INDUSTRIAL AND ENGINEERING CHEMISTRY
770
change in shear strength will occur until it falls to a k e d value where it remains indefinitely. While the shear strength is changed, outward physical appearance may remain the same. On the other hand, for nonsolvents such as benzene and toluene on cellulose acetate-butyrate, the loss in shear strength is accompanied by swelling, and the reason may be that swelling is due to increase in intermolecular distances with a decrease in molecular-cohesion forces.
Literature Cited (1) A. S. T. M. Specification D543-39T, Resistance of Plastics to Chemical Reagents. (2) Baker, J. Chem. SOL, 103, 1653 (1913). (3) Brunkow, IND. ENG.CHEW.,22, 178 (1930). (4) Davidson, Ibid., 18,670 (1926). (5) Delmonte, Modern Plastics, 19,63 (Sept., 1941). (6) Doolittle, IND.ENG.CHEM.,27, 1169 (1935). (7) Ibid., 30, 189 (1938). (8) Durrans, “Solvents”, London, Chapman & Hall, 1930. (9) Fermazin, Chem.-Ztg., 54, 605 (1930). (10) Frazier, IND.ENG.CHEW.,22, 607 (1930). (11) Gardner and Sward, “Physical and Chemical Examination of Paints, Varnishes, Lacquers and Colors”, p. 440, Washington, Inst. of Paint and Varnish Research, 1939. (12) Houwink, “Elasticity, Plasticity and the Structure of Matter”, Cambridge Univ. Press, 1937.
Vol. 34, No, 6
(13) Jordan, “Technology of Solvents”, New York, Chem. Pub. Co., 1QR8.
and Bass, IND.ENG.CHEM.,30, 74-9 (1938). (15) Keyes, Ibid., 17,505 (1925). (16) Kline, Rinker, and Meindl, 44th Ann. Meeting A. S. T. M., June 24. 1941. (17) McBain, J. Phys. Chem., 30,239 (1926). (18) McBain, Grant, and Smith, Ibid., 38, 1217 (1934). (19) McBain, Harvey, and Smith, Ibid.. 30, 312 (1926). (20) Mantel1 and Allan, IND.ENG.CHEW.,30, 262 (1938). (21) Mellan, “Industrial Solvents”, New York, Reinhold Pub. Corp., 1939. (22) Meyer and Fordyce, IND.ENG.CHEW.,32, 1053 (1940). (23) Ostwald, Kolloid-Z., 59, 25 (1932). (24) Park and Hofmann, IND.ENG.CHIDW., 24, 132 (1932). (25) Peierls, Modern Plastics, 18,53 (Feb., 1941). (26) Reinhart and Kline, IND.ENG.CHEM.,31, 1522 (1939). (27) Sakurada and Shojino, J. SOC.Chem. Ind. J a p a n , 37, Suppl. Binding, 603 (1934). (28) Sakurada and Watanabe, Ibid., 39,Suppl. Binding, 50-1 (1936). (29) Sproxton, 3rd Colloid Rept., p. 82, Brit. Assoc. Adv. of Sei., 1920. (30) Staudinger and Heber, J. Phys. Chem., A171, 129-80 (1935). (31) Strain and Kennelly, IND. ENG.CHEW.,31, 382-7 (1939). (32) Surtmeister, “Casein and Its Industrial Applications”, p. 150, New York, Reinhold Pub. Corp., 1939. (33) Ware and Teeters, IND. ENG.CHEU., 31,738-41 (1939). (34) Ibid., 31, 1118-41 (1939). (35) Wilson, Ibid., 21,592 (1929). (14) K ;;;
CORRESPONDENCE Viscosity Pole and Pole Height ( V p ) of Ubbelohde SIR: This note is written because t h e pole height, W p , of Ubbelohde (9) was recently used in INDESTRIAL AND ENGINEERING CHEMISTRY b y Neyman-Pilat and Pilat (8) without any indication of how the function is calculated and without a clear reference as t o where this information can be obtained, Pole height has been extensively used by German petroleum chemists but has received little notice in American or English journals. The concept of viscosity pole (Viskosit(itspoE) is based on t h e fact t h a t if viscosity-temperature curves are plotted on A. S. T. M. type viscosity paper (1, 2, 3) for a series of cuts from one crude, these lines will converge, a t least approximately, toward a point. This point is characteristic of t h e crude and is called the “viscosity pole”. The vertical height of this point above t h e base line corresponding t o zero viscosity is defined as t h e “pole height” (Polhdhe). This constant is characteristic of t h e crude type in much the same way thatviscosity-gravity constant ( 7 ) and viscosity index ( 4 ) are characteristic of crude types. For calculation of pole height, Ubbelohde recommends t h e following equations: 11 w, = (log TI - 2410 + - WI) = pole height (; - 0.19,) m
m
=
W1 =
(1)
+
Wi Wz log Tz - log Ti log log (Vl
+ 0.8)*
(3)
where TI,TZ = absolute temperature, K. Vi, VI = kinematic viscosity, centistokes Pole height is somewhat similar t o viscosity-gravity constant and viscosity index. Roughly, a paraffin base oil will have a pole height of about 1.0 t o 2.0, and a naphthenic oil, a pole height of about 3.0 t o 4.0. A pole height of 10 corresponds roughly t o 0.900 viscosity-gravity constant. T h e d a t a available indicate t h a t i t is probably not practical t o establish a conversion curve between pole height and either viscosity-gravity constant or viscosity index, even though they are alternative ways of measuring the same general effect. It should be noted t h a t pole heights calculated for different temperature intervals do not always check, and t h a t TIused b y Ubbelohde is 323’ K. (50” C.).
Bibliography (1) Am. Soc. for Testing Materials, Procedure D-341-32T (1932). (2) Ibid.. D-341-39 (1939). (3j Barnard, D. P.‘in “Science of Petroleum”, Vol. 11, p. 1079, London, Oxford University Press, 1938. (4) Dean, E. W., and Davis, G. H. B., Chem. & M e t . Eng., 36, 618 (1929). (5) Docksey, P., in “Science of Petroleum”, Vol. 11, p. 1091, London, Oxford University Press, 1938. (6) Geniesse, J. C., private communication. (7) Hill, J. B., and Cootes, H. B., IND.ENG.CHEM.,20, 641 (1928). (8) Neyman-Pilat, E., and Pilat, S., I bid., 33, 1382-90 (1941). (9) Ubbelohde, L., “Zur Viskosimetrie”, 2nd ed. rev., pp. 9-18, Leipsig, S. Hirzel, 1936.
S.S.KURTZ,JR.
* A modulus of
0.8 was used prior t o 1937 in preparing t h e A. S. T. M. charts (1,9). Sinoe 1937 a modulus of 0.6 has been used above 1 . 5 centistokes (8, 6).
SUNOIL COMPANY MARCUB HOOK, PEKNA.
