Title: A ZONE DRAWING METHOD TO DETERMINE OPTIMUM INITIAL CONCENTRATION OF POLY(VINYL ALCOHOL) TO MAKE FILMS WITH DIFFERENT DEGREES OF SAPONIFICATION
Page Range: p.235-242
Author(s): Joon Ho Kim; Won Sik Yoon; Jeong Hyun Yeum; Byung Chul Ji; Hee Sam Kim; Han-Yong Jeon; Won Seok Lyoo
File size: 147K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 12
Issue No: No. 3
Abstract
The optimum preparation conditions for atactic polyvinyl alcohol films were investigated by measuring the polymer concentration, draw ratio and degree of saponification. Atactic PVA films were prepared by casting in water with different polymer concentrations. The a-PVA films were zone-drawn under various conditions. Using the optimum polymer concentration of the a-PVA/water solutions caused significant changes in the draw ratio of the films, which were maximised at the initial polymer concentration, but which gradually decreased at higher or lower concentrations. The birefringence, degree of crystal orientation and tensile properties of a-PVA films, having the same draw ratios were the highest at these optimum polymer concentrations. Optimum concentrations were reconfirmed by viscometry. Optimum conditions of the film casting of atactic PVA with various degrees of saponification were established by the zone drawing method. The agreement between the optimum concentration values obtained by zone drawing and viscometry suggests that the zone drawing method is an appropriate and convenient way to establish the optimum concentration for maximum draw ration, birefringence, degree of crystal orientation, and tensile properties. 18 refs.
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