April 1955
.
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
sample with potassium permanganate. I n ah1 cases the original color remained, indicating that not more than a trace of lactic acid passed overhead. Furthermore, complete material balances showed that the volatile acids could be removed without losing a significant amount of lactic acid-for example, 99.6y0 of the original lactic acid remained in the distillation flask following runs 1 and 2. The distribution ratios of the acids in the overhead were determined wherever there was sufficient acid present; these confirmed that little lactic acid was volatilized and that acetic acid was the major acid impurity. These experiments indicated that a steam to solvent ratio of about 7.9 is required. By better control and contacting this could undoubtedly be reduced considerably. Process Flow. Figure 8 gives a flow diagram for a possible process based on the preceding laboratory scale work. ,4 continuous countercurrent extraction column is shown in the process flow. I n addition, a vacuum concentrator would have to be used to concentrate the product from the steam stripper because of the high boiling point of concentrated lactic acid solutions. The product was slightly colored after batch extraction and steam stripping, but the coloration was easily removed with a small amount of activated charcoal. Lactic acid losses during this decoloration were less than 1 %. Bench and pilot unit data are needed to determine such factors as solvent losses, feasibility of the process, and over-all economics. LITERATURE CITED
(1) Bass, S. L., U.S. Patent 2,092,494 (Sept. 7, 1937). (2) Diets, A. A., Degering, E. F., and Schopmeyer, H. H I IND. ENG.CHEN.,39, 82 (1947).
863
(3) Eder, R., and Kutter, F., Helv. Chim. Acta, 9, 557 (1926). (4) Filachione, E. M., and Fisher, C. H., IND. ENG.CHEM.,36, 225 (1944). (5) Ibid., 38, 228 (1946). (6) Filachione, E. M., and Fisher, C. H., U. S.Patent 2,420,234 (May 6, 1947). (7) Filachione, E. M., Lengel, J. H., and Fisher, C . H., IND.ENQ. CHEM.,37, 388 (1945). riedemann, T. E., and Graeser, J. B., J. Biol. Chem., 100, 291 11933) (9) Handbook of Chemistry (N. A. Lange, editor), 7th ed., p. 941, Handbook Publishers, Sandusky, Ohio, 1949. (10) Hickinbotham, A. R., Analyst, 73, 509 (1948). (11) Jenemann, J. A., U. S. Patent 1,906,068 (April 25, 1933). (12) Leonard, R. H., Peterson, W. H., and Johnson, M. J., IND. ENG. CHEM.,40, 57 (1948). (13) Montgomery, R., and Ronca, R. A., IND. ENG.CHEM.,45, 1136 (1953). (14) Needle, H. C., and Aries, R. S., Sugar, 44, 32 (1949). (15) Othmer, D, F., and Thakar, 13. S., IND.ENG.CHEM.,44, 1654 (1952). (le) Peckham, G. T., Chem. Eng. News, 22, 440 (1944). (17) Ratchford, W. P., Harris, E. H., Jr., Fisher, C. H., and Willits, C. 0.. IND. ENG.CHEM..43. 778 (1951). (18) Seidell, ’Atherton. “Solubilities of Organic Compounds,” Vol. 11, pp. 194-5, Van Nostrand, New York, 1941. (19) Smith, L. T., and Claborn, H. V., Ind. Eng. Chem., News Ed., 17, 641 (1939). (20) Waite, C. N., U.S. Patent 686,170 (November 1901) (21) Watson, P. D., IND.ENQ.CHEM.,32, 399 (1940). RECEIVED for review June 11, 1954. ACCEPTED December 1, 1954. Based on a dissertation in chemical engineering presented by Robert Bruce Weiser to the faculty of the Graduate School, Ohio State University, in partial fulfillment of the requirements for the degree of doctor of philosophy, June, 1954. Grateful acknowledgment is made to the Prooter and Gamble Go. for their fellowship and to the National Science Foundation for their fellowship which aided financially in carrying o u t this work.
