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

Naofumi Naga, Yuji Yoshida, Keiichi Noguchi, Shigemitsu Murase

Department of Applied Chemistry, Material Science Course, College of Engineering, Shibaura Institute of Technology, Tokyo, Japan.
Department of Organic and Polymer Materials Chemistry, Faculty of Technology, Tokyo University of Agriculture and Technology, Tokyo, Japan.
Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, Tokyo, Japan.

DOI: 10.4236/ojpchem.2013.32006                

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℃. 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.

Keywords

Poly(Lactic Acid); Acetone; Crystallization; Transparency

Conflicts of Interest

The authors declare no conflicts of interest.

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