INDUSTRIAL A N D ENGINEERING CHEMISTRY
March, 1945
was carried out as rapidly and at as low a temperature as practicable. Moreover, for the most part, the digestive coefficients for the protein in the dehydrated product compared favorably with those previously reported for meat in general. With respect to certain vitamins, meat and some meat products are now known to be good sources. I n fact, vitamin A is abundantly supplied by liver. Of the B vitamins, riboflavin is found in extremely large amounts in liver, heart, and kidneys. Niacin also occurs in large amounts in these products, especially in liver and kidneys. Thiamine is supplied to an intermediate extent by these same three products, to only a slightly lesser extent by beef, lamb, and veal muscle, and very liberally by pork muscle. LITERATURE CITED
Barbella, N. G., Hankins, 0,G,, and Alexander, L, M., proc, Am. SOC.Animal Production, 29, 289-94 (1936).
Barbella, N. G.; Tannor, B., and Johnson, T. G., Ibid., 32,3204 (1939) I
Black, W. H., Warner, K. F., and Wilson, C. V., U. S. Dept. Agr., Tech. Bull. 217 (1931). Child, A. M., and Esteros, Gertrude, J . Home Econ., 29, 183-7 (1937).
[ G d4 s
223
(5) Committee on Dehydration of Meat, U. 8. Dept. Agr., Circ. 706 (1944). (6) Gorman, J. A,, Hultz, F. S., Hiner, R. L., Hankins, 0. G., and Spencer, D. A., Wyo. Agr. Expt. Sta., Bull. 254 (1942). (7) Griswold, R.M., and Wharton, M. A,, Food Research, 6,517-28 (1941). (8) Hankins, 0. G., and Hiner, R. L., Proc. Am. SOC.Animal Production, 31,260 (1938): Food Ind., 12, 49-51 (1940). (9) Hankins, 0.G., and Titus, H. W., Yearbook of Agriculture, U. S. 'Dept. Agr., 1939. (10) Hiner, R. L., and Hankins, 0. G., Refrig. Eng., Sept., 1941. (11) Howe, P. E.,and Barbella, N. G., Food Research. 2. 197-202 (1937). (12) Howe, P. E., and Hankins, 0. G., Proc. Am. Soc. Animal Pmduction, 27, 79 (1934). (13) McMeekan, C. P.,and Hammond, J., J . Ministry Agr. (Eng.), 46 (3).238-43 (1939). (14) Noble, 1. T., Halliday, E. G., and-Klass, K. K., J . Home Econ., 26, 238-42 (1934). (15) Tannor. Bernard, Clark, N. G.t and Hankins, 0.G., J. ABr. Research, 66, 403-12 (1943). (16) U. 5. Bur. of Animal Ind.. unpublished results. (17) U. S.Bur. of Animal Ind., Rept. of Chief of Bur., p. 14 (1941). (18) Univ. of Ill. Agr. Expt. Sta., Ann. Rept. of Director, pp. 85-8 (1930-31).
-w1
Predicting Volume Increase of Perbunan Compounds in Petroleum Products R. M. HOWLETT Esso Laboratories, Standard Oil Development Company, Eliaabeth, N. J .
I
N T H E formulation of oil-resisting synthetic rubber stocks, it is frequently desirable to know what will be the approximate volume increase of the proposed compound in a certain immersion medium under specific test conditions. If available volume increase data on a synthetic rubber compound could be used in formulating the new recipe, the amount of work required to establish the new stock could be considerably reduced. The purpose of this paper is to show the development of a relatively simple system to predict the volume increase of Perbunan compounds. Catton and Fraser (8)reported that the swelling of neoprene compositions depends on the volume of neoprene in the compounds. A subsequent paper (4) showed how the volume increase of a compound may be calculated if the oil immersion medium is used as a softener in the compound. Aniline point, viscosity-gravity constant, and Diesel index @,4,6,7)may beused tomeasure the propertiesofpetroleumproducts which govern the swelling characteristics of synthetic rubber compounds. plso, the swell of Perbunan compounds (IO) is a function of the aromatic content of the gasoline. These factors will not be considered in this discussion; rather, specific values will be presented for a variety of petroleum products, and an attempt will be made to relate the effect of various compound changes on the resistance of Perbunan compounds to petroleum products. If, as previously stated, the swelling of a synthetic rubber compound is due to swelling of the polymer, V = KP/100 where V = Q volume increase of compound K volume swell of cured polymer P = polymer by volume in compound
%
(1)
A study has been made of the volume increase of Perbunan compounds immersed in various petroleum products. As a result of this work a method has been developed for calculating the volume swell of a P e r b u n a n compound when it is immersed in a given petroleum product under certain test conditions. The work of prediction or calculation of volume increase has been simplified by the construction of two graphs which m a y be used with experimentally determined constants of swell and extraction.
