystyrene, which were used as control membranes. They also obtained similar asymmetric membrane structures, however with slightly higher porosity (from 47.54 ± 5.53% for control membranes to 52.31 ± 4.33% for recycled polymeric membranes). The presence of additives in the recycled polymeric structure was confirmed by EDX results. Such additives made the membranes to become more hydrophilic, reducing the water contact angle value from 81.78 ± 3.42° obtained for control membranes to 79.19 ± 4.15°. Moreover, irreversible fouling was satisfactorily minimised and humic acid rejection was very slightly enhanced (from 95.5 ± 0.2 to 96 ± 0.1%). This indicates that the more hydrophilic the membrane is, the better antifouling properties it possesses. Thus, the results of the post-consumer recycled high-impact polystyrene suggest that they can provide a sustainable and environmental alternative when implemented in low-pressure membrane processes.

Development of Ecofriendly Concrete Incorporating Recycled High-Impact Polystyrene from Hazardous Electronic Waste

AbstractElectronic plastic waste from outdated computers and their accessories have been on an exponential growth in recent decades. In light of using such a nondegradable, hazardous waste effectively, this study was carried out using the recycled computer plastic waste as coarse aggregate in concrete. The computer plastic waste was collected and made into chips, which predominantly have high impact polystyrene (HIPS). The coarse aggregate was partially replaced with HIPS by volume percentages of 10, 20, 30, 40, and 50% for different water–cement ratios such as 0.53, 0.49, and 0.45. A total of 486 concrete specimens were cast to investigate the effect of HIPS and water–cement ratio on the fresh and hardened properties of concrete. The concrete specimens were tested under compression, tension, and flexure on the 7th and 28th day. The engineering properties such as workability, compressive strength, flexural strength, split tensile strength, and elastic modulus of concrete were obtained experimentally and w...

Performance of cement mortar made with recycled high impact polystyrene

Abstract This paper investigates the possibility of utilizing recycled high impact polystyrene (HIPS) as a sand substitute in cement mortar, in order to reduce the solid waste disposal problem and thereby environmental pollution and energy consumption. The results show that the compressive strength and splitting tensile strength of mortar are decreased by replacing sand with HIPS, but the decrease in the splitting tensile strength is much smaller. HIPS makes the mortar become more ductile and increases the energy dissipation capacity. HIPS decreases the dry bulk density, dynamic modulus of elasticity, thermal conductivity, and also water vapor permeability, but does not affect the resistance to freeze–thaw cycles. The use of mortar made with various percentages of HIPS offers promise for applications as medium or light weight concrete, mostly due to its improved thermal isolation, while adding value to a post-consumer plastic material that is now generally treated as solid waste.

Estudo da recuperação das propriedades de poliestireno de alto impacto (HIPS) através da incorporação de borracha termoplástica tipo estireno-butadieno-estireno (SBS)

A tenacificação de termoplásticos vítreos através da adição de partículas de borracha na matriz polimérica é um processo amplamente estudado. Neste trabalho foi avaliada a recuperação das propriedades de poliestireno de alto impacto (HIPS) reciclado através da incorporação de copolímeros estireno-butadieno-estireno (SBS) de estrutura linear e radial. As blendas foram processadas em uma extrusora dupla rosca. Os copolímeros foram adicionados em teores de 5, 10 e 15% em massa. As propriedades avaliadas foram o índice de fluidez, a morfologia e o comportamento frente a ensaios de tração, flexão e resistência ao impacto das blendas formuladas. Em todos os casos, o SBS radial foi mais eficiente na recuperação das propriedades do poliestireno de alto impacto que o SBS linear quando comparadas às propriedades do HIPS reciclado.

