MOLECULAR-MASS AND CONFORMATIONAL CHARACT ERISTICS OF COPOLYMERS OF ACRYLONITRILE WITH N-VINYLCAPROLACTAM

The hydrodynamic characteristics of vinylcaprolactam (m-dash)-acryloni trile copolymer solutions in DMFA were studied at various compositions of the copolymer. The relation between these characteristics and the molecular mass of the copolymer was established. The equilibrium stiff ness of the copolymer molecules was estimated in terms of Stokmayer-Fi xman and Kovi-Bywater theories with account of the excluded volume. Th e length of the Kuhn's segment was found to be A = 35 x 10(-10) m, thi s value being 1.5 times larger than similar values for homopolymers po ly(N-vinylcaprolactam) and poly(acrylonitrile). The dependence of bire fringence in copolymer solutions upon the velocity gradient G of a lon gitudinal hydrodynamic field was studied. It was found that at G > 400 0 sec-1, nearly complete extension of macromolecules of the copolymer can be achieved.