Effect of alkalies on suspension polymerization of vinyl acetate monomer, properties of poly(vinyl acetate) beads and poly(vinyl alcohols)

✍ Scribed by S. K. Verma; P. Arvindakshan; S. C. Bisarya

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 497 KB
• Volume: 46
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1992.070460417

✦ Synopsis

Abstract

The use of weak alkalies such as sodium carbonate (Na~2~CO~3~), sodium bicarbonate (NaHCO~3~) and their 1 : 1 molar mixture, and strong alkalies such as sodium hydroxide (NaOH) and sodium methoxide (NaOMe) as pH controllers in suspension polymerization of vinyl acetate monomer (VAM) has shown to have diverse effects on the yield of resulting poly(vinyl acetate) (PVAC) beads. Carbon dioxide as such or the carbonate seems to influence the yield. Further, these alkalies have a deep‐seated effect not only on properties like viscosity, stereoregularity, glass transition temperature (T~g~), and swelling coefficient (Q) of the PVAC beads but also on those of poly(vinyl alcohol) (PVA) obtained by alcoholysis of PVAC beads. The PVAC beads obtained using Na~2~CO~3~ showed higher viscosity, higher swelling coefficient (Q), and the PVA derived from these beads had higher Q, higher syndiotacticity/isotacticity ratio, and lower T~g~.