Polyvinylpyridine Emulsifiers for Polymerization in Acidic Media JAMES E. PRITCHARD, MILTON H. OPHEIM, AND PATRICIA H. MOYER Research Division, Phillips Petroleum Co., Bartlesville, Okla.
V
INYL and diene polymers may be prepared from the monomers by polymerization in systems of the mass, solution, suspension, or emulsion types. *4lthough any one of these systems may be used to produce polymer, each suffers from important limitations. Mass polymerizations, for example, are noted for simplicity, but problems of temperature control and elimination of unreacted monomer reduce their usefulness. Solution polymerizations offer advantages over mass systems with regard to temperature control, but removal of traces of solvent from the polymer is difficult. Suspension polymerizations provide good temperature control as well as products of relatively high purity. However, the polymer is obtained in the form of beads or pearls and cannot be utilized directly in many surface coating, adhesive, or textile finishing applications where an emulsion or latex is required. Polymerization in emulsion offers many advantages with regard to temperature control and reaction rate, but provides products which ordinarily are contaminated with emulsifiers. In the case of emulsion-polymerized synthetic rubber, contamination of the polymer with nonpolymeric materials derived from the emulsifier is not a disadvantage, since these materials-stearic acid, for example-often are added intentionally as part of the curing system. However, vinyl polymers such as polystyrene, when contaminated with emulsifier, may suffer from lack of clarity, heat stability, and structural strength.
Vinylpyridine polymers a n d copolymers
. . .are
useful emulsifiers for acidic polymerizations of styrene, butadiene, acrylonitrile, and other monomers
. . . allow superior process control and high reaction rate while yielding a product free of emulsifiers and nonpolymeric contaminants Some attempts have been made to prepare vinyl polymers in special emulsion systems designed to reduce polymer contamination. For example, salts of styrene-maleic anhydride copolymers have been proposed as auxiliary emulsifiers in conjunction with conventional fatty acid soaps for styrene polymerization ( 1 1 ) . Other surface active polymeric materials which have been
864
INDUSTRIAL AND ENGINEERING CHEM'ISTRY Table I.
Vol. 41, No. 4
Preparation of Polymeric Emulsifiers
Alkaline Recipes, Parts by Weight Recipe No. 1 2 3 4 5 6 2-Methyl-5-vinylpyridin 100 ... 75 50 20 75 2-Vinylpyridine 100 ... ... Butadiene ... ... 25 ... ... ... Acrvlonitrile ... ... ... 50 ... . . . StyFene ... .. .. 25 Methyl acrylate ... ... ... 80 ' ... Sodium fatty acid soap 5 5 '5. 10 5 5 Daxad l l a ... ... 5 ... ... Water 180 180 180 300 180 180 Mixed tert-mercaDtans 0.3 0.3 0.3 ... 0.5 0.3 Potassium persulfate 0.3 0.3 0.3 0.9 0.3 0.3 Sodium bisulfite ... ... ... 0.5 ... . . . Acetic acid (glapial) ... ... ... ... ... ... Hydrogen chloride ... ... ... ... ,.. ... Time, hours 15 15 3.75 3.0 24 26 Temperature, C. 50 50 50 50 50 50 Conversion, % 90 90 80 56 100 76 Polymerized sodium salts of alkyl naphthalene sulfonic acid.
...
...
...
7 100
... ... ... ... ... ...
...
...
