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Separation of styrene‐methacrylate copolymers by composition using normal and reversed‐phase high‐performance liquid chromatography

1991; Wiley; Volume: 29; Issue: 9 Linguagem: Inglês

10.1002/polb.1991.090290905

1099-0488

Hisaya Sato, Kenji Ogino, Susumu Maruo, Masato Sasaki,

Analytical chemistry methods development

Abstract The separation of styrene‐methacrylate copolymers by chemical composition was studied using high‐performance liquid chromatography (HPLC). With the combination of acrylonitrile (polar) gel and nonpolar eluent or of styrene (nonpolar) gel and polar eluent, poly(styrene‐co‐methylmethacrylate) was separated by the adsorption mechanism. The former is designated as normal and the latter as reversed phase. With other combinations, the copolymer was separated mainly by fractional dissolution mechanism. The sample eluted slightly earlier as molecular weight decreased. The molecular weight effect on the reversed‐phase HPLC was smaller than that on the normal phase. A gel with an exclusion limit of 3 × 10 3 exhibited greater molecular weight dependence and worse resolution than a gel with an exclusion limit of 50 × 10 4 . Poly(styrene‐co‐ n ‐butyl methacrylate) also was separated on the basis of chemical composition by normal and reverse‐phase HPLC. However, poly(styrene‐co‐ t ‐butyl methacrylate) was separated only by reverse‐phase HPLC. When octadecyl methacrylate gel was used instead of styrene gel in reverse‐phase HPLC, a good separation was not obtained. This indicates a specific interaction between the phenyl group of the styrene gel and the sample.