A polylactic acid supplier explains what the production methods of polylactic acid are.
What are the production methods for polylactic acid, as explained by a PLA supplier? Polylactic acid is produced using lactic acid as the raw material. Traditionally, lactic acid fermentation has relied on starch-based feedstocks. Today, countries such as the United States, France, and Japan have developed and adopted agricultural by-products as feedstocks to produce lactic acid, which is then used to synthesize polylactic acid (PLA). 1. Direct Condensation Polymerization A PLA supplier explains that condensation polymerization involves the direct condensation of lactic acid monomers, also known as one-step polymerization. In the presence of a dehydrating agent, the hydroxyl and carboxyl groups in lactic acid molecules undergo heating and dehydration, leading to the direct polycondensation of oligomers. By adding a catalyst and continuing the heating process, low‑molecular‑weight PLA is further polymerized into higher‑molecular‑weight PLA. 2. Two‑Step Process According to a PLA supplier, this method first converts lactic acid into cyclic dimeric lactide, followed by ring-opening polymerization to form polylactic acid. This technique is relatively mature. The main steps include fermenting raw materials to produce lactic acid, then purifying, dehydrating, oligomerizing, and thermally decomposing it before finally polymerizing it into PLA. 3. High‑Molecular‑Weight PLA via Reactive Extrusion By combining an intermittent stirred reactor with a twin‑screw extruder, continuous melt polymerization of lactic acid can yield PLA with molecular weights as high as 150,000. Low‑molecular‑weight lactic acid prepolymers are further condensed in the twin‑screw extruder to produce high‑molecular‑weight PLA.
2023-03-09
