Effect of pressure on dissociation of poly(methacrylic acid) in aqueous solution

✍ Scribed by Suzuki, Keizo ;Taniguchi, Yoshihiro

• Publisher: Wiley (John Wiley & Sons)
• Year: 1970
• Tongue: English
• Weight: 323 KB
• Volume: 8
• Category: Article
• ISSN: 0449-2978
• DOI: 10.1002/pol.1970.160081004

✦ Synopsis

Abstract

The effect of pressure (up to 6300 atm) on the electrical conductivity of poly(methacrylic acid) (PMA) in aqueous solution was investigated in the concentration range 0.001__M__ to 0.1__M__ (in equivalents of carboxyl groups) at 30°C. The degree of ionization α calculated from the conductivity data increased linearly with pressure. From dilatometric measurements of volume changes when PMA was partially neutralized with NaOH, a conformational transition was confirmed to take place above α = 0.12, and the volume change accompanying the dissociation of the side chain groups (carboxyl groups) was found to be − 12.5 ml/H^+^. It may be inferred from the values of α at each polymer concentration and from the dilatometric data that there is no conformational transition from a compact structure to the coiled form below at least 6,000 atm in the absence of Na^+^ counterions.