Investigating the crystallization behavior of poly(lactic acid) using CdSe/ZnS quantum dots as heterogeneous nucleating agents

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• 作者：Xinghou Gong^a ; ^b ; Ling Pan^a ; Chak Yin Tang^b ; ^{mfcytang@polyu.edu.hk" class="auth_mail" title="E-mail the corresponding author} ; Ling Chen^b ; Chunqing Li^a ; Chonggang Wu^a ; Wing-Cheung Law^b ; Xiaotao Wang^a ; Chi Pong Tsui^b ; Xiaolin Xie^c
• 关键词：A. Polymer-matrix composites (PMCs) ; B. Physical properties ; Quantum dots ; B. Thermal analysis
• 刊名：Composites Part B: Engineering
• 出版年：2016
• 出版时间：15 April 2016
• 年：2016
• 卷：91
• 期：Complete
• 页码：103-110
• 全文大小：2102 K

文摘

Heterogeneous nucleation is a frequently encountered phenomenon in the crystallization of inorganic nanoparticle/polymer systems, and has a great influence on the morphology and properties (such as optical, mechanical and degradable properties) of the nanocomposites. In this study, a solution casting method was adopted to fabricate CdSe–ZnS quantum dots (QDs)/poly(lactic acid) (PLA) nanocomposites films of various QDs concentrations by using chloroform as the solvent. Fourier transform infrared (FT-IR) spectroscopy, polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffractometry (XRD) were used to characterize the crystallization behavior of the nanocomposites films that had been thermally treated differently from the as-cast state. The FT-IR and POM results showed that the nucleation density and the crystallization ability of PLA are greatly enhanced with addition of the QDs in the processes of isothermal crystallization at 403 K. The results of DSC revealed that the glass transition temperature of PLA has no obvious change with the addition of QDs. For the QDs/PLA samples which were isothermally annealed at 403 K for 30 min, the degree of (melt) crystallinity increased with increase of QD concentrations in the PLA matrix. All the results obtained from FT-IR spectroscopy, POM, DSC, and XRD were consistent, suggesting that the CdSe–ZnS QDs can serve as an efficient heterogeneous nucleating agent for the acceleration and enhancement of the melt crystallization of PLA at the optimized condition.