Mabch 11, 1921] 



SCIENCE 



241 



RITBBEE DIVISION 



W. K. Lewis, chairman 

 Arnold H. Smith, seoretary 



Eeports. 



•Discussion: Shall the Rubljer Division publish an 

 annual volume of reprints and lengthy abstracts 

 of everything of interest to the rubber chemist 

 made public during the year? 



Election of officers. 



Buller energy: W. B. Wiegand. (Lantern.) 



Tlie aging of some rubber compounds: New Jer- 

 sey Zinc Co. Eeseareh Laboratories. (Lantern.) 



Some miorosections cut from vulcanised rubber 

 articles: New Jersey Zinc Co. Research Laborator- 

 ies. (Lanltern.) 



The action of certain organic accelerators in the 

 vulcanization of rubber. II.: G-. D. Kratz, A. H. 

 Flower and B. J. Shapiro. The relative activities 

 of molecularly equivalent amounts of aniline and 

 diphenylthiourea in the acceleration of vulcaniza- 

 tion were compared in rubber-sulfur mixtures and 

 in mixtures which contained zinc oxide. In a 

 rubber-sulfur mixture the activity of aniline was 

 found to be much greater than that of diphenyl- 

 thiourea. In mixtures which contained zinc oxide, 

 the reverse was true. With aniline as the accele- 

 rator, either in the presence or absence of zinc 

 oxide, the same maximum tensile strength was ob- 

 tained, accompanied by a higher sulfur coefficient 

 in the absence of zinc oxide than when this sub- 

 stance was present. The mixtures which contained 

 zinc oxide, attained the same maximum tensile 

 stren^hs at approximately the same sulfur coeffi- 

 cients, irrespective of whether aniline or diphenyl- 

 thiourea was employed as the accelerator. It is 

 evident that there is apparently no general rela- 

 tion between the physical proipeiities and sulfur 

 coefficients of accelerated mixtures. 



The action of certain organic accelerators in the 

 vuloanieation of rubber. (II.) : G. D. Keatz, A. 

 H. Flower and B. J. Shapiro. The activities of 

 certain synthetic, nitrogenous organic accelerators, 

 in a mixture of rubber and sulfur, were compared 

 with the dissociation constants of the original sub- 

 stances. With the exception of members of a 

 closely related series, no definite relation was 

 found to exist between the activities of the sub- 

 stances as accelerators and their dissociation con- 

 stants. Substances which decompose, or react, 

 .with other components of the mixture to form 

 substances of acid character do not accelerate unless 

 a neutralizing base, or salt, is present. The re- 



sults obtained, and the conclusions drawn from 

 them, compare favorably with other results ob- 

 tained with ammonium salts. 



Method for the determination of free sulfur and 

 antimony tri- and penta-sulfides in golden anti- 

 mony: J. F. SCHTJETER. 



The action of heat and light on vulcanised rub- 

 ber: J. B. TuTTLE. The action of heat and light 

 on vulcanized rubber is frequently spoken of as 

 being identical and oxidation is said to be the 

 cause of the deterioration. From published and 

 unpublished tests it is shown that the action of 

 heat is one of change in the rate of the chemical 

 reaction between rubber and sulfur and goes on 

 throughout the entire mass, whereas the action of 

 light is one of oxidation, taking place on the sur- 

 face. Heat produces no change in the solubility 

 of the rubber substance in solvents such as acetone 

 and alcohol, whereas light breaks up the rubber 

 molecule forming decomposition products which 

 are readily soluble in acetone. 



A theory of vulcanisation based on the forma- 

 tion of poly sulphides during vulcanisation: Win- 

 riELD Scott and C. W. Bedford. All organic ac- 

 celerators and a number of inorganic accelerators 

 function as catalysts of vulcanization through the 

 formation of polysulphides. These accelerators 

 may be placed into two classes: (1) Hydrogen 

 sulphide polysulphide accelerators. Organic bases 

 are believed to form polysulphides by the aid of 

 hydrogen sulphide. Examples are piperidene and 

 dimethylamine which form polysulphides in the 

 presence of hydrogen sulphide and sulphur. Inor- 

 ganic bases, such as sodium hydroxide, calcium hy- 

 drate, magnesium oxide and basic magnesium car- 

 bonate, function in the same manner as the above. 

 (2) Oarbo-sulpih-hydrol polysulphide accelerators. 

 Thio ureas and dithiocarbamates are believed to 

 form some type of polysulphides through the 

 grouping C-SH. Differentiated from the above 

 two classes of accelerators are such accelerators as 

 zinc oxide and litharge which do not form poly- 

 sulphides. These aire termed "secondary accele- 

 rators " owing to the fact that they decompose 

 polysulphides to give active sulphur. 



division op water, sewage and sanitation 



J. W. EUms, chairman 



W. W. Skinner, secretary 



Water softening for the manufacture of raw 



water ice: A. S. Beheman. The manufacture of 



