奇偶PA5X晶体的制备及其性能表征OA

This study employed bulk melt polycondensation to synthesize a series of odd-even polyamide PA5X(X=6,8,10,12,14)materials using bio-based 1,5-pentanediamine and dicarboxylic acids of varying chain lengths as monomers.The effects of dicarboxylic acid chain length on the condensed-phase structure and properties of these materials were systematically investigated.The study revealed that increasing the carbon chain length X of the dicarboxylic acid enhances the molecular chain conformation mobility of PA5X,facilitating crystallization and the formation of more complex single-crystal morphologies.Concurrently,the strength of single-crystal hydrogen bonds also increases with X.In dilute solutions,longer-chain PA5X readily forms highly ordered monoclinic α-crystals(independent of solvent).Performance studies indicate that the water absorption rates of PA56 and PA58 significantly increase over time,reaching 2.41%and 1.53%respectively after 30 days.In contrast,the water absorption rates of longer-chain polyamides such as PA510,PA512,and PA514 show smaller increases.It is hoped that the above research will provide theoretical support for the development of high-performance polyamides.