Volume increase results were obtained in duplicate by A.S. T.M. method D471-43" (I), except that a Jolly balance was used in weighing. Table I shows volume increase data for Perbunan compounds containing various amounts of carbon black. The polymer swell values for each gasoline were calculated, and the deviation from the average was found to be small. Additional K values, or percentage volume swell of the polymer, are reported in Table 11. Two concentrations of black were used, and the K values for the different polymer concentrations were found to be nearly equivalent. The data cited appear to demonstrate that the swell of Perbunan compounds in various immersion media is due tu the swell of the polymer, the compounding ingredients serving to dilute the Perbunan and thus reduce the swell of the total compound. This conclusion.assumes that all the compounds have approximately the same state of cure and that there are no extractable softeners in the compound. I n this work the same accelerator, sulfur concentration, and time of cure were used. The recipes are the type in which the state of cure should be similar, even though the amyunt of loading is widely varied.
224
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
TABLE I. VOLUME INCREASE OF PERBUNAN COMPOUNDS IN Two GASOLINES,AFTER 168 HOURSAT 25' c. (Bane recipe: Perbunan JOO, iinc oxide 6 , atearic acid 1,.benrothiaeyl dinulfide 1, sulfur 1.5, senureinforcing furnace black as indicated; cured 60 minutea a t 287' F.) % Vol. Swell of Cured % Vol. Increase in: Polymer (K)in: Parts % Black Perbunan Gasoline Gasoline Gpsoline Gasoline by Wt. by Vol. 14 2) 14 2) 76.6 31.8 59.0 24.6 50 77 75 70 52.3 22.8 74.8 32.6 100 63.8 47.6 20.7 74.5 32.5 160 64.6 40.3 17.6 74.2 32.1 176 80.8 37.7 16.4 74.2 32.3 Average K value 7 a 32.3
Vol. 3'1, No. 3
in Equation 2 and solving for E. Volume increase data and extract Coefficient values are included in Table IV. The outstanding point in these data is that the extract coefficient for a given softener 'ppeass t' be but little influenced by the immersion media. The extract coefficients in the two gasolines and in the three hot oils are quite similar. SIMPLIFICATION OF CALCULATIONS
The calculations for determining volume increase are somewhat involved. This procedure has been considerably simplified by use of three plots; two are given in Figure 1 and the other in .60yo 66-octane gaaoline, 5% benzene, 20% toluene, 16% xylene (by 2. In the top Of Figure '9 parts by volume). weight are plotted against per cent Perbunan by volume for b 100-octane aviation gasoline, lot A. compounds containing 0, 10, 20, 30, 40, and 50 parts softener having a specific gravity of 1.0, The SWELLOF PERBUNAN IN PETROLEUM PRODUCTS bottom half is a plot of per cent volume increase plus TABLE 11. POLYMER per cent by volume of extractable softener against (Bwe recipe: Perbunan 100, zinc oxide 6 , stsaric acid 1,benzothiawl disulfide 1, sulfur 1.6, semireinforcing furnace black as noted; cure 60 minutes a t 287' F.) % vel. swell per cent Perbunan by volume for various K values Aniline 7% VOl. of Cured (per cent swell due to cured polymer). From the two Porta p:int, Tpp,, Increase Polymer (K) Black Fluid F. c, 70 hr, 168 hr. 70 hr, hr, graphs of Figure 1 it is possible to determine I' by Wt. , . , Gasol/ne 1 .. 25 .. 75.6' 74.9" E8 (volume increase plus volume of extractable 25 , , . Gasoline 2 76 petroleumbase oil 3 (1) 158 100 2i:o 2i:e softener). The per cent volume of extractable 160 76 Extreme Same pressurelubricant iil ;g":! softener, ES, can be obtained from the extraction 160 Same 100 10.0 12.1 18.4 22.2 coefficient, specific gravity of softener, and the plot, 76 WS 491 hydraulic oil 177 100 9.8 9.0 14.0 12.8 160 Same 100 7.3 7.2 13.6 18.2 in Figure 2. This figure is a graph of parts carbon 76 Esso aviation oil 100 256 100 -0.8 .. -1.1 .. black by weight against per cent softener by volume, 0 Average for range of loadings (Table I givee composition of gasolines). 8, for compounds containing 10 to 50 parts of softener. The volume increase of the comDound. V , is then easily determined by difference. EFFECT OF EXTRACTABLE SOFTENER To illustrate how these graphs are used, let us calculate the volume increase of a Perbunan compound containing 75 parts of The effect of extractable softener on the volume increase of an semireinforcing furnace black and 20 parts of tributoxy ethyl oil-resisting synthetic rubber stock was discussed by Juve and Garvey (9). They stated that, on immersion in hot oil, the volume increase is reduced by. three factors: change due to heat 1 hardening, hardening due to loss of softener, and evaporation plus extraction of softener. The volume increase of a compound containing no softener would be influenced only by the firat factor. It has been further pointed out ( 6 , I I ) that the swelling characteristics of the immersion medium may be altered by the presence of plasticizer which may have been extracted from the synthetic rubber stock. For compounds containing extractable softener, Equation 1 may be modified by a term which indicates the amount of softener extracted from the compound:
+
I
ft:
V = (KP/100) - ES where E = extract coefficient S = % softener by volume in compound
i::
.
