ABSTRACT
VIII-A-5}, poly(3-hydroxybutyric acid) {VIII-A-6}, and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) {VIII-A7}, and the polylactones, such as polycaprolactone {VIII-A-8}, are biodegradable. They are often used in medical applica-
362ChapterVIII
tionsoras"environmentallyfriendly"packaging[1].Aliphaticpolyestersmayalsobeincorporatedintopolyurethanes{IXB-3,IX-B-4}andothercomplexpolymersystems.Aromaticpolyesters,inwhichtheacidcomponentisabenzenedicarboxylicacid(suchasphthalicorterephthalicacid)oranaphthenedicarboxylicacid,arefamiliarmaterials.Themostcommonispoly(ethyleneterephthalate)(PET){VIII-B-1},whichformsthebasisofmost"polyester"fibers(suchasDacron), films(suchasMylar),tapebackings,andclearplasticbeveragebottles.Almost3billionlb(1.4billionkg)ofPETwereproducedintheUnitedStatesin1995[2].Otheraromaticpolyestersandcopolymersareputtospecialusesinfiber,tape,and packagingapplications[1];severalarecommerciallysignificant.In1995,U.S.manufacturersproduced:1.5billionlb(0.68 billionkg)ofunsaturatedpolyesters,suchaspoly(4,4'-dipropoxy-2,2-diphenylpropanefumarate){VIII-A-ll},poly(diallyl phthalate){VIII-B-7},andpoly(diallylisophthalate){VIII-B-8};900millionlb(408billionkg)ofpoly(bisphenolAcarbonate){VIII-B-11},alsoknownasLexan(GeneralElectric)anditsblends;and270millionlb(122.5billionkg)of poly(butyleneterephthalate){VIII-B-4}[2].
