Preparation method of long chain branched polyethylene

Abstract

The invention discloses a preparation method of long chain branched polyethylene. The preparation method comprises the following steps of: A, under the action of an initiator, performing a graft reaction on a vinyl monomer containing a polyfunctional group, and a polyethylene substrate under the synergistic action of a second olefin monomer to obtain grafted polyethylene of which the side chain is provided with a functional group; B, and performing a branching reaction on the grafted polyethylene obtained in the step A and an additive to obtain long chain branched polyethylene in which the additive is taken as a core and a polyethylene macromolecule is taken as an arm. Due to the adoption of the preparation method disclosed by the invention, long chain branched polyethylene with high melt strength can be produced, the branching degree is relatively controllable, the cost is low, the production efficiency is high, and superior foaming performance is realized. Expanded polyethylene with various functionality such as a wood-plastic composite expanded material added with wood fiber, an enhanced polyethylene expanded material added with glass fiber, a fire-proof polyethylene expanded material added with an expansion flame retardant and the like can be prepared according to different use requirements.

Description

technical field [0001] The invention relates to organic chemical products, in particular to a preparation method of long-branched polyethylene. Background technique [0002] Polyethylene resin is one of the most widely used thermoplastic polymer materials. The polyethylene foam material obtained by foaming technology from polyethylene resin is widely used because of its soft quality, good toughness, excellent elastic recovery performance, and non-toxicity. However, among the types of polyethylene resins, only low-density polyethylene and linear low-density polyethylene can be directly used for foaming, while high-density polyethylene cannot be used for foaming due to its lack of branched structure and low melt strength. forming. However, on the other hand, although low-density polyethylene and linear low-density polyethylene have relatively good foaming properties, due to their high melt flow rate, it is difficult to process foamed boards with a thickness of more than 20 c...

AI Technical Summary

Problems solved by technology

However, generally speaking, the irradiation method is limited by the thickness, and has disadvantages such as high cost and limited radiation source; the peroxide cross-linking method has defects such as low branching rate, easy degradation or excessive cross-linking, and difficulty in stabilization; and The silane cross-linking method also needs water as a cross-linking agent, and then cross-links after completing the product. In fact, it lacks other industrial production value except for pipes.

It can be seen that there are different defects in the above several commonly used methods, which cannot satisfy the long-branching and industrial application of polyethylene.

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