Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)
Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)
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DOI：
10.1021/acsapm.2c02155
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发表时间：
2023-02
影响因子：
5
通讯作者：
M. Yamaguchi;Wen Shu;Takeyoshi Kimura;Hoang-Giang Dai Vo;Takumitsu Kida;Toyoichiro Mori;Makoto Kitani;Norifumi Aridome;Akira Miyamoto
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文献类型：
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作者：
M. Yamaguchi;Wen Shu;Takeyoshi Kimura;Hoang-Giang Dai Vo;Takumitsu Kida;Toyoichiro Mori;Makoto Kitani;Norifumi Aridome;Akira Miyamoto
本研究表明，包含聚乳酸（PLA）和聚（乙烯醇）（PVAL）的注塑产品在后处理退火后表现出异常的尺寸变化，即沿流动方向膨胀（在80-100°C退火3小时后膨胀约2.9%）。尽管添加PVAL并没有加速PLA在冷却过程中的结晶，但在后处理退火过程中，PLA显示出分散的PVAL液滴的跨晶化，这些液滴在流动方向上变形。因此，退火后，注塑产品表现出高度的分子取向，而原始未退火产品则没有取向。应注意这种异常行为，作为控制加工后尺寸变化的一种手段。
The present study revealed that an injection-molded product comprising poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVAL) exhibited an anomalous dimensional change, i.e., expansion in the flow direction, after postprocessing annealing (around 2.9% expansion by annealing at 80–100 °C for 3 h). Although the crystallization of the PLA during cooling was not accelerated by the addition of PVAL, the PLA showed transcrystallization from the dispersed PVAL droplets, which were deformed in the flow direction, during postprocessing annealing. Therefore, after annealing, the injection-molded products exhibited a high degree of molecular orientation, in contrast to the original unannealed products, which were not oriented. This anomalous behavior should be noted as a means of controlling dimensional change after processing.