ELASTIC DEFORMATIONS IN A MAGNETIC-FIELD OF A LIQUID-CRYSTALLINE POLYMER WITH MESOGENIC GROUPS IN THE MAIN AND SIDE-CHAINS

Orientational elastic deformations in a magnetic field and phase trans ition temperatures of a thermotropically mesogenic ''combined'' aromat ic polyester with mesogenic groups, both in the main and in the side c hains, have been investigated in the range of 900 to 10,200 mol. wt. I t was shown that in this molecular weight range the birefringence of a completely oriented nematic and correspondingly, the degree of its or ientational order S are independent on molecular weight. When the rela tive temperature DELTAT changes from -2 to -30-degrees-C the orientati onal order parameter increases from 0.35 to 0.55. The bend elasticity constants K3 coincide in the order of magnitude with those for high an d low molecular weight nematics investigated previously and their depe ndence on molecular weight has not been detected.