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 Ipatieff, V. N . , and Zdaitovetsky, B. S.,Ber., 40, 1827 (1907); Chem. Abstr., 1, 2075 (1907). Ipatieff, V. N., and Zdaitovetsky, B. F., J . Russ. Phys. Chem. Soc., 39, 897 (1907); Chem. Abstr., 2, 259 (1908). Kharasch, 1LI. S., and Darkis, F. R., Chem. Revs., 5,571 (1928). Kilpatrick, J . E., Prosen, E. J., Pitzer, K. S., and Rossini, F. D., J . Research aVatZ.Bur. Standards, 36, 559 (1946). Lankford, J. D., and Ellis, C. F., IND.ENG.CHEY., 43, 31 (1951). Lieber, E., C . S.Patent 2,281,941 (May 5 , 1942). McCarthy, W. W-., and Turkevich, J., J . Chem. Phys., 12, 405 (1944). Moldavski, B. L., and Kamusher, H., Compt. rend. acad. sci. U.R.S.S., 1, 335 (1936): Chem. Abstr., 30, 6713 (1936). Mulligan, M. J., and Cramer, P. L., U. S. Patent 2,423,612 (July 8, 1947). Saragon, E. A,, IND.ENG.CHEM.,42,2490 (1950). Nemtsov, M. S., Nizovkina, T. V., and Soskina, E. A., J . Gen. Chem. U.S.S.R., 8 , 1313 (1938); Survey Foreign Petroleum Literature Index, Part 1 (1937-39). Nikolaeva, A. F., and Frost, A. V., J . Gen. Chem. U.S.S.R., 13, 733 (1943); Chem. Abstr., 39, 662 (1945). Norris, J . F., and Reuter, R., J . Am. Chem. Soc., 49, 2624 (1927). Oblad, A. G., and Gorin, &I. H., ISD. EKG.CHEX., 38, 822
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(61) Schneider, V., and Frolich, P. K., IND.ENG.CHEM., 23, 1405 (1931). (62) Sehuit, G. C. A , , Hoog, H., and Verheus, J., Rec. trav. ehim., 59, 793 (1940); Chem. Abstr., 35, 4728 (1941). (63) Serebryakova, E. K., and Frost, A. V., J . Gen. Chem. U.8.S.R , 7, 122 (1937); Chem. Abstr., 31, 4570 (1937). (64) Serebryakova, E. K., Rudkovski, D. M., and Frost, A. V., Compt. rend. acad. sci. U.R.S.S., IV, 359 (1936); Survey Foreign Petroleum Literature, Special Trans. S-24 (Sept. 23, 1938). (65) Sherrili, M.L., Otto, B., and Pickett, L. W., J . Am. Chem. SOC.,51, 3023 (1929). Smith, A. E., and Beeck, 0. A, U. S. Patent 2,474,440 (June 28, 1949). Standard Oil Co. (Indiana), Petroleum Rejiner, 27, 170 (Sept. 1948, Section 2). Standard Oil Dev. Co., Brit. Patent 641,121 (Aug. 2, 1950). Thacker, C. M., Folkins, H. O., and Miller, E. L., IND.ENG. CHBM., 33, 584 (1941). ‘I., G. E., U. S. Patent Thiele, E. W.,Hull, C. &Schmitkons, 2,326,704 (.lug. 10, 1943). Ibid., 2,326,705 (Aug. 10, 1943). Ibid., 2,410,908 (Nov. 12, 1946). Thiele, E. W.,and Schmitkons, G. E., Ibid., 2,326,703 (Aug. 10, 1943). Thomas, C. L., IND.
[email protected],41, 2564 (1949). Thomas, C. L., U. S. Patent 2,328,754 (Sept. 7, 1943). Thomas, C. L., and Ahlberg, J. E., Ibid., 2,371,079 (March 6, 1945). Thomas, C. L., and Bloch, H. S.,Ibid., 2,216,284 (Oct. 1, 1940). Ibid., 2,352,416 (June 27, 1944). Thorne, H. RI., Murphy, W. I. R., Ball, J. S., Stanfield, K. E., and Horne, J. W.,IND. ENG.CHEM.,43,24 (1951). Twigg, G. H., Proc. Ray. SOC.London, A-178, 106 (1941). Van Peski, A., and Lorang, H. F., U. S. Patent 2,220,693 (Nov. 5 , 1940). Voge, H. H., Good, G. M., and Greensfelder. B. S.,IND.ENG. CHEM.,38, 1033 (1946). Voge, H. H., and May, N. C., J . Am. Chem. SOC.,6 8 , 550 (1946). Waterman, H. I., Leendertse, J. J., and MoMaringal, Rec. traa. chim., 54, 79 (1935); Brit. Chem. Abstr., A, 325 (1935). Watson, C. W., U. S.Patent 2,400,795 (May 21, 1946). . 26, 668 (1948). Whitmore, F. C., Chem. E ~ QNews, Whitmore, F. C., et al., J . Am. Chem. Soc., 62, 795 (1940). Whitmore. F. C., and Meunier, P. L., J . Am. Chem. Soc., 55, 3721 (1933). Zelinskif, N. D , Arbuzov, Y . A., and Batuev, M. I., Comgt. rend. mad. Sci., U.R.S.S., 46, 150 (1945); Survey Foreign Petroleum Literature, No. 6 or 515 (June 22-29, 1945).
