Structure and properties of thermoplastic saponite/poly(vinyl alcohol) nanocomposites

Thermoplastic saponite/poly(vinyl alcohol) (PVA) nanocomposites were prepared by melting processing, in which water and formamide were used as plasticizer and saponite as reinforcing filler. The microstructure of the saponite/PVA nanocomposites was investigated by Fourier transform infrared spectra, Raman spectra, X-ray diffraction and transmission electron microscope. It was shown that formamide could form inter-molecular complexes with PVA through hydrogen bonds, which resulted in controlling the supermolecular structure of PVA, confining the crystallization of PVA and making PVA composites processable in melting state at relatively low temperature. Saponites influenced the molecular chain packing of PVA and confined its crystallization, which would be favorable for the melting processing of PVA. Saponite nanolayers were intercalated or partially exfoliated into PVA matrix and would enhance their dispersion as well as the interfacial adhesion with PVA matrix. Compared with PVA, saponite/PVA nanocomposites exhibit remarkable improvement in mechanical properties, thermal stability, and water resistance.