发泡聚乳酸/热塑性聚氨酯/二氧化硅纳米复合材料的泡孔结构

摘要

以超临界二氧化碳作为物理发泡剂,通过快速降压法制备聚乳酸( PLA)/热塑性聚氨酯( TPU)/二氧化硅(SiO2)纳米复合材料发泡样品。发泡样品的泡孔结构使用扫面电子显微镜进行观察。在低频区,SiO2增加PLA/TPU共混物的储能模量和复数黏度。 SiO2的加入使PLA/TPU共混物发泡样品的泡孔直径减小、泡孔密度增大。 SiO2对PLA/TPU共混物发泡样品泡孔结构的改善归因于SiO2的异相成核作用和对共混物流变性能的改善作用。%Using supercritical carbon dioxide(Sc-CO2)as physical foaming agent,foamed poly(lactic acid)(PLA)/thermoplastic polyurethane( TPU)/silica( SiO2 ) nanocomposite samples were prepared in a batch process via rapid depressurization. The cellular structures of the foamed samples were observed by means of scanning electron microscope. Storage modulus and complex viscosity of PLA/TPU blend at low frequency were enhanced upon addition of SiO2 . Adding SiO2 into the PLA/TPU blend contributed to the re-duction of cell diameter and the increase of cell density. The improved cellular structures observed in the nanocomposite foams were attributed to the nucleating effects of SiO2 and improved rheological properties of the PLA/TPU blend.