Effect Of Benzoyl Peroxide Research Articles

Preparation and Properties of Rubberlike High Polymers. I. Polymerization of Dienes and Vinyl Compounds in Bulk

Abstract The polymerization of dienes under the influence of heat, of diazoaminobenzene, and of benzoyl peroxide has been studied. Diazoaminobenzene probably acts as a slow but continuous source of free radicals, giving quantitative yields of methyl rubber of good quality from dimethylbutadiene after a few days to a few weeks at 100–125° C. The effect of diazoaminobenzene on butadiene is the same, but the rate of the uncatalyzed dimerization of butadiene at 100° C is as fast as that of dimethylbutadiene at 150° C and, therefore, dimerization interferes much more strongly with the polymerization of butadiene. Only 60 per cent of polybutadiene has been obtained. A few experiments with isoprene showed its position between the two other dienes. The effect of benzoyl peroxide on the polymerization of the dienes appeared to be much smaller than was expected from its known catalytic action on the polymerization of vinyl compounds, e.g., styrene, for in this case its activity is about 100–1000 times greater than that of diazoaminobenzene. It is assumed that a larger number of radicals, produced by the fast decomposition of benzoyl peroxide, causes this difference. Diazoaminobenzene has about the same effect on the polymerization of styrene and acrylonitrile as on that of dienes. The catalytic effect of benzoyl peroxide on the polymerization of dienes is, on the contrary, 10,000–100,000 times smaller than on that of vinyl compounds. This difference can be understood by the assumption that the catalyst is quickly used up by oxidizing the dienes and their polymers. Whereas methyl rubber and the polyisoprene resemble raw natural rubber, polybutadiene, prepared under comparable conditions, is hard, swells moderately, and has a tendency to become brittle as a result of oxidation (aging).

Polymerisation of Tung Oil. V. Effects of Treated Fatty Oils upon the Gelation of Tung Oil

Abstract 1. The gelation—preventing actions of oxidised and polymerised linseed oil were measured. The value of x∞ increases with the increasing degree of cooking and the value for oxidised oils is always greater than that for polymerised oils of the same cooking degree. 2. Perilla oil was oxidised at 100°C., 200°C. and 300°C. to the degrees of iodine values 170, 150, 140 and the effects upon the gelation were meas？red. In the cases of oxidised oil prepared at 300°C. the relation of 1⁄t∼x was linear and the value of x∞ increase according to the increase of cooking degree. In the cases of oxidised at 100°C. and 200°C. curved lines were obtained. This tendency is supposed to be due to the peroxide contained in it. 3. The effect of benzoyl peroxide also was examined. Benzoyl peroxide has a strong gelation accelerating action. The effect of perilla oil added with benzoyl peroxide is similar to that of perilla oil oxidised at low temperature. 4. The gelation—preventing action of brominated oils is very strong and the value of x∞ is less than 4%. Therefore, these substances can be used as a strong gelation—preventing agent.