FRACTIONATION AND CHARACTERIZATION OF IMIDIZED POLY(METHYL METHACRYLATE)

Physical-chemical studies on a sample of NCH3-imidized poly(methyl met hacrylate) (PMMA-I-CH3) were performed by several characterization tec hniques. Fractional precipitation by solvent/non-solvent at constant t emperature was used, obtaining 12 fractions characterized by different molecular weights. With these fractions of the PMMA-I-CH3, in the ran ge 2 x 10(4) < M(w) < 2 x 10(5), a Mark-Houwink equation was determine d. This relationship, in tetrahydrofuran at 30 degrees C, was found to be [eta] = 2.22 x 10(-4)M(w)(0.66). This equation is the starting poi nt for studying the polymer-structure relationships. The determination of various properties, such as viscosity, glass transition temperatur e, nitrogen content and molecular weights, allowed us to obtain struct ural information on the copolymer. The imidization degree, evaluated b y H-1 n.m.r. spectroscopy, was used to correlate glass transition temp erature and polymer structure.