Polyaryl sulfone plastic

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Polyaryl sulfones are injection moldable or extrudabie on standard processing equipment. These plastics are used for meter housings, light fixture sockets, aircraft components, household appliances, hardware, and film. 

Fortunately, the deficiencies of both the classic thermosets and general purpose thermoplastics have been overcome by the commercialization of a series of engineering plastics including polyacetals, polyamides, polycarbonate, polyphenylene oxide, polyaryl esters, polyaryl sulfones, polyphenylene sulfide, polyether ether ketones and polylmides. Many improvements in performance and processing of these new polymers may be anticipated through copolymerization, blending and the use of reinforcements. 

Sauers, M.E., Polyaryl Sulfones, in Engineering Plastics, vol. 2, Engineered Materials Handbook, ASM International, Metals Park, OH, 1988, p. 146. 

The engineering thermoplastie, Polyaryl Sulfone (Asirel 360 plastic)/ supplied by the 3M Company is structurally useful at temperatures of up to 260 °C. The manufacturer s literature mentions welding by thermal, ultrasonic, or solvent techniques. Air Force studies evaluated sandblasting, acid etch, and solvent-wash methods, with the latter effective for surface preparation for steel—plastic—steel bonds. 

Figure 18.18 Map of dielectric properties of engineering plastics. Among engineering plastics, SPS (impact modified and GF-reinforced HB and IR grades) has very low dielectric dissipation factor and dielectric constant following those of fluorocarbon polymers. PSF, polysulfone PPE, poly(phenylene ether) PES, poly(ether sulfone) PAr, polyarylate...

Aromatic polyesters having an amorphous molecular structure. Compared with other amorphous engineering plastics in terms of heat resistance, polyarylates are generally positioned between polycarbonate on the low side and sulfone and polyether polymers on the high side. Compared with crystalline and semi-crystalline engineering plastics, polyarylate resins offer better resistance to warping, and generally comparable mechanical properties. 

The term HT-thermoplastics is used for polymers, which in the absence of fillers, have a continuous-use temperature above approx. 200 °C. In contrast, standard plastics, such as PVC, polyethylene or polystyrene, have continuous-use temperatures of the order of 100 °C. In addition to their high temperature stability, HT-thermoplastics, in general, possess good resistance to chemicals and usually also low flammability. Among the most important HT-thermoplastics are polyphenylene sulfides (PPS), polysul-fones (PSU), polyether sulfones (PES), polyether imides (PEI), polyetherether ketones (PEEK) and polyarylates (PAR). 

Several polyarylates are liquid cr stalline materials and are widely used as industrial plastics. The synthesis of polyarylates from industrially used diphenols and various diacids has been investigated by Moore and Stupp (Moore, 1990) who published a procedure based on a carbodiimide-mediated esterification in the presence of dimetliylaminopyridinium p-toluene sulfonate (DPTS). 

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