Polyarylate plastic

Bisphenol A. One mole of acetone condenses with two moles of phenol to form bisphenol A [80-05-07] which is used mainly in the production of polycarbonate and epoxy resins. Polycarbonates (qv) are high strength plastics used widely in automotive appHcations and appHances, multilayer containers, and housing appHcations. Epoxy resins (qv) are used in fiber-reinforced larninates, for encapsulating electronic components, and in advanced composites for aircraft—aerospace and automotive appHcations. Bisphenol A is also used for the production of corrosion- and chemical-resistant polyester resins, polysulfone resins, polyetherimide resins, and polyarylate resins. 

Uses. A principal use of thionyl chloride is in the conversion of acids to acid chlorides, which are employed in many syntheses of herbicides (qv), surfactants (qv), dmgs, vitamins (qv), and dyestuffs. Possible larger-scale appHcations are in the preparation of engineering thermoplastics of the polyarylate type made from iso- and terephthaloyl chlorides, which can be made from the corresponding acids plus thionyl chloride (186) (see Engineering plastics). 

For a part to exhibit stmctural stiffness, flexural moduH should be above 2000 N/mm (290,000 psi). Notched l2od impact values should be deterrnined at different thicknesses. Some plastics exhibit different notch sensitivities. For example, PC, 3.2 mm thick, has a notched l2od impact of 800 J/m (15 fdbf/in.) which drops to 100 J/m (1.9 fflbf/in.) at 6.4-mm thickness. On the other hand, one bisphenol A phthalate-based polyarylate resin maintains a 250-J /m (4.7-fdbf/in.) notched l2od impact at both thicknesses. Toughness depends on the stmcture of the part under consideration as well as the plastic employed to make the part. Mechanical properties, like electrical properties, ate also subject to thermal and water-content changes. 

Both PET and PBT resin serve some of the same markets as other plastics. Nylon, unsaturated polyester fiber glass, phenoHc, PC, and polyarylate resins sometimes compete for the same molded part. 

Polyarylate (PAR)-b-PSt and PAR-b-PMMA for compatibiiizers are described 135,39,40). The addition of PAR-b-PSt (1-10 parts) to 100 parts of a blend of PAR-PSt (7w-3w) resulted in improvement of the tensile and flexural modulus (Fig. 4), and PSt dispersed particles were diminished from 1-5 microns to an order that is undetectable by SEM, indicating the excellent, compatibilizing effect of the block copolymer. The alloy thus formed exert the characteristic of PAR, an engineering plastic, as well as easy processability of PSt. Addition of PAR-b-PMMA (3 or 8 parts) to 100 parts of a blend of PAR-polyvinylidenefluoride (PVDF) (7w-3w) resulted in improved microdispersed state of PVDF due to compatibility of PMMA with PVDF, while segregation of PVDF onto the surface was controlled. 

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. 

Dendritic analogues of engineering plastics-A general one-step synthesis of dendritic polyaryl ethers [T. M. Miller, T. X. Neenan, E. W. Kwock, S. M. Stein, Macromol. Symp. 1994, 77, 35-49]. 

To the range of engineering plastics were added polyethylene and polybutylene tereph-thalates (PET and PBT), as well as General Electric s polyethers, the PPO (polyphenylene oxide) produced through polymerization of 2,6-xylenol and the Noryl plastic produced by blending PPO with polystyrene. Other special polymers, derived like the polycarbonates from bisphenol A, were added to this range polyarylates, polysul-fones, polyetherimides. 

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...

Specialty polymers achieve very high performance and find limited but critical use in aerospace composites, in electronic industries, as membranes for gas and liquid separations, as fire-retardant textile fabrics for firefighters and race-car drivers, and for biomedical applications (as sutures and surgical implants). The most important class of specialty plastics is polyimides. Other specialty polymers include polyetherimide, poly(amide-imide), polybismaleimides, ionic polymers, polyphosphazenes, poly(aryl ether ketones), polyarylates and related aromatic polyesters, and ultrahigh-molecular-weight polyethylene (Fig. 14.9). 

The epsilon CTPZ, however, is a special case which requires the shearing process to be activated at the same time that a craze is developing and in locations directly adjacent to the craze. This is unusual since both craze and shear band initiate from essentially the same location, the crack tip. The same polymer can exhibit either the DCG process without epsilon plastic zones or the DCG process with epsilon plastic zones depending upon the conditions existing at the crack tip. Epsilon CTPZs have been identified in several ductile amorphous polymers BPA-polycarbonate " " , BPA-polyestercarbonate polyphenylsulfone and BPA-polyarylate... 

Investigation of a wide range of block copolymers, consisting of various flexible (polydimethylsiloxane, polybutadiene) and rigid (polycarbonate, polysulphone, polyarylate) phases [44], shows that irrespective of the chemical nature of copolymer, content and molecular weight of blocks as well as pressure and composition of the hydrocarbon mixture, sorption, and mass transfer of alkanes take place primarily in the rubbery phase. The phenomenon of plasticization of polymers by hydrocarbons was demonstrated by baromechanical methods [7,45 8]. Figure 9.13 shows baromechanical curves for the block copolymer... 

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. 

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. 

Durd . (Hoechst Ceianese/Engineering Plastics] Polyarylate resin engineering therW)plastic for glazing and lifting applies., lenses, automotive panels, appliance parts, solar collection panels. 

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). 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and fumes NFPA Health 0, Flammability 1, Reactivity 0 Uses Plasticizer for PVC, PVB, PS, cellulosics chemical intermediate comonomer for polyarylate resins perfume fixative Manuf./Distrib. Aldrich http //www.sigma-aldrich.com] ChemService http //www.chemservice.com] Fluka http //www.sigma-aldrich. com] M orflex http //www.morflex.com] Unitex http //www. unitexchemical. com Trade Name Synonyms Bisomer DMIP (Standard) [Laporte Perf. Chems. http //www.laporteperform.com]] M orf lex 1129 [Morflex http //www.morflex.com]] Uniplex 270 [U n itex http //www. unitexchemical. com]... 

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