Effect of Petroleum. Products on
0 As with other petroleum products the aniline point may be used to indicate the swelling effect of commercial gosozines on neoprene vulcanizates. However, i t is felt that the Diesel index is a more precise indication with product.~having A . P . I . gravities greater than 40 (kerosenes and gasolines). This may be particularly true in the case of recently proposed oromatic aviation gosoline blends.
0 DONAID F. FRASER E. I. du Pont de Nernours &Company. Inc., Wilmington, Del. Pr-nt
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Neoprene Printing Blankets Maintain Their Ori&ud Propcetiee Despite Exposure to Oil, Ink, and Chemic& in Weaning Solutions
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HE third paper of this series (3) showed that the Diesel index may be used a8 a criterion of the swelling effect on neoprene of kerosenes and kerwne-benzene blends. It ~ 8 erroneously 8 stated, however, that “swelling caused by kerosene is not a simple function of the . . . . aniline point”. A recheck of the data, together with additional work, indicates that the aniline pint may be used as a miterion of the swelling power of kerosenes, hut this correlation is not so precise as with the Diesel index. This is particularly true in the ca8e of kerosenebenaene blend when bencene the blend, & with kernsen@, the aniline or ~ i index~ may~be used ~ as$an indication of the swding power of gasolines, and thus these constants m y he used to specify standard immersion media of these types.
The neoprene composition used in the work was identical with that used in the previous investigations (I, 2, 3). The specimens were prepared for the volume increase test as previously described. The physical data for and the description of the gasolines used in swe~ingtests are shown in Table I. Also shown is the volume increase after immersion of the neoprene specimens in the gasolines at 27.80 c, (g2e F,), The results shown &pe those of the maximum swelling. The immersions were continued for 14 days, but maximum swelling was attained, except in the ease of isooctane, within 3 days. The volume increases at the end of 14 day8 were the same, within the experimental error, as the results shown in Table I. Because of the volatility of gasoline,care NBBtaken 941
INDUSTRIAL AND ENGINEERING CHEMISTRY
948
to make the necessary weighings as soon as possible after removal of the specimen from the gasoline. I n Figure 1 the logarithm of maximum swelling is plotted against Diesel index, and a straight-line relation is obtained. The plot for isooctane (sample 15) is the swelling after 14-day
Vol. 35, No. 9
For instance, in the case of samples 5, 6,7,and 8 (showing the effect of the addition of tetraethyllead) no change was observed in the aniline point, but the Diesel index and swelling results showed that the addition of tetraethyllead did affect these properties.
Figure I
immersion and does not fall on the curve. This material has very little swelling power, and consequently the time necessary to reach maximum or equilibrium swelling is probably considerably in excess of 14 days. If the aniline point is substituted for the Diesel index, a good correlation is also obtained; but it is felt that the latter is a more precise criterion.
Sample Number 1 2 3 4 5 6
7 8 9 10 11 12
13
14 15
Practically all commercial motor fuels (gasolines) represent blends of straight-run and cracked stocks. However, the Diesel index may be used as a criterion of swelling of either type of stock or of intermediate blends as indicated by samples 9, 10, 11, 12, and 13. As would be expected, a straight-run stock has considerably less swelling effect than a cracked stock. Sample 14 was prepared by adding 0.0043 per cent of a commercial antioxidant (du Pont gasoline antioxidant, solution 14) to TABLEI. SUMMARY OF DATAFOR GASOLINES cracked stock sample 13. The swelling results indicate that some commercial antioxidants, at hlax. Vol. A. P. I. Aniline Increase of Point, Refractive Neoprene at least, increase the swelling power of gasolines Description Index (60° F.) O F . Index 27.8OC. containing them. 54.0 Comparison of the swelling results in Table I 115.5 69.99 1.4340 Commercialmotor fuel 60.6 Commercial motor fuel 62.4 110.5 68.95 1.4380 56.5 with those in Table I of the preceding paper (3) Commercial motorfuel 61.8 111.0 68.60 1.4375 56.5 1.4450 Commercial motor fuel 59.7 103.0 61.49 63.4 shows that commercial gasolines do not vary in (unleaded) swelling power as much as commercial kero1.4105 52.9 Commercialmotor fuel 59.7 68.36 114.5 (unleaded) senes and that the average swelling effect of the 1,4160 54.5 No.5+lcc.Pb(CtHs)r 59.1 114.5 67.67 per gal. gasolines is a little greater.
No.5+2cc.Pb(CtHs)i per gal. h7o.5f3cC.Pb(CtHs)~ per gal. Straight-run stock 50:50 No. 9:No. 13 40:60 No. 9:No. 13 30:70 No. 9:No. 13 Cracked stock No. 13 antioxidant Isooctane
+
54 3
58.6
114.5
67.10
14175
58.1
114.5
66.82
1.4151
53.1
67.7 61.6 60.3 59.3 56.3 56.0 71.7
133.5 116.5 113.0 109.0 99.5 98,O 176.0
90.38 71.70 68.15 64.64 56.02 54.88 126.19
1.4098 1.4276 1.4267 1.4282 1.4372 1.4359
41.2 52.0 55.0 57.3 65.0 69.6 18.5
1.3904
LITERATURE CITED
(1) Fraser, IND.ENG.CHEM., 32, 320 (1940). (2) Fraser, Rubber Chem. Tech., 14, 204 (1941). (3) Fraser, IND.ENQ.CHEM.,34, 1298 (1942). PRES~NTBLI before the Division of Rubber Chemistry a t the 105th LMeeting of the AMERICANCHEMICALSOCIETY, Detroit, Mich.
