INDUSTRIAL AND ENGINEERING CHEMISTRY
1136
3. The hardening reaction, as measured by the increase in motlulus, appears to be little affected by increased oxygen concent i':i tion :ibove that in air and is the predominant reaction in the air oven.
Vol. 39, No. 9
tllc scission r t w t i o n : c~~nsequently, increased oxygen concentration will be more effective in making a larger number of active niolcrul(~savailable for re 8. The grvatc'i' i i t y m w i t r a t ion may alw he re both reactions arc apparer reactions leading i o rhain n-hile tlici rc:ictinii. i.cmlti
actions npon physical properties is different, no direct rorrelation e:in be cxpected betn-een methods o i aging Ivhirh tliffcr i i t both tciiiperature and oxygen conccntration. 7. .lctivation energies calculated from the temperat urc rm'fficienia obsci T - F ~ for t,ensile breakdown in the oxygen bornl) (29.7 lcg.-cal. and for modulus increase in the air ovc'n ilS.2 ky.-cal.) ma>- be regardtd as approximations of the activatinn enerpirs required for chain scissioii and cross linking, respectivel)-. The ol,sc:\-atioii has lwcn mack t h a t the latter reaction is virtually indibpc'ndcnt of o s - g e n concentration above that in air, whercxs t,he former increases ~ i t oh s - g e n concentration. Tlii. may l)r interpreted as indicating t h a t , a t the temperatures inatively large riumber of ozygcn niolccules arc -atcd to maintain the lower energy reaction, 1 much mialler nunibcr haye the enc:.gy requiro 1
Effect of Fungicides on Natural
and Synthetic Rubber J
J. L. STIEF, J R . , AND ,J. J . BOTLE T h e E n g i n e e r B o a r d , Corps of E n g i n e e r s , C . S. I r i n j , Fort DelLoir, F'a. clc>ii,uc,tivcsc.ffvc,t iin thc ru1it)c.r co:Lting. T t p I i i ~ n ~ mcl 1 1 2,'2 '-mctl~ylerie-tii~ ~ - ( ! h l i i ~ i i r ) l i t ~I l iiry ~ i l t w i industrial V O I I W ~ I I Sh;id indicat e ~ that l thvsc tir-o turigicicles had no adverse c.ffcct o n c4tliclr natur:tl i,uhl)er or GI{-S \\.hen uzed in sninll conwii~riilioii~.Twts by another indu*tikI concern had inciirated .liar i:riic~~.l:itiilidc v a s $:atisfactor>- fur usc rT-ith natural rubber and i i w i 1 ) i t ' i t t ' . IIiin.evc.r, txv,:iusc, of the meager amount of ini'orni>itii)iiavail:iblc,, a stuily was concluctcd to determine ir-hat iungiei(lc~, :inti i i i \\.hat roncciitratioris. might a1)normally tlctcm:it ing>. P>rid? 1 mercuric *tearate, salic~lanilicle, peiit.~c*hloro- riortttcL i~iit)tx~r This ~ j i ~ ~ ~ t ) I i m itlivided into two parts. The firdt \\-as to phcnol, and 2,2'-nieth: lene-bis( l-chlorophenol) c nilsed tii~tc.riixinoI h i s c ' f f t ~ t of t h e various fungicides on the physical littlr or n o ad\crSe effect \+henincorporated dircc ( I > i t t t o i>i,iipcrtiea o f mttiiixl : ~ n dy n t h e t i c rubbcr n h e n inciii~porated thew tlirce pes of rubber before curing. IIo\re\er. ( o p p r r (lii.wt1y i i i t n thci rubber cwnipourid prior t o vulcanizing. The naplithenate had a %lightweal\ening efrect 011 tieoprerir. sccoriil part 1 ~ x 5t o tl~-tc~riiiini~ ihc. c4Twt, of the iungicitlis o i i the a sonic\+hat greater ireahening effect on n a t u r a l r u i h c r , :icIh(~>iori, : ~ I J I ~ : ~ ~:iiitl I ~ I Igc,nc.ral , \r.cwirig qualitie>of coated i'atxics partictilarl> after aging, ant1 a nlarl\ed I+ eaLening elFcc.t w1ic.n the lungit~itlci- inipregn:tted into the fabric prior to coating. on C1t-S. five fungicides and three types of rubThe \\-iir1< to datc, ( ~ l ! \ her. Til(% I'ungiridci tc:sted include copper naplithenate, pyridyl I - I ? l S Gthe' iwent w a r n great part of thc niilitary o p c ~ , a f i o r ~ , ~ mercuric st car:itcB, salicylanilide, pentachlorophenol, and 2,2'1iicthyle1ie-bis~4-chlor.ophenol), sometimes dcsignated as dihyr r - c ~ rcontiacted in n'arm, humid, tropical regionq, i t l d for tirosydichloro diphenylmethane. (.-in abbreviated form of the the grL>ln-tlLiii fungi. The protection of the cotton clotli ( 2 ' u r t d latter designation is used in the figures for simplicity.) These in rrthhc,r-c'ontt,d fabrirs thus ticmune a major probleni of t h e fungicides vere selected as representative of the types found most . Because the area was oi minor importance. in the c,ffectivc: in preventing the fungus deterioration of cotton fabrics ier market, comparatively little work had been in a considcrable number of tests conducted by The Engineer on this problem by the rescarch laboratories of private intlu Board. Table I lists t'he types of rubber tested and the comA tropicnl testing chamber (I I , vhich simulated tropiral contiipounding formulations used. S a t u r a l rubber, GR-S, and neotions, [\as built at Fort Belvoir to study the problems of fungus prene are the subject of this report, but other coating materials g r o w li and effective countermeasures. such as vinyl butyral, the vinyl copolymers, Butyl rubber, and The problem was complicated by t,he possibility that the fungibutadiene-acrylonitrile rubber, are to be included in future work. cide which had a protective effect on the cloth might have had a Rlilitar?
