PPO/polystyrene blends

Although the first commercial modified PPOs may be considered as derived from such PPO-polystyrene blends, today three distinct classes of material can be recognised ... 

The major interest in polymer blend technology emerged in the late 1960s. One of the catalysts for this interest was the conunercialization of poly(2,6-dimethyl-l,4-phenylene oxide) (PPO)/polystyrene blends by General Electric under the tradename Noryl . It was recognized... 

Poly(phenylene ether). The only commercially available thermoplastic poly(phenylene oxide) PPO is the polyether poly(2,6-dimethylphenol-l,4-phenylene ether) [24938-67-8]. PPO is prepared by the oxidative coupling of 2,6-dimethylphenol with a copper amine catalyst (25). Usually PPO is blended with other polymers such as polystyrene (see PoLYETPiERS, Aromatic). However, thermoplastic composites containing randomly oriented glass fibers are available. 

Polycarbonate-polystyrene blend along with poly(alkylene-dicarboxylate) such as SMA SEBS copolymer for toughening blends of PPO with nylon and polyolefin (proprietary compatibilizer)... 

Commercial examples are notably PVC-ABS blends and the blends of polyphenylene oxide with polystyrene. In the case of PPO-PS blends, it has been shown that the good char forming ability of the PPO greatly helps flame... 

For a fixed strain rate, a comparison of Eq. (74) and experimental data [51, 52] of miscible blends is shown in Fig. 32. Curves 1 and 2 represent, respectively, the PPO/PS blends in compression, and the PPO/PS-pCIS blends in tension.Table 2 lists the three parameters fjf2, CK, and A/f2 used in curves 1 and 2. The unique feature here is the presence of a maximum yield (or strength) for 0 <

nonequilibrium interaction (A < 0). Such phenomenon does not occur in incompatible blends or composite systems. Table 2 also reveals that the frozen-in free volume fractions which are equal to 0.0243 and 0.0211 for polystyrene and for PPO, respectively. These are reasonable values for polymers in the glassy state. In the search for strong blends, we prefer to have —A/f2 > 1, and a larger difference between the yield stresses of blending polymers. 

No data are available for evaluating this latter possibility, although it has been reported that both the solubility and permeability of CO2 In PPO are decreased when PPO is blended with polystyrene (35). ... 

MAJOR APPLICATIONS Automotive, business machine, and electrical/electronics industries. PPO is mainly used to manufacture blends with high-impact polystyrene (HIPS). PPO/nylon, PPO/PBT, and PPO/polyolefin blends are also available on the mcuket. PPO based materials rank first in terms of total consumption among blends based on engineering resins such as nylon, polycarbonate (PC), polyacetal, and reinforced terephthalate polyesters (PET and PBT).( ... 

Polyphenylene oxide (PPO) ru A thermoplastic, linear, non-crystalline polyether obtained by the oxidative polycondensation on 2,6-dimethylphenol in the presence of a copper-amine complex catalyst. The resin has a wide useful temperature range, from below —170 to +190°C, with intermittent use to 205° C possible. It has excellent electrical properties, unusual resistance to acids and bases, and is pro-cessable on conventional extrusion and injection-molding equipment. Because of its high coat PPO is also marketed in the form of polystyrene blends (see Noryf ) that are lower-softening (Tg of PS is about 100°C vs 208°C for PPO), and have working properties intermediate between those of the two resins. 

Figure 8.28 Glass-transition temperatures, Tg, of poly(2,6-dimethyl-1,4-phenylene oxide)-Wend-polystyrene (PPO/PS) blends versus mass traction of PPO, Afppo. The full curve was calculated from equation (8.71) as circles. ACp, = 0.0671 cal K" g ACps = 0.0528 cal K" g" Tgi = 378 K, Tg2 = 489 K. PPO was designated as component 2 (114,120).

Miscible blends are less commonly found. One of the most studied blends is that between polystyrene and poly(phenylene oxide) (PPO). This blend is miscible in all proportions and the films of the blends are optically clear. Only one glass transition intermediate in temperature between the Tg s of polystyrene and PPO has been reported. The compositional dependence of the Tg of a compatible... 

Prest and Portermeasured the viscoelastic properties of several poly(2,6-dimethylphenylene oxide)/polystyrene (PPO/PS) blends at T= 220 C. 

As noted earlier, the first major engineering polymer blend was poly(2,6 dimethyl-1,4-phenylene oxide) (PPO) with impact polystyrene. PPO and polystyrene exhibit miscibility over the entire composition range and thus mechanical compatibility. PPO/impact polystyrene blends were commercialized by General Electric in the late 1960s [52, 53] under the trade-... 

Fig. 2. Glass-transition temperature, T, for two commercially available, miscible blend systems (a) poly(phenylene oxide) (PPO) and polystyrene (PS) (42) ...

Blends of PPO with a styrenic material, usually, but not always, high-impact polystyrene. (Referred to below as Styrenic PPOs.)... 

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