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
1482
T~&,.: \rTII, Cation
sCRriTCH R~~~~~~~~~ OF
METHACRYLIC Acrn COPOLYMER
Weight Increase,
G.
...
700 SO00 700 800 500 900 700 700 900
58
Zn++ s i++
21 51
E"+++
c",".'; Mg++ 41+++ Ba++ KH4 + Fe Cd
;='
_P h_ + +
TI'++ A@;Co++ Hg++ Cu(NHa)r++
cot
+
Sn++
+
Shear Hardness,
Mg.
None Cr+++
K+
sAtTs OF 8 5 : 15
L~ETAL
32 2s
27 28 21 20 34 38 25
900
700 900 700 900 ,?00
44
36
40
-0
56
35 68 39
a Highest ralue for 7.0, and 7.5.
.?nn ___
1000 600 700 700 900 900 700 series of six samples; other
4
45 27
Mar Resistance 4.5 1..i 1.6
1.6 1.8 1.8 1.8 21.9 .2 2.5 2.5 2.5
2.8 2.8 3.1 3 1 4 0
4 0 4 5 4 5
5 0 8 0
so
oa
Total Transmission,
7c
92 90 91 90
90
92
87 9s 91
90 91 91 89 89 90 $47
91 24 89
87
I5
89 91
values were 5.0, .5.5, 6.0.
Vol. 41, No. 7
inold consisted of two sheets of plate glass separated by edge spaces'0.125 inch thick and having the same composition as the expected product. The edges were sealed x i t h bond paper using an aqueous solution of polyvinyl alcohol as the adhesive. S U R F A C E R E A C T I O N WITH bIEIETAL SALTS. Cast sheets cut into 1.75-inch squares mere immersed in 10% aqueous methanol solution containing 10 grams of potassium hydroxide in 90 grams of solvent in absence of agitation for a t least 100 minutes a t 2.5" C. The treated sheets were immersed in 10% aqueous methanol for 30 minutes a t 25" C. to remove excess alkali, then in a 10% aqueous methanol solution containing 5 grams of metal salt,and 1 gram of concentrated hydrochloric acid in 95 grams of solvent, and finally immersed again in 10% aqueous methanol solution and dried for 72 hours a t 50" C. or until there was no further loss in Keight. The sodium and ammonium salts were formed dirwtlv from the copolymers. ACKNOWLEDGBIEKT
This investigation constitutes one phase of a joint effort of the Industrial Research Institute of the University of Chattanooga and the Office of Kava1 Research undei Contract NBori-229. The assistance of J. H. Coulliette in the construction of the testing inStI'UmentS iS greatly appYeciated. BIRLIOGK 4PHY
itors and most salts have limited solubility in methyl methacrylate, i t seems improbable that clear, hard sheets could be prepared by the copolymerization of salts of the unsaturated acids with methyl methacrylate. The techniques described are not coniplicated and unlike many of the coating procedures do not require heating between platens.
