High molecular weight polylactic acid synthesized via polycondensation catalyzed by bionic creatinine guanidinium chloride

Patent metadata

Field	Value
Publication number	US-9062006-B2
Application number	US-201114129323-A
Country	US
Kind code	B2
Filing date	Nov 2, 2011
Priority date	Jun 30, 2011
Publication date	Jun 23, 2015
Grant date	Jun 23, 2015

Abstract

Disclosed is a high molecular weight polylactic acid synthesized by using a method for synthesizing and catalytically-polycondensing bionic creatinine-guanidinium chloride. Creatinine is used as the material in a reaction with aqueous hydrochloric acid to synthesize a bionic creatinine-guanidinium salt catalyst, creatinine-guanidinium chloride (CR.Cl). The creatinine-guanidinium chloride synthesized is used as a catalyst, an industrial grade lactic acid (LA, 85% to 90%, aqueous solution) is used as a monomer, a solvent-free two-step polycondensation method is used to synthesize and afford metal-free and toxic residue-free polylactic acid featuring high biological safety and high molecular weight.

First claim

What is claimed is:

1. A method of making a high molecular weight polylactic acid (PLA) that is free of intentionally added tin salt catalysts, the method comprising:
autocatalytically reacting an industrial grade lactic acid (LA) comprising an aqueous solution of about 85 mass percent to about 90 mass percent lactic acid, in a polycondensation reaction as represented by the following chemical equation,

the polycondensation reaction comprising:
i) heating the industrial grade lactic acid from about 130° C. to about 160° C. for about 1 hour to about 3 hours, in an argon atmosphere at normal pressure,
ii) heating the industrial grade lactic acid from about 130° C. to about 160° C. for about 1 hour to about 3 hours, in an argon atmosphere at a pressure of about 100 Torr, and
iii) heating the industrial grade lactic acid from about 130° C. to about 160° C. for about 2 hours to about 4 hours, in an argon atmosphere at a pressure of about 30 Torr,

to thereby make oligolactic acid (OLA) having a weight average molecular weight of from about 1100 to about 1200; and
reacting the oligolactic acid (OLA) and creatinine-guanidinium chloride (CR.Cl) in a mass ratio between creatinine-guanidinium chloride (CR.Cl) and oligolactic acid (OLA) from about 1:100 to about 1:1000, in a two-step solvent-free melt polycondensation reaction as represented by the following chemical equation,

the two-step solvent-free melt polycondensation reaction comprising:
a) heating the oligolactic acid and the creatinine-guanidinium chloride to a temperature of from about 160° C. to about 190° C. for about 80 hours to about 120 hours, at a pressure of about 10 Torr, and
b) heating the oligolactic acid and the creatinine-guanidinium chloride to a temperature of about 150° C. for about 10 hours to about 16 hours, at a pressure of 0.5 Torr,

to thereby make the high molecular weight polylactic acid (PLA) that is free of intentionally added tin salt catalysts.

2. The method according to claim 1 , wherein the high molecular weight polylactic acid has a weight average molecular weight (Mw) of from about 1.4×10 5 to about 2.5×10 5 .

Assignees

• Li Hong
• Zhang Quanxing
• Huang Wei
• Jiang Wei
• Zong Xupeng
• Pan Bingcai
• Nanjing University Of Technology

Inventors

• Li Hong
• Zhang Quanxing
• Huang Wei
• Jiang Wei
• Zong Xupeng
• Pan Bingcai

Classifications

• A61L27/18

  obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08G63/87

  Non-metals or inter-compounds thereof (boron C08G63/84) · CPC title

• A61L17/12

  Homopolymers or copolymers of glycolic acid or lactic acid · CPC title

• A61K47/34

  Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyesters, polyamino acids, polysiloxanes, polyphosphazines, copolymers of polyalkylene glycol or poloxamers (A61K47/10 takes precedence) · CPC title

• C07D233/32

  One oxygen atom · CPC title