66 SYNTHETIC RUBBER 



firm has recently patented a method in which a piece 

 of the polymerised rubber is used to bring about the 

 polymerisation of a further quantity of isoprene or 

 butadiene. 



The group of English chemists already referred to has 

 worked out three possible processes for the preparation 

 of isoprene or butadiene : (1) the production of isoprene 

 from isoamyl alcohol, a process which will only be of value 

 if a cheap method of manufacturing isoamyl alcohol is 

 discovered ; (2) the production of butadiene from butyl 

 alcohol, the latter being stated to be obtainable at a price 

 probably not exceeding £40 to £45 per ton by a new 

 fermentation process discovered by Professor Fernbach ; 

 and (3) the conversion of ordinary alcohol into aldehyde, 

 aldol, and finally butadiene. In addition Dr. Matthews 

 discovered the important fact that metallic sodium brings 

 about the polymerisation of isoprene and butadiene 

 almost quantitatively at the ordinary temperature, a 

 point which Harries also discovered independently. 



The present position of synthetic rubber may be summed 

 up as follows : 



The production of rubber synthetically by chemical 

 means has been successfully accomplished, but it is still 

 doubtful whether synthetic rubber could be manufactured 

 at a price which would enable it to compete with the 

 natural product, especially in view of the gradual fall in 

 the price of rubber which is likely to take place in the 

 future as the result of the increasing production from the 

 plantations. At the present time, therefore, it would 

 appear that natural rubber is not likely to be displaced 

 by the synthetic product, but it must always be borne in 

 mind that the situation may be materially altered by 

 the results of the chemical research work which is actively 

 proceedmg in many different quarters with a view to 

 cheapening the cost of manufacturing the synthetic 

 material. 



Analysis of Crude Rubber.— In the analysis of crude 

 rubber the following determinations are usually made : 



(1) Loss on washing. 



(2) Ash. 

 (;i) Resin. 



(4) Protein. 



(5) Caoutchouc. 