(1) Am. SOC.Testing Materials, Standards, d l l B , 209. 11673 -44 (1946). (2) Barnes, C . E., U. S. Patent 2,259,513 ( O r t 21, 1941) (3) I b i d , 2,369,520 (Feb 13, 1945). (4) I b i d . , 2,397,231 (Mar. 26, 1946). (5) Ibid , 2,404,268 (July 16, 1946). (6) Bcchtold. M. F.. U. S. Patent 2.404.357 iJulv 23. 1946). ( 7 ) Bechtold, M. F., and Pinkiie>-, P. S., U. S. Patent 2,404,426 i.TuIv 23. 1946'i. ~< (8) Boor, Id.,Ryan, J. D., Marks, M. E., and Bartoe, W ,F., Am,. SOC.Testing X a t e r i a l s , Bull. (March 1947). (9) Fikenscher, H., and Hogan, G . , French Patent 841,299 (May 15, 1939) ; German Patent 695,097 (July 1 8 , 1940). (10) Groves, W. W., Brit. Patent,s 420,533, 420,589 (1934). (11) Hall, F. W., U. S. Patent 2,381,495 (Aug. 7 , 1945). (12) Hubbuch. L. P., U. S. Patent 2,244,702 (June 10, 1941). (13) Longkamnieier, C. >I., U. 8 . Patent 2,283,128 (Aug. 19, 1941). and Gerlaoh, C., J . Chem. SOC.,90 [ l ]6 1 (1906). (14) Lossen, W., (15) Mitchell, J . A . , L'. S. Patent 2,292,393 (Aug. 11, 1942). (16) K'orton Grinding Wheel Co., Ltd., Brit. Patent 531,956 (Jan. 15, 1941). (17) Pollach, M. A., St,raiii,F., and Muskat, I. E., U. S, Patent 2,320,536 (June 1, 1943). (18) ltatchford, V i'. P., Reliberg, C. E . , and Fisher, C. Ihanthe unreacted copolymer. Sodium carbonate was used as catalyst for this esterification since its effectiveness, as measured by the increase in weight of cast sheets of copolymer when immersed in ethylene glycol, was four, five, and seven times greater than pyridine, hydrochloric acid, and zinc chloride, respectively. Half esters of most liquid alcohols were formed on the surface when the 85: 15 copolymer was immersed in these liquids for 16 hours a t 70' C. in presence of 0.5% sodium carbonate. However, all products were softer than the unreacted copolymer and many of the alcohols dissolved the plastic and marred the surface. The solvent effect was diminished by immersing the cast sheets in a 5y0 solution of alcohols in heptane in presence of 10% so-
mersed in a 5% solution of this amine in methanol for 40 minutes a t 25" C. Aniline, 0- and p-chloroaniline, p-bromoaniline, 0- and p aminophenol, 2-amino-4-nitropheno1, p-amino-dimethylaniline, sulfanilic acid, p-aminobenzoic acid, p-aminobenzene sulfonamide, p-aminobenzophenone, p-aminobiphenyl, 2-amino-p-cymene, 1-aminoanthraquinone, a-naphthylamine, 2,4-diaminodiphenyl-
TABLEI V . , SCRATCH RESISTANCES OF REACTION PRODUCTS OF AMINEBAND 8 5 : 15 COPOLYMER
Amine
Wt. Shear In- Hardcrease, ness, Mg. G. . 400 8 600 0 500 GOO 2 48 700 3 700 ~ ~ G ~ 400 o ~ 0 700
2genylenediarnine Ethylenediamine m-Phenylenediamine Triethylenetetramine
' ' ~ ~ ~ ~ ~ Tetraethylenepentamine l-Amino-S-naphth01-3,6-disulfonic acida
g&&zlznediaminea Quinolinea
30 16 9
41
600
600 800 800
Total Mar Trans-
Re-
sistance 0.9 1.2 1.2 1.3
mis-
sion,
%
74 G6
. 64 .
1.4 , . 1.4 n e 1.6 79
2.0
.,
1.2 1.3
71 75
1 . 3 ' 64 1.3 64
Appearance ,.....
Crazed Cnchanged Unchanged Unchanged Unchanged Grey Unchanged Crazed Yellow Cnchanged Grey
Tetraethanol hydroxiden ammonium 19 900 1.5 79 Unchanged a Copolymer sheets were ini:nersed in solutions containing 5 grams of amine in 95 grams of SOYo aqueous methanol for 18 hours a t 2 5 O C . ; the reactionproduoed amine salts rather tilan half amides.
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
1484
TABLE V.
SCRATCH RESISTANCE OF METAL SALTSOF 85:15 COPOLYMER TTt. Increase,
Cation h-one H+ NH4 -
Mg.
