Zinc(Ⅱ)acetylacetonate catalyzed chain extension and compatibilization of PBAT vitrimers
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 of β-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)acetylaceto-nate is 0.1%.The PBAT vitrimers has the best durability and hydrolysis degradation performances,and can still maintain a high elon-gation at break of 684%and good tensile strength of 18.94 MPa after four tensile cycles.
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