Phenohc polyethers

The tendency of aliphatic ethers toward oxidation requires the use of antioxidants such as hindered phenoHcs (eg, BHT), secondary aromatic amines, and phosphites. This is especially tme in polyether polyols used in making polyurethanes (PUR) because they may become discolored and the increase in acid number affects PUR production. The antioxidants also reduce oxidation during PUR production where the temperature could reach 230°C. A number of new antioxidant products and combinations have become available (115,120,124—139) (see Antioxidants). 

Reactive (unsaturated) epoxy resins (qv) are reaction products of multiple glycidyl ethers of phenoHc base polymer substrates with methacrylic, acryhc, or fumaric acids. Reactive (unsaturated) polyester resins are reaction products of glycols and diacids (aromatic, aUphatic, unsaturated) esterified with acryhc or methacrylic acids (see POLYESTERS,unsaturated). Reactive polyether resins are typically poly(ethylene glycol (600) dimethacrylate) or poly(ethylene glycol (400) diacrylate) (see PoLYETPiERs). 

As of 1992, the first specialty platable plastic, acrylonitrile—butadiene—styrene (ABS) terpolymer (see AcRYLONiTRimpolymers, absresins), is used in over 90% of POP applications. Other platable plastics include poly(phen5iene ether) (see Polyethers), njion (see Polyamides), polysulfone (see Polymers CONTAINING SULFUR), polypropylene, polycarbonate, phenoHcs (see Pphenolic resins), polycarbonate—ABS alloys, polyesters (qv), foamed polystyrene (see Styrene plastics), and other foamed plastics (qv). 

Poly(phenylene ether) Alloys. Poly(phen5lene ether) resins (91), composed of phenoHc monomers, have a very high T. The commercial resins are based on 2,6-dimethylphenol. The resin is produced by oxidative polymerization in toluene solution over an amine catalyst (see also PoLYETHERS, aromatic). 

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