Several dinitrile oxides were investigated as vulcanizing agent for EPDM. They were terephthalodinitrile oxide (TNO), 2, 5-dimethylterephthalodinitrile oxide (DMNO), 2, 3, 5, 6-tetramethylterephthalodinitrile oxide (TMNO), 2-chloroterephthalodinitrile oxide (CNO) and anthracene-9, 10-dinitrile oxide (ANO).
The rate of vulcanization reaction decreased in the order of CNO>TNO>DMNO>TMNO>ANO. The crosslinking efficiencies of TNO and DMNO were both about unity, but those of TMNO, ANO and CNO were less than about 0.5. At the same crosslinked chain density, tensile moduli or hardnesses of the vulcanizates decreased in the order of the vulcanizer CNO≅TNO>DMNO>ANO≅TMNO>sulfur or peroxide. Moreover, elongation at break and stress relaxation of these vulcanizates, respectively, were found to decrease or increase with an increasing tensile modulus. Similar tendecies were found on carbon black stocks.
It was assumed that these peculiarities were due to the inhomogeneous distribution of the network chains caused by too rapid vulcanization.
From the data on the stress relaxation at 140°C, the crosslinks in the vulcanizates cured with the dinitrile oxides were found to be relatively heat-resistant in comparison with sulfur crosslinks.

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Although the effect of the temperature on the crosslinking efficiencies of several dinitrile oxides is almost equal, the crosslinked chain density decreases slightly with increasing vulcanization temperature. In the case of vulcanization with TNO or DMNO the cure rate is extremely high. The tensile modulus of the EPDM vulcanizate increases, whereas elongation at break decreases with a drop of the vulcanization temperature. It was found that stress relaxation, especially initial relaxation, of the vulcanizates having a higher modulus was larger, and that the equilibrium modulus was also higher than that calculated from the swelling data according to the theory of ideal rubber elasticity. These peculiarities seem to be due to the presence of pre-extended chains. These networks might be caused by the scorch because of a much higher cure rate than the flow rate of rubber under the experimental conditions. The effect of vulcanization temperature on the properties of vulcanizates was little when TMNO or ANO was used as curing agent becuase their cure rates were rather slow.

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For the purpose of modifying the mecahnical properties of cis-polybutadiene and natural rubbers by the addition of bulky groups to the unsaturated double bonds, the rubbers were reacted with saligenin. The reaction was carried out at 180°C under a nitrogen atmosphere in a sealed tube. The amount of combined saligenin and the change of the micro-structure were measured by elementary and infra-red analyses. Dynamic and tensile properties were investigated with the vulcanizates of those modified rubbers.
It was found that saligenin reacted with natural rubber quantitatively to give rise to a shift in the transition temperature of the modified rubber and an increase of the tensile modulus according to the amount of the saligenin charged. On the contrary, butadiene rubber did not react with saligenin but formed a large amount of gel. The cis-trans isomerization does not seem to occur in these reactions.

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Some poly(vinyl chloride) containing allyl group at different degrees were prepared by the coupling reaction between poly(vinyl chloride) and allylmagnesium chloride in tetrahydrofuran. The polymers obtained were crosslinked by using peroxide at 140°C
The measurements of physical properties of the modified polymers lead to the following results:
The insoluble portion of the polymer in tetrahydrofuran increased with an increase in the time of molding and the unsaturation cantent. The mechanical properties suchas tensile strength, 100%-modulus and hardness became poor with an increase in the unsaturation content. With an increasing unsaturation content, the valve of elongation decreased for non-crosslinked polymer, but increased for crosslinked polymer.

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Commercially available styrene-butadiene block copolymers were studied t determine the block structure. The contents of polystyrene and the microstructure of polybutadiene parts in block cpolymers were determined by means of infrared spectrum method. Polystyrene parts were obtained by oxidative scission of polybutadiene parts in the block copolymers and the content of polystyrene was determined also by weighting. The contents of polystyrene in the block copolymers obtained by the above two methods agreed.
Molecular weight of the block copolymers and polystyrene parts was mersured by gel permeation chromatography (GPC) method.
From these results, the block structure of the block copolymers was estimated.

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The orientation of kaolinite (Dixie clay) in SBR rubber which was vulcanized with an injection molding machine was determined by X-ray diffraction and electron microscope, and the relation between orientation degree of the kaolinite and compression set of the vulcanized rubber was discussed.
Following results were obtained:
1) Plane (001) of the kaolinite was orientated parallel to direction of flow of the rubber in the center of the vulcanized rubber, but it was orientated parallel to each surface on surface portion of the vulcanized rubber.
2) The compression set was decreased in proportion to the decrease of the orientation degree of the kaolinite.
Therefore, it is thought that physical properties of the vulcanized rubber is influenced by orientation degree of the kaolinite

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