SYNTHESIS AND PROPERTIES OF POLY(DIOXYNAPHTHYLENEISOPHTHALOYL)S WITH VARIOUS ISOMERIC NAPHTHYLENE LINKS

By condensation of 1,4-, 1,5-, 1,6-, 2,3-, 2,6-, and 2,7-naphthalenedi ol (ND) isomers with a isophthaloyl chloride six aromatic polyesters w ere prepared, and after removal of low molecular weight materials by e xtraction with acetone their properties were investigated. Effects of the isomerism of the naphthylene units on the properties of the polyes ters were discussed, All the polyesters except one derived from 2,7-ND were soluble in a mixed solvent of phenol/p-chlorophenol/1,1,2,2-tetr achloroethane (TCE). Weight-average molecular weight of the polymer de rived from 2,3-ND having the lowest inherent viscosity of 0.10 dL/g wa s measured to be 12,200 g/mol in TCE by means of a laser light scatter ing spectrometer. Polydispersity of this sample was determined to be 1 .59 by a gel permeation chromatography with o-chlorophenol at 100-degr ees-C. Glass transition temperatures of the polymers ranged from 144 t o 195-degrees-C, depending on their molecular weight and chain structu re. The polyesters derived from 1,6-and 2,3-NDs were amorphous and all the others were crystalline. Melting temperatures (T(m)) of the polym ers range from 341-degrees-C to 417-degrees-C and the polymer derived from 2,6-ND showed the highest T(m). All the polymers had initial deco mposition temperature higher than 400-degrees-C and showed residue mor e than 50 wt% at 600-degrees-C.