Hyperbranched PBAT polyester and preparation method thereof

Abstract

The invention belongs to the technical field of biodegradable materials, and particularly relates to hyperbranched PBAT polyester and a preparation method thereof.The hyperbranched PBAT polyester is obtained by synthesizing a series of hydroxyl-terminated hyperbranched polyesters (HBPE) with specific hydroxyl values through gradual reaction of a core unit and a monomer and then copolymerizing the hyperbranched polyesters with terephthalic acid, 1, 4-butanediol and adipic acid. The active terminal hydroxyl group of HBPE can participate in esterification and polycondensation reaction, and can be used as polyhydric alcohol to extend the linear structure of a molecular chain into a branched structure, so that the crosslinking density of PBAT is improved, and the strength of PBAT is improved; meanwhile, the polycondensation time is shortened, and the product acid value is lower; the HBPE molecules have a hyperbranched structure similar to a sphere, the molecules are not tangled, after the PBAT molecular chain is introduced, the biodegradable polyester has the characteristics of low viscosity and high flowability, and the polyester is particularly suitable for biodegradable products such as special-shaped injection molding parts and thin-wall injection molding parts with complex structures.

Description

technical field [0001] The invention belongs to the technical field of biodegradable materials, and in particular relates to a hyperbranched PBAT polyester and a preparation method thereof. Background technique [0002] The increasingly serious "white pollution" problem has attracted great attention from countries all over the world, and it is imperative to develop biodegradable plastics. Polybutylene terephthalate-co-polybutylene adipate (PBAT) combines the degradation properties of aliphatic polyesters and the mechanical properties of aromatic polyesters, and has good ductility and elongation at break. However, most of PBAT cannot be used alone due to its low melt strength and low mechanical strength. It needs to be blended with PLA and other degradable materials for injection molding, while PLA and other biodegradable polyesters are expensive and hinder The popularization and application of degradable materials; the melt viscosity of PBAT is too high, the fluidity is poo...

AI Technical Summary

Problems solved by technology

In the prior art, the method to reduce and improve the fluidity of PBAT melt is mainly to add flow aids such as hyperbranched polyester after the PBAT polymerization is completed, but the carboxyl group content in commercially available PBAT products is mostly below 50mol / t, and some products Even up to 10mol / t, these commercially available products have less active carboxyl groups available for reaction, the utilization rate of additives is low, and some ungrafted small-molecule polyesters are easy to migrate; moreover, the blending method needs to combine PBAT with flow Secondary heating of the auxiliary agent will easily lead to thermal degradation of PBAT, causing a series of problems such as acid value increase and yellowing; CN105237750B adds polyol trimethylolethane in the esterification stage to increase the molecular weight of the product, but the polyester When the molecular weight increases, the melt viscosity also increases simultaneously

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