CHEMICALS
ODOR PROBLEM ? Penick's experienced perfume chemists are available for consultation . . . discreetly a n d without obligation on your p a r t . With a c o m p r e h e n s i v e library of industrial m a s k i n g a g e n t s , reodorants and d e o d o r a n t s c u s t o m designed to meet a b r o a d range of specific e n d - u s e s , we a r e capable of c o r r e c t i n g i n d u s t r i a l o d o r s of every d e s c tion. If y o u want to suppress a l a r a c t e r i s t i c o d o r or < impart a r • one, w e can offer construct) recommendations that wil? fully c o m p a t i b l e with your p. duct and p r o c e s s i n g requirements. We invite you to m a k e the fullest use of o u r u n e q u a l l e d facilities. Your l e t t e r to t h e T e c h n i c a l Director, A r o m a t i c C h e m i c a l s Division will bring p r o m p t response.
PENICK I
S. B. P E N I C K
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Research a t Bell Labs has turned up some new antioxidants for carbon black polyethylene. \V. L . Hawkins checks samples after accelerated oxidation test
Longer Life for Polyethylene
CO.
50 CHURCH ST., NEW YORK 8 735 W. DIVISION ST., CHICAGO 10
FACTORY MUTUAL APPROVED F O ^ THE ULTIMATE IN SAPETY
TEFLON SEALS
Bell Telephone Labs has special antioxidants that give c a r b o n black polyethylene a d d e d stability
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ACS NATIONAL
ethers, made bv c o n d e n s i n g aromatic amines or phenols with sulfur di c h l o r i d e , are used as antioxidants in rubber. Now these thioethers have a n e w use—and the use could be a big one because polyethylene is involved. Chemists a t Bell Telephone Labs, while looking for more weather resistant coatings for telephone cables, have found that t h e thioether antioxidants, along with certain other sulfur compounds, have a place in polyethylene. In clear polymers they are just about as effective as conventional amine and phenol antioxidants. But in carbon black polyethylene, the Bell tests indicate, they will inhibit thermal oxidation at least twice as long as the best of the nonsulfur stabilizers. Bell's W. L. Hawkins also told the Division of Polymer Chemistry tha) there is a growing market for polyethylene in outdoor uses such as phone PolyfaeiS Chemistry,
STAINLESS CHEMICAL FAUCET FOR FLAMMABLES AND CORROSIVES Constructed of 303 Stainless a n d equipped with Teflon O-ring seals, this dispensing f a u c e t has been designed for minimum maintenance. An anti-flash screen assures maximum safety by preventing flame p r o p a g a t i o n in dispensing f l a m mable solvents. Write for full information
H33
v
ENGINEERING
DIVISION
Economy FaUcet^Co: ; 12 New York ;Aye Newark 1,/N. J;
86
C&EN
SEPT.
16,
1957
Substituted thio-
cable sheathing, plastic pipe, and temporary shelters. These applications are made possible by antioxidants which reduce polyethylene's tendency to break down when exposed to heat and sunlight. Finely divided carbon black adds light stability, and aromatic amines or phenols can be used as thermal antioxidants. The results are good, although less than ideal. • Five Times Better. Thio-/?-naphthol, one of the sulfur compounds tested by Hawkins and his coworkers, protects carbon black polyethylene for 1000 hours at 140° C. The best current formulation stands up for less than 200 hours under the same test conditions. What does this mean in terms of field service life? It's very hard to tell, Hawkins says. Polyethylene-coated phone cables have been in use for only about 10 years, and thus there are not enough data available to extend accurately these lab tests to actual field life. But nevertheless there's little doubt that the sulfur compounds are better than any of the present stabilizers. Testing will continue to pin down results further. A factor which may hasten regular use is that some of the antioxidants are ahead', commercially available. For example, dodecyl mercaptan—currently used as a rubber antioxidant—is one of the compounds Hawkins finds to be effective in carbon black polyethylene. • Because of Synergism. The sulfur compounds apparently owe part of
their success to carbon black. Together in polyethylene, at about 2% or 3f."< of carbon black and 0.1 rc antioxidant, they have a synergistic effect. And while carbon lends a helping hand to the sulfur compounds, it has just the opposite effect on other heat stabilizers. For example, 0.1% diphenyl-pphenylenediamine inhibits oxidation of clear polyethylene for 300 hours at 140° C. T h e same material in a polymer containing carbon black gives heat protection for only 150 hours. In some cases amine and phenol antioxidants are no more effective than carbon black alone, Hawkins declares. Carbon black is believed to act as a light stabilizer through absorption of ultraviolet light. However, this mechanism isn't completely understood. Also it's not clear just why carbon cancels the effectiveness of some heat stabilizers. Hawkins work does show that a lot depends on particle size. The coarser carbon blacks have no effect on the action of heat stabilizers. But at the same time the coarser carbons don't protect very well against ultraviolet radiation.