operation- in tiopic'il region. nr( essilatc tre'ntnirnt for the protection from fungus attac 1%of ( o t t o n . cloth 1 1 - c d in fabrics coated with s3nthetic riibber. I'hii paprr clr-cribeh the effect of crleral coninion fungiuliatancc~, r to handle than the other fungicides which n Slabs were press-cured in an -1.S.T.11. foui,-c:tvity -ere die cut into test specimens. These n-rrr tc~rtcdfor tensile strength, ultimate per cent elongation, niodulus at 30OC; elongation, Shore lisrdnesi, and tear strength. Tlir, effcxcat (1f t h c fungicides on the n-eathering and age reeistaiicc of t h c vulcaiiizate \\-as investigated by subjecting test specinletis t u light iigiiig. heat aging, 0x1-gen bomb aging, and soil burial ti.st coiiditioris. r, only the tcrisile strength, elongation, tear strcngtli, rind un:igid anti oxygen liomb aging test coiiditioiis arc reportcTt1 i l i , l ( x sincsc, thvj- arc suficierit t o illustratc thr obqoryrd rffwi,~. The, rcsults of the soil burial tests oii vulr:iriizates cwnt:Liiiiiig no atlclc~clfuiigiciclii, suiiiiiiarized in Figurc 1, iiidic:itid that t1ici.c. xai: : i o higiiific:iiit loss of strength tluc, t o i i i i ~ ~ i :itt:ic.l,. is So Figure I . Fungi
1000
Effcct o f Eipoburc to
AGING
AFTER
1 O X Y G E N BOUB
BEFORE AGIHG
AFTER
OXYGEN
BEFORE
0
5
400
9 w
200
2
0
-. r
500
I
I
T
-
.-
p-
400
I-
300
2
BOMB
W
200 (n
a
a
100
I W -
" n
Figure 2 .
FUNGICIDES TESTED
FUNGICIDES TESTED
Effect of Fungic.icle6 o n \:iturai
R111)l)cr
1000
I
BEFORE AGING
AFTER OXYGEN BOMB AGING
-.
.2'
-.2' z
600
E
e-
1000,
0
BEFORE
AGING AGING
II 600
0
5z
400
w
200
5 0 z
s
9
0
-5
AGING
400
AFTER
OXYGEN BOMB AGING
n
2 0
300
s
200
z
I-
200
0
BEFORE
-
400
-,
600 I
I,
c_
g
500
r
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vr 300
(n
n
2
100
a
200
I-
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I
-
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FUNGICIDES TESTED
Figure 3 .
FUNGICIDES TESTED
Effect of Fungicides on GR-S
100
FUNGICIDES TESTED
Figure 4.
FUNGICIDES TESTED
Effect of Fuugicides
011
Seoprcne
1138
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 39, No. 9
The results on GR-S (Figure 3) indicated that copper naphthenate caused a serious loss of strength when incorporated into Natural Rubber GR-H. Tensile and tear strengths were materially reduced, and ured 20 hlin. GR-S (Cured 35 Keoprene (Cured 20 “at 300’ F.) Rlin. a t 300° F.) hIin. a t 300’ F.) elongation at break rvas increased. The copper naphthenate had Parts Parts Parts Component by w t . Component by art. Component by w t . a considerable retarding effect on the rate of cure of GR-S. The vulcanized slabs were soft and tacky when i,emoved from the Smokedsheet IO0 0 GR-S, 100.0 Seoprene GN-A 100.0 2.0 Reogen Stearic acid 2.0 XLC magnesia 4.0 mold. Very little resilience, or snap, was observed. This test 3.0 , Stearic acid Zinc oxide 5.0 Stearic acid 0.5 Pine tar 1 0 E P C black 50.0 E P C black 30.0 was made on a GR-S vulcanizate containing 2y0 fungicide. Xeozone U 1.0 Sulfur 2 0 Neoeone D 2.0 5.0 Zinc oxide Altax 0.75 Accelerator 552 0.1 Uther ksts on specimens containing 1 and 0.5y0fungicide indi50.0 E P C black Rarak 1.0 Zinc oxide 5.0 cated a considerably lesser and progressively decreasing effect. 3.0 Sulfur Fungicide 2,0 Fungiride 2 (1 Altax 2.0 1’5-ridyl mercuric stearate had a very slight injurious vffect on Thionex 0.2 Fungicide 2.0 GR-S. Salicylanilide, pentvchlorophenol, and 2,2’-nictthylenetiia(~-clilor~iphenoIj had little or no adverse effect on tho piiysical properties of GR-S. visual evidence of fungus growth vivas observed. Thereforf~,I t Tlie results of tests on Scoprene (Figure 4j iudicatcd that appeared t h a t no fungicide was necessary for the protection uf pyritiyl mercuric stearate, salicylanilide, pentachlorophorlol, and the vulcanizates themselves. 