FLOW BIREFRINGENCE AND ELECTROSTATIC BIRE FRINGENCE OF CYANOETHYLNITROCELLULOSE SOLUTIONS IN CYCLOHEXANONE

The optical and electrooptical properties of the samples of mixed ethe r-ester, cyanoethylnitrocellulose of varied composition in cyclohexano ne solutions were studied using flow birefringence and equilibrium ele ctrostatic birefringence. The optical anisotropy of the Kuhn segment o f cyanoethylnitrocellulose, (alpha(1) - alpha(2)) was found to substan tially depend on the degree of substitution with respect to NO2 group, gamma(1), and (CH2)(2)CN group, gamma(2), the value of (alpha(1) - al pha(2)) changing sign from positive to negative upon increase in gamma (1) and decrease in gamma(2). The Kerr constant of cyanoethylnitrocell ulose also strongly depends on gamma(1) and gamma(2) and changes its s ign from positive to negative. The signs of the flow and electrostatic birefringences for all samples of cyanoethylnitrocellulose coincide. This indicates that macromolecules of this polymer in both hydrodynami c and electric fields experience orientation proceeding via large-scal e mobility.