Interfacial interaction enhancement between biodegradable poly (butylene adipate-co-terephthalate) and microcrystalline cellulose based on covalent bond for improving puncture, tearing, and enzymatic degradation properties

Interfacial interaction enhancement between biodegradable poly (butylene adipate-co-terephthalate) (PBAT) and microcrystalline cellulose (MCC) to improve mechanical properties has always been a considerable challenge. Herein, a series of copolyesters (MCP) to solve the above problem are prepared from terephthalic acid, adipic acid, 1, 4-butanediol, MCC, glycerol, and citric acid via atmospheric pressure esterification–polycondensation–reduced pressure esterification. The crystallinity of MCP-1 (1 wt% MCC) compared with pure PBAT (P-0) was enhanced by 7.8%. The melting point and the initial decomposition temperature of MCP-1 were 133 ℃ and 402 ℃, respectively. These results demonstrated superior thermal stability of MCP-1. Based on rheological measurements, dynamic mechanical analysis and scanning electron microscope results, within the added amount of 1 wt% MCC, better compatibility, interfacial interaction enhancement, and micro-phase separation nearly disappeared from PBAT and MCC in MCP was displayed. Additionally, the puncture load and tearing strength of the MCP-1 were attained 25.69 N and 197.61 N/mm, which was increased by approximately 113.7% and 66.4% compared to P-0. Surprisingly, the enzymatic degradation of blend PBAT/MCC (P) seemed to be little affected by MCC, whereas the degradation performance of MCP, relative to the P-0 was improved. These results indicate that MCP-1 possessed better compatibility, crystallinity, puncture load, tearing strength, and interfacial interaction. Overall, a new strategy to solve the problem for interface between PBAT and MCC is provided and promotes the application of PBAT in degradable film, foam, and elastomer.