May 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
solvent (preferably ether) containing a catalyst (preferably perchloric acid), and treatment with ketene as prepared by pyrolysis of acetone. Samples containing up t o 17% acetyl retained their fibrous structure with only slight degradation. The ketene acetylation was accompanied by a n objectionable polymerization of ketene which produced a yellow to dark brown coloration of the sample. The color could be removed by hot alcohol. Although the emphasis was on the reaction of water-activated, solvent-dehydrated cellulose with ketene, some experiments were tried in which the cotton was swollen with acetic acid before the introduction of the ketene. The acetylation was probably due t o the acetic anhydride formed. LITERATURE CITED
(1) Davis, B. L., Goldblatt, L. A., and Palkin, S., IND. ENG.CHEM..
38, 53 (1946).
mulsion
1021
(2) Goldthwait, C. F., MoLaren, J., and Voorhies, S. T . , Jr., Textile WorEd, 96, No. 2, 115 (1946). (3) Graves, G. De W., U. S. Patent 1,990,483 (Feb. 12, 1935). (4) Heuser, E., “Cellulose Chemistry,” p. 248, New York, John Wiley & Sons, 1944. (5) Ketoid Company, Brit. Patent 237,575 (July 22, 1924). (6) Middleton, E. B., U. S. Patent 1,685,220 (Sept. 25, 1928). (7) Murray, T . F., Jr., Staud, C. J., and Gray, H. Le B., IND.ENG. CHEM.,ANAL.ED.,^, 269 (1931). (8) Nightingale, D. A , , Brit. Patent 237,591 (Oct. 29, 1925). (9) Nightingale, D. A,, U. S. Patent 1,604,471 (Oct. 26, 1926). (10) Rice, F. O., Greenberg, J., Waters, C. E., and Vollrath, R. E., J . Am. Chem. Soc., 56, 1760 (1934). (11) Talley, E. A., and Smith, L. T., J. 0 ~ gChem., . 10, 141 (1945). (12) Wolcott, B., U. S. Patent 1,474,574 (Dee. 10, 1921). (13) Wooster, H. A., Lushbaugh, C. C., and Redemann, C. E., J.Ind. Hug. Toxicol., 29,56-7 (1947). RECEIVEDJuly 10, 194% Presented before Meeting-in-Miniature of the Louisiana Section, BMERICAN CHEXICAL SOCIETY, S e w Orleans; La., May 14 t o 15, 1948.
olyrnerization of Methyl etone with Butadiene CHARLES W. GOULD AND G. E. HULSE Hercules Powder Company, Wilmington 99, Del.
v .
I he emulsion copolymerization of methyl isopropenyl ketone with butadiene has been investigated to determine the effects of emulsifier, modifier, temperature, ratio of monomers, and pH on the rate of reaction and viscosity of the copolymer. It was found that the reaction could be carried out using a wide variety of emulsifiers and a pH ranging at least from 3 to 10. Mercaptan modifiers had the usual effect on the molecular weight and were necessary to produce a soluble, plastic polymer. The polymerization rate was proportional to the per cent ketone in the monomer mixture and was increased about threefold by raising the reaction temperature from 40” to 50” C. In comparing the copolymerization with that of styrene and butadiene, the chief points of contrast are: the much faster rate (about four times that of a comparable styrenebutadiene copolymerization) and the formation of polymers which have a very high Mooney viscosity (170), yet are completely soluble, even at conversions of 80% or more.
