Elastic constants and order parameters of comblike copolymers

Orientational elastic deformations of nematic phase of comblike copolymers in a magnetic field were studied. The temperature dependences of birefringe nce Delta n, order parameter S and splay elastic constant K-I were determin ed. It is shown that with increasing of the molar fraction of nonmesogenic component from 0 to 0.4, the parameter S depends on copolymer composition x only near the phase transition point nematic - isotropic melt, at which S decreases with increasing x. For a copolymer with x = 0.51 at all temperatu res, a decrease in the order parameter is detected. In the investigated tem perature range the values of constant K-I do not depend on copolymer compos ition. The results are compared with characteristics of thermotropic linear aromatic polyesters.