Conversion Factors for Polystyrene Molecular Weight into Molecular Weights of Polymethacrylates in Size Exclusion Chromatography

Abstract Relationships of molecular weights between polystyrene (PS) and several polymethacrylates, poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA), poly(isobutyl methacrylate) (PIBMA), and poly(lauryl methacrylate) (PIMA), were examined. A conversion equation, was first defined, where s and t are constants, and Mps and Mpolymethacrylate are molecular weights of these polymers at the same retention volume. Conversion factors s and t for these polymethacrylates were estimated by using a PS calibration curve and corresponding polymethacrylates having broad molecular weight distributions. Pairs of s and t are as follows: 0.362 and 1.107 for PMMA; 0.2078 and 1.153 for PEMA; 0.01859 and 1.348 for PBMA; 1.727 and 0.978 for PIBMA; 21.64 and 0.746 for PLMA. These conversion factors are effective in the mobile phase of tetrahydrofuran at room temperature. By knowing these conversion factors and a PS calibration curve, molecular weight averages for these polymethac...