142 Kansas Academn of Science. 



ARTIFICIAL RUBBER. 



L. E. Sayre. 



IN another paper presented at this meeting reference has 

 been made to the subject of rubber in connection with corn 

 oil. The writer had an opportunity of examining some splen- 

 did examples of artificial rubber made from corn oil as a start- 

 ing point, exhibited at one of the recent meetings of the Amer- 

 ican Chemical Association at Urbana, 111., and this has become 

 such a matter of interest to the writer that he has thought it 

 worth while to put into a compact form some of the points of 

 value in connection with the subject. 



It is safe to say that there are very few articles made of 

 pure rubber. In the manufacture of rubber goods some sort 

 of "mixings" or "fillings" or "compounding materials" are al- 

 most invariably employed. The mixings used are of various 

 kinds, according to the use of the rubber, the color, surface and 

 cost desired. Oils, waxes, especially paraffin wax, asphaltum 

 and pitch, sometimes resins or shellac, are used in mixings. 

 Of the fillings, whiting, plaster of paris, gypsum, the barytes, 

 magnesia and litharge are the most frequent. Some of the 

 synthetic rubbers or other substitutes for rubber are used with 

 real rubber in the manufacture of rubber goods. I present 

 here a sample of asphaltum such as is used in paving, and 

 which has a value in the manufacture of commercial rubbers. 



I also present here a rubber substitute, artificial rubber, so 

 called, which on analysis proved to have the following com- 

 position : 



Rubber 29 % 



Asphalt compound 15 



Lithiphone (BaS04 + ZnS) 15 



Litharge (PbO) 10 



Sulphur 1 



This rubber was used for the Schau cone tire, but this was 

 proven to be, after some time, not a success. At present, in 

 the making of these shoes 75 percent of rubber has been found 

 necessary to give satisfaction. The composition of the rubber 

 substitute is stated to be bitumen (Trinidad asphalt) and sul- 

 phurized oil. Bitumen is known in the trade as mineral 

 rubber. 



