The effect of furan molecular units on the glass transition and thermal degradation temperatures of polyamides

Interfacial polymerization is used to prepare biobased furan polyamides from the carbohydrate-derived monomer, 2,5-furan dicarboxylic acid, aromatic diamines, and varying chain length aliphatic diamines. The molecular weights of the furan polyamides variations range 10,000-70,000 g/mol. These biobased polyamides have improved solubility relative to petroleum-derived polyamides affording enhanced processability options. The glass transition temperatures (T-g) of the biobased furan polyamides are higher than that of aliphatic analogs, but lower than phenyl-aromatic analogs. The T-g for these furan polyamides are as high as 280 degrees C. Also, the furan polyamide glass transition temperatures increase with decreasing aliphatic diamine chain length similar to results exemplified in petroleum-based nylons. Group contribution parameters are determined for furans to enable simple prediction of the glass transition temperature and decomposition temperature of furan polyamides. The molar glass transition function for the furan is calculated to be 27.6 +/- 1.5 Kkg/mol. Thermal analysis measurements of the biobased furan polyamides have maximum thermal degradation temperatures at 350 degrees C or higher, similar to that of aliphatic polyamides when scaled with the number average molecular weight. The molar decomposition temperature functions are determined to be 37 Kkg/mol for furans bonded to aliphatic units and 42 Kkg/mol for furans bonded to phenyl units. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45514.