Synthesis of molecular weight controllable polylactic acid without metal residual

Abstract

The invention provides a method for synthesizing a polylactic acid which has no metallic residue and has controllable molecular weight. The method is as follows: a reaction solvent is added into lactide to prepare a lactide solution the mol concentration of which is between 0.5 and 1.5 M under the protection of inert gas, and an initiator and catalyst are added into the lactide solution in turn, and subjected to polymerization for 0.25 to 2 hours, wherein the mol ratio of the lactide to the initiator to the catalyst is 6-350 to 1 to 0.06-0.35; a terminator is added into the lactide solution, and subjected to termination reaction for 10 to 20 minutes, wherein the mol ratio of the initiator to the terminator is 1 to 1-5; and methanol is prepared, wherein the volume ratio of the reaction solution to the methanol is 1 to 10-20, the reaction solution is dripped into the methanol to form polylactic acid deposit, and the polylactic acid deposit is separated out, filtered, subjected to methanol washing for 2 to 3 times, and subjected to vacuum drying for 24 to 48 hours at a temperature of between 20 and 40 DEG C to obtain the product. The synthesis method can be performed under the condition of room temperature and normal pressure, has high product yield and simple technique, does not require the conditions of heating and decompression, is easy to operate, and can effectively control the molecular weight of the polylactic acid product; and the product has no metallic residue and can be used as a medical material.

Description

(1) Technical field [0001] The invention relates to a method for synthesizing organic polymer materials, in particular to a method for synthesizing polylactic acid which is non-toxic and can be used as a medical material. (2) Background technology [0002] Polylactic acid is a polymer material with good biocompatibility and biodegradability. It is widely used in drug sustained-release capsules and surgical sutures because of its non-toxic, non-accumulating, and degradation products that can participate in human metabolism. Wire, orthopedic internal fixation materials, etc. It can be completely decomposed under the action of microorganisms, water, acid, alkali, etc. in nature, and the final product is CO 2 and H 2 O, the intermediate product lactic acid is also a product of normal glucose metabolism in the body. It will not accumulate in important organs and cause adverse reactions, and it is also non-polluting to the environment. Therefore, it is used as an environmentally...

AI Technical Summary

Problems solved by technology

The disadvantage is that the production process is complicated, the process is long, it needs to be reacted under heating and decompression conditions, the investment in equipment is large, and the technical requirements are high.