Molecular weight determination of vinylidene chloride copolymers by gel‐permeation chromatography and viscometry

Abstract

SynopsisThis is the first report on the characterization of several pairs of random copolymers of vinylidene chloride by gel-permeation chromatography in conjunction with viscometry. Such copolymers have not previously received much attention, so we first determined the individual viscosity-molecular weight relationship. The K-a values were compared with known values for the parent homopolymers. We then derived calibration cirves (different for each composition) and the calculation of the average molecular weight. These results are compared to those obtained by direct methods, without fractionation, and to kinetic observations. This method avoids misinterpretation of viscosity data and elution volume. Chromatograms may indicate heterogeneity of the compounds as related to polymerization conditions.

Copolymer analysis

“…A similar type of automatic viscometer, with a capillary diameter of 004 or 0.5 mm and a length of 200 mm, was applied to copolymers of vinyl chloride (vq, methyl acrylate, and MMA with vinylidene chloride (VDq [33]. At the peak maximum the viscosity was not very different from that of the whole polymer.…”

“…A series of random, block and graft copolymers of VC with styrene (S), butadiene (B), MMA, V Ac, and VDC was characterized with the help of three consecutive detectors: a differential refractometer (RI), an ultraviolet absorption detector (UV) and an automatic viscometer [33]. Figure 5.2 summarizes the relation between solution viscosity and molecular mass for these copolymers.…”