A kind of low molecular weight, high trans-1,4-polyisoprene and preparation method thereof

Abstract

A low molecular weight, high trans-1,4-polyisoprene and a preparation method thereof. The invention belongs to the field of catalytic polymerization of conjugated dienes. The invention aims to solve the technical problem that the cyclization side reaction is difficult to control in the existing process of cationic polymerization of isoprene, resulting in the loss of double bonds. Starting from suppressing the side reaction of cyclization, the protonic acid (bissulfonylimide protonic acid containing different substituents) is used as the catalyst, and the ionic liquid is used as the solvent to reduce the electron cloud of the double bond of the molecular chain. Density is used to reduce side reactions of cyclization, and a low-molecular-weight, high-trans-1,4-polyisoprene and a preparation method thereof are provided. The microstructure composition of a low molecular weight, high trans-1,4-polyisoprene of the present invention consists of 90% to 98% trans-1,4-polyisoprene and 2% to Composed of 10% 3,4-polyisoprene; its number average molecular weight is 500g / mol-3000g / mol, molecular weight distribution is 1.2-3.0; double bond retention rate DB is 82%-94.

Description

A kind of low molecular weight, high trans-1,4-polyisoprene and preparation method thereof technical field The invention belongs to the conjugated diene catalytic polymerization field, be specifically related to a kind of low molecular weight, high trans-1,4-polyiso Pentadiene and its preparation method. Background technique Trans-1,4-polyisoprene is used as a class of important material intermediates in materials such as tires, films and adhesives. It is widely used in the preparation of materials. Acid-catalyzed cationic polymerization of isoprene yields high trans‑1,4 low molecular weight polymers have been extensively studied. However, because the cyclization or branching side reactions in the polymerization process are difficult to control effectively, leading to resulting in the absence of double bonds in the polymer chain. [0003] For a long time, Lewis catalyst systems have received a lot of attention. e.g. BF 3 Derivatives, AlCl 3 , SnCl 4 ...

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Problems solved by technology

[0004] The present invention aims to solve the technical problem that the cyclization side reaction is difficult to control in the process of existing cationic polymerization of isoprene, resulting in the loss of double bonds, starting from the suppression of the cyclization side reaction, to study less but cheap protonic acid (containing different The substituent's bis-sulfonimide protonic acid) is used as a catalyst, and an ionic liquid is used as a solvent to reduce the side reaction of cyclization by reducing the electron cloud density of the double bond of the molecular chain, thereby providing a low-molecular-weight, high-trans-1 , 4-polyisoprene and preparation method thereof

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