Anionic Polymerization of Styrene

Abstract

X study of the kinetics of the initiation and propagation reactions in the polynlerization oE styrene by butyllithium in benzene solution has been made. The initiation has been shown to be first order in styrene and 0.155 order in butyllithium, the propagation to be first order ill styrene and half order with respect to active chain ends. The apparent activation energies oE the two reactions have been shown to be 18,000 calories and 14,300 calories respectively. The ultraviolet absorption spectra oE colored species produced has been measured and compared with others found in similar systems.

Experimental techniques in high‐vacuum anionic polymerization

“…Canadian Technique in Detail 3,24,25 An alternative geometry of an all-glass apparatus, which permits purging, is shown in Figure 49. This apparatus was developed and highly refined by the Canadian school of anionic polymerization, during the 1960s and 1970s, an elegant culmination of contributions from Worsfold, Bywater, and Roovers, among others.…”

An improved general kinetic analysis of non-linear irreversible polymerisations

“…After a few fundamental studies on its chemical kinetics (Worsfold, 1970;Eschwey and Burchard, 1975) have been carried out, this system was later found to be useful as a model for RIM encapsulation of electronic parts (Your et al, 1989;Christiansen et al, 1990;Karles et al, 1991).…”

“…For p-divinylbenzene, kinetic measurements (Worsfold, 1970;Karles et al, 1991) show that the pending vinyl group is about 10 times less reactive than the initial one, and about as reactive as the vinyl groups in styrene and mdivinylbenzene. On the contrary, anion reactivities look more or less similar.…”

“…Only a fraction of the anions is available at every moment for participating in initiation or propagation. That fraction should be the same for every chemically similar anionic group, irrespective of molecular chain length (Worsfold and Bywater, 1960;Arest-Yakubovich, 1997). Apparent kinetic constants should follow a power law with respect to overall anion concentration, with a negative exponent slightly less than 1, explaining thus the observed apparent orders with respect to initiator which are much less than 1.…”

“…An example is n-butyllithium initiated bulk polymerisation of styrene in benzene, for which m I = 6 (Worsfold and Bywater, 1960), and m P = 2. Karles et al (1991) have found that m P =1.2±0.8 for bulk polymerisation of DVB, different from styrene, which is a source of some complications in kinetic modelling.…”