The Structure of Various Natural Rubbers

Abstract

Abstract Although Columbus, on his second journey to America, found the natives playing with balls which bounced and were elastic, it was almost 300 years later before use was made in Europe of the gum used in these balls. Priestley found that it could be used for erasing lead pencil marks. However, when further applications of this material were attempted, it became recognized that rubbers from different parts of the country differed. These differences arose partly from the botanical origin of the plants from which the gum, or rubber, was collected and partly from the methods of collecting and preparing it. With the passage of time, fine Para rubber came to be recognized and used as the best rubber and it held this position until it was supplanted by plantation rubber from Hevea brasiliensis trees. These differences in rubbers from different sources made it necessary for the user to know more about the material. Even the distinguished physicist Faraday became involved in the problem and in 1826 he published an analysis of the latex and also the dry rubber. His results were as follows :