Development of polyvinyl alcohol/intercalated MMT composite foams fabricated by melt extrusion

ABSTRACT In this work, novel polyvinyl alcohol (PVA)/intercalated montmorillonite (MMT) nanocomposite foams were fabricated by melt extrusion with fixed amount of foaming agent, and the structure and properties were investigated with X‐ray diffraction, transmittance electron microscope, differential scanning calorimetry, plate rheometer, scanning electron microscope, density analysis, and mechanical testing in detail. The results revealed that pristine MMT could be intercalated by PVA during melt‐extrusion. Both exfoliation and intercalation structure was formed in the composites. The strong interaction between PVA and MMT restricted the motion of PVA molecules, leading to the enhanced complex viscosity, storage modulus, and melt flow index, suggesting the improved melt elasticity and melt strength. The improved melt strength of PVA through MMT incorporation facilitated the foaming process. With the increase of MMT, cell rupture was limited and the thickness of cell‐wall decreased, leading to the decreased density. The homogeneous cells and the closed cell structure with the foaming density of 0.35 g/cm 3 could be formed with 2 wt % MMT incorporation. With the increase of MMT, the tensile strength of PVA/MMT foams decreased because of the enlarged foaming ratio and decreased density. This work aims to pave a simple and convenient way to produce biodegradable foams. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42706.