studied in aqueous solutions, although not in polymerization recipes, include the quaternary salts of polyvinylpyridines (1, 3, 4,8,10, 12,13) and certain silicone-containing polymers (9). A new approach to the problem of obtaining high-quality vinyl polymers from emulsion systems has become available as a result of the finding that polymers and copolymers derived from vinylpyridines,are useful emulsifiers for the polymerization of styrene, acrylonitrile, butadiene, methyl acrylate, and other monomers in acidic media. Latices or dispersions prepared in acidic systems emulsified with a polyvinylpyridine are characterized by high fluidity and general absence of prefloc. Coagulation of the latex with dilute base provides a product comprising an intimate mixture of polymers substantially free of emulsifiers or other nonpolymeric contaminants. Systems of this type have been found to offer the process control, high reaction rates, and other advantages inherent in emulsion polymerization plus the purity of product associated with mass or suspension polymerization. PREPARATION O F POLYMERIC EMULSIFIERS
Polyvinylpyridine emulsifiers may be prepared in alkaline systems with fatty-acid emulsifier or in acidic systems in the absence of preformed emulsifiers. Typical polymerization recipes for emulsifier preparation are presented in Table I. Polymerizations are conducted in crown-capped, glass bottles of 6- to 32ounce capacity. The water and soap or acid are charged first, followed by monomers and finally activator. I n general, those polymeric emulsifiers prepared in fatty acid emulsified recipes are precipitated from the latex by adding acid to break the soap emulsion, then adding base to precipitate the acid-soluble resin from solution. After further washing with base t o liberate residual soap, the resin is dried. The acidic recipes, which cont,ain no preformed emulsifier, offer important advaqtages over the alkaline systems, in that the need for separating the resin from the fatty acid emulsifier is eliminated. These resins may be precipitated by addition of base to the solutions or latices and redissolved in aqueous acid for use as emulsifiers. I n many instances it is desirable to prepare emulsifier solutions directly from the acidic latices as received from the polymerization vessel. This may be accomplished simply by diluting the latex with an appropriate amount of water. Ordinarily no additional acid is required for effective emulsifying activity, unless a p H adjustment is necessary for optimum performance of the new polymerization system. The polymerization of vinylpyridines in acidic media in the absence of preformed emulsifier has been said to require the use of acids having dissociation constants in excess of 1.49 X (6). This generalization, however, has been found to apply only to vinylpyridines having vinyl groupa in the 2- and 4positions (Table 11). When the vinyl group is in the 3- position, as in 3-vinylpyridine or 2-methyl-5-vinylpyridine (MVP),
Acidic Recipes Parts by W e i g h 1 8 9 100 50
300'
...
0.9 0.5 125 '2'
50 96
... ... ... ... ...
50'
300 '
600 '
...
...
0.9 0.5
...
26
* 5;
99
... ...
... ... ...
0 9 0.5
ii
'
2.5 50 91
acids of much lower dissociation constant such as acetic acid (1.75 X perform satisfactorily. POLYMERIZATION OF STYRENE
The polymerization of styrene in the presence of polymeric emulsifiers has been studed in systems containing either potassium persulfate and sodium bisulfite or hydrogen peroxide and triethylenetetramine as the activator pair. As indicated in Table 111,the polymerization rate of styrene a t 50' C. in the persulfatebisulfite recipe containing 0.9 part of potassium persulfate increases with increasing levels of bisulfite through the range of 0 to 0.52 part. However, a t the higher level of bisulfite, instability of the latex is encountered because of the high electrolyte level. Latices which are obtained a t bisulfite levels of 0.1 t o 0.4 part are opaque white fluids of relatively good stability. Some of these latices exhibit phase separation on standing for a period of days, but they appear to recover their original character when subjected to mild agitation. The quantity of polymeric emulsifier which is used in the preparation of polystyrene latices has a, pronounced effect upon
Table 11. Effect of Vinyl Group Position on Polymerization of Vinylpyridines i n Presence of Weak Acids Recipe (part? by weight). Monomer, 100; water, 300; potassium persulfate, 0.9; sodium bisulfite, 0.5; acid, variable. Temperature, 50' C. Reactor, 6-ounce bottle.