:::;
i;::
(2)
Extract coefficient E is defined as per cent by volume of extractable softener divided by per cent by volume of softener in the compound. In most synthetic rubber compounds there is an extract which is due to stabilizer, fatty acid, emulsifier, etc. No attempt will be made to determine specifically the extract due to these factors, and for purposes of calculation all extract will be attributed to softener. Table I11 illustrates how this method of calculation ean be applied to compounds containing an extractable softener. The agreement between the calculated and experimental values is excellent. The extract coefficient for tributoxy ethyl phosphate appears to be about 0.8. This means 80% of the softener was extracted by the gasoline. VoIume increase data were obtained on seven stocks under six conditions of immersion in petroleum products. Six stocks contained softeners commonly used in Perbunan, and the seventh ww without softener. Polymer swell value K was determined on the stock which contained no softener. Extract coefficient E was obtained by substituting the known values of K,P,S, and V
Figure 1. Calculation of Volume Increase of Perbunan
Compounds
INDUSTRIAL A N D ENGINEERING CHEMISTRY
March, 1945
parts softener. This is then extended downward, and S is found to be 11.6%. The extract coefficient, K, for tributoxy ethyl phosphate is 0.8. Hence ES 11.6 X 0.8 5 9.3% volume of extractable softener S. Then V = 46 9.3 36.7% volume increase of the compound. The experimental value was found to be 37.2%. The Perbunan used in this study came from the same large blended lot of polymer. Tables I11 and IV indicate slight differences in the K values, on the same recipe and immersion fluid. In Table IV K was determined on a stock containing no softener. This stock was run in the same series as those containing the various softeners. The experience of this laboratory has been that the variation of several volume increase determinations in 40% aromatic gasoline run at different times by the same operator is 2%. When the volume increase becomes smaller, the percentage error tends to increase. When these data in Tables I11 and I V are examined in the light of the limitations of precision, the variations do not appear to be great. In normal practice other factors than actual measurement which will also affect results are variation from lot to lot of the swelling power of the various classes of petroleum products, the state of cure of the stock, and the small variation in composition between various mixes of compound. Commercial practice on most specifications takea these factors into consideration when volume increase limits are set, so that these factors and other possible limitations do qot appear to detract from the usefulness of this method. Qee reported (8) that the absolute swelling of rubber in a good swelling agent is reduced by reinforcing fdlers. Preliminary evidence indicates this to be true for Perbunan, but the differences are small in the liquids with which Perbunan compounds come in contact in service. This point is the subject of another investigation.
-
0
Figure 2.
10
30
20
*k SOFTENER BY VOLUME IS) Calculation of Volume Increaee of Perbunan Compounds
phosphate after 7 days in 40% aromatic gasoline. From previous data it is known that the K value or per cent swell of the polymer is 75 for a Perbunan compound in this gasoline. The figures are constructed using parts black by weight and parts softener by weight. The softener has a specific gravity of 1.0. If the softener does not have a gravity of 1.0, it must be corrected to this basis. This may be accomplished by expressing the softener as parts by volume, since a specific gravity of 1.0 means that parts by volume are equivalent to parts by weight. Thus for 20 parts tributoxy ethyl phosphate (specific gravity 1.02), 20/1.02 = 19.6.
