Semicrystalline Polyamide Engineering Thermoplastics Based on the Renewable Monomer, 1,9-Nonane Diamine: Thermal Properties and Water Absorption

A series of poly(1,9-nonamethylene adipamide-co-1,9-nonamethylene terephthalamide) copolymers were produced using melt polymerization and the thermal properties, crystal structure, and moisture uptake characterized. The results confirmed that the copolymers exhibit isomorphism. As expected, glass transition temperature and the apparent melting temperature increased with increasing terephthalmide content. Using the difference in the apparentmelting temperature to the crystallization temperature as a measure of relative crystallization rate, it was observed that crystallization rate decreased as the terephthalamide content of the copolymer was increased from 0 to 50mole % but then sharply increased when increased beyond 50mole %. This behavior may be the result of extensive inter-and intramolecular interactions in the melt associated with terephthalmide units in the polymer chain that nucleate crystallization upon cooling below the equilibrium melting temperature. Comparing the thermal properties of copolymers possessing an excess of terephthalmide units to the commodity polyamide Nylon 6,6, it is believed that these copolymers may have utility as partially renewable engineering thermoplastics.