4-Vinylpyridine 2-Vinyl-5-ethylpyridine 3-Vinylpyridine 2-Vinylpyridine
2-Methyl-5-vinylpyridine
Acid Mole ratio to monomer 2.0 2.0 2.0 2.0 2.0 2.0 HC1 2.0 Acetic 2.0 Propionic 2.0 Lactic 2.0 HCI 2.0 Type Acetic Acetic Acetic Acetic Propionio Lactic
Conversion a t 1.5 Hours,
% 11 0 76 12 13 19
100 98
98 100
100
Table 111. Effect of Sodium Bisulfite on Styrene Polymerization with Poly-2-vinylpyridinium Sulfate as Emulsifier Recipe (parts by weight). Styrene, 100; water, 180; potassium persulfate 0.9. mixed tert-mercaptans 0.3. sodium bisulfite, variable; poly-2vinylpyridine, 5 0; sulfuric acid,' 1.16: Temperature, 50° C. Reactor, 6ounce bottle. Mole NaHSOs, Ratio Part HSOa-/SzOa-0 0.17 0.35 0.52
-
0.5
1.0
2.0
Conversion, 7" 16 hr. 24 hr. 22 29 58 93 64 100 78 100
Latex Condition Fluid Fluid Fluid 25% prefloc
April 1955 Table IV.
Effect of Emulsifier Level on Styrene Polymerization
Recipe (parts b y weight). Styrene, 100; water, 180; potassium persulfate, 0.9; mixed ter&mercaptans, 0 3; sodium bisulfite, 0.5; poly-2vinylpyridine, 5 0 ; sulfuric acid, 1 16. Temperature, 50°C. Reactor, 6ounce bottle. Emulsifier, Conversion, Latex Parts 16 Hours, 7 '0 Condition
0 1.0 2.5 5.0
2 20 35 97
VI). Tensile strength, elongation, and Izod impact strength values on the particular sample evaluated are not equal to the maximum values reported for the various commercial polystyrenes, but are above the minimum levels' In the important property of heat distortion temperature, the emulsion polystyrene is given a value of 215' F., which is 15" to 30' above that indicated for moRt commercial polystyrenes.
....
Paste Viscous liquid Fluid liquid
Table V. Acid-side Copolymerization of Styrene and 2-Methyl-5-vinylpyridine Recipe (parts by weight). Monomer, 100; 2-methyl-5-vinylpyridine variable; poly(2-methyl-5-vinyI~yridine)~ variable; water, 180; acetic acid, variable; potassium persulfate, 0.9; sodium bisulfite, 0.2. Temperature, 50° C. Time, 23 hours. Reactor, 6-ounce bottle. Poly(-22-Methvl-5methyl-5Acetic vinyivinylAcid Styrene, pyridine, pyridine), (Glacial), Conversion, Parts Parts Parts Parts %
Table VI.
865
INDUSTRIAL AND ENGINEERING CREMISTRY
Physical Properties of Polystyrene Prepared
with Poly(-%-methy1-5-vinylpyridine) Emulsifier
Emulsion Recipe (parts by weight). Styrene, 100; water, 200; poly(2 methy1-5-vinylpyridine), 5.0; acetic acid (glacial), 6 25; H ~ 0 2(30%). 2.1. triethylenetetramine, 0 15. Time, 25 hours. Temperature, 50' C. Con: version, 977". Reactor, 6-ounce bottle Emulsion PolyCommerciala Physical Property styrene Polystyrenes Inherent viscosity 2.9 1.lh Tensilestrength, lb./sq. inch 6900 5000-9000 Elongation, % 2.0 1-3.6 Impact strength, Izod 0.4 0 25-0 50 Heat distortion. Temperature, ' F. 215 160-2 10 a Data from Xlodern Plastics Encyclopedia, except inherent viscosity value b Value determined on Koppers "general purpose" polystyrene.
