Synthesis and some properties of a series of polyterephthalates having side‐chain branching

摘要

AbstractPolyterephthalates made from terephthalic acid and a series of cyclic alkylene carbonates to give short side‐chain branching were amorphous. TheTgincreased from poly(ethylene terephthalate) to poly(1,2‐propylene terephthalate), and then an expected decrease inTgresulted from a further increase in side‐chain length. The initial increase inTgwas attributed to increased chain rotational energy barriers. Further alkyl substituent length increases did not significantly raise these barriers but lowered chain packing densities. New group contribution factors for polyesterTgcalculations were derived from the data. Interpretations of the dynamic mechanical spectra showed an apparent decrease intrans‐glycol unit fraction with increasing alkyl substituent length along with several interchain