STUDY OF MECHANICAL BEHAVIOR OF REPROCESSING HIGH IMPACT POLYSTYRENE, RECOVERY WITH SEBS

The effect of reprocessing High Impact Polystyrene (HIPS) has been studied in this paper. To simulate recycled HIPS, we reprocessed virgin HIPS through 5 cycles. The HIPS has been mechanically characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone. Our results show that tensile strength increases, while lengthening at break decreased as the number of reprocessing cycles increases. 1. INTRODUCCTION High Impact Polystyrene is a thermoplastic formed in two phases: a styrene phase and a butadiene phase. Among the diverse applications of this material is its use in the manufacture of packaging materials. This type of product can be characterized as having a short life cycle, and consequently a huge quantity of domestic waste is generated, which must be dealt with to reduce environmental impact. The problems which arise in the recovery of polymer materials are basically the variations that occur in their properties, due to either thermic degradation or the presence of impurities. Many studies have been carried out on the degradation of polymers. Su (3) analyzed the influence of the reprocessing cycles on the mechanical properties of polyamide 6 (PA6). Su's work is relevant to our work because he carried out a study of mechanical and rheological properties, although it was with a different material. Su's work is interesting, but we do not consider that reprocessing the material 16 times is very useful, because other studies show that the loss of property occurs in the first 5 reprocessed. (2,8) Other authors, including Santana (8) in their work in 2002 and Soriano (3) have carried out similar studies on HIPS. Santana investigated the themo-mechanical properties of post- consumer HIPS (from disposable cups) through five consecutive injection moulding steps to simulating the recycling cycles. Santana states that tensile strength, modulus of elasticity and elongation at break properties of HIPS were slightly reduced, which indicate an effect of decreasing of molecular weight. Soriano analyzes influence of the number of processing cycles on the microstructure and macroscopic properties on a HIPS in coextruded sheet, maintaining a constant composition of 70 wt% of virgin HIPS and 30 wt% of recycled HIPS. On the other hand, Balard (6) analyzed the compatibility of polycarbonate (PC) with acrylonitrile-butadiene-styrene (ABS) using waste material from the electrical sector, reaching the conclusion that the composition range comprised between 10 and 20 wt% PC is most interesting in order to obtain an industrial material with balanced properties, for different reasons: firstly, mechanical ductile properties do not decrease. Secondly, processing conditions are similar to other styrenic derivatives and finally, this composition range reflects the generation ratio of these wastes which is close to 4:1 for ABS/PC. Finally, Navarro (7) and Garcia (1) analyzed mixtures of polymers with the aim of improving properties of the recovered material. Navarro, in his study of the influence of polyethylene (PE) on recycled polyethylene terephtalate (PET) analyzed, among other things, mechanical and rheological properties.

STUDY OF RHEOLOGICAL BEHAVIOR OF REPROCESSING HIGH IMPACT POLYSTYRENE

The effect of reprocessing High Impact Polystyrene (HIPS) has been studied in this paper. To simulate recycled HIPS, we reprocessed virgin HIPS through 5 cycles. The HIPS has been rheologically characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone. Our results show that viscosity decrease, as the number of reprocessing cycles increases. 1. INTRODUCCTION High Impact Polystyrene is a thermoplastic formed in two phases: a styrene phase and a butadiene phase. Among the diverse applications of this material is its use in the manufacture of packaging materials. This type of product can be characterized as having a short life cycle, and consequently a huge quantity of domestic waste is generated, which must be dealt with to reduce environmental impact. The problems which arise in the recovery of polymer materials are basically the variations that occur in their properties, due to either thermic degradation or the presence of impurities. Many studies have been carried out on the degradation of polymers. Su (3) analyzed the influence of the reprocessing cycles on the mechanical properties of polyamide 6 (PA6). Su's work is relevant to our work because he carried out a study of mechanical and rheological properties, although it was with a different material. Su's work is interesting, but we do not consider that reprocessing the material 16 times is very useful, because other studies show that the loss of property occurs in the first 5 reprocessed. (2,12) Other authors, including Santana (12) in their work in 2002 and Soriano (3) have carried out similar studies on HIPS. Santana investigated the themo-mechanical properties of post-consumer HIPS (from disposable cups) through five consecutive injection moulding steps to simulating the recycling cycles. Santana states that tensile strength, modulus of elasticity and elongation at break properties of HIPS were slightly reduced, which indicate an effect of decreasing of molecular weight. Soriano analyzes influence of the number of processing cycles on the microstructure and macroscopic properties on a HIPS in coextruded sheet, maintaining a constant composition of 70 wt% of virgin HIPS and 30 wt% of recycled HIPS. With respect to the rheological properties, Soriano shows that the viscosity of the material subjected to one processing cycle is higher than of the virgin material, especially at low shear rate, but as shear rate increases, all, curves tent to concur to a similar value and this difference in viscosities becomes very small. After the second and up to the sixth processing cycle, the viscosity decreases. Soriano calculates the value of n (the model constant which symbolizes the pseudoplastic behavior slope of the material) obtaining a value of 0.31 for virgin material and 0.35 for the sixth processing cycle. This data is calculated from apparent viscosity (ηap) as Soriano used only one die (L/D 30mm) instead of the three recommended by ISO 11443. On the other hand, Balard (10) analyzed the compatibility of polycarbonate (PC) with acrylonitrile-butadiene-styrene (ABS) using waste material from the electrical sector,