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(1946).
Oblad, A. G., and Messenger, J. V., C. S. Patent 2,471,647 (May 31, 1949). ENG. Oblad, A. G., Messenger, J. V., and Brown, H. T., IND. CHEM.,39, 1462 (1947). Oblentsev, R., Pazhitnov, B., Rudkovski, D., and Trifel, A., Khim. Referat. Zhur., 4, No. 9, 119 (1941): Chem. Abstr., 38, 950 (1944). Petrov, A. D., and Cheltsova, M. L4., Compt. rend. acad. sci. U.R.S.S., 15, 79 (1937); Survey Foreign Petroleum Literature, No. 28 (1938). Petrov, A. D., Cheltsova, M. A., and Batuev, M. I., C ~ m p trend. . acad. sci. U.R.S.S., 56, 273 (1947); Chem. Abstr., 43, 6152 (1949). Petrov, A. D., Meshcheryakov, A. P., and Andreev, D. N., Ber. 68B,l(1935); J . Gen. Chem. U.S.S.R., 5, 972 (1935); Chem. Abstr., 29, 2145 (1935). Petrov, A. D., and Shchukin, V. I., J . Gen. Chem. U.S.S.R., 9, 506 (1939); Survey Foreign Petroleum Literature, Trans. 209 (Jan. 26, 1940). Petrov, A. D., and Shchukin, V. I., J . Gen. Chem. U.S.S.R., 11, 1092 (1941); Oil Gas J., 43, No. 37, 77 (January 20, 1945). Pines, H., J . Am. Chem. Soc., 55, 3892 (1933). Plate, A. F., and Tarasova, G. A,, J . Gen. Chem. U.S.S.R., 20, 1092 (1950); Chem. Abstr., 44,8215 (1950). Rose, A., J . A m . Ghem, Sac., 62,793 (1940). Schmitkons, G. E., U. S. Patent 2,323,570 (July 6, 1943).
RECEIVED f o r reviem May 12, 1952.
.kCCEPTED
Kovembor 24, 1952.
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HOWARD C. HAAS, LEONARD 6. FARNEY, AND CLAUDE VALLE, JR. Chemical Research Laboratories, Polaroid Corp., Cambridge, Mass.
IGH polymeric materials are in general incompatible with each other. This has been demonstrated experimentally b y Dobry and Boyer-Kamenoki ( 5 ) and explained thermodynamically by Gee ( 6 ) , who has shown t h a t the entropy gain on mixing two polymers is so small that even a slight positive heat of mixing would result in almost complete immiscibility. T h e difficulty of finding pairs of compatible polymers apparently accounts for the scarcity of information on systems of this type. Among t h e derivatives of cellulose, certain compatible pairs do exist, For example, ethylcelluloses and nitrocelluloses are miscible, probably because of specific interactions bet\\ een these two polymers which overcome differences in cohesive energy
density (11). During a study of ether derivatives of hpdroxyethylcellulose (4), the authors of this paper found t h a t several of these seem compatible with ethylcellulose. A butyl ether of hydroxyethylcellulose containing 1.5 ethylene oxide and 2.0 t o 2.1 butyl groups per anhydroglucose unit appears compatible with ethylcellulose over the entire composition range. (The ethylcellulose was standard ethoxy Ethocel, Dow Chemical Co., Lot 14037,100 cps. viscosity, [VI = 2.18 in 80:20 toluene:ethanol, 48.5 % ethoxyl corresponding to 2.50 ethoxyl groups per anhydroglucose unit.) This compatibility probably results from similar cohesive energy densities rather than from any specific interactions between the two polymeric species.
March 1953
This pair of polymers is interesting in that ethylcellulose is a relatively high modulus material, whereas the butyl ether of hydroxyethylcellulose is a low modulus material of high extensibility. Blending these two polymers should enable the investigator to obtain a spectrum of mechanical properties without the introduction of low molecular weight materials and without the sacrifice of optical clarity.
