Studies on the preparation of the polysulfide rubber from dichloromethane, 1, 2-dichloroethane, β, β′ dichloroethylether, epichlorohydrin and sodium polysulfide were carried out; and the softening points, solubilities in various solvents, external appearances and shearing adhesive strengths of the above products to the aluminum test pieces were measured. In comparison between binary and ternary components systems, strong adhesive strength was observed in the non elastic products obtained from epichlorohydrin and sodium polysulfide in binary system, and also the polymers containing epichlorohydrin as a raw material were more adhesive than the others containing non epichlorohydrin in ternary system. And so, the presence of OH group in the products was necessary for high adhesion. When the mol ratio of epichlorohydrin and 1, 2-dichloroe thane was 1:1, stronger adhesion was obtained as compared with 2:1 and 1:2 in ternary system.
As the result of oxidation of the above samples by hydrogen peroxide, the densities, elasticities and the adhesive strengths-when they are initially low adherent non-oxidized polymers-were improved.

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When an ethylene-vinyl acetate copolymer (EVA) was crosslinked with a dicumyl peroxide (DCP) using a Brabender Plasticorder, the degree of crosslinking for the copolymer increased with an increasing VAc content. The mechanism of crosslink formation of EVA with DCP was speculated as follows: the labile site of crosslink was primarity a carbon atom of methyl group on the end of acetoxy group, as a result of a decrease in gel content by hydrolyzing the crosslinked copolymer with KOH, which is considered the same mechanism of long chain branching formation as in a poly (vinyl acetate).

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The strain at break vs. temperature diagrams were obtained for varous filler loaded vulcanized rubbers. Application of the empirical equations for the diagram, which have recently been proposed for those on the pure gum vulcanizates, to the experimental data was found successful. It was found that the temperture at which the extenstions ratio at break reaches its maximum value increased with the amount of fillers and that this characteristic temperature seemed to become a little higher and lower for those including the active and the inactive fillers, respectively, than that of the pure gum vulcanizate when they were compared at the same vulcanization level.
The extension of the blending law previously proposed appeared successul in application to the data on the maximum extension ratio at break for the filler-loaded vulcanizates in general.

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In the preceding report, the author reported separation of fractions A₂ and R₁ having photo-staining property and strong fluorescence from light colored rubber processing oil, applying elution chromatography. Of these fractions, the author obtained IR and UV absorption spectra and examined their composition.
The author observed that the fractions A₂ and R₁ comprise a variety of polycyclic aromatic hydrocarbons possessing alkyl side chain, as well as anthracene, phenanthrene, pentacene, etc. It was also found that certain amounts of S, and N, etc. too are included in their composition.
After discoloring these fractions A₂ and R₁ by irradiation of light, their IR and UV absorption spectra were analyzed and as a result, a wide range of >C=O absorption was observed in 1700-1800-cm band, with per oxide, ketone, aldehyde, alcohol, carboxylic acid, etc. being found to be formed. Apart from this, the author tried irradiation of the fractions A₂ and R₁ in N₂ gas, but observed no photo-staining at all.
Summing up these facts, the photo-staining phenomenon of light colored processing oil compounded rubber goods in presumed to be a phenomenon of oxidation of polycyclic aromatic hydrocarbons existing in oil being caused by irradiation of light in the existence of oxygen.

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