LAURA URSU, MIHAI POSTOLACHE, MAGDALENA POSTOLACHE, DANA ORTANSA DOROHOI THE STRETCHING EFFECT ON THE ANISOTROPY OF POLY (VINYL) ALCOHOL (PVA) FOILS
The polymer foils, obtained from pure and coloured (with cycloimmonium ylids) poly (vinyl) alcohol (PVA) gel, are studied from the optical anisotropy point of view. The dried foils were stretched under heating and their optical birefringence was measured for different degrees of stretching. The changes in the birefringence were correlated with the stretching degree of the polymer foils. The influence of the cycloimmonium ylid structural peculiarities on the coloured foils’ anisotropy is also discussed.
Keywords: cycloimmonium benzoyl anilido-benzoyl methylids, optical birefringence, stretched coloured and pure PVA foils