Jung Bich-Nam, Jung Hyun-Wook, Kang Dong-Ho, Kim Gi-Hong, Shim Jin-Kie
Korea Packaging Center, Korea Institute of Industrial Technology, Bucheon 14449, Korea.
Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Korea.
Polymers (Basel). 2021 Aug 17;13(16):2760. doi: 10.3390/polym13162760.
Polypropylene (PP) has poor oxygen barrier properties, therefore it is manufactured in a multi-layer structure with other plastics and metals, and has been widely used as a packaging material in various industries from food and beverage to pharmaceuticals. However, multi-layered packaging materials are generally low in recyclability and cause serious environmental pollution, therefore we have faced the challenge of improving the oxygen barrier performance as a uni-material. In this work, PP/nanoclay nanocomposites were prepared at nanoclay contents ranging from 0.8 to 6.4 wt% by the biaxial stretching method, performed through a sequential stretching method. It was observed that, as the draw ratio increased, the behavior of the agglomerates of the nanoclay located in the PP matrix changed and the nanoclay was dispersed along the second stretching direction. Oxygen barrier properties of PP/nanoclay nanocomposites are clearly improved due to this dispersion effect. As the biaxial stretching ratio and the content of nanoclay increased, the oxygen permeability value of the PP/nanoclay nanocomposite decreased to 43.5 cc·mm/m·day·atm, which was reduced by about 64% compared to PP. Moreover, even when the relative humidity was increased from 0% to 90%, the oxygen permeability values remained almost the same without quality deterioration. Besides these properties, we also found that the mechanical and thermal properties were also improved. The biaxially-stretched PP/nanoclay nanocomposite fabricated in this study is a potential candidate for the replacement of the multi-layered packaging material used in the packaging fields.
聚丙烯（PP）的氧气阻隔性能较差，因此它常与其他塑料和金属制成多层结构，并已在从食品饮料到制药等各个行业广泛用作包装材料。然而，多层包装材料通常可回收性较低，并会造成严重的环境污染，因此我们面临着将其作为单一材料提高氧气阻隔性能的挑战。在这项工作中，通过双轴拉伸法（一种顺序拉伸法）制备了纳米黏土含量在0.8至6.4 wt%范围内的PP/纳米黏土纳米复合材料。观察到，随着拉伸比的增加，位于PP基体中的纳米黏土团聚体的行为发生变化，纳米黏土沿第二拉伸方向分散。由于这种分散效应，PP/纳米黏土纳米复合材料的氧气阻隔性能明显提高。随着双轴拉伸比和纳米黏土含量的增加，PP/纳米黏土纳米复合材料的透氧率值降至43.5 cc·mm/m·day·atm，与PP相比降低了约64%。此外，即使相对湿度从0%增加到90%，透氧率值也几乎保持不变，且质量没有下降。除了这些性能外，我们还发现其机械性能和热性能也得到了改善。本研究中制备的双轴拉伸PP/纳米黏土纳米复合材料是包装领域中用于替代多层包装材料的潜在候选材料。