the polymerization rate as well as the fluidity of the latex (Table IV). I n the absence of emulsifier, little if any polymer is obtained, but as little as 1.0 part of emulsifier gives a fairly stable paste product with rezction rates in the range of 1% per hour or more. As the polymeric emulsifier level is increased to 5.0 parts, the reaction rate increases t o an average of 6% per hour a t quantitative conversion and the fluidity of the latex improves markedly. Emulsion copolymerization of styrene and 2-methyl-5-vinylpyridine may be accomplished in acidic recipes in the absence of preformed emulsifier, providing 2-methyl-5-vinylpyridine levels of 10 parts or more per hundred of monomer are used (Table V). A t lower levels of 2-methyl-5-vinylpyridine it is advantageous to use small amounts of poly(2-methyl-5-vinylpyridine) emulsifier to provide high reaction rates and stable latices. Polymerization systems containing hydrogen peroxide and triethylenetetramine as the activator pair also are useful for the polymerization of styrene in acidic media. With the recipe indicated in Table VI it has been possible to prepare smooth, opaque white latices of high fluidity and excellent stability. These latices are not coagulated either by freezing or by heating to the boiling point. When the latex is coagulated with ammonium hydroxide and washed with water, it is possible to obtain a product essentially free of electrolytes or other nonpolymeric contaminants. Further purification is believed to result from volatilization of residual ammonium acetate on drying. Physical tests on polystyrene prepared with poly( 2-methyl-5vinylpyridine) emulsifier reveal that the molecular weight, in so far as it can be determined by inherent viscosity measurements, is relatively high compared to general-purpose polystyrene (Table
POLYMERIZATION OF ACRYLONITRILE
Stable, fluid polyacrylonitrile latices usually are not obtainable from conventional emulsion polymerization systems ( 2 ) . Corn-. mon emulsifiers such as fatty acid soaps, alkyl aryl sulfonates, alkyl sulfates, and nonionic emulsifiers in moderate amounts have been found to give low rates of reaction and complete preflocculation of polymer. One investigator (6) has proposed the use of fatty acid soaps a t levels of 10 to 60 parts per hundred of monomer in conjunction with 10 to 50 parts of an organic halide as an emulsifying system for acrylonitrile. Another proposed emulsion system (7) requires the use of 1 part of emulsifier and 1800 parts of water for the preparation of polyacrylonitrile latex. The use of polyvinylpyridines as emulsifiers for the polymerization of acrylonitrile in acidic media eliminates many of the difficulties inherent in other emulsifier systems. I n general, the use of polymeric emulsifiers permite a reduction in water level t o 300 parts or less, while fluidity and stability of the polymer dispersion or latex are retained. Furthermore, reaction rates are high and prefloc formation may be completely eliminated. Variations in the level of polymeric emulsifiers in the range of 0.5 t o 5.0 parts have no appreciable effect on the polymerization rate of acrylonitrile in the persulfate-bisulfite acidic system (Table VII). However, about 2.0 to 5.0 parts of emulsifier is required to obtain fluid polymer dispersions of reasonable stability. At the higher level of emulsifier it is possible to obtain opaque white latices which show no evidence of phase separation after several weeks of shelf storage. The copolymerization of acrylonitrile and 2-methyl-5-vinylpyridine may be conducted satisfactorily in acidic systems which
Table VII.
Effect of Emulsifier Level on Acidic Polymerization Acrylonitrile
Recipe (parts, by weight) Acrylonitrile, 100: water, 300; potassium persulfate, 0 9 ; sodium bisulfite, 0 52; emulsifier, variable. Temperature, 50' C. Reactor, 6-ounce bottle. EmulsiConverfier, HCI, sion, Condition Hours, Yo of Latex Parts Parts Poly(2-vinylpyridine) 0.5 0 5 71 Wet crumb 1.0 0 29 63 Grainy 0 58 93 Paste 2.0 5.0 1 45 88 Fluid Poly (2-methyl-5vinylpyridine) 0.5 0 3 100 Wet crumb 1.0 0 26 74 Grainy 2.0 0 52 95 Slightly grainy 5.0 1.29 93 Smooth paste Santomerse 1 (sodium 5 Prefloc alkyl aryl sulfonate) 5.0
Table VIII. Acidic Copolymerization of Acrylonitrile and 2-Methyl-5-vinylpyridine in Absence of Preformed Emulsifiers Monomers Charged Acrylonitrile MVP 25 75 50 50 75 25 90 10 90 10 90 10 95 95 100 100
0 0
HCI. Parts 22.5 15 7.5 7.5 3.8 1.9 7.5
0.95 7.5 0
Conversion at 1.5 hr. 2.5 hr. 60 63 85 67 48 61 9 35 41 42 52 52
.. .. .. ..
, . , .
..
..
