High-impact polystyrene mechanical properties

High Impact Polystyrene (UPS) obtained by means of copolymerization of styrene with rubber represents heterogeneous system consisting of polystyrene matrix and the particles of rubber phase dispersed in it the particles in their turn keep the graft copolymer and a great number of occluded polystyrene O/,Physical and mechanical properties of HIPS are defined... 

Styrene and butadiene also form copolymers known as high impact polystyrene, or rubber-modified polystyrene, when the content of butadiene is 10%. This type of material has excellent mechanical properties, and it is widely used in practice for the manufacturing of numerous objects, including parts for household appliances, furniture, etc. Rubber-modified polystyrene is commonly used as wood replacement and also for packaging. The synthesis of this material typically is done by dissolving polybutadiene in styrene monomer, followed by free radical polymerization achieved using a peroxide catalyst. This procedure leads to block or graft type copolymers. 

Perhaps the best known member of the "heat-resistant" styrene plastics family is General Electric s Noryl (34). Noryl is an alloy of poly(phenylene oxide) and high-impact polystyrene. Heat deflection temperatures for Noryl range as high as 300 °F. The balance of mechanical properties is excellent, although processability is more difficult than for conventional styrene plastics. 

GRT particles of sizes of lower than 500 xm and between 500-1000 trm were blended with a postconsumer PP and high impact polystyrene (HIPS) at ratios of 90/10 and 70/30 (Montagna and Santana, 2012). The rheological, physical, and mechanical properties of blends were measured. The addition of GRT reduced the mechanical properties with the reduction being dependent on the particle size. The incorporation of GRT particles into the recycled HIPS and PP matrix led to a decrease and an increase of viscosity, respectively. The extent of the effect was dependent on particle size. 

Siregar JP, Sapuan SM (2009) Mechanical properties of pineapple leaf fibre (PALF) reinforced high impact polystyrene (HIPS) composites. In Sapuan SM (ed) Research in natural fibre reinforced polymer composites. UPM, Serdang, Selangor, Malaysia... 

Interesting research on the dynamic mechanical and thermal properties of fire-retardant high-impact polystyrene (HIPS) is published by Chang and co-workers [19]. HIPS may be produced by the free-radical chain polymerisation of styrene in the presence of an unsaturated elastomer. The authors showed that the melting point of the additive in relation to the processing temperature of the thermoplastics and the compatibility of the additive with the polymer phases are the two important variables governing the interaction of additive with polymer matrix. 

Initially compounding was mainly performed between amorphous polymers and elastomers, resulting in a polymer matrix with small domains of elastomers. This morphology can increase the mechanical properties considerably. In later developments special attention was paid to better and controlled phase separation, to control the domain size, and to increase the impact strength, as for instance in high-impact polystyrene (HIPS) and in ABS-latex mixtures. The search for better compatibility between the phases leads also to fully compatible combinations of polymers. Although over 300 pairs of miscible polymers are known (2), only a few systems have actually been commercialized, like PS/PPE... 

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