U
KSATURATED ketones such as methyl isopropenyl ketone have been copolymerized with butadiene by a number of investigators (3-6, 7 , IO). However, little has been published concerning the effect of systematic variation of reaction conditions on the rate of copolymerization and the properties of the polymers. It was to be expected that substitution of a n acetyl group for a phenyl group side chain in a vinyl-butadiene copolymer would give a polymer considerably different from, a n d with some advantage over, GR-s. The greater electronegativity and hydrogen bonding ability of the carbonyl group should lead to a definite difference in intermolecular forces, which should be reflected in the physical properties. I n addition, the smaller size of the acetyl group probably permits closer packing of the molecular chains. A further difference exists in the substitution of a methyl group for hydrogen on the alpha carbon of the vinyl group. This eliminates from the polymer the tertiary carbon atom, which is particularly subject to dehydrogenation by a free radical, thus initiating a chain branching reaction,
Because preliminary experiments indicated that the copolymer had attractive properties and the ketone monomer can be prepared from readily available raw materials ( I , l l ) ,i t w m of interest to investigate the copolymerization further. Accordingly, experiments have been made t o determine the effects of emulsifying agent, modifier, temperature, ratio of monomers, and p H on the rate of reaction and the viscosity of the polymer. EXPER1:MENTAL
The general procedure was similar to t h a t described by Fryling (6). The polymerizations were carried out in ordinary %ounce carbonated beverage bottles, closed with a crown cap. The standard recipe used in this work, unless otherwise noted, was as follows: Emulsifying agent Potassium persulfate Double-distilledwater to make Monomers, butadiene methyl isopropenyl ketone Modifier, primary mercaptan
+
2.50 grama 0.15 gram 90.0 ml. 50.0 grams 0.25 gram
Most of the work reported here was done with Duponol C emulsifier in a buffered system, usually at p H 5 . In this case, the following reagents were added: 0.5432 N sodium hydroxide
Potassium acid phthalate
3.96 ml. 0.92 gram
DESCRIPTION OF REAGENTS. It was found t h a t more consistent and higher conversions could be obtained if the usual laboratory distilled water was redistilled in a glass apparatus before use. Similarly, better results were obtained when the buffer solutions were freshly prepared each time, and the methyl isopropenyl ketone monomer was fractionated t o give a product with a refractive index, n%o, in the range 1.4233 t o 1.4237. As determined in this laboratory, the refractive index, nk0,of pure methyl isopropenyl ketone is 1.4233; Morgan (11)has reported a value of 1-4220.
The emulsifying agents suchas Duponol C (Du Pont), Triton K60 @ohm and Haas), and f a t t y amine acetate (Armour) were used as received. The inorganic reagents such as potassium persulfate
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1022
Vol. 41, No. 5
INDUSTRIAL AND ENGINEERING CHEMISTRY
TABLE I. EFFECT OF EMCLBIFIER AKD MODIFIER ON REACTION AND ON POLYMER AT DIFFERENT TEMPERATURES, p H LEVELS AND MOXOYER COMPOSITIO~~S Sample Designation 1
10 11 12 13
i216
17 18
Con-
Monomers Emulsifier Kind Ratio Kind 25:75 Duponol Ca 25:75 Duponol C 25:75 Duponol C 26:75 Duponol C 25:75 Triton K-600 MIK-butadiene 25:75 Triton K-60 MI K-butadiene 25:75 Triton K-60 M IK-butadiene 25:75 Triton K-60 MIK-butadiene 25:75 Triton K-60 MIK-butadiene 25:75 A X A C 1120d MIK-butadiene 25:75 AMAC 118.5B6 MIK-butadiene 30:70 S F Flakesf NIK-butadiene 30:70 Sodiumdehydroabietate hIIK-butadiene 3 0 : i O Dresinate 7310 MIK-butadiene 3 0 3 0 Duponol C Styrene-butadiene 30:70 Duponol C Styrene-butadiene 25:75 SF Flakes Styrene-butadiene 25375 Dresinate 731
70
Modifier, %' Primary mercaptanb Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan Primary mercaptan
0.5
10.0
5 . 0 Tertiary mercaptanh 5 . 0 Primary mercaptan 5 . 0 Primarymercaptan 5.0 Primary mercaptan 5 . 0 Primary mercaptan
0.5 0.5 0.5 0.5 0.5
10.4 10.0 10.0 9.0 10.0
0.5 1.0 2.0 5.0 1.O 2.0 3.0
4.0 5.0 5.0 5.0 5.0 5.0
0.5
0.5
0.5
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
verTemp., Time, sion, Solu.a C. bility Hours 70 50 5 42 Gel 50 5 54 Gel 50 5 64 Gel 50 5 70 Complete 50 4.5 2 50 4.5 14 . . ... . . 50 4.5 76 Complete 50 4.5 93 Gel 50 4.5 96 Much gel 40 12 72 Complete 40 12 77 Complete 40 6 74 Much pel 40 6 71 hluchgel
.......
5.2 5.6 9.7
40 40 40 40 40
6 7 27.5 32 32
64 85 84 86 69
Complete Complete Complete Complete Complete
Mopey viscosity
Remarks
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... ... ...
...
,..
,..
...
...
.. .. ..
121 113
.. .. ,.
,..
...
46 176 50 55 83
,
. ,.
.. ...
... .. .
Sodium lorol sulfate, D u Pont. Office of Rubber Reserve standard D D M , chiefly dodeoyl mercaptan Beneslcetsldimethvlalnlnonium chloride. Rohm and Haas. d Laur