Study of rheological behavior during the recovery process of high impact polystyrene using cross-WLF model

The effect of reprocessing two mixtures: recycled high impact polystyrene (HIPS) with polybutadiene (PB); and HIPS with styrene-ethylene-butylene-styrene (SEBS) have been studied in this article. To simulate recycled HIPS, we reprocessed virgin HIPS through five cycles. The virgin HIPS, the recycled HIPS, and the mixtures have been mechanically and rheologically characterized after the various cycles of reprocessing to evaluate their corresponding properties and correlate them with the number of cycles undergone. To widen our injection simulation analysis by computer (CAE: Computer Aided Engineering) of these new materials with additives, it was necessary to determine the viscosity using a mathematical model, in this case the Cross-WLF, to determine the relevant parameters. Our results show that tensile strength increases, while the lengthening and viscosity decrease, as the number of reprocessing cycles increases. If we mix PB or SEBS with degraded HIPS, the mechanical properties of the virgin material are recovered and the rheological behavior maintains the viscosity values for the mixture with PB but these diminish notably for the mixture with SEBS. The results on mechanical properties show that the mixture with SEBS behaves better than the mixture with PB as the number of cycles increases. The viscosity of the mixture with SEBS diminishes more than the viscosity of the mixture with PB as the number of reprocessing cycles increases. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Chromatographic pattern in recycled high-impact polystyrene (HIPS) – Occurrence of low molecular weight compounds during the life cycle

The analysis of the chromatographic pattern of virgin, reprocessed, thermo-oxidised, and recycled high-impact polystyrene (HIPS) proves to be a suitable and sensitive tool to assess the degree of degradation of HIPS during its first life and subsequent recycling. Different low molecular weight compounds, such as residues of polymerisation, degradation products, and additives have been identified and relatively quantified in HIPS, using microwave-assisted extraction and further analysis by gas chromatography–mass spectrometry (GC–MS). The release of residues of polymerisation has been proven to occur during reprocessing, thermo-oxidation, and in recycled samples, which may show the emissions of volatile and semi-volatile organic compounds during the life cycle of HIPS. A wide range of oxidised degradation products are formed during reprocessing and thermo-oxidation; these products can be identified as oxidised fragments of polystyrene (PS), oxidised fragments from polybutadiene (PB) phase, and oxidised fragments from the grafting points between the PS and PB phase. Real recycled HIPS samples may also contain contaminations and fragments from additives included in their original formulations; the presence of brominated fragments from flame retardants in electronic waste is here observed.

Emission pattern of semi-volatile organic compounds from recycled styrenic polymers using headspace solid-phase microextraction gas chromatography–mass spectrometry

