Method for synthesizing high-molecular-weight poly(lactic acid) through melt polycondensation of lactic acid under catalysis of three-way composite catalyst

A catalyst catalyzing lactic acid and ternary composite technology, which is applied in the field of polylactic acid, can solve the problems of long reaction cycle and achieve the effects of short polymerization time, low cost and simple process

Active Publication Date: 2012-10-24
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can obtain higher molecular weight polylactic acid, but the biggest disadvantage is its long reaction cycle

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Weigh 200g of L-lactic acid with a purity of 90%, control the reaction temperature at 150°C, and obtain a lactic acid oligomer with a molecular weight of 5,000 after dehydration at normal pressure, dehydration with a water pump, and dehydration with an oil pump for 3 hours each; weigh 20g of poly Lactic acid oligomers were placed in a 100mL three-necked bottle at normal pressure, 100°C, N 2 Under protection, Ti[OCH(CH 3 ) 2 ] 4 , and Ti[OCH(CH 3 ) 2 ] 4 p-toluenesulfonic acid (TSA) with a molar ratio of 1:4 and 2,2-dimethylolpropionic acid (DMPA) with a molar ratio of 1:4, stirred for 1 h, the temperature rose to 180 ° C, and the vacuum degree was Under 30 Pa, the polycondensation reaction was carried out for 12 hours to obtain polylactic acid with a weight average molecular weight of 123,000 in a yield of 72%.

Embodiment 2

[0023] Weigh 20g of polylactic acid oligomers in a 100mL three-necked bottle, under normal pressure, 100℃, N 2 Under protection, Ti[OCH(CH 3 ) 2 ] 4 , and Ti[OCH(CH 3 ) 2 ] 4 p-toluenesulfonic acid (TSA) with a molar ratio of 1:3 and 2,2-dimethylolpropionic acid (DMPA) with a molar ratio of 1:3, stirred for 1 h, the temperature rose to 180 ° C, and the vacuum degree was Under 30Pa, the polycondensation reaction was carried out for 6 hours to obtain polylactic acid with a weight average molecular weight of 168,000 in a yield of 75%.

Embodiment 3

[0025] Weigh 20g of polylactic acid oligomers in a 100mL three-necked bottle, under normal pressure, 100℃, N 2 Under protection, Ti[OCH(CH 3 ) 2 ] 4 , and Ti[OCH(CH 3 ) 2 ] 4 p-toluenesulfonic acid (TSA) with a molar ratio of 1:3 and 2,2-dimethylolpropionic acid (DMPA) with a molar ratio of 1:3, stirred for 1 h, the temperature rose to 180 ° C, and the vacuum degree was Under 30Pa, the polycondensation reaction was carried out for 6 hours to obtain polylactic acid with a weight average molecular weight of 119,000 in a yield of 82%.

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Abstract

The invention provides a method for synthesizing high-molecular-weight poly(lactic acid) through melt polycondensation of lactic acid under catalysis of a three-way composite catalyst, which belongs to the field of poly(lactic acid). The method is as follows: lactic acid oligomer is synthesized at first and is then subjected to melt polycondensation under catalysis of the three-way composite catalyst so as to obtain high-molecular-weight poly(lactic acid) in a short time, wherein the three-way composite catalyst is a compound of a metallic compound, protonic acid and dihydroxycarboxylic acid.The method provided in the invention has the advantages of a simple process, low cost, few side reactions, a short polymerization time and high yield; prepared poly(lactic acid) has a molecular weight in a range of 40, 000 to 210, 000 and can be used in the medical domain with high additional values and the field of environment-friendly materials for general purposes.

Description

technical field [0001] The invention belongs to the field of polylactic acid, and in particular relates to a method for preparing high-molecular-weight polylactic acid by using a ternary composite catalyst to catalyze direct melt polycondensation. technical background [0002] In today's society, with the rapid development of modern science and technology, the problems of environmental pollution and resource shortage have attracted widespread attention and become global problems. Petroleum-based plastic materials are widely used, because they are difficult to recycle after use, resulting in increasingly serious "white pollution"; in addition, petroleum is a non-renewable resource, and a large amount of unreasonable use of petroleum-based materials will inevitably lead to facing shortage of resources. The emergence of biodegradable materials provides an effective means to solve these problems. [0003] Polylactic acid is an environmentally friendly aliphatic polyester polym...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/87C08G63/85C08G63/80
Inventor 杨晶陈黎明赵怡翔谭天伟
Owner BEIJING UNIV OF CHEM TECH
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