THE CHEMISTRY OF INDIARUBBER 



By SAMUEL S. PICKLES, M.Sc. 

 Scientific and Technical Department, Imperial Institute. 



To-day the elastic substance indiarubber, or caoutchouc, as it it 

 sometimes called, holds a position in the front rank of natural 

 products. In a century it has advanced from being almost a 

 botanical curiosity of little value, step by step at first, and 

 latterly by leaps and bounds, until at the present time it must 

 be classed amongst the most valuable of our raw materials of 

 commerce. 



On account of its peculiar nature and many characteristic 

 properties, the position of indiarubber is unique. Its applica- 

 tions, at first few and limited, have gradually been extended, 

 until now there is scarcely an industry in which it does not play 

 some part. So wide and varied are its adaptations that it comes 

 somewhat as a surprise to us if we recount the thousand-and- 

 one articles, household and textile, in the construction of which 

 it is employed — waterproof clothing, goloshes, rubber mats, 

 erasing materials, teeth settings, hose pipes, vulcanite articles, 

 elastic threads, scientific apparatus, electrical insulators, water- 

 proof sheetings, and the tyres of vehicles are only a few of 

 the numerous instances where rubber has found commercial 

 application. 



That much patient experimental inquiry, ingenuity, and 

 technical skill have been concentrated on these applications is 

 obvious, but the remarkable fact is that, in the manipulation of 

 this substance, in its conversion into so many different products, 

 the chemical reactions involved have never been clearly under- 

 stood. It is only during the last few years that we have been 

 able to arrive at even an approximately correct conception of 

 the chemical nature of indiarubber itself. 



Botanically, caoutchouc is one of the constituents of the 

 milky juice or " latex " of certain trees and shrubs belonging 

 chiefly to the natural orders Euphorbiacece, Moracece, Artocarpacece 



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