High-impact polystyrene-poly phenylene

The oxidative coupling of 2,6-dimethylphenol to yield poly(phenylene oxide) represents 90—95% of the consumption of 2,6-dimethylphenol (68). The oxidation with air is catalyzed by a copper—amine complex. The poly(phenylene oxide) derived from 2,6-dimethylphenol is blended with other polymers, primarily high impact polystyrene, and the resulting alloy is widely used in housings for business machines, electronic equipment and in the manufacture of automobiles (see Polyethers, aromatic). A minor use of 2,6-dimethylphenol involves its oxidative coupling to... 

Poly(2,6-dimethyl-l,4-phenylene oxide)/ high impact polystyrene (PPO/HIPS), 20 360... 

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. 

A.B. Boscoletto, M. Checchin, L. Milan, P. Pannocchia, M. Tavan, G. Camino, and M.P. Luda, Combustion and fire retardance of poly-(2,6-dimethyl-l,4-phenylene ether)-high-impact polystyrene blends. II. Chemical aspects,/. Appl. Polym. Sci., 67(13) 2231-2244,1998. 

Compatible Polyblends. When the polymeric materials are compatible in all ratios, and/or all are soluble in each other, they are generally termed polyalloys. Very few pairs of polymers are completely compatible. The best known example is the polyblend of polyCphenylene oxide) (poly-2,6-dimethyl-l,4-phenylene oxide) with high-impact polystyrene (41). which is sold under the trade name of Noryl. It is believed that the two polymers have essentially identical solubility parameters. Other examples include blends of amorphous polycaprolactone with poly(vinyl chloride) (PVC) and butadiene/acrylonitrile rubber with PVC the compatibility is a result of the "acid-base" interaction between the polar substituents (1 ). These compatible blends exhibit physical properties that are intermediate to those of the components. 

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. 

As we said earlier, the introduction of aromatic units into the main chain results in polymers with better thermal stability than their aliphatic analogs. One such polymer is poly(phenylene oxide), PPO, which has many attractive properties, including high-impact strength, resistance to attack by mineral and organic acids, and low water absorption. It is used, usually blended with high-impact polystyrene (HIPS), to ease processability in the manufacture of machined parts and business machine enclosures. 

Figure 12.43 Relationship between the stress intensity range h.K, corresponding to an arbitary value of Ac/AN 7.6 X 10 mcycle , and the maximum stress intensity factor range AZmax observed at failure for a group of polymers. The polymers are (1) cross-linked polystyrene, (2) PMMA, (3) PVC, (4) LDPE, (5) polystyrene, (6) polysulphone, (7) high-impact polystyrene, (8) ABS resin, (9) chlorinated polyether, (10) poly(phenylene oxide), (11) nylon 6, (12) polycarbonate, (13) nylon 6 6, (14) poly(vinylidene fluoride) (Reproduced with permission from Manson and Hertzberg, CRC Crit. Rev. Macromol. Sci., 1, 433 (1973))...

Another example is poly p-phenylene oxide (PPO) and polystyrene. The General Electric Noryl is a blend of PPO with rubber modified polystyrene (i.e., high impact polystyrene, often known as HIPS) (see Section 6.8). HIPS is much tougher than glassy polystyrene but HIPS miscibility with PPO (Formula 5.13) is based upon HIPS polystyrene content. The improvement in toughness of the brittle PPO by HIPS makes this blend a commercial success. 

The most important commercial polymer is a blend of poly[oxy-(2,6-dimethyl-phenylene)] with high-impact polystyrene (HIPS). The corresponding material exhibits variable characteristics, depending on the PS content. It is a widely used technical polymer in mechanical engineering. Indeed, it exhibits a good impact resistance at very low temperatures in addition to its good thermal and mechanical properties. Its marked electrical insulating character even in wet atmospheres finds applications in electric and electronic industries. 

Homopolymerization of styrene polystyrene PS Mixing with butadiene rubber (SBR) increasing impact strength (high impact PS or PS-HI) Mixing with poly(phenylene ether) (S/PPE) increasing temperature stability ... 

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