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cizer is defined as any nonvolatile material which modifies mechanical properties, then, in a broad sense, butylhydroxyethylcellulose can be considered a polymeric plasticizer for ethylcellulose. Like other plasticizers, butylhydroxyethylcellulose (Figure 2, A ) follows the Flory-Boyer ( I ) equation which predicts a linear decrease in tensile strength with plasticizer content. Like other polymeric plasticizers, i t is inefficient in that large amounts are required to appreciablj increase the elongation and the hardness (yield stress) suffers proportionately. It has been shown ( 7 ) that the higher the viscosity of the plasticizer the lower the efficiency; thus for use specifically as a plasticizer, a more highly degraded butyl ether than the derivative of [77] = 0.74 studied b y the authors would be advantageous. The softening points of these films, as determined by the method of Lorand (8),have also been found to be linear with film composition (Figure 3). Employing a rapid deformation type of ultimate strength test, a brittle temperature test, the data of Figure 4 have been obtained. Although the observed maximum in the TB versus composition curve was somewhat unexpected, i t may possibly be explained. The rate of deformation-i.e., the anvil velocity of 16.4 feet per second, exceeds the critical velocities which allow plastic flow and chain uncoiling in ethylcellulose ( I O ) . Thus, pure ethylcellulose absorbs energy in this test only by the elastic bending of bond angles along the chain backbone. Plasticization of ethylcellulose results in a shift of these critical velocities to much higher values, and i t is reasonable to assume t h a t the response of highly internally
STRAIN (AL/L)
Figure 1. Stress-Elongation Behavior of Mixed Ethylcellulose-ButylhydroxyethylcelluloseFilms Composition, Wt. Fraction Butylhydroxyethylcellulose
Ethylcellulose 1 0.75 0.5
0.25
0.25 0.5 0.75 1
*
Perfectly transparent mixed films of these two polymers were prepared by casting on glass benzene solutions containing different weight ratios of the polymers, allowing the solvent to e v a p orate, and drying. The stress elongation behavior of these films was studied a t room temperature, using a constant rate of elongation of 1 inch per minute. The stress-strain data, averages of several m'easurements, are presented in Table I and plotted in Figures 1 and 2. The curves of Figure 1 show a smooth transition in properties from ethylcellulose to butylhydroxyethylcellulose. This supports the belief that the two polymers are truly miscible, since incompatibility usually results in mixtures having properties which are inferior to those of either pure component. All properties of the stress-strain curves (Figure 2) are simple functions of the butylhydroxyethylcellulose content of the films. Polymeric Plasticizer. Recently there has been a marked tendency toward the use of polymeric plasticizers. If a plasti-
WEIGHT FRACTION OF BUTYL HYOROXYETHYLCELLULOSE
WEIGHT FRACTION
OF BUTYLHYDROXYETHYLCELULOSE
Figure 2. Properties of Mixed EthylcelluloseButylhydroxyethylcellulose Films
TABLEI. STRESS-ELONGATION OF MIXED ETHYLCELLULOSE-BUTYLHYDROXYETHYLCELLULOSE FILMS (Room temperature)
Film A B C
D
E
Composition, Wt. Fraction Butylhydroxyethylcellulose 0.00 0.25 0.50 0.75 1.00
Youn 's Modulus (E), Lb.fSq. In. X 10-8 2.78 2.05 1.31 1.05 0.61
Yield Stress, Lb./Sq. In. 6390 5500 3985 2545 1499
Ultimate Tensile Strength Lb./Sq. 1;. 7648 6870 5673 4 148 2455
Elongation a t Break, % 22.7 27.0 40.1 55 6 82 6
Energy to Break Ft. Lb./Sd. I n . 245 250 294 287 264
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plasticized butylhydroxyethylcellulose is in a large part viscoelastic and plastic, which accounts for its relatively low Tg. Introduction of small amounts of ethylcellulose into butylhydroxyethylcellulose will indeed reduce the concentration of internal plasticizer and account for the rise in TB. As the concentration of ethylcellulose is increased to large values, the high modulus character of the mixtures becomes more evident and the brittle points start to decrease-approaching t h a t of pure ethylcellulose.
i
EXPERIMENTAL
BUTYLETHEROF HYDROXYETHYLCELLULOSE. This deriva-
tive has been prepared ( 4 ) from Blend 1C hydroxyethylcellulose (WPLH, Carbide and Carbon Chemicals Corp.) steeped in aqueous alkali by reaction with excess butyl bromide. The hydroxyethylcellulose has been found (3)to contain 1.50 moles of combined ethylene oxide per anhydroglucose unit. Analysis of the butyl ether for carbon and hydrogen has yielded t h e following results: Carbon, 60.1%; hydrogen, 9.5%, corresponding t o a D.S. (degree of substitution) of 2.03 butyl groups per anhydroglucose unit. Analysis by the acetylation method (9) led t o a value of 2.09, in good agreement with the carbon and hydrogen analyses. The intrinsic viscosity in acetone a t 30' C. was determined t o be 0.74 by extrapolation of an q s p . / C versus C plot (C expressed in grams per 100 ml.) Unfractionated polymer was used in this study.
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WEIGHT FRACTfON OF ETHYLCELLULOSE
Figure 4. Brittle Temperature of Mixed Ethylcellulose Butylhydroxyethylcellulose Films
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BRITTLETEMPERATURES. The method used for the determination of brittle temperatures was an adaptation of that employed by Clash and Berg (a) who have modified the tentative A.S.T.M. Method D746-43T. RIeasurements were made using an anvil velocity of 16.4 feet per second and an arbitrary span length of 0.045 inch. Test pieces vere 1.5 X 0.5 inch X sample thickness and were conditioned prior to testing a t 25" C. and 50% relative humidity for a t least 40 hours. The lowest temperature of nonfailure of five consecutive test specimens 'was taken as T B . Samples were allowed to remain a t the test temperature 15 minutes before they were struck.
100-
ACKNOWLEDGhIENT
90-
Carbon and hydrogen analyses were made by C. I
