A technique for crystallizing polylactide (PLA) biopolymer trays to make them more heat resistant was disclosed in a recent patent application by NatureWorks LLC, Minnetonka, Minn. U.S. Pat. Applic. 20080258357 describes heating a sheet of amorphous PLA at 80 to 155 C to develop a critical level of crystallinity, and then forming the sheet on a mold heated to less than the Tg or the crystallization temperature of PLA. The target crystallinity of 15 to 24 J/g is achieved by a combination of resin, nucleating agent, sheet temperature, and oven dwell time. The principle is similar to forming CPET, but doesn’t require a hot mold or longer cycles. The CPLA process can also be used to form PLA foam sheet. The process has been demonstrated on full-scale forming lines using NatureWorks’ Ingeo PLA. (952) 742-0400 • www.natureworksllc.com
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Editor PickThe Need for Generalists: Part 3
In failure analysis, there is a tendency to gravitate to a few common test protocols. But this approach can result in a mismatch of techniques to the problem.