IS 



THE INDIA RUBBER WORLD 



[I >. roBER 1 1914. 



THE VISCOSITY OF RUBBER SOLUTIONS. 



1). Spence and G D. Krai (Kolloid Zeil I, 1914, p. 262, 

 have shown thai the viscositj of a rubber solution may be 

 lowered to almost that of the solvent, and then the insoluble 

 nitrogenous portion may be easil) separated Sunlight and 

 heat assist in reducing viscosity. One hundred grains oi 

 washed and dried rubber were treated with IS. oi benzine 

 containing 0.3 to 0.5 per cent of trichloroacetic acid and 

 warmed. After 48 hours with occasional shaking it was e1 

 tied, decanted, washed with the solvent, then with pure ben- 

 zine, then dried and extracted with benzol, washed with 

 alcohol and dried. 



In lour samples plantation rubber gave nitrogen as fol- 

 lows: 9.83 per cent., 10.90 per cent.. 11.58 per cent, and 12.08 

 peri ent. It is soluble in 1 per cent. Na.O.H. and precipitates 

 with dilute acid. It agrees in nitrogen contents and reactions 

 with the glucoproteins. 



I lard cure Para gave 7.75 per cent.. 9.6 per cent, and 10.3 

 per cent, nitrogen. The insoluble constituent of balata con- 

 tamed 5 per cent. X. and specimens of proteins from Funtumia 

 elastica showed N. 9.S per cent, and 11.5 per cent. These 

 results establish the fact that the nitrogenous constituent 

 of rubber is a complex of protein and carbo-hydrate — prob- 

 ably a gluco-protein. The proper factor for nitrogen is 

 probably 10 instead of the usual 6.25. 



Clayton Beadle and H. P. Stevens seem to have carried out 

 an extensive series of tests on viscosity of Para rubber and 

 at the same time tested vulcanized samples of the same 

 rubbers. They have contributed a rather voluminous article 

 in the "Chemical World" (London) of August, 1914, but a 

 large part of it is devoted to comments on previous work 

 • it themselves and other authors, and no detailed figures are 

 given to show just what their results were. 



THE UNION id- SULPHUR WITH RUBBER. 

 Mr. F. Ahrens, in "Gummi-Zeitung," No. 28, p. 490. makes a 

 contribution to the vulcanization of rubber in which he points 

 out that rubber does not add sulphur in the ordinary con- 

 ception as charcoal does in the case of dyes, gases, etc. He 

 thinks that blooming shows the presence of a "solution product" 

 and a "reaction product." The relation of the two changes 

 continually until equilibrium is reached, the chemically com- 

 bined sulphur increasing and the free or dissolved sulphur 

 diminishing in amount. He claims the phenomenon of re- 

 versed action is frequently noticed in vulcanized goods. As 

 an example he cites the analysis made of two identical sam- 

 ples, one analyzed directly after making and the other 

 analyzed after aging several months. The rubber used was 

 low grade. In the fresh sample the total sulphur was 15.80 

 pel cent., acetone soluble sulphur 7 per cent, and combined 

 sulphur 5.9. In the old sample the total sulphur was 13.60 

 per cent., the acetone soluble sulphur 9 per cent, and the 

 combined sulphur 2.83 pel cent. This seems a remarkable 

 change in composition and on, nol often observed. The 

 author thinks that tin old sample has eliminated the sulphur 

 as IP S, The decrease in combined S. tends to the con- 

 clusion that this i- less firmly bound in the old sample. Para 

 is said to show much less variation, and it is concluded that 

 the particular nature of the Colloid requires the S. to be 

 present in something more than the mechanically dissolved state. 



SUBSTITUTE FOR RUBBER AND GUTTA PERCHA. 



The Industrial Chemical Co. with executive offices at 200 

 Fifth avenue, has recently erected a new plant with a capacity 

 double that of the old one. This company makes "Alba Whit- 

 ing" a specially pn] and rubber white, so wall adapted for rub- 

 ber compounding use that this department of the business has 

 increased 100 per cent, within the past two years. It is claimed 

 to be economical both in cost and continuous use. This com- 

 pany also makes an excellent grade of rubber black. 