Condition of Latex Clear solution Fluid, white latex Fluid, white latex Some prefloc Some prefloc Fluid, white latex Totally prefloc Totally prefloc Totally prefloc Totally preAoc
866
I N D U S T R r A L A N D E N G I N E E R I N G CHEMISTRY
contain no preformed emulsifier, providing about 10% or more of the monomer charged is 2-methyl-5-vinylpyridine (Table VIII). When 2-methyl-5-vinylpyridine levels are reduced to 5% or below, the product is obtained only as prefloc. Since 5 parts of poly(2-methyl-5-vinylpyridine) in acrylonitrile polymerizations yield stable latices, it is apparent that the polymer is more effective than the monomer as an emulsifier. Copolymers as well as homopolymers of 2-methyl-5-vinylpyridine are useful emulsifiers €or acrylonitrile polymerization (Table IX). The use of copolymeric emulsifiers derived in part from acrylonitrile permits a reduction in the amount of poly(2-methyl-5-vinylpyridine) equivalent which is retained by the acrylonitrile polymer. For example, a system emulsified with 5 parts of 50/60 acrylonitrile-2-methyl-5-vinylpyridinecopolymer provides a totally polymeric product containing 97.5% material derived from acrylonitrile. I n other instances the use of copolymeric emulsifiers of lower 2-methyl-5-vinylpyridine content has led to the production of emulsion polymers containing less than 1 % poly(2-methyld-vinylpyridine) equivalent as the single constituent not directly derived from the desired monomer.
Table IX.
Acidic Polymerization of Acrylonitrile with Copolymeric Emulsifiers
Recipe (parts by weight). Acrylonitrile, 100; water, 600; emulsifier, 5; hydrochloric acid, variable: potassium persulfate, 0.9; sodium bisulfite, 0.5. Reaction time, 2 hours. Temperature, 50° C. Reactor, 6-ounce bottle. ConverHCl, sion, Parts yo Condition of Latex Emulsifier 25/75 Bd/MVP 4 100 Fluid, some phase separation 50/50 acrylonitrile/MVP 2 100 Fluid, stable latex Acidio latex (23 parts latex Za 100 Fluid, stable latex containing 5 parts polymer) SO/ZO methyl acrylrtte/MVP 2 100 Fluid, stable latex Acid contained in emulsifier latex, no other acid added.
As indicated in Table VIII, it is possible to use acidic latices directly as emulsifiers without isolation of the polymeric emulsifier. When this is to be done, it is convenient to prepare the emulsifier, such as the 50/50 acrylonitrile-2-methyl-5-vinylpyridine copolymer, in the polymerization vessel which is to be used for the subsequent polymerization of acrylonitrile. Upon completion of the copolymerization reaction, the required amounts of water, acrylonitrile, and catalyst are added and the homopolymerization proceeds. POLYMERIZATION O F BUTADIENE, VINYL CHLORIDE, OTHER MONOMERS
AND
Although polyvinylpyridine emulsifiers appear to be particularly useful for the polymerization of styrene and acrylonitrile, they are potentially valuable for polymerization of other vinyl or diene monomers as well. The copolymerization of butadiene
Vol. 47, No. 4
and acrylonitrile, for example, proceeds at a rate of perhaps 5 % per hour when butadiene is a minor component of the monomer charge (Table X). This is below the rate experienced in the homopolymerization of acrylonitrile and further decreases in rate to 3 or 4aj, per hour are noted when butadiene is charged as the major monomer component. Polymerizations of vinyl chloride or copolymerizations of vinyl chloride with other monomers may be accomphhed with polymeric emulsifiers. Ordinarily these products are obtained either as smooth