Abstract

The purpose of this work was to evaluate the morphological, mechanical, barrier and phase-transition properties of poly(lactic acid) (PLA) films with nanofillers such as nanocrystalline cellulose (NCC, 1–5%) and chitin whiskers (CHW, 3%). Nanofiller addition using melt extrusion led to decrease in heat capacity change at glass transition as observed from differential scanning calorimetry data. Transmission electron microscopy and x-ray diffraction studies showed that the nanofillers were dispersed in the polymer matrix. This indicated confinement of the motion of polymer chains between layers of nanofillers. Tensile strength (TS) of PLA-based nanocomposite films increased from 50.2 to 70.9 MPa with addition of 5% NCC to PLA. However, addition of CHW did not significantly improve TS. Addition of 3% NCC reduced oxygen transmission rate of films from 209.9 to 180.8 cm³/m²/day, which further reduced to 109.3 cm³/m²/day by adding compatibilizer, methylene diphenyl diisocyanate (MDI, 4%). Water vapor transmission rate of PLA reduced from 44.4 to 28.6 g/m²/day with 3% NCC and 4% MDI addition. This research suggested the promising application of NCC as a nanofiller in PLA films with enhanced thermal, mechanical and barrier properties, and potential application in bio-based food packaging.

Graphic abstract

中文翻译：

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聚乳酸与纳米晶纤维素和几丁质晶须复合熔体挤出复合纳米薄膜的形貌和性能特征

摘要

这项工作的目的是评估具有纳米填料（例如，纳米晶纤维素（NCC，1-5％）和几丁质晶须（CHW，3）的聚乳酸（PLA）薄膜的形态，机械，势垒和相变特性）。 ％）。从差示扫描量热法数据观察到，使用熔融挤出的纳米填料添加导致玻璃化转变时的热容变化减小。透射电子显微镜和X射线衍射研究表明，纳米填料分散在聚合物基质中。这表明聚合物链在纳米填料层之间的运动受到限制。通过向PLA中添加5％NCC，PLA基纳米复合材料薄膜的拉伸强度（TS）从50.2 MPa增加到70.9 MPa。但是，添加CHW并不能显着改善TS。³ / m ² /天，通过添加增容剂亚甲基二苯基二异氰酸酯（MDI，4％）进一步降低到109.3 cm ³ / m ² /天。在添加3％NCC和4％MDI的情况下，PLA的水蒸气透过率从44.4降至28.6 g / m ² /天。这项研究表明，将NCC用作具有增强的热，机械和阻隔性能的PLA薄膜中的纳米填料具有广阔的应用前景，并有望在生物基食品包装中应用。

图形摘要