High-impact polystyrene chemical resistance

Polystyrene One of the high volume plastics, is relatively low in cost, easy to process, has sparkling clarity, and low water absorption. But basic form (crystal PS) is brittle, with low heat and chemical resistance, poor weather resistance. High impact polystyrene is made with butadiene modifiers provides significant improvements in impact strength and elongation over crystal polystyrene, accompanied by a loss of transparency and little other property improvement. PS is used in many different formulations. 

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

High-impact grades have lower rigidity, lower chemical resistance and are more difficult to join and weld. Alloys made of polystyrene and polybutadiene are opaque. 

The polymers described above have been chemically pure, although physically helerodisperse. It is oflen possible lo combine two or more of these monomers in the same molecule to form a copolymer. This process produces still further modification of molecular properties and, in turn, modification of the physical properties of file product. Many commercial polymers are copolymers because of the blending of properties achieved in this way. For example, one of the important new polymers of the past ten years has been the family of copolymers of acrylonitrile, butadiene and styrene, commonly called ABS resins. The production of these materials has grown rapidly in a short period of time because of their combination of dimensional stability and high impact resistance. These properties are related to the impact resistance of acrylonitrile-butadiene rubber and the dimensional stability of polystyrene, which are joined in the same molecule. 

As block copolymers are still rather expensive materials, it may be advantageous to use them as additives to important industrial polymers. In this domain, possibilities are extremely numerous and diverse. They include an improvement of chemical properties such as resistence to degradation agents, or rheological properties such as adhesion of vinylic paints, high impact properties of conventional thermoplastics, or a compatibilization of polyolefins, polystyrene and poly(vinyl chloride) allowing the reuse of polymeric waste products. The above examples illustrate the great intrinsic potential of block copolymers in the quest of new materials with specific properties. 

Polystyrenes Polymers that contain the styrene monomer. Styrenes can be used as high impact grades, or heat resistance substances, or light stable substance or chemically stable polymer by simply blending the styrene homopolymer or creating a styrene co-polymer. 

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