A method for controlling the transformation of crystal form ii to crystal form i by adding liquid additives that can be matched to the melt processing of isotactic poly-1-butene

Abstract

The invention discloses a method for regulating the transformation of crystal form II-crystal form I by adding liquid additives that can be matched with the melt processing of isotactic poly-1-butene. The liquid additives are added during the processing to rapidly transform them into thermodynamically stable ones. The time required to basically complete the crystallization transformation is controlled within 2 minutes, which can avoid the loss of required mechanical properties or the dependence on specific processing methods caused by the promotion of II-I transformation through modification methods such as copolymerization.

Description

technical field [0001] The present invention belongs to the technical field of polymer processing, and more particularly, relates to a crystal form II formed by promoting isotactic poly-1-butene (iP-1-B) from melt processing by adding suitable liquid additives Rapidly transforms to Form I and can match the technical approach of the iP-1-B melt processing process. Background technique [0002] iP-1-B has many excellent properties, such as good flexibility and bending, brittle crack resistance, impact resistance, environmental stress crack resistance, high temperature creep resistance, low temperature freeze crack resistance, thermal insulation and self-cleaning It is called "plastic gold" and has potential wide applications in many fields, such as processing and manufacturing hot water pipes and fittings. However, iP-1-B usually forms a thermodynamically unstable II crystal rather than a thermodynamically stable I crystal during the melt processing process, and it is difficu...

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Problems solved by technology

However, iP-1-B usually forms a thermodynamically unstable II crystal instead of a thermodynamically stable I crystal during melting processing, and it is difficult to find an effective I crystal nucleating agent, resulting in the occurrence of II→I after processing. The transformation causes the product to be unstable in size and performance, and it usually takes two weeks or more during the storage period to complete the transformation to achieve stability in size and performance

This not only prolongs the processing cycle of iP-1-B products to a large extent, but also causes difficulties in the precise control of product size during melting processing, which limits the development of processing and manufacturing applications of iP-1-B products

[0003] The current prior art shows that by adjusting the isotacticity, carrying out monomer copolymerization, and applying stretching, the CO 2 Assisted foaming, adding auxiliary components and other methods can speed up the II-I transformation to varying degrees, but there will be a certain loss of mechanical properties, limited by specific processing methods and product forms, and the regulation efficiency is not high enough to be compatible with Problems such as the matching of the melt processing process of iP-1-B are difficult to promote in the processing and application field of iP-1-B

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