Polylactic acid preparation method

Abstract

The invention discloses a polylactic acid preparation method, belongs to the field of preparation of polylactic acid, and concretely provides an aminopolylactic acid preparation method with simple preparation process and high amino termination rate. The aminopolylactic acid preparation method comprises the following steps: reacting tert-butoxycarbonyl carbonic anhydride with aminopropanol to synthesize tert-butyloxycarbonyl aminopropanol, initiating ring-opening polymerization of L-lactide with tert-butyloxycarbonyl aminopropanol as an initiator under the catalysis of stannous octoate to synthesize tert-butyloxycarbonylamino-terminated polylactic acid, carrying out trifluoroacetic acid treatment to remove a tert-butyloxycarbonyl group to obtain amino-terminated polylactic acid, and initiating ring-opening polymerization of w-benzyloxycarbonyl-L-lysine-N-carboxylic anhydride with aminopolylactic acid as a macromolecular initiator to synthesize polylactic acid-polylysine. The method has a simple preparation process, and the polylactic acid-polylysine prepared in the invention has a high amino termination rate.

Description

technical field [0001] The invention belongs to the field of polylactic acid preparation. Background technique [0002] Polylactic acid (PLLA) is known as the most promising degradable polymer material because of its excellent biocompatibility. However, the main chain of the PLLA molecule does not contain reactive side groups, and the terminal group is a hydroxyl group with very low reactivity. It can only react with other substances under severe conditions. How to solve this problem has always been the focus of exploration. At present, a better solution is to modify the terminal hydroxyl groups of PLLA. The most commonly used method for modification of terminal hydroxyl groups is to convert them into amino groups. For example, the terminal amination of polyethylene glycol can greatly improve the reactivity of the terminal groups. The amino-terminated polylactic acid (PLLA-NH 2 ). However, later studies confirmed that due to the agglomeration effect of macromolecular chai...

AI Technical Summary

Problems solved by technology

However, the main chain of the PLLA molecule does not contain reactive side groups, and the terminal group is a hydroxyl group with very low reactivity. It can only react with other substances under severe conditions. How to solve this problem has always been the focus of exploration.

However, later research confirmed that due to the agglomeration effect of macromolecular chains, the reaction of terminal hydroxyl groups in PLLA was not sufficient, and at least 30% of the terminal hydroxyl groups in the PLLA system did not undergo condensation reactions.

Synthesis of PLLA-NH by Ring-opening Polymerization of L-Lactide Initiated by Initiator with Amino Group 2 , but the naphthalene used in the polymerization process has certain toxicity and pollutes the polymer