CONFORMATIONAL CHARACTERISTICS OF POLY(METHYL ACRYLATE) .1. DIPOLE-MOMENT MEASUREMENTS

A sample of poly (methyl acrylate) with Mv = 4.57 × 105 has been synthesized via free-radical polymerization. Six fractions having molecular weights Mv = 4.70 × 106, 10.12 × 105, 6.90 × 105, 4.99 × 105, 4.49 × 105, and 3.33 × 105 were isolated, and their dipole moments in benzene solution were determined at different temperatures in order to study the effect of molecular weight and temperature on the dipole moment. The plot of dipole moment ratio against temperature exhibits a minimum at T ≃ 35 °C that, to our knowledge, has not been reported before; however, this ratio does not depend on molecular weight. © 1979, American Chemical Society. All rights reserved.