✍ Scribed by K. Nyitrai; F. Cser; G. Csermely; Bui Doc Ngoc; L. Füzes; G. Samay; G. Hardy
No coin nor oath required. For personal study only.
The solid-, cholesteric-and liquid-state polymerizations of cholesteryl-vinyl-succinate (CVS) are studied. Only one of the three polymorphic modifications of CVS oligomerizes in the solid state into oligomers of degree i 5 = 2 to 6 in a homogeneous topochemical reaction. The rate of polymerization in the cholesteric state is lower than that in the liquid state at the same temperature. Kinetic constants were measured at 85 ~ using benzoyl peroxide as initiator and the Banfield radical, givin~ E ..... . = 15.4, 36.4kcal/mole-1; f = 0.52, 0.19; kp/k~/2= 0.0167, 0.0192, (l/mole sec) 1/2, (Ep-½Et) = 0.40, 21.4 kcal mole-1. The values refer to the liquid-and the cholesteric-state reactions, respectively. The average degree of polymerization is low in both cases (P = 20 and 22). It was concluded that the molecular weights are controlled by chain transfer and that the initiation reaction is mostly dependent on the phase where the reaction takes place.
📜 SIMILAR VOLUMES
It was demonstrated that the liquid-phase polymerization of CMA is more rapid by several orders of magnitude than that in the solid state. In monoclinic crystals of CMA, preconditions of a topochemical process can be established but polymerization has a heterogeneous character. The heterogeneous pol