Pesticides from Niagara Two phosphorus-containing compounds protect fruit a n d other crops from mites and aphids
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Now
in
a d-
NATIONAL vanced stages of MEETING Agricultural & _ development is t h e most active contact Food Chemistry m it ic id e ever s c r e e n e d in t h e laboratories of Niagara chemical division of Food Machinery and Chemical. The product is bis[S- (diethoxyphosphinothioyl) mercapto] methane. Recently designated as Nialate (previously called Niagara 1240), it is recommended for use against a variety of pests that attack cotton, citrus and deciduous fruit, and other crops. In controlling mites, Niagara says, Nialate kills rapidly, has excellent ovicidal action, and shows good residual activity. It is especially effective against the two-spotted mite complex on cotton. Although generally not as good against aphids as against mites, it has been used successfully in combating rosy apple aphid and several other
I n a recent UV spectrophotometer test w i t h three other w h i t e oleines, G R O C O 51 was shown to h a v e t h e lowest quantity o f linoleic a c i d (233 m/x w a v e l e n g t h ) . This was d e m o n s t r a t e d by density r e a d i n g s o f 0 . 2 9 1 , 0 . 4 3 1 , 0 . 6 6 1 for c o m p e t i t i v e acids . . . a n d 0 . 2 7 4 f o r G R O C O 51.
Linoleic is Lowest In GROCO 5 L W h i t e Oleine W h e n GROCO 5L L O W L I N O L E I C W H I T E O L E I N E is tested a g a i n s t c o m p e t i t i v e oleines, the s p e c t r o p h o t o m e t e r clearly proves what m a n y p r o c essors h a v e discovered t h r o u g h use — G R O C O 5 L is lowest of all in linoleic a c i d content—3.5/? m a x i m u m . This means unexcelled lightness of color a n d unexcelled color stability u n d e r heat. T h e unusual oxidation stability of G R O C O 5L L O W L I N O L E I C W H I T E O L E I N E m a y b e j u d g e d from M a c k e y Test r e s u l t s - i t r e m a i n s below 105 C . for b e t t e r than 5 hours. W i t h 88% to 9(Y/c oleic acid, G R O C O 5 L also is ideal for c h e m i c a l use. A m o n g competitive acids it has t h e highest real fatty acid content a n d t h e lowest unsaponifiables. G R O C O 5L L O W L I N O L E I C W H I T E O L E I N E is a s t r a i g h t line to t h e t o p quality end product you want . . . w h e t h e r u s e d as a chemical, in cosm e t i c s , soaps, polishes, wool oils, or oleates. "Always specify A. Gross."
a.gross
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C O Ni P
A "N Y
295 Madison Ave., N . Y. 1 7 , N. Y.
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Distributors
Manufacturers
in
principal
cities
•
Factory: N e w a r k , N . J. since
1837
Please send m & , without o b l i g a t i o n : } | Samples o f A . GROSS distilled w h i t e oleines | | A. GROSS b o o k l e t , " F a t t y Acids in M o d e r n I n d u s t r y " I w a n t to evaluate this sample f o r use i n _ Name
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1957
C&EN
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