A New Transformation Product of Rubber

Abstract

Abstract As investigations carried out long ago have shown, rubber reduces silver nitrate. On the contrary, experiments with specially purified unvulcanized rubber films have shown that the rubber itself is not the reducing agent, but rather impurities in the non-rubber components; in fact, it is even possible to incorporate large quantities (up to about 20 per cent by weight) of silver nitrate in rubber. In the experiments to be described, rubber films were prepared by drying latex which had been electrodecanted repeatedly; these films were swollen in a solution of silver nitrate in a mixture of water and acetone, and were then dried. The films obtained in this way were noteworthy for their high tensile strength compared with the original films, and were studied by means of x-rays. Instead of the diffused ring which appears ordinarily when unstretched rubber is examined, the x-ray diagram of this new product showed a series of sharp rings (see Fig. 1a) which did not correspond to any of those of inorganic silver compounds. When the product was stretched, the diagram changed, without appreciable alteration of the glancing angle, into that shown in Fig. 1b and finally into that shown in Fig. 1c. Figure 1c also shows a fiber diagram different from that of ordinary stretched rubber.