Polymerization Kinetics Optimization for Synthesizing Biobased Long Carbon‐Chain Polyamide Elastomers With Tunable Hardness and Mechanical Properties

ABSTRACT Biomass‐based long carbon‐chain polyamide elastomers (LCPAEs) have attracted widespread attention due to their favorable physical and mechanical properties, excellent flexibility, and good heat resistance, and so on. However, the precise structure and molecular weight control of long carbon‐chain polyamide (LCPA) hard segments remains underexplored, yet is pivotal for fabricating high‐performance LCAPEs. Herein, the effects of temperature and time on the polymerization of dicarboxylic‐terminated polyamide 1010 prepolymer (PA1010dC) are detailedly studied by end‐group titration technique, and the reaction kinetic equation of PA1010dC prepolymerization stage is established. By optimizing the polymerization process based on kinetic parameters, different PA1010dC with ideal chemical structures and molecular weights (ca. 500 ~ 2700 g·mol −1 ) is obtained. Subsequently, a series of LCPAEs with various wholly‐biobased hard segment (PA1010dC) contents are successfully prepared via polycondensation reaction with polytetramethylene ether glycol (PTMG) soft segments. The resulting LCPAEs show excellent comprehensive properties that can be tuned orientationally by varying the relative content of hard and soft segments. Their Shore hardness, tensile strength, and elongation at break can be varied within 20–55 D, 13–45 MPa, and 340%–1080%, respectively. This work provides a facile method for the efficient and stable preparation of LCPA hard segments and corresponding biomass LCPAEs.