Addition d'un polymère “flexible” la polyvinylpyrrolidone à des solutions aqueuses mésomorphes d'un polymère semirigide l'hydroxypropylcellulose

Mesomorphic solutions of a semi-rigid polymer, hydroxypropylcellulose in water, have been studied; the effects of the replacement of a part of the solvent by a flexible polymer, polyvinylpyrrolidone, have also been investigated. The principal effects are (i) lowering of the critical concentration of onset of the anisotropic phase, (ii) raising of the temperature of appearance of the “gel”, (iii) decrease of the pitch of the cholesteric structure. Investigations on different molecular weights of PVP seem to show a modification of the mesomorphic phase in the blend without demixing.