| 초록 |
It is well known that stereoregular configuration of vinyl polymer gives changes of physical characteristics and enhancement of mechanical properties. As compared with atactic poly(vinyl alcohol) (PVA), syndiotactic PVA (s-PVA) has been known to have different properties due to the increased intermolecular hydrogen bondings between the adjacent chains. Actually, s-PVA films have superior mechanical properties to those of atactic ones. So, challenging attempts have been made to increase syndiotacticity of PVA. In this study, to precisely clarify the molecular weight effect on the physical properties of s-PVA film, low molecular weight (LMW) s-PVA with number-average degree of polymerization of 900, syndiotactic diad content of 63.1%, and degree of saponification of 99% was prepared by solution polymerization of vinyl pivalate in tetrahydrofuran and subsequent saponification. Also, s-PVA film was prepared by casting in dimethyl sulfoxide at initial optimum polymer concentration of 2.5 g/dl and drawn under various zone-drawing conditions such as drawing temperature, drawing stress and heat band speed. Physical properties of LMW s-PVA film were also investigated.
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