L. Toman

A new family of telechelic copolymers

SummaryA new initiation system is described, allowing bulk polymerizations of isobutylene to be carried out at about-78°C, in the absence of a polar chlorinated solvent. The initiation system consists of two components, the first of which is boron trichloride (BCl3) used as co-initiator, and the other component is a polymer insoluble in the monomer and containing chloroallyl structures or structures with a chlorine atom bound at the tertiary carbon atom in their chains. Bulk polymerizations of isobutylene proceed at the boundary between the solid and the liquid phase for many hours, and the polymeric initiator used is grafted by isobutylene. Dichloromethane raises reactivity of the initiation system.

Isobutylene polymerization in the presence of t-BuCl/SnCl4

SummaryThe effect of tert-butyl chloride in the polymerizations of isobutylene carried out in the presence of SnCl4 in dichloromethane at temperatures-20°C and-78°C was investigated. Synthesized polyisobutylene samples showed a bimodal molecular weight distribution (MWD) and it was found that the weight content of the lowermolecular weight (LMW) fraction increased with increasing t-BuCl concentration in the polymerization mixture. The effect of ageing of the initiation mixture t-BuCl/SnCl4 in CH2Cl2 prepared in advance on MWD of the PIB samples was also studied. Ageing of the initiation system supports the formation of the LMW fraction and this oily PIB is the only product of the polymerization at-20°C,

The polymerization of isobutylene with VCl4 and ammonia

\bar M_n \sim 500,\bar M_w /\bar M_n \leqslant 1.4

Photoinitiation by radical‐cationic mechanism in the polymerization of isobutylene with lewis acids

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Spectrophotometric investigation of the mechanism of polymerization of isobutylene with vanadium tetrachloride and visible light

SummaryThe polymerizations of isobutylene in dichloromethane at-20°C initiated with the system 2,5-dichloro-2,5-dimethylhexane (DDH)/SnCl4 were investigated. The polyisobutylene (PIB) samples obtained were examined by GPC and their molecular weight distribution curves were determined. It was found that PIB products obtained by the conventional procedure have a bimodal MWD and the weight content of the lower-molecular weight fraction increases with increasing concentration of DDH in the polymerization feed. The effect of ageing of DDH/SnCl4 mixtures prepared in advance on MWD of the PIB samples was also proved. The results achieved lead to a conclusion that the ageing of the initiation system consists probably in the formation of the complex DDH-SnCl4-H2O, which protogenically again initiates the oligomerization of isobutylene, giving rise to oils with a narrow MWD, the polydispersity index

Formation of the radical‐cation of monomer in the photoinduced polymerization of isobutylene in the presence of SnCl4

{{\bar M_{_w } } \mathord{\left/ {\vphantom {{\bar M_{_w } } {\bar M_n }}} \right. \kern-\nulldelimiterspace} {\bar M_n }} \leqslant 1.3