Effect of stereosequences on crystallinity and properties of zone-drawn poly(vinyl alcohol) microfibrils

To effectively orient the molecular chains of novel syndiotactic poly(vinyl alcohol) (PVA) microfibrillar fiber (PVA fibril), a high‐temperature zone‐drawing method was adopted. The PVA fibrils were directly prepared from the saponification and in situ fibrillation without a spinning procedure. The...

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Bibliographic Details
Published in:Journal of polymer science. Part B, Polymer physics Polymer physics, 2001-06, Vol.39 (12), p.1263-1271
Main Authors: Lyoo, Won Seok, Kim, Joon Ho, Koo, Kang, Lee, Joon Seok, Kim, Sam Soo, Yoon, Won Sik, Ji, Byung Chul, Kwon, Ick Chan, Lee, Chul Joo
Format: Article
Language:English
Subjects:
Applied sciences
crystal orientation
Exact sciences and technology
Fibers and threads
Forms of application and semi-finished materials
high-temperature zone drawing
maximum draw ratio
Polymer industry, paints, wood
PVA fibril
syndiotacticity
Technology of polymers
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Summary:To effectively orient the molecular chains of novel syndiotactic poly(vinyl alcohol) (PVA) microfibrillar fiber (PVA fibril), a high‐temperature zone‐drawing method was adopted. The PVA fibrils were directly prepared from the saponification and in situ fibrillation without a spinning procedure. The maximum draw ratio of the PVA fibril increased with a decrease in the syndiotactic diad (r‐diad) content, indicating that the deformability of PVA molecules was lowered in higher syndiotactic PVA. Degree of crystal orientations up to 0.990 were achieved by stretching the PVA fibril with the r‐diad content of 65.1% and the original degree of crystal orientation of 0.902 at 250 °C close to its crystal melting temperature (Tm). When the same draw ratio was applied to the fibrils, a higher crystal orientation was achieved for the fibrils having higher syndiotacticity. Wide‐angle X‐ray data show that the longitudinal crystal sizes of drawn PVA fibrils were larger in higher syndiotacticities. The degree of crystal orientation, crystallinity, Tm, longitudinal crystal size, and tensile strength of the maximum drawn PVA fibril with a r‐diad content of 65.1% were 0.99, 0.97, 279 °C, 187 Å, and 4.66 N/tex, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1263–1271, 2001
ISSN:0887-6266
1099-0488
DOI:10.1002/polb.1100