乙酰丙酮锌催化扩链增容PBAT类玻璃体

Zinc(II)acetylacetonate catalyzed chain extension and compatibilization of PBAT vitrimers

与传统塑料相比,现有的聚对苯二甲酸-己二酸丁二酯(PBAT)仍存在力学性能低、热稳定性和耐久性差的缺点。因此,为了增强PBAT的综合性能,利用乙酰丙酮锌催化环氧扩链剂ADR扩链增容PBAT类玻璃体,研究了催化剂含量对PBAT类玻璃体化学结构、分子量、热性能、力学性能和水解降解性能的影响。结果表明,PBAT的端羧基和端羟基与ADR的环氧基之间存在相互作用。乙酰丙酮锌的催化介入可以有效促进ADR上的环氧基团开环,导致生成大量交联支链结构和大量β-羟基,与PBAT上丰富的酯基之间发生酯交换反应,从而形成了更致密的交联网络结构。乙酰丙酮锌可在一定程度上提高PBAT类玻璃体的分子量,但降低了PBAT类玻璃体结晶温度和熔点。适量乙酰丙酮锌的加入可明显提升PBAT类玻璃体的力学性能,当乙酰丙酮锌质量分数为0.1%时,PBAT类玻璃体拥有最好的耐久性和水解降解性,在4次拉伸循环后仍能保持较高的断裂伸长率(684%)和拉伸强度(18.94 MPa)。

Compared to traditional plastics,existing poly(butyleneadipate-co-terephthalate)(PBAT)products still exhibit weaker mechanical properties,thermal stability,and durability.Therefore,in order to enhance the comprehensive performance of PBAT products,the chain extension and compatibilization of epoxy chain extender ADR for PBAT vitrimers were catalyzed by zinc(II)acetylacetonate.The effects of catalyst contents on the chemical structure,molecular weight,thermal properties,mechanical properties and hydrolytic degradation properties of PBAT vitrimers were studied.The results indicate that there is an interaction between the carboxyl or hydroxyl end group of PBAT and the epoxy group of ADR.The catalytic intervention of zinc acetylacetone can effectively promote the ring opening of epoxy groups on ADR,resulting in the formation of a large number of cross-linked branched chain structures and a large amount ofβ-Hydroxyl groups which undergo ester exchange reactions with the abundant ester groups on PBAT,forming a denser cross-linked network structure.Zinc acetylacetonate can increase the molecular weight of PBAT vitrimers to some extent,but reduce the crystallization and melting temperatures of PBAT vitrimers.Adding zinc(II)acetylacetonate in moderation can significantly improve the mechanical properties of PBAT vitrimers,when the mass fraction of zinc(II)acetylacetonate is 0.1%.The PBAT vitrimers has the best durability and hydrolysis degradation performances,and can still maintain a high elongation at break of 684%and good tensile strength of 18.94 MPa after four tensile cycles.