Mastication of Rubber An Oxidation Process

Abstract

possible with the various solvents now available, but it is probable that few, if any, are true constant-evaporating mixtures. The behavior of a mixture of benzene, butyl acetate, and amyl alcohol has been referred to by Hofmann and Reíd (9). The ingredients are removed from the mixture by evaporation, more or less completely, in the order named, although of course all are evaporating simultaneously at different rates. Summary 1. Evaporation rates of organic liquids are not proportional to their boiling points.2. Determinations of rates of evaporation by the usual method are sufficiently indicative for practical purposes, but the results are not capable of numerical expression.3. For pure liquids the slopes of the evaporation curves may be used to express the rate of evaporation. 4. A simple method of determining rates of evaporation of pure liquids is described. In this method temperature, humidity, and air velocity are controlled, and the apparatus is preferably calibrated with a standard liquid. (Normal butyl acetate was used.) 5. The rate of evaporation of a liquid may be approximately predicted by means of the formula: vapor pressure X mol. wt. -s-11 which gives a rate of 100 for n-butyl acetate (20°C.).6. The compositions of several new binary constantevaporating mixtures and of two ternary mixtures which may be called "apparent constant-evaporating mixtures," have been determined. Literature Cited (1)

Mastication of rubber, I. Mechanism of plasticizing by cold mastication

“…The reaction with benzoquinone has already been discussed and it is believed, from their behavior in polymerization processes, that maleic anhydride, acrylonitrile, and acrylic acid behave similarly (cf. Le Bras2') The graded efficiencies of the quinones follow the order of their retardation efficiency in styrene p~lymerization,~~ supporting the analogous reactions of equation (2). The last three compounds above are reactive comonomers (e.g., cf.…”

“…Other reactions of these radicals may also occur, and it is clear that any interaction with another rubber molecule immediately opens up the possibility of the production of branching or cross-linking. This is especially evident in cases such as (1) benzoquinone where the new radical is already attached to a rubber chain, (2) comonomers such as maleic anhydride which can react readily with unsaturated molecules, or (3) radical acceptors which contain more than one functional group (e.g., dithiols). Without further detailed discussion of the individual chemical reactions, it is therefore suggested that there is no difliculty in understanding qualitatively why branching and cross-linking often occur concomitantly with degradation.…”

A real‐time study on the evolution of the degradation of polypropylene during mixing process

“…According to the classical theory of mixing process, mechanochemical degradation of PP may take place in the mixing processing 5–27. Additionally, thermooxidative degradation of PP may take place simultaneously for the characteristic of the chemical structure of PP 28–32, 47, 48.…”

“…Early in the initial stage of the research of the polymer processing, the action of mechanochemical degradation of the polymer caused by the shear effect during mixing or extrusion processing was found and then paid closed attention to for a long time 5–27. The mechanochemical degradation may give a remarkable influence on the molecular structure, the molecular weight, and the mechanical properties of the polymer processed.…”

Rapeseed Oil: Air-Blowing in Presence of Catalysts

“…So far as present results go, the presence of peroxides could not be detected in any of the samples that had been blown with any of the catalysts. However, Busse (1), in his article on the mastication of rubber, points out that the addition of driers (lead, cobalt, manganese soaps) reduces the amount of hydrogen peroxide given off by the drying film of linseed oil, whereas nondriers (soaps of zinc, cadmium, aluminum) enormously increase the amount.…”