The Chemistry Of The Rubber Industry

This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1915. Not illustrated. Excerpt: ... CHAPTER VI VULCANISED RUBBER Vulcanised rubber represents the technically important derivative of raw rubber. In practice the term is used to denote any rubber mixing which has been vulcanised; thus, in vulcanised rubber we are not only concerned with the modification of properties caused by the operation of vulcanisation itself (see Chapter V), but also with the various effects produced by the compounding ingredients which have been used (see Chapter IV). As far as the modifications induced by vulcanisation itself are concerned, it will be clear from the previous chapter that they really resolve themselves into a question of greater stability-- a stability to chemical change, and also to various physical influences, more especially to heat and mechanical stresses of different kinds. That is the working effect, so to speak. The theoretical aspect of the whole case has undergone curious vicissitudes. Leaving out of consideration the period of wild hypothesis, it is remarkable that at the present time the most important and far-reaching of Weber's views (as expressed in his famous "Outlines of a Theory of Vulcanisation ") are really those which consider rubber from the colloidal standpoint. His series of rubber sulphides cannot be accepted now; but his conception of vulcanisation, as a process whereby the physical condition of raw rubber was perpetuated, still remains exceedingly luminous and fruitful. In fact, if we translate this view into the language of the colloidal chemistry of the day, we will find it very helpful to consider vulcanisation in this way. Looking at it thus, it seems best and safest to regard vulcanisation as a process of coagulation, though not in the same sense as with latex. What is meant is that raw rubber is a body more of the sol type (s...