Optical Properties of Blown Films of PA6/MMT Nanocomposites

In this work blown films of polyamide 6 (PA6) nanocomposites were produced at different processing conditions, with the addition of montmorillonite (MMT), pure and surface modified by an organic salt. The films' optical properties were evaluated according to ASTM D-1003 and the results correlated with the degree of crystallinity, nanoparticle's dispersion state and processing conditions. It was observed that the thinner the film, the lower the haze and higher the clarity, due to the presence of less internal scattering structures in the direction of the incident light. The PA6 films with the unmodified MMT had the lowest clarity values, due to nanoparticles' agglomeration. The organic modification of the montmorillonite led to its exfoliating through the PA6 matrix, resulting in an optimization of the films' optical properties (decreased haze and increased clarity) when compared to the pure PA6 films.

本研究在不同加工条件下制备了聚酰胺6（polyamide 6，PA6）基纳米复合材料吹塑薄膜，所采用的蒙脱土（montmorillonite，MMT）分为纯蒙脱土与经有机盐表面改性的蒙脱土两类。本研究依据ASTM D-1003标准对该类薄膜的光学性能开展表征测试，并将测试结果与材料结晶度、纳米粒子分散状态及加工条件进行关联分析。研究结果表明，薄膜厚度越薄，其雾度越低、透光清晰度越高，这是由于较薄薄膜内沿入射光方向的内部散射结构占比更少。添加未改性蒙脱土的PA6薄膜透光清晰度最低，这源于纳米粒子发生了团聚。蒙脱土经有机盐改性后，可在PA6基体中实现剥离分散，相较于纯PA6薄膜，该复合材料吹塑薄膜的光学性能得到显著优化：雾度降低且透光清晰度提升。