*T" 1 1 1 increasing use of both india rubber and gutta percha has 



^ turned the .attention of industrial chemists to the pro- 

 duction of substitutes therefor; and among these is a 

 series which has been brought out by Dr. Ziihl and llerr 

 Zimmermann, of Berlin. The intention is. of course, to 

 pro, luce a substitute lor the two flexible vegetable substances, 

 which shall have the same chemical and physical properties 

 and be equally valuable for insulating against electricity. It 

 is based on the fact that Chinese wood oil, which, as is well 

 known, when heated at high temperatures is transformed 

 into a mass resembling caoutchouc, can also be similarly 

 changed when treated with chloride of sulphur. If the wood 

 oil in question is mixed with resin or resinous substances, as 

 for instance pitch, asphalt, or the like, and then subjected 

 to the action of chloride of sulphur, there will be produced 

 a substance which may be employed in the same manner as 

 india rubber or gutta percha. It is desirable to heat the mass 

 thus obtained to about 160 degrees C, after mixing it with a 

 certain percentage of sulphur. 



If it be desired to make artificial gutta percha, pitch, 

 asphalt or similar substance — better still, paraffin wax — should 

 be added to the resin before these are added to the wood 

 oil and heated. Or the oil may also be treated with the 

 sulphur chloride, and then the pitch, resin, etc., added. A 

 less convenient method, but which also leads to good results, 

 is said to consist in heating the mixture of resin, pitch or 

 the like, with the wood oi! to 200 degrees or 300 degrees C. 

 for a long time, and then vulcanizing. 



The proportions given in the German patent papers (No. 

 119,635) are as follows: 



For making gutta percha: Two kilograms of paraffin wax 

 are melted with 6 of pitch, 2,^2 of wood oil added, and the 

 mass stirred until thoroughly homogeneous. Then 1.1 kilo- 

 grams of sulphur chloride are added slowly and well stirred; 

 next, about 100 grams of fine pulverized sulphur, and the mass 

 is then heated about one hour to 160 degrees C. 



For making india rubber. 2 kilograms of pitch are mixed 

 with 1 kilogram of wood oil and heated under pressure about 

 8 hours to 280 degrees C. The product is vulcanized with 

 250 grams of sulphur chloride. 



A subsequent process, tending to increase the tensile 

 strength of the products, consists in dissolving 100 grams of 

 crude rubber in 300 of melted naphthalin at the lowest prac- 

 ticable temperature, then adding to the solution 400 grams of 

 Chinese wood oil and 700 of some resin or resinous substance 

 as pitch, asphalt, or the like. The naphthalin must then be driven 

 off by steam heat, which effects the vulcanization of the mass. 



Or one kilogram of the material produced by following the 

 directions in the first patent mentioned is dissolved in 3 kilo- 

 grams of naphthalin. and then 100 grams of caoutchouc dissolved 

 in 300 of naphthalin are added. The latter being driven off by 

 distilling with steam heat, the mass is ready for use. 



A PARACHUTE FOR THE AEROPLANE. 



Obviously the drawback to all aeroplanes is tin great p ssi 

 bility of coming too suddenly to earth. A number of para- 

 chutes have been invented for the personal use of the airman, 

 the purpose being that if anything happens to the aeroplane he 

 can cut loose from it, letting it take its own course, while he, 

 buoyed by his parachute, drifts down quietly and safely to 

 earth. But a more comprehensive parachute has recently been 

 devised which aims to keep up the entire machine. It is folded 

 away in a little box over the flyer's head and has ropes attached 

 to all corners of the frame. If anything happens to the machine 

 the pilot releases the parachute, which opens up above and 

 brings pilot and aeroplane both gently to earth. At least this 

 is the theory. 



