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Method for synthesizing polylactic acid through mixed catalyst

A technology of mixing catalysts and polylactic acid, which is applied in the field of polymer material synthesis, can solve problems that need to be improved, achieve high molecular weight, narrow molecular weight distribution, and increase the degree of polymerization

Inactive Publication Date: 2018-05-08
沈阳金博地生态环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In recent years, there have been many reports about lactide ring-opening polymerization of polylactic acid. The patent publication No. CN 102643418 A discloses a composite catalyst using a titanium catalyst and toluenesulfonic acid. The obtained product polylactic acid The molecular weight is between 20,000 and 200,000; the patent with the publication number of CN 105504237 A discloses a quaternary complex compound using rare earth compounds, ionic liquids, titanium compounds, and sulfamic acid compounds. The obtained polylactic acid product has molecular weight, thermal stability Sexuality has improved, but there is still room for improvement

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Embodiment 1 synthesizes polylactic acid

[0027] Add 100g of L-lactic acid with a purity of 90% to a 250ml three-necked flask equipped with a stirrer and a condenser, vacuumize, replace nitrogen 4 times, and add praseodymium trifluoromethanesulfonate and dichloromethanesulfonate to the three-necked flask under nitrogen protection Titanium oxide, ground SBA-3 molecular sieve mixed catalyst (the mass ratio of the three is 1:0.1:1.5, and the amount of rare earth compound added is 0.4% of the raw material lactic acid mass), and the system is placed in an oil bath at 100°C , stirred and dehydrated for 2 hours under the condition of a total pressure of 10KPa, then gradually reduced the pressure to 0.6KPa, while the temperature rose to 170°C, and continued to stir and react for 6 hours to obtain a lactic acid oligomer. The temperature was raised rapidly to 210°C, and the system pressure was reduced to 0.05KPa at the same time. After 20 hours of reaction, PLLA with a weight av...

Embodiment 2

[0028] Embodiment 2 synthesizes polylactic acid

[0029] Add 100 g of L-lactic acid with a purity of 90% to a 250 ml three-necked flask equipped with a stirrer and a condenser, vacuumize, replace nitrogen 4 times, and add lanthanum oxide, titanium dichloride, and grind to the three-necked flask under nitrogen protection. The final SBA-3 molecular sieve mixed catalyst (the ratio of the three is 1:0.1:1.5, and the amount of the rare earth compound added is 0.4% of the raw material lactic acid mass), the system is placed in an oil bath at 100 °C, and the total pressure is Stir and dehydrate under the condition of 10KPa for 2 hours, then gradually reduce the pressure to 0.6KPa, and at the same time, raise the temperature to 170°C, continue to stir and react for 6 hours to obtain a lactic acid oligomer. The temperature was raised rapidly to 210°C, and the system pressure was reduced to 0.05KPa at the same time. After 20 hours of reaction, PLLA with a weight average molecular weight...

Embodiment 3

[0030] Embodiment 3 synthetic polylactic acid

[0031] Add 100 g of L-lactic acid with a purity of 90% to a 250 ml three-necked flask equipped with a stirrer and a condenser, vacuumize, replace nitrogen 4 times, and add lanthanum oxide, titanium dichloride, and grind to the three-necked flask under nitrogen protection. The final ZSM-5 molecular sieve mixed catalyst (the ratio of the three is 1:0.1:1.5, and the amount of the rare earth compound added is 0.4% of the raw material lactic acid mass), the system is placed in an oil bath at 100 °C, and the total pressure is Stir and dehydrate under the condition of 10KPa for 2 hours, then gradually reduce the pressure to 0.6KPa, and at the same time, raise the temperature to 170°C, continue to stir and react for 6 hours to obtain a lactic acid oligomer. The temperature was raised rapidly to 210°C, while the system pressure was reduced to 0.05KPa. After 20 hours of reaction, PLLA with a weight average molecular weight of 200,000 was o...

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PUM

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Abstract

The invention discloses a method for synthesizing polylactic acid through a mixed catalyst. The method comprises the steps that under the conditions of the mixed catalyst, 5-20 KPa, 70-120 DEG C and inert gas protection, lactic acid is subjected to a stirring reaction for 1-5 hours to obtain a low polymer of lactic acid, then the pressure is lowered to 0.2-1 KPa, the temperature is raised to 120-180 DEG C, and the stirring reaction is continued and lasts for 1-10 hours to obtain a lactic acid oligomer, wherein the mixed catalyst is prepared from a rare earth compound, a titanium type metal compound and a molecular sieve, and the mass ratio of the rare earth compound to the titanium type metal compound to the molecular sieve is 1 to (0.07-0.15) to (1-2); the lactic acid oligomer is obtainedthrough reaction under the conditions of 0.01-0.8 KPa, 180-230 DEG C and inert gas protection for 12-30 hours. According to the method, the utilized catalyst is higher in activity, the process is more convenient, and the prepared polylactic acid is high in performance, high in thermal stability and narrow in molecular weight distribution.

Description

technical field [0001] The invention relates to a method for synthesizing polylactic acid by using a mixed catalyst, and belongs to the technical field of polymer material synthesis. Background technique [0002] Polylactic acid is mainly a polymer product obtained after fermentation and polycondensation of starch as a raw material. Because polylactic acid has biodegradability, biocompatibility, and good mechanical properties, it has broad application prospects in medical treatment, environmental protection, and agriculture. [0003] At present, the synthesis methods of polylactic acid are mainly divided into two types. One is to obtain polylactic acid by direct polymerization of lactic acid, but its molecular weight is generally low and its distribution is wide. The other is to obtain polylactic acid through ring-opening polymerization of lactide, a cyclized dimer of lactic acid. First, lactide is synthesized from lactic acid, and polylactic acid (also known as polylactide...

Claims

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Application Information

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IPC IPC(8): C08G63/82C08G63/87C08G63/85C08G63/84
CPCC08G63/823C08G63/84C08G63/85C08G63/87
Inventor 赫凯敖广宇周乔
Owner 沈阳金博地生态环保科技有限公司