The oxidation of polybutadiene. II. Property changes during oxidation

The oxidation of emulsion polybutadiene has been followed by observation of changes in gel content, swelling index, intrinsic viscosity, and infrared spectra. The results show that, whereas simple heating of the polymer leads primarily to crosslinking, the presence of oxygen causes both scission and crosslinking, with the predominance of either of these processes being dependent on the amount of oxygen absorbed. Increase of temperature or degree of oxidation favors crosslinking. During oxidation acid, ester, aldehyde, ketone, ether, and alcohol groups appear, but their relative proportions remain essentially constant. Also, a large extent of the oxidation occurs without resultant decrease in unsaturation, indicating, in all probability, that the double bond is not the direct point of oxygen attack.