Change of Melting Temperature for Copolyester by Hest-Treatment

Abstract

The behavior of melting temperature (MT) for annealed copolyester (I) was studied by differential scanning calorimeter (DSC). MT of I of terephthalic acid series was observed to increase by heattreatment below the MT of I. The MT of the annealed I was found to deviate from the Flory equation for the MT of random I. (1) In the case when I is composed of acid or glycol both having long aliphatic chain, the degree of increase in MT is remarkable, while for I having benzene ring the tendency is small. (2) With decreasing crystallinity of I the MT increases. X-ray diffraction measurements show that this increase is independent of the spacing.