Comb-shaped polyesters of aliphatic dicarboxylic acids and 2-octadecyl-1,3-propanediol: 1. Synthesis and microstructure

Comb-shaped polyesters are prepared by polytransesterification of 2-octadecyl-1,3-propanediol and diphenyl suberate, sebacate, dodecanedioate, tetradecanedioate and hexadecanedioate in turn. The developed melt polycondensation procedure generally results in polyesters with intrinsic viscosities in the range 0.76-1.28 dl g-1. High performance size exclusion chromatography reveals symmetrically shaped traces with peak maxima corresponding to molecular masses in the range 48 000-65 000 by use of the universal calibration. These molecular masses equivalent to degrees of polymerization, 97-124, can be shown to result from total functional group conversions > 98.5%. Detailed C-13 nuclear magnetic resonance investigations of polyester solutions reveal many structural features originating from both main- and side-chain carbons and point to lack of stereoregularity. Infra-red spectra of polyesters reveal characteristic polyester absorption bands including bands indicative of the existence of a crystalline phase.