A!x
1 no
TiTT+ +
CU+'
En+++
Mg + + Mn++ Ca++
Cd;++ Ni Ra+++ Sn-
. . I
0
- 13
14 34
7
8 8 6 2
AI++-
12
Cr'++
-8 25 6
+ + + -::
Co++
Ci$KHz)r++ SI
UOn
+
Mar Resistance 1.0
600 600
1 1 1.2 1.2 1.2 1.2 1 2
600 1100 000 goo
413 9
3 3
Shear Hardness, G. 600 600
-
700
son
700
600
inn 700 600
ionn
9
1100 800 goo 700 1000
-5 27
700
7
inon
1.2
1 0 1 0
1.3
1.3 1.5 1.6
16
1.8 1.8 1.0 2.0 2.6 3.1 3 .7 4.0
Transmission,
%
74 82 82 69
64.6 62.5
78.7 78.7 84.5 69.5 23.0 ra.3 75.0 69.6 78.6 71.0 69.6 81.0 73.0 78.0 43.2 r3.n 81.6
amine, dibutylamine and stearylamine reacted with the 8 5 : 15 copolymer to give products having values for mar resistance that were not superior to polymethyl methacrylate. However, reaction products of the copolymer and aromatic amines gave good values for shear hardness. The relative effects of other amines on surface hardening of the 85:15 copolymer are summarized in Table IV. REACTION OF 85:13 COPOLYMER WITH METAL SALTS
Copolymers of methyl methacrylate and maleic anhydride can be hydrolyzed with aqueous alkali and the resulting sodium or potassium salts can be replaced by other metals. The sodium, ammonium, and potassium salts of the 85: 15 copolymer were soluble in methanol, slightly soluble in water, and insoluble in acetone. As the ratio of maleic anhydride t o methyl methacrylate was increased, these salts became more readily soluble in water. Heat resistant precipitates which were insoluble in water, methanol, ethylene dichloride, and ethyl acetate, swollen in benzene, and soluble in glacial acetic acid (mercury and uranyl salts excepted) were formed in good yield when aqueous solutions of metal salts were added t o solutions of the sodium, ammonium, or potassium salts of the 85: 15 copolymer. All precipitates mere colorless except copper ammonia, blue; chromium, copper, and nickel, light green; iron, buff; and uranyl, light yellow. The silver salt darkened on exposure to light and the uranyl salt fluoresced when exposed t o ultraviolet light. The optimum conditions for the reaction of metal salts with the surface of the methyl methacrylate-maleic anhydride copolymer were developed by determining the weight change of cast sheets of the 85: 15 copolymer after they m-ere immersed in solutions of potassium hydroxide in aqueous methanol under varying conditions of roncentration, solvent composition, time, and temperature. These conditions-24 hours immersion at 25" C. in a solution of 10 grams of potassium hydroxide in 90 grams of 80% aqueous methanol followed by washing, immersing in a solution of cupric chloride in aqueous methanol, washing, and dryingwere used t o determine the most suitable composition of copolymer for intpnsive study, Copolymers prepared from monomcr compositions having less than 80% methyl methacrylate contained sufficient residual maleic anhydride to cause crazing and embrittlement of the surface. Good results were obtained with the 8 5 : 15 copolymer, and this was used for a n intensivc investigation of thc effect of salts of various metals (Table Y). The completely hydrolyzed 85 : 15 methyl methacrylate-maleic anhydride copolymer should have had more surface carboxyl groups available for reaction with metal salts than the 85: 15 acrylic acid copolymer and yet the scratch resistance of metal
Vol. 41. No. 7
salts reported in Table V were inferior t o those reported for the metal salts of the copolymers of acrylic acid (4). This anomaly might be explained by incomplete hydrolysis or partial esterification of the anhydride groups, since residual anhydride or methyl ester groups on the surface would exert a softening effect. EXPERIMENTAL
Methyl methacrylate n-as purchased from E. I. du Pont de Nemours & Company, Inc. ; methacrylonitrile, Rohm & Haas Company; stearyl amine: Armeen HTD, Armour and Company; methacrylic acid, E. I. du Pont de Kemours & Company, h e . ; and triethylenetetramine, and tetraethylenepentamine, Carbide & Carbon Chemicals Corