Dynamic Viscoelasticity of Syndiotactic Poly (vinyl alcohol) Derived from Vinyl Pivalate

Ryohei Fukae; Tohei Yamamoto; Hitoshi Masago; Nobuhiro Kawatsuki; Osamu Sangen; Mikiharu Kamachi

doi:10.2115/fiber.53.5_195

Ryohei Fukae, Tohei Yamamoto, Hitoshi Masago, Nobuhiro Kawatsuki, Osamu Sangen, Mikiharu Kamachi

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JOURNAL FREE ACCESS

1997 Volume 53 Issue 5 Pages 195-203

DOI https://doi.org/10.2115/fiber.53.5_195

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Published: May 10, 1997 Received: - Available on J-STAGE: June 30, 2008 Accepted: March 06, 1997 Advance online publication: - Revised: -
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Date of correction: June 30, 2008 Reason for correction: - Correction: ABSTRACT Details: Wrong : Dynamic viscoelasticity of poly (vinyl alcohol) (st-PVA) with high syndiotacticity (diadsyndiotacticity > 61%), which is derived from vinyl pivalate, was investigated to compare with that of commercial atactic PVA (at-PVA, diad-syndiotacticity=54%). Cast films of at-PVA with D_p of 1, 800 (at-L), st-PVA with D_p of 1, 700 (st-L) and st-PVA with D_p of 12, 500 (st-H) were prepared and annealed to provide for the desired crystallinity. at-L and st-L show four damping dispersions, i.e., βa, αa, βc, and αc, on their tanδ curves. βa and αa relaxations are mechanical damping of amorphous regions, whereas βc and αc are those of crystal regions. Dynamic storage modulus E′ of (st-L) s increased with increasing crystallinities and could exceed E′ of (at-L)s at temperatures beyond αa dispersion region. In particular, st-L having a crystallinity more than 50% holds E′ of 10⁹ Pa order of magnitude at temperatures above 100°C. The higher value of E′ throughout the temperature ranges of glass transition-, rubbery plateau- and crystal relaxation-regions were observed when st-PVA films were drawn by 4 time the length at 180°C . In this case, tanδmax(T_g) of st-PVA shifted to a higher temperature than that of at-PVA. There are no marked differences in the changes of E′ and tanδ between st-L and st-H. The effects by water swelling against amorphous region, sizes of crystallites for at-PVA and st-PVA on the dynamic viscoelastic behaviors were discussed.
Right : Dynamic viscoelasticity of poly (vinyl alcohol) (st-PVA) with high syndiotacticity (diadsyndiotacticity > 61%), which is derived from vinyl pivalate, was investigated to compare with that of commercial atactic PVA (at-PVA, diad-syndiotacticity=54%). Cast films of at-PVA with D_p of 1, 800 (at-L), st-PVA with D_p of 1, 700 (st-L) and st-PVA with D_p of 12, 500 (st-H) were prepared and annealed to provide for the desired crystallinity. at-L and st-L show four damping dispersions, i.e., βa, αa, βc, and αc, on their tanδ curves. βa and αa relaxations are mechanical damping of amorphous regions, whereas βc and αc are those of crystal regions. Dynamic storage modulus E' of (st-L) s increased with increasing crystallinities and could exceed E' of (at-L)s at temperatures beyond αa dispersion region. In particular, st-L having a crystallinity more than 50% holds E' of 10⁹ Pa order of magnitude at temperatures above 100°C. The higher value of E' throughout the temperature ranges of glass transition-, rubbery plateau- and crystal relaxation-regions were observed when st-PVA films were drawn by 4 time the length at 180°C . In this case, tanδmax(T_g) of st-PVA shifted to a higher temperature than that of at-PVA. There are no marked differences in the changes of E' and tanδ between st-L and st-H. The effects by water swelling against amorphous region, sizes of crystallites for at-PVA and st-PVA on the dynamic viscoelastic behaviors were discussed.

Date of correction: June 30, 2008 Reason for correction: - Correction: PDF FILE Details: -

Abstract

Dynamic viscoelasticity of poly (vinyl alcohol) (st-PVA) with high syndiotacticity (diadsyndiotacticity > 61%), which is derived from vinyl pivalate, was investigated to compare with that of commercial atactic PVA (at-PVA, diad-syndiotacticity=54%). Cast films of at-PVA with D_p of 1, 800 (at-L), st-PVA with D_p of 1, 700 (st-L) and st-PVA with D_p of 12, 500 (st-H) were prepared and annealed to provide for the desired crystallinity. at-L and st-L show four damping dispersions, i.e., βa, αa, βc, and αc, on their tanδ curves. βa and αa relaxations are mechanical damping of amorphous regions, whereas βc and αc are those of crystal regions. Dynamic storage modulus E' of (st-L) s increased with increasing crystallinities and could exceed E' of (at-L)s at temperatures beyond αa dispersion region. In particular, st-L having a crystallinity more than 50% holds E' of 10⁹ Pa order of magnitude at temperatures above 100°C. The higher value of E' throughout the temperature ranges of glass transition-, rubbery plateau- and crystal relaxation-regions were observed when st-PVA films were drawn by 4 time the length at 180°C . In this case, tanδmax(T_g) of st-PVA shifted to a higher temperature than that of at-PVA. There are no marked differences in the changes of E' and tanδ between st-L and st-H. The effects by water swelling against amorphous region, sizes of crystallites for at-PVA and st-PVA on the dynamic viscoelastic behaviors were discussed.

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