2,2‘-ineth-lrne-bis(i-chlorophenol) caused no measurable loss of teiisili. strength (nithin the limits of ex$drimental e ~ , r o r )aiid , only E F F E C T OF FUNGICIDES x w r y slight reduction of tear strength. Copper ntipht lienate T h e test results suniniarized in Figure 2 shoa that rioiie 01 the raused an appreciable loss of tensile strength after aging, but fungicides tested had any appieciable effect on the unaged n ~ t u ~ a l xpparc~ntlyproduced an increase in the ultimate c~longationand rubber test specimens. However, test specimens containing copI cwiiig sfrerigtli. ;wr naphthenate appeared to age more rapidly in the oxygen bomb test. T h e rubber became much stiffer, as evidenced by t!ie LITERATURE C I T E D sharp decrease in elongation a t break. Tear strength was considerably reduced. Thw it seemed probably that fabrics treated (1) c‘ookc, T. F., aiid Vicklund, R. E., IXD. ENG.Camr., NIL. ED., 18,59-60 (1946). wjth copper naphthenate and having a natural rubber contiiig ( 2 ) Grenthouse. G . -4., and Ames, L. h l . , A1fycologia, 37, KO.1, 138might be expected t o crack when used after lengthy periods o f 55 (1945). storage. Pyridyl mercuric stearate, salicylanilide, pentacliloiophenol, and 2,2’-niethylene-bis(4-chlorophenol)had little or no adverse effect on natural rubber.
TABLE I. COMPOLTDISG FORMULAS
.
TESTING OF CRACKING CATALYSTS 31. E. CON” Esso Laboratories, Baton Rouge, La.
T
HE catalyst is one of the paramount factors
.V. .I.
A
fixed Led method for testing craching catal>ats is described, and data are gi’en to iudicate how the test results were applied to show the effect of cataljst qualit? 011jields in fluid ratal>st crac.hing iinits. Craching acti5ity expressed as throughput for a g i \ e n con\erhion ib b e a r with surface area for catal? cts of a gi\en c~hemicalcomposition. Carbon formation i s increased when the catalyst has or acquires dehldrogenatiug properties. i d \ antages and disad\antages of \arious t>f)csof testiiirr uuits are discussed.
in determining the rate of the formation of the various products in a given catalytic process. Furthermore catalysts are notoriously busceptible to changm which mav appear small and are -often difficult to predict, but which have a profound effect on production. These factors are important in catalytic cracking as in other cw!alytic proceaws; hence, early in the developnierit of catalytic cracking it becanic desirable t o devise a small laborator?- scde test t o niea3ure catalyst quality quickly. More important than this was the requirement, for evaluating thc effects of preparatiou variables on catalJ-st quality and evaluatiilg the effects of changes of catalyst quality occurring during use in catalytic criicliing e,quipment. Consequently a test unit of the fixed-bed type was designed, constructed, and operated t o test simultaneously four small samples of catalyst (generally 200 cc.) in four KS,S tubes supported in a n electrically heated aluminum-bronze block. Other such units have since been constructed, and have been employed for investigating a wide variety of reactions and for studying I
G. C. COSNOLLY Esso Laboratories, Elizubeth,
Present address, Esso Laboratories, Elizabeth, N. J.
.-
.
tl1roug!1’ the 2- a f l d 100I)arrelr-per-day 1Jilo: plant stages to the u)iniiii:rciaI x:ile plaiits havc bcvii previously tlcscriljed ( 2 , J ) . 1)iii,ing this devolopilli~nt,il l l t l ince tlic coninicrrid j i l m t . ~h:i\.e t i i ~ ~ inn operation, c:ctniyct sariiplcs hrire been rciiiu\-c,il fro111t i i i i ( ’ I II time aiid teetcd in the 200-cc. test unitb in order t u dctcrnii1lc wtalyst qu:ilit,y. The infomiation gained in tliia n.ay !itis h r r o i i i i ful in TIE design and operntion of fluid catalyst equipnir:nt. Tlie siniilaritics and diffcrencc>sbct\rc.iin fiscd-bcd crtLrking (as in the test metliotl) and fluid catalyst crackirig from Tvhich the test sample:: arc talicn were discusscd in a previous paper (5). I n this paper the general methods for espressiiig coriyeraions and yields rvere described and defined, arid the rariables affccting conversion and yields, particularly of carbou, ryere also defined and discussed. The purpose of this paper is t o describe the test apparatus, the test proredure, the pilling and pretreating of the catalyst samplea,
