The cationic polymerization of isobutene by the "inifer"-technique was studied. Preliminary experiments are described which suggest that useful polymer can be prepared only when BCI, is rapidly added to the premixed monomer/inifer mixture and that such polymerizations do not go to completion. Some questions regarding the mechanism are discussed and remain open.0025-1 16X/83/$03 .OO
Experimental details are given of attempts to enumerate the binary ionogenic equilibria (B.I.E.) of i-chloro-1-methylethylbenzene (l)/BC13, 1,4-bis(l-chloro-l-methylethyl)benzene (2)/BCI3 and 1,3,5-tris(l -chloro-I methylethy1)benzene (3)/BCI3 in CH2C12. Due to chemical reaction (dimerisation or polymerisation) no experimental values for the B.I.E. constants could be obtained. A Born-Haber cycle is constructed to estimate the relative sequence of the overall B.I.E. constants. A similar treatment for 2-chloro-2-methylpropane as a thermodynamic model for a,w-dichloropoly(2-methylpropene) (4) suggests that the overall B.I.E. constant for these polymers is somewhat smaller than those for 1 and 2 but greater than that for 3. Using 2/BCI3 as initiator for the polymerisation of 2-methylpropene(IB) it is shown, that the degree of polymerisation of 4 can be controlled within the limits 10 < DP < 100. It is shown that 4 can also act as an initiator for the polymerisation of IB, that these polymerisations involve only free ion propagation and, from a kinetic analysis of these polymerisations, that: (kp'y/kc = 12 1 . mol-' . s -' , kZt = 1,2~10-31.mol-'~s-',k,+[P,+] = 1,7.1O-,s-',andk,+/(k:~,5) = 102.Thesame analysis demonstrates that the self-ionisation of BCI, can be neglected in terms of any influence on the molar mass of the products. Experiments are also described which show that 2-chloro-2methylpropane is not suitable as a substitute initiator for IB, but that 2-chloro-2,4,4-trimethylpentane is a useful model for 4 as an initiator for the polymerisation of IB. CI transfer J via Zd -2c[.20) --------4 *) The nomenclature for the B.I.E. constants used here is based on that suggested by Grattan and Plescd).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.