Crystallization of Amorphous Poly(Lactic Acid) Induced by Vapor of Acetone to Form High Crystallinity and Transparency Specimen

Abstract

Crystallization of amorphous poly(lactic acid) (PLA) was investigated by exposing to vapor of acetone. The vapor of acetone induced crystallization of the amorphous PLA effectively. It took about 24 min to complete the crystallization of a 1 cm × 2 cm × 0.55 mm specimen at 25˚C. The crystallization rate increased with increasing of conducting temperature. The crystallization method yielded high crystallinity about 40%, which was almost equal to that attained by annealing or immersion methods conducted as references. The specimens crystallized by the vapor showed higher transparency than those prepared by the reference methods. The crystallization was induced by diffusion of acetone into the amorphous phase of PLA, and polarized optical photomicrographs cleared that the diffusion obeyed Fick type diffusion.

Fabrication and evaluation of poly(lactic acid), chitosan, and tricalcium phosphate biocomposites for guided bone regeneration

“…PLA showed the typical profile of a semi‐crystalline polymer consisting of both crystalline and amorphous regions. The positions of the peaks aligned with results reported previously . The strong crystalline peak of PLA corresponded to the (110) and/or (200) plane of a typical orthorhombic crystal .…”

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“…DSC-heating thermograms of all samples are shown in Figure 6. The isotropic PLA film and electrospun PLA nanofiber mat showed cold crystallization and a low degree of crystallinity (v c ) of around 14%-16%, which is common for PLA due to its slow crystallization rate [33]. On the other hand, there was no cold-crystallization present in all the SR-PLA nanocomposite film samples and here crystallinity was found to be greatly increased.…”

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