Method for preparing aliphatic polycarbonate through melt transesterification and polycondensation

Abstract

The invention relates to a method for preparing aliphatic polycarbonate through melt transesterification and polycondensation. The method is characterized in that the aliphatic polycarbonate is prepared from dialkyl carbonate and aliphatic diol by adopting a composite oxide catalyst; the composite oxide catalyst is prepared through a sol gel technology, a co-precipitation technology or a uniform precipitation technology; and the used carbonate can be dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, dihexyl carbonate, dioctyl carbonate, diphenyl carbonate, phenylethyl carbonate or methylethyl carbonate, and the diol can be ethylene glycol, propylene glycol, butylene glycol, pentanediol, hexanediol, heptanediol, 2-methylpropylene glycol or alicyclic diol. The aliphatic polycarbonate is synthesized through normal pressure melt transesterification and low pressure polycondensation processes.

Description

technical field [0001] The invention discloses a method for preparing high molecular weight aliphatic polycarbonate by melt transesterification polycondensation. The method adopts a composite oxide-based catalyst, uses carbonates such as diphenyl carbonate and dimethyl carbonate, and aliphatic diols such as 1,4-butanediol as raw materials, and synthesizes aliphatic polymers by melting transesterification and polycondensation. Carbonate. Background technique [0002] Polycarbonate can be roughly divided into two types: aromatic polycarbonate (PC) and aliphatic polycarbonate (APC). Aromatic polycarbonate (PC), as one of the five general-purpose engineering plastics, has good performance and has been industrialized. Aliphatic polycarbonate (APC) is a photodegradable and fully biodegradable plastic. High molecular weight aliphatic polycarbonate (APC) is widely used in disposable medical materials, food packaging materials, agricultural mulch, drug carriers, casting Modificati...

AI Technical Summary

Problems solved by technology

[0005] Aliphatic dihydric alcohol and dimethyl carbonate (DMC) are transesterified to synthesize high molecular weight aliphatic polycarbonate. DMC has a low boiling point and needs to be pressurized during the transesterification stage. At the same time, it will azeotrope with methanol, so the reaction conditions Under low conditions, DMC is volatile and lost, the utilization rate of raw materials is low, and the process conditions are harsh

The phenol in the transesterification method of diphenyl carbonate (DPC) and aliphatic dihydric alcohol can be recycled, and the reaction process is solvent-free, which is a clean production process, but the carbonyl utilization rate in the reaction monomer DPC is low