NOTCMBER 1, 1916.] 



THE INDIA RUBBER WORLD 



67 



further work will reveal sooner or later other quite diverse sub- 

 stances capable of vulcanizing caoutchouc like sulphur.f 



[Second Paper.] 



Ifrom the "Journal of the Russian Physico-Chemical Society," 1915. pages 



1,462-1,467. Abstract from "Journal of Society of Chemical 



Industry," Vol. XXXV, p. 59.) 



Further investigation of this method of vulcanization shows 

 that natural Para caoutchouc is completely vulcanized by as little 

 as O.S per cent of trinitrobenzene, whereas 6 per cent of sulphur 

 would be required. Further, in the latter case, the unavoidable 

 presence of free, uncombined sulphur lowers the technical value 

 of many rubber wares. The use of different organic compounds 

 for vulcanization of caoutchouc allows of considerable variation 

 in the pliysical properties, c. g.. flexibility, elasticity, etc., besides 

 in the color, smell, etc. Vulcanization may be eiTected by mono-, 

 di-, and trinitrobenzenes, -toluenes, etc., tri- and tetra-nitronaph- 

 thylamines, picramic acid, picryl chloride, artificial musk, nitro- 

 cyclohexane, nitro-dyestuffs, etc. Metallic oxides, which facilitate 

 the vulcanization of rubber by sulphur and enhance the value of 

 the product obtained, exert a similar efifect on vulcanization by 

 nitro-derivatives ; lead oxide is most valuable in this respect, and 

 then follow, in order, oxides of zinc, calcium, magnesium, barium. 

 On the other hand, mixtures of aliphatic amines with the above 

 oxides, although they accelerate vulcanization by sulphur or 



tit might be expected on theoretxal grounds that caoutchouc would be vul- 

 can'7ei under suitable conditions by o.xides of nitrogen, hydrogen jieroxide, 

 ozo: e, ozonides of the teri)enes, oxygen or air in presence of compounds 

 whicli activate o.xygen, and many other substances. 



low-er the temperature of the process to 10 to 15 degrees C, 

 retard vulcanization by nitro-compounds and lower the value of 

 the corresponding product. Like sulphur and sulphur chloride, 

 nitro-derivatives vulcanize, not only caoutchouc, but also vari- 

 ous vegetable oils yielding products analogous to factice. 



[Thirp P.\per.] 



[From the "Journal of the Russian Physico-Chemical Society," 1915, pages 

 1,467-1,471. Translated from the original Russian by T. H. Pope, B.Sc.^ 



The vulcanization of caoutchouc by means of pero.xides pro- 

 ceeds considerably more rapidly and at a lower temperature than 

 vulcanization by means of sulphur or even nitro-compounds. The 

 theoretical significance of this process has been already consi- 

 dered in earlier papers. 



Vulcanization by the action of benzoyl peroxide has been in- 

 vestigated in detail. It is found: (1) That metallic oxides which 

 accelerate the vulcanization of caoutchouc by means of sulphur 

 or nitro-compounds — PbO, ZnO, MgO. CaO, etc. — are almost 

 without efifect on vulcanization by benzoyl peroxide; in some 

 cases they diminish the velocity of the process, and in most in- 

 stances increase the oxidizability, that is, the rate of decomposi- 

 tion, of the given vulcanizate. (2) Colophony and other resins 

 lower the stability of caoutchouc on vulcanization by benzoyl 

 peroxide. (3| ^lixtures of ainines and metallic oxides, which 

 were foiuid liy the author to act as accelerants of the ordinary 

 vulcanization of caoutchoucs by sulphur, retard vulcaniza- 

 tion by the new method and decrease the stability of 

 the corresponding vulcanizate. (4) Proteins exert a similar in- 



T.\nLE .\.— HOT VULCAMZ.\TIOX V,\ NITRO-COMPOUNDS WITHOUT SULPHUR. 



Caoutchou 

 Used. 



Para 

 Para 

 Para 

 Crepe 



E 5 



100 

 100 



ICO 



Vulcanizing 

 Substance 



1:3: 5-C„H3(No..), 

 1:5: 5-C„H3(No..)3 

 1:3: S-CHsfNo.™), 



Ortho-CHjCNo.o), 



Crepe 10 Ortho-CHjCNo..), 



Crepe 100 Ortho-CaHiCNo..)! 