pastes or as fine dispersions. Emulsion polymerieatioq of methyl acrylate in the presence of polymeric emulsifiers leads to the formation of stable, fluid latices. In this instance, quantitative conversions are obtained within a 1-hour reaction time a t 50" C. Copolymers such as the 80/20 methyl acrylate-2-methyl-5-vinylpyridine copolymer as well as 2-methyl-5-vinylpyridine homopolymers are effective emulsifiers. Khen the copolymer is used, the latex is coagulated as usual by addition of base. The product obtained is a totally polymeric granular material, more than 99% of which is derived from methyl acrylate. The polymerization of vinyl acetate in the presence of polyvinylpyridines may take the form of solution polymerization or emulsion polymerization, depending upon the conditions used. A t high levels of water or acid with homopolymers of a vinylpyridine as the emulsifier, clear solutions of polymer are obtained. The use of water levels in the range of 200 parts or less, the reduction of acid levels below that required for neutralization of the polyvinylpyridine, or the use of butadiene-vinylpyridine copolymers as emulsifiers are factors which lead to emulsion rather than solution-type products Regardless of the type of system used, reaction rates are relatively high and quantitative conversions with persulfate-bisulfite catalyst are obtained within 1 to 5 hours a t 50" C. LITERATURE CITED
Aggarwal, S.L., and Long, F. A., J . Polymer Sci., 11, 127 (1953). Fikentscher, H., and Heuck, C. (to I. G. Farbenindustrie A.-G.), Ger. Patent 654,989 (Jan. 6, 1938). Fuoss, R. M., and Gathers, G. I., J . Polymer Sci., 4, 97 (1949). Fuoss, R. -M., and Strauss, U. P., Ibid.,3, 246 (1948). Harmon, Jesse (to E. I. du Pont de Nemours & Co.), U. S. Patent 2,491,472 (Dec. 20, 1949). Harrison, S. A. (to B. F. Goodrich Co.), Ibid., 2,471,742 (May 31, 1949).
(to E. I. du Pont de Kemours & Co.), Ibid.,2,471,959 Hunt, AM. (May 31, 1949). Jackson, E. G., and Strauss, U. P., J . Polymer Sci., 7 , 4 7 3 (1951). Klein, D. X. (to E. I. du Pont de Nemours & Co.), U. S. Patent 2,476,308 (July 19, 1949). Layton, L. H., and Jackson, E. G., J . Polymer Sci.,9 , 2 9 6 (1952). Norris, F. H. (to Monsanto Chemical Co.), U. S. Patent 2,548,318 (April 10, 1951).
Strauss, U. P., Assony, S.J., Jackson, E. G., and Layton, L. H., J . Polymer Sei.,9, 509 (1952). Strauss, U. P., and Jackson, E. G., Ibid., 6 ,649 (1951). RECEIVED for review September 20, 1954.
ACCEPTED December 2, 1954.
Table X. Polymerization of Butadiene and Vinyl Monomers with Polymeric Emulsifiers Recipe (parts by weight). Mpnomers, 1 0 0 ; emulsifier, 5 . 0 : water, variable: acid, variable: potassium persulfate, 0.9; sodium bisulfite, 0.5. Temperature, variable. Reactor, 6-ounce bottle. CqnverWater, Acid, Temp., SlOn Monomers Charged, Parts Emulsifier Parts Parts C. % Hours 30/70 butadiene-acrylonitrile Poly(-Z-vinylpyridine) 180 I.4'acetic 50 88 18 70/30 butadiene-acrylonitrile Poly(-2-vinylpyridine) 180 1 . 4 acetic 50 67 18 100 vinyl chloride Poly(-2-methyl-5-vinylpyridine) 300 1 . 3 HCl 40 74 3.6 100 vinyl chloride 5 0 / 5 0 acrylonitrile-2-methyl-5300 1 , 3 HC1 40 88 2.8 vinylpyridine 50/50 vinyl chloride-acrylonitrile Poly (2-vinylpyridine) 300 1 . 5 HCI 50 86 18 100 methyl acrylate 80/20 methyl acrylate-2-methyl- 600 0 . 7 5 HC1 50 100 1 100 vinyl acetate 100 vinyl acetate
5-vin ylpyridine
Poly(2-methyl-5-vin Ipyridine) 200 25/75 styrene-2-met~yl-5-vinyl- 600 pyridine
5 . 0 acetic 6 . 0 acetic
\
50
50
100 100
5 1
