Copolymerization of isobutylene and styrene at low temperatures in the presence of friedel‐crafts catalysts

Abstract

Isobutylene and styrene were copolymerized at low temperatures, in methyl chloride solution, in the presence of aluminum chloride. The temperature was varied from −30 to −94°C., and the monomer/solvent ratio, the ratio of monomers, and the catalyst concentration were varied over a considerable range. The copolymerization equation was found to be applicable to the data, and the reactivity ratios were determined for various experimental conditions. For an “open” system in which the volume steadily increases during the course of polymerization, it is shown that the copolymerization equation is formally identical to that of Mayo and Lewis, except that concentrations are replaced by amounts of the reacting species. The temperature coefficients of the reactivity ratios in the present system are compared with those for free‐radical systems; some important differences are noted. The reactivity ratios of isobutylene and styrene in the present system are greatly increased under conditions of turbulent agitation. A procedure for the compositional fractionation of the copolymers is described. The results are interpreted in terms of the copolymer chain structure; they appear to admit the postulate that the reactivity ratios and corresponding propagation rate constants are functions of chain length.

Tripolymers from Butyl Rubber Polymerization

“…The others are discussed in more detail in a continuing series of articles on the butyl rubber polymerization system. Experimental Batch polymerization reactions (6) were carried out in a 2-liter copper reactor submerged in liquid ethylene which maintained the temperature at -100°C. (Figure 1).…”

“…However, in many applications, such as paint, paper, and textile coatings and carpet backsizings, it is necessary to control the viscosity of the final compound at a relatively high level. The desired viscosity varies with each application, and this is frequently controlled by the addition of high molecular weight water-soluble thickeners (6). The viscosity response to a given thickener varies with the chemical and colloidal composition of the latex being used (7).…”

Frequency control of crossover reactions in concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers and oxiranes: specific roles of weak Lewis bases and solvent polarity

“…In contrast, in copolymerizations of monomers with different structures (such as cationic copolymerization between a VE and a styrene derivative), the relative reactivities of monomers considerably differ depending on the reaction conditions. [3][4][5][6][7][8][9][10][11] Notably, the monomer reactivity ratios are greater than one in many cases, such as in reactions using 2-chloroethyl VE and p-methoxystyrene 4,5,8 or in those using isobutylene and styrene. 6,9 These specific behaviors have partially been explained in terms of the "selective solvation" effect, although the details of these behaviors are not clear.…”

“…[3][4][5][6][7][8][9][10][11] Notably, the monomer reactivity ratios are greater than one in many cases, such as in reactions using 2-chloroethyl VE and p-methoxystyrene 4,5,8 or in those using isobutylene and styrene. 6,9 These specific behaviors have partially been explained in terms of the "selective solvation" effect, although the details of these behaviors are not clear. [5][6][7][8][9] In the copolymerization of two monomers with different structures, the reaction conditions strongly influence the monomer sequence distributions, in which the monomers generate different types of growing ends.…”

“…6,9 These specific behaviors have partially been explained in terms of the "selective solvation" effect, although the details of these behaviors are not clear. [5][6][7][8][9] In the copolymerization of two monomers with different structures, the reaction conditions strongly influence the monomer sequence distributions, in which the monomers generate different types of growing ends. This situation potentially occurs also in the concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl and cyclic monomers.…”