Poly l-lactide-layered double hydroxide nanocomposites via in situ polymerization of l-lactide

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• 作者：Vimal Katiyar ; Nathalie Gerds ; Christian Bender Koch ; Jens Risbo ; Hans Christian B. Hansen ; David Plackett
• 关键词：Polylactide ; Layered double hydroxides ; Nanocomposite ; in-situ Polymerization
• 刊名：Polymer Degradation and Stability
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：95
• 期：12
• 页码：2563-2573
• 全文大小：1938 K

文摘

The use of clay nanofillers offers a potential route to improved barrier properties in polylactide films. Magnesium–aluminium layered double hydroxides (LDHs) are interesting in this respect and we therefore explored synthesis of PLA-LDH nanocomposites by ring-opening polymerization. This method is attractive because it should ensure good dispersion of LDH in the polymer. The effect of adding either LDH carbonate (LDH-CO₃) or laurate-modified LDH (LDH-C₁₂) was investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that exfoliated nanocomposites were obtained when using LDH-C₁₂ but that LDH-CO₃ gave a partly phase-separated morphology. Thermogravimetric analysis showed that PLA-LDH combinations exhibited higher degradation onset temperatures and differential scanning calorimetry confirmed that LDHs can act as nucleating agents. However, PLA molecular weight was significantly reduced when in-situ polymerization was conducted in the presence of the LDHs and we suggest that chain termination via LDH surface hydroxyl groups and/or metal-catalyzed degradation could be responsible.