Study On The Poly (Vinyl Alcohol)/Montmorillonite Nanocomposites

Polymer/Layered Silicate (PLS) nanocomposites is a new type of composites based on polymers that filled with silicate layers in nanoscale dispersion. PLS nanocomposites have been widely studied in recent years because of its amazing performances in mechanical, thermal, optical and physical-chemical properties compared to the pure polymers or conventional (microscale) composites.The preparation, characterization, properties and chemical modification of Poly (Vinyl Alcohol)/Montmorillonite (PVA/MMT) nanocomposites were studied in this paper, with it main contents summarized as follows:First, the changes of physical and chemical peroperties of bentonite during shattering process were studied and highly purified Na~+-montmorillonite was obtained. The result showed that the properties of bentonite powder varied as the milling time increased. These properties included the average particle size, cation exchange capacity (CEC), Hunter whiteness, value of Methylene-blue absorption, expansion value, Gel swelling value and the rheological property, which enabled the bentonite widely used in many fields and usually were regarded as invariable values. The XRD and FT-IR characterization of bentonite revealed that, the property changes were actually aroused by the crystalline distortion and amorphism that caused bymechanochemistry effect during ball milling. The experiment also revealed that theyield of MMT purification varied as the milling time of bentonite changed.Second, PVA/MMT nanocomposites were prepared directly from PVA solution and MMT aqueous suspension by solution-intercalation film-casting method, and characterized by means of XRD, TEM, SEM and TGA. The XRD results revealed that, the interlayer space of MMT increased after composing with PVA, which indicated that the PVA chains had intercalated into the galleries of MMT. The TEM and SEM images showed that the MMT layers dispersed in the PVA matrix...