The emission of low molecular weight compounds from recycled high-impact polystyrene (HIPS) has been investigated using headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). Four released target analytes (styrene, benzaldehyde, acetophenone, and 2-phenylpropanal) were selected for the optimisation of the HS-SPME sampling procedure, by analysing operating parameters such as type of SPME fibre (polarity and operating mechanism), particle size, extraction temperature and time. 26 different compounds were identified to be released at different temperatures from recycled HIPS, including residues of polymerisation, oxidated derivates of styrene, and additives. The type of SPME fibre employed in the sampling procedure affected the detection of emitted components. An adsorptive fibre such as carbowax/polydimethylsiloxane (CAR/PDMS fibre) offered good selectivity for both non-polar and polar volatile compounds at lower temperatures; higher temperatures result in interferences from less-volatile released compounds. An absorptive fibre as polydimethylsiloxane (PDMS) fibre is suitable for the detection of less-volatile non-polar molecules at higher temperatures. The nature and relative amount of the emitted compounds increased with higher exposure temperature and smaller polymeric particle size. HS-SPME proves to be a suitable technique for screening the emission of semi-volatile organic compounds (SVOCs) from polymeric materials; reliable quantification of the content of target analytes in recycled HIPS is however difficult due to the complex mass-transfer processes involved, matrix effects, and the difficulties in equilibrating the analytical system.

Analytical strategies for the quality assessment of recycled high-impact polystyrene: A combination of thermal analysis, vibrational spectroscopy, and chromatography

Various analytical techniques (thermal analysis, vibrational spectroscopy, and chromatographic analysis) were used in order to monitor the changes in polymeric properties of recycled high-impact polystyrene (HIPS) throughout mechanical recycling processes. Three key quality properties were defined and analysed; these were the degree of mixing (composition), the degree of degradation, and the presence of low molecular weight compounds. Polymeric contaminations of polyethylene (PE) and polypropylene (PP) were detected in some samples using differential scanning calorimetry (DSC). Vibrational spectroscopy showed the presence of oxidised parts of the polymeric chain and gave also an assessment of the microstructure of the polybutadiene phase in HIPS. The presence of low molecular weight compounds in the HIPS samples was demonstrated using microwave-assisted extraction followed by gas chromatography–mass spectrometry (GC–MS). Several volatile organic compounds (VOCs), residues from the polymerisation, additives, and contaminations were detected in the polymeric materials. Styrene was identified already in virgin HIPS; in addition, benzaldehyde, α-methylbenzenaldehyde, and acetophenone were detected in recycled HIPS. The presence of oxygenated derivates of styrene may be attributed to the oxidation of polystyrene (PS). Several styrene dimers were found in virgin and recycled HIPS; these are produced during polymerisation of styrene and retained in the polymeric matrix as polymerisation residues. The amount of these dimers was highest in virgin HIPS, which indicated that emission of these compounds may have occurred during the first life-time of the products. This paper demonstrates that a combination of different analytical strategies is necessary to obtain a detailed understanding of the quality of recycled HIPS.

Determination of volatile and semi-volatile model contaminants in recycled high-impact polystyrene from food-contact applications. Comparison of extraction by purge-and-trap, co-evaporation, and total dissolution

Seven samples of high-impact polystyrene (HIPS) flakes, from post-consumer coffee cups, previously deliberately contaminated with four volatile and semivolatile model compounds (1,1,1-trichloroethane, methylbenzene, chlorobenzene, and phenylcyclohexane) to simulate misuse, have been collected at different times from a recycling plant and analyzed directly after extraction by purge-and-trap or by co-evaporation (a modified static headspace procedure).

Photochemical Degradation of Recycled High-Impact Polystyrene

Abstract Photooxidative aging of high-impact polystyrene sheets at 25°C was followed for different intervals of 25, 40, 50, 75, and 80 h. Five different types of samples were used, viz. virgin, and recycled once, twice, three, and four times. The optical properties of exposed samples exhibited changes as a result of discoloration. The transmittance and reflection deceases whereas absorbance increases with increasing recycling of high-impact polystyrene.

Effect of Thermal Aging on the Thermal Stability of Recycled High-Impact Polystyrene

Abstract Thermo-oxidative aging of high-impact polystyrene sheets at 100°C was followed for a period of 1300 h. Four different types of samples were used, viz., virgin and recycled once, three, and five times. The samples exhibited systemic changes as a result of discoloration. The DTA of those samples indicates a rapid deterioration in thermal stability as well as deterioration in the optical properties.

Thermal Aging on the Dielectric Properties of Recycled High Impact Polystyrene

Abstract The dissipation factor and dielectric constant of thermally aged recycled high impact polystyrene (HIPS) were measured at different aging temperatures. The results indicates that the degradation of HIPS is mainly due to surface action with minor chemical change.