Preparation and characterization of syndiotacticity-rich ultra-high molecular weight poly(vinyl alcohol) imogolite blend film

Abstract

To enhance the physical properties of syndiotacticity-rich (syndiotactic diad content 63.4%) ultra-high molecular weight (UHMW) (number-average degree of polymerization 12300) poly(vinyl alcohol) (PVA) him, it was solution blended with rigid-rod imogolite in dimethyl sulphoxide. In addition, the blend him prepared was stretched using a high-temperature zone drawing technique for effective orientation of the film. Through a series of experiments, it was found that imogolite caused significant changes in the structure and properties of syndiotacticity-rich UHMW PVA film, i.e. imogolite acted as an important agent which increased crystal orientation of syndiotacticity-rich UHMW PVA, resulting in enhanced tensile strength of the him. However, imogolite played a hindering role in raising the amorphous orientation of syndiotacticity-rich UHMW PVA. The maximum tensile modulus of 19.8 GPa and maximum tensile strength of 1.8 GPa could be obtained at the maximum draw ratio of 7.45 for PVA/imogolite blend film. In the case of PVA homo him, the highest tensile modulus and strength were 25.2 GPa and 1.4 GPa, respectively. (C) 1998 Society of Chemical Industry.