Analytical Sciences

A Nonaqueous Potentiometric Titration Study of the Dissociation of t-Butyl Methacrylate-Methacrylic Acid Copolymers

Kiyoharu NAKATANI,*  Jun YAMASHITA,* Tomomi SEKINE,* Minoru TORIUMI,** and Toshiro ITANI**

*Department of Chemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8571, Japan
**Semiconductor Leading Edge Technologies, Inc. (Selete), 16-1 Onogawa, Tsukuba 305-8569, Japan

The dissociation of t-butyl methacrylate-methacrylic acid copolymers in dimethyl sulfoxide was analyzed by a nonaqueous potentiometric titration technique. The negative logarithm of the dissociation constant of the monomer unit of a methacrylic acid (MAA) monotonously increased with the increasing degree of dissociation corresponding to the titrant/MAA amount ratio, and was highly influenced by the copolymerization ratio. The results are discussed in terms of the suppression of the dissociation of MAA by a neighboring charged methacrylate anion unit.

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