STEREOSPECIFIC CATIONIC POLYMERIZATION OF MESOMORPHIC VINYL ETHERS CHARACTERIZED BY C-13-NMR, DSC AND X-RAY-DIFFRACTION

Butylvinyl ether, 4-ethoxyphenyl 4-[4-(vinyloxy)butyloxy]benzoate and 4-ethoxyphenyl 4[11-(vinyloxy)-undecyloxy]benzoate have been polymeriz ed using boron trifluoride diethyl etherate and tin tetrachloride as c ationic initiator. Polymers produced at different temperatures and wit h different solvents exhibited different stereoregularities. Dyad reso nances were assigned from the beta-methylene absorption in a decoupled C-13 nuclear magnetic resonance spectrum, assuming that the polymeriz ation proceeded according to the first-order Markovian trial. The liqu id crystalline side-chain polymers were characterized by differential scanning calorimetry, hot-stage polarized light microscopy and X-ray d iffraction in order to study the influence of tacticity on mesomorphis m and organization. The polymers based on 4-ethoxyphenyl 4[11-(vinylox y)undecyloxy]benzoate with different tacticities exhibited the same in terdigitated smectic A and B structures. Recorded differences in isotr opization temperatures could be attributed to differences in molar mas s. Copyright (C) 1996 Elsevier Science Ltd.