A kind of multi-block copolyester and preparation method thereof

Abstract

The general structural formula of the multi-block copolyester disclosed in the present invention is: in the formula, R represents the hydrocarbon group of diisocyanate, x, a, b are all integers from 2 to 10, and y and c are integers from 0 to 8 , and when x=b, y≠c, when y=c, x≠b, j, k, n are all integers greater than 5, and the intrinsic viscosity of the multi-block copolyester is 0.7~4.7dL / g , the melting point is 70-240°C, the tensile strength is 10-67MPa, and the elongation at break is 20-1100%. The invention also discloses a preparation method of the multi-block copolyester. The multi-block copolyester prepared by the invention has high melting point and molecular weight, good mechanical properties, and better controllability and repeatability than the traditional transesterification method, which can make the multi-block copolyester prepared by it have a wider application range. for extensive.

Description

technical field The invention belongs to the technical field of block copolyester and its preparation method. Background technique Due to the widespread use of traditional plastic materials, the problem of plastic pollution is becoming increasingly serious. Aliphatic polyester, as a class of environmentally friendly biodegradable materials, has been favored by people. However, due to the difficulty in preparing high-molecular-weight aliphatic polyesters by conventional methods, and their poor mechanical properties and thermal stability, the application of aliphatic polyesters is severely restricted. Therefore, in order to expand the application range of aliphatic polyesters, it is necessary to increase the molecular weight of aliphatic polyesters and modify aliphatic polyesters. Copolymerization with other monomers or polymers is one of the common methods to improve the properties of aliphatic polyesters. For example, Amin Cao et al. (Amin Cao, Takashi Okamura, Kazuo Nak...

AI Technical Summary

Problems solved by technology

Although this method can prepare block copolyesters, there are still some following defects. First, the degree of transesterification is difficult to control, especially when the degree of transesterification is too large, even random copolyesters are obtained, so the method The reproducibility is poor; secondly, the thermal degradation of the polyester is obvious when reacting at a higher temperature, so the molecular weight of the polyester will be reduced, thereby reducing its mechanical properties