More heat-resistant PLA

The packaging industry is increasingly using biopolymers made from polylactides (PLAs) as an alternative to petroleum-based plastic. They are obtained from corn starch and completely biodegradable. Previously, however, PLA began to soften at about 60 ºC, so it was not suitable for heat-intensive processes. But now, researchers at the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam have found a way to make this bioplastic even more heat-resistant. An interesting application comes from the food industry: The filling of yogurt in plastic cups, because this process takes place at higher temperatures. Cups made of PLA stereo complexes retain their shape and remain stable even at temperatures of up to 120 ºC. Dr. Johannes Ganster, division director at IAP, explains the principle behind this: “To make PLA plastics more form-stable at higher temperatures, we introduced stereo complexes with special components of L-lactides and D-lactides. These right-and-left rotating molecules complement each other and make the bond even more stable.”

Corporations have already expressed interest, considering the potential. Production of biopolymers made of PLA is independent of the growing scarcity of petroleum. In addition, they can be readily composted, and they are ideal for recycling by decomposition in lactic acid. The greatest advantage is that they have since become just as durable and sturdy as any petroleum-based plastic, and can even be used for other products, such as protective films, computer housing and shopping bags. IAP is already working closely with a German factory builder that intends to incorporate the new process into its business operations soon.

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