Peruvian 10 CoHsNo.™ 



8 Peruvian 



10 



1:2:6: 8-tetranitronaph- 

 thalene 



m ^ K 



. 4 



. 4 



. 4 



. 1 



. 1 



. 16 

 . 0.5 

 1 



9 Crepe 10 1: 3: 5-C„H3(No.2)3 



10 Crepe 10 1: 3: 5-C„H3(No.2)3 



0.05 

 0.08 



n Crepe 

 12 Crepe 



!00 

 .0 



1:3: 5-C«H3(No..),, .... 8 

 iS-tetranitronaphthalene. 24 



13 Crepe 10 /3-tetranitronaphthalene. 24 



14 Crepe 10 0-tetranitronaphtbalene. 1 



15 Peruvian 10 Picramic acid 1 



16 Peruvian 10 Picramic ac'd 1 



17 Peruvian 



10 Picric acid O.f 



18 Peruvian 10 Picryl chloride 0.8 



19 Peruvian 10 1 : 3: S-CoHaCNo.z), 2 



20 Mixture from 19 9.3 1 : 3: S-CeHal No..), 



21 Peruvian 10 1 : 3 ; S-CaHaCNo.i), 



22 Peruvian 10 0.05 grm. 



1:3: S-CHsCNo.j), 

 and 0.05 grm. sulphur 



23 Normal ery- 10 1 : 3 : 5-C„H3(No.s)3 .. . . 



threne 



24 Normal isoprene 8 1 : 3: S-CeHjCNo.a), 



25 .\bnormaI dieme- 100 1 : 3 : S-CeHjCNo.i), 



thylerythrene 



0.8 

 0.8 



7.5 



3 



3 



20 



3 



3 



Foreign 



Substances 



Present. 



Pressure of Steam in 

 the Chambers of the 

 Vulcanizing Press. 



45 lbs. . 

 45 lbs. . 

 45. lbs. . 

 3 atmos. 



:"■" c 



''*- w-^ 

 - c u*i 



45 

 45 

 20 

 45 



rks. 



10 grams piperidine 

 preparation No. 2 



3 atmos 



3 or 4 atmos. 



3 atmos 



3 atmos 



4 atmos. for 40 minutes and 



3 atmos. for 30 minutes 

 3 atmos 



20 grams Mgo 3 atmos 



3 3 atmos. for 90 minutes and 



4 atmos. for 30 minutes 

 3 3 atmos 



0.35 grm. piperidine 4 atmos. for 30 minutes and 

 3 atmos. for 30 minutes 



4 atmos. for 30 minutes and 

 3 atmos. for 90 minutes 



4 atmos. for 30 minutes and 

 3 atmos. for 90 minutes 



3 atmos. 



1.2 grm. linseed oil 3 atmos. 

 1.2 grm. linseed oil 3 atmos. 

 3 atmos. 



3 atmos. 



3 1.5 grms. colophony 3 atmos. 

 2.4 3 atmos. 



3 3 atmos. 



\'ulcanization complete. 

 Somewhat over-vulcanized. 

 Vulcanization incomplete. 

 \'ulcanization complete; prod- 

 uct smells of bitter almonds. 

 60 or 120 Product^ difficult to distinguish 

 from No. 4. 

 t. 10,45, 120 No vulcanization. 



120 Vulcanization complete: pos- 



sesses smell of bitter almonds. 



120 \^ulcanization complete: the 



high m.p. 204^ probably deter- 

 mines the slowness of the 

 process in this case. 

 Vulcanization complete. 



120 30 mins. — vulcanization begins, 



at 90 mins. becomes apparent, 

 ?nd in 120 mins. is complete. 

 45 \'uIcanization com])lete. 



Vulcanization complete. 



150 Vulcanization complete; product 



possesses an abnormal volume 

 much greater than the form. 

 Vulcanization complete. 



40 Only traces of vulcanization 



observed. 



Almost complete vulcanization, 

 but pro<luct not so good as 

 the preceding ones. 



Incomplete vulcanization, prod- 

 uct sticky, plasticity partly re- 

 tained; little elastic and 

 supple. 



30 Product surpasses Nos. 15, 16 



and 17. 

 120 Not vulcanized. 



45 Wdcanization complete. 



60 Physical properties almost 



identical with No. 20. 

 30 Complete vulcanization. 



5 \'ulcanization complete. 



5 Vulcanization complete; in 15 



mins. (3 atmos.) strongly over- 

 vulcanized product obtained. 



5 \'ulcanization complete; elastic 



point of the vulcanizate lies 

 at about 89-90'. 



