Method for preparing aliphatic polycarbonate through continuous solution polymerization method

Abstract

The invention provides a method for preparing aliphatic polycarbonate through a continuous solution polymerization method. The method comprises the following steps of a, injecting an epoxy monomer, carbon dioxide and catalyst into a circulation flow reactor through a continuous way, utilizing a circulation pump to provide power for the reaction materials, circularly returning partial reaction materials to the circulation flow reactor, driving one part of the reaction materials to leave the circulation flow reactor at a speed being identical to the feeding speed to enter a tubular reactor with a built-in static mixer; b, controlling the retention time of the pulp in the tubular reactor through the ratio of the pipe length and the flowing linear speed of the reaction materials, and gradually charging a solvent step by step through a plurality of feeding ports along the length of the tubular reactor; c, feeding an end sealing agent and a stabilizer through a feeding port on the tail end of the tubular reactor to carry out the in-situ chemical or physical modification; d, ensuring the reaction endpoint pulp which continuously flows out of a discharging end to enter a middle-pressure flash evaporator, carrying out the flash evaporation by utilizing the reaction pressure, removing the solvent, and returning the pulp to the tubular reactor after the pulp is condensed; and e, devolatilizing and drying the pulp to obtain a polymerization product.

Description

【Technical field】 [0001] The invention belongs to the field of polymer compound preparation, in particular to a method for preparing aliphatic polycarbonate by copolymerizing carbon dioxide and epoxide through a continuous solution polymerization method. 【Background technique】 [0002] Due to the excessive emission of carbon dioxide caused by the massive burning of fossil fuels, the "greenhouse effect" is increasing, which has a serious impact on the global climate and environment. On the other hand, carbon dioxide is a cheap and widely sourced chemical raw material. Therefore, the chemical utilization of carbon dioxide has good social and economic significance. Aliphatic polycarbonate, a carbon dioxide-based plastic represented by polypropylene carbonate (PPC) produced by the alternating copolymerization of propylene oxide and carbon dioxide, is a class of fully biodegradable polymer materials with broad application prospects. The aliphatic polycarbonate has very broad ap...

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Problems solved by technology

[0016] In order to solve the deficiencies and problems in the above-mentioned existing carbon dioxide copolymerization process, improve the production efficiency and product quality of aliphatic polycarbonate, and reduce production energy consumption at the same time, the present invention proposes a combination of a loop reactor and a tubular reactor The above problems are solved by means of the circulating liquid flow as the driving force of the loop reactor, which solves the problem that the carbon dioxide content limits the circulation power. While ensuring the circulating mass transfer effect of the loop reactor, the pressure of the reaction system can be adjusted arbitrarily to the reaction The best conditions required by itself; the static mixer built into the tubular reactor solves the problem of poor radial mass transfer effect when the viscosity increases in the later stage of polymerization

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