Polymerization of vinylcarbazole in the presence of butyllithium and titanium tetrachloride

Abstract

The polymerization of large cyclic vinyl compounds is of considerable interest in the interpretation of the mechanism of action of complex organometallic catalysts. Numerous vinyl compounds have been investigated up to now but no study has been made of compounds containing large rings. Studies on the isotactic polymerization of vinylcarbazole have brought to light very important facts permitting of a number of inferences as to the mechanism of isotactic polymerization. Despite the large molecular volume of vinylcarbazole and the steric hindrances that should be expected due to this, a study of the polymerization kinetics has revealed reaction rates similar to those observed in the polymerization of other monomers. The study of the polymerization of vinylcarbazole and of other monomers showed that the butyllithium‐titanium chloride catalyst belongs to the class of organometallic complexes that act either by a stepwise or ionic mechanism. The specific features of complex organometallic catalysts in the polymerization of vinylcarbazole are evidently associated with preliminary activation of the active centers during which activation of the monomer also takes place. The formation of polymers with an isotactic microstructure is due to one of the possible mechanism of the catalysis, namely, to nonstepwise action. In the polymerization of vinylcarbazole in the presence of organolithium compounds and titanium tetrachloride the microstructure of the resultant polymer and the rate of polymerization depend upon the formation of other than primary complex compounds. The microstructure of isotactic polyvinylcarbazole shows a particular shape of spherulites, depending upon the nature of the catalyst.

Polymerization of N-Vinylcarbazole Initiated by Metal Salts

“…Two detailed investigations were performed independently by Solomon et al [38,39] and Heller et al [40]. It is interesting t o note that they reported mutually contradictory results on the s t e r e ospecific polymerization of NVC by Ziegler-type catalyst s y s t e m s such as BuLi-TiC1, [39,40] and TiCl,-AlR,.…”

“…It is interesting t o note that they reported mutually contradictory results on the s t e r e ospecific polymerization of NVC by Ziegler-type catalyst s y s t e m s such as BuLi-TiC1, [39,40] and TiCl,-AlR,. Solomon e t al.…”

Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran

“…To apply to these fields, it is essential to prepare PVCZ of high molecular weight and high linearity by adopting a new method to polymerize N-vinylcarbazole (VCZ). 14 -16 Up until now, several methods has been developed for the polymerization of VCZ such as a free radical, 16 -19 conventional cation (protonic acids, Lewis acids, carbocations), 20 -24 photoinitiation, 25,26 ZieglerNatta, 27 charge transfer, 28 electrochemical, 29,30 vapor deposition, 15 solid state, 31 etc. Free radical polymerizations of VCZ using azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO) as initiators have been performed to prepare PVCZ of a molecular weight of below 100,000.…”

Preparation of high molecular weight poly(N-vinylcarbazole) in high yield by low-temperature precipitation polymerization ofN-vinylcarbazole

“…Several methods have been developed for the polymerization of VCZ, eg free radical,16, 17 conventional cation (protonic acids, Lewis acids, carbocations),18–20 photo‐initiation,21 Ziegler–Natta,22 charge transfer,23 electrochemical,24 vapour deposition,15 and solid state 25. It is well known that low molecular weight PVCZ with number average molecular weight below 100 000 g mol −1 is prepared by free radical polymerization of VCZ using azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO)16, 17 as an initiator.…”

“…17 In contrast, the precipitation polymerization method has the advantage that molecular weight and conversion increase simultaneously. These polymerizations were, however, conducted at temperatures above 40 °C, moreover, polymerization at temperatures below 40 °C was only possible by the use of cationic,18–20 photoinitiation,21 Ziegler–Natta,22 charge transfer23 and electrochemical24 methods. The above polymerization processes inevitably require very complicated and expensive polymerization apparatus and special polymerization initiator, and hence could be difficult to commercialize.…”