Synthesis and molecular structure of highly compact star-like poly(methyl methacrylate) and poly(butyl methacrylate)

Abstract

Poly(methyl methacrylate) and poly(n-butyl methacrylate) highly dense star-like polymers with a varied number and length of arms were prepared by the arm-first group transfer polymerization. The work is focused on the detailed characterization of the molecular structure and dilute solution properties of star-like polymers. The refractive index increment of the star-like polymers was compared with that of corresponding linear homopolymers. The prepared polymers were characterized by size exclusion chromatography coupled with a multi-angle light scattering detector and an online viscometer. Except for the commonly used molar mass, root mean square radius, and intrinsic viscosity, the obtained data also allowed the determination of the distribution of the arms per molecule, the calculation of the average number of arms per molecule, and the determination of the molar mass dependency of the draining factor. The relation between the number of arms per molecule and molar mass was estimated using various theoretical equations and compared with the true values obtained by the division of the slice molar mass by the molar mass of arms.