反应性增容改性生物可降解聚乙醇酸(PGA)/聚对苯二甲酸–己二酸丁二醇酯(PBAT)共混物的力学性能与热稳定性

Mechanical Properties and Thermal Stability of Biodegradable Polyglycolic Acid (PGA)/Poly(butylene Adipate-Co-Terephthalate) (PBAT) Blends Modified by Reactive Compatibilization

摘要: 本研究以聚对苯二甲酸–己二酸丁二醇酯(PBAT)为增韧剂对生物基可降解塑料聚乙醇酸(PGA)进行增韧改性，并采用二苯基甲烷二异氰酸酯(MDI)作为反应增容剂实现原位增容。通过傅里叶变换红外光谱(FTIR)、差示扫描量热法(DSC)、热重分析(TGA)等测试结果表明，MDI已成功与PGA/PBAT发生反应。随着PBAT含量的增加，PGA/PBAT共混物的冲击强度随之增加。当PBAT含量达到70%时，PGA与PBAT之间的界面结合力增强，使共混物的冲击强度从2.5 kJ/m²大幅提升至55.6 kJ/m²。由于PGA与PBAT的熔融温度(T_m)存在明显差异，链延伸效应降低了共混物的结晶度和结晶温度，这也有利于韧性的提升；同时，与PBAT共混可改善PGA的热稳定性。综上，本研究成功制备出一种韧性与热稳定性均得到增强的新型生物可降解共混材料。

Abstract: In this study, poly(butylene adipate-co-terephthalate) (PBAT) was used as a toughening agent to modify polyglycolic acid (PGA), a bio-based biodegradable plastic, for toughness enhancement, and diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer to achieve in-situ compatibilization. Results from Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and other characterizations demonstrated that MDI had successfully reacted with PGA/PBAT. With the increase in PBAT content, the impact strength of the PGA/PBAT blends increased accordingly. When the PBAT content reached 70%, the interfacial adhesion between PGA and PBAT was enhanced, leading to a significant increase in the impact strength of the blends from 2.5 kJ/m² to 55.6 kJ/m². Due to the significant difference in melting temperature (T_m) between PGA and PBAT, the chain extension effect reduced the crystallinity and crystallization temperature of the blends, which was also beneficial to toughness improvement; meanwhile, blending with PBAT could enhance the thermal stability of PGA. In conclusion, this study successfully prepared a novel biodegradable blend material with improved toughness and thermal stability.