In Figure 1 the dotted line indicates how a value of 46% swell represents the volume increase of the compound plus the volume of extractable softener, V ES. In Figure 2 the dotted line indicates how the per cent softener by volume, S,is determined. A line is extended from 75 parts black by weight to the value of 19.6
The author wishes to acknowledge the assistance of Mrs. M.
F.Bergh in securing the experimental data.
TABLE 111. CALCULATION OF VOLUME INCIWASE OF PERBUNAN COMPOUNDS CONTAINING EXTRACTABLE SOFTENER 287' F.)
Semireinforcin furnace blsok 76 160 75 150 Tributoxy ethyl phosphate 20 20 40 40 61.7 49.4 65.8 45.8 Perbunan by voiume 11.6. 9.8 20.7 17.0 softener b volume by vol. o f extractable softener (E&, as measured by .% ahrinkage of dried volumeincrease Bpecimena 9.1 8.3 16.2 18.8 I% extractable softener by vol. ( E a 0.79 0.90 0.79 0.81 softener b vol in compound 87.1 aa.7 25.1 20.8 v ClSk/lOO, $8; iir 74.9) 37.2 ao.0 26.9 19.8 % vol. increase' Difference between calcd. and exptl. volume -0.1 -1.8 -0.8 +0.6 increase a After 168 hours at 2S0 C. in gasoline 1 (containing 40% added aromatiem).
b
-
-
-
-
ACKNOWLEDGMENT
+
(Base recipe: Perbunan 100, zinc oxide 5, stearic add, 1, benzothjazyl disulfide 1. sulfur 1.6, black and softener as indicsted; cured 60 minutes at
22s
LITERATURE CITED (1) Am. Soc. for Testing Materials,Standards on Rubber Products, DD. 136-9 (1944). (2) C k e n , F. H., Powers,P. O., and Robinson, H. A., IND.ENO. CHIPM., 32, 1069 (1940). (8) Catton, N. L.,and Fraaer, D. F., I b X , 31, 956 (1939). (4) Fraser, I). F.,Ibid., 32, 320-3 (1940). (6) Ibid., 35, 947-8 (1943). (6)
Fraser, D. F.,persond communication.
(7) Fraser, D. F., Rubber C h m . Tech., 14, 204-10 (1941). 8) Gee, G., Tram. Inat. Rubber I d . , 18, No.6, 266-81 (1943). 9) Juve, A. E.,and Garvey, B. S., Jr., IND.ENO.CHEW., 34, 1319 (1942). (10) Moll, R. A., Howlett, R. M., and Buckley, D. J., IND. ENG. C E ~ M34, . , 1284-91 (1942). (11) Powers, P. O., personal oommunication. PB~O~N before T~D the apring meeting of the Division of Rubber Chemistry, AM5WCAN CS~MICAL SOOlSTY in Neat York, N. Y., 1944.
t
TABLE IV. VOLUME INCRH~ASE AND EXTRACT COEFFICIENTVALUIIB OF PERSUNAN COMPOUND^ PRODUCFB
ABTE~RIMMERSION IN PETROLEUM
(Baserecipe: Perbunan 100,ainc oxide 6,stearic aaid 1, aemireinforcing furnace black 76,benaothiaayl disul6de 1. sulfur 1.5,softener 20) % Volume Incresre with: Extrsot Coeffioient B with:
16s 168 70 70
2s 26 100 100 I68 70 70 I00 I BRT No. 7.
Gasoline 1 (4o%~stomatiW)
61.3
Petroleum base or1 8 W S 491 hydraulic oil WE 491 hydraqo oil EMO aviation oil 100 6 Bardol. a Lot B.
21.8
100-octaneavlatrongasoline~
19.8 9.7 7.8
-0.8
86.9
7.4 9.4
-1.1 -8.6
-11.6
88.4 41.8 88.4 87.9 36.7 73.4 6.6 13.0 10.4 8.9 8.8 27.6 7.5 14.1 11.2 9.2 8.9 81.2 -2.3 2.3 0.7 -0.8 -3.1 13.9 -4.1 0.8 0.6 2.3 -4.4 11.2 -12.2 -6.5 -9.1 -9.9 -12.1 -1.14
0.76 0.81 0.47 0.66 0.89
0.84 0 . 8 4 0.44 0.66 0.90 0.88 0.95 0.56 0.78 1.00 0.88 0.87 0.66 0.73 1.00 0.86 0.88 0.63 0.88 0.99 0.96 0.92 0.60 0.77 0.88
0.82
0.71 0.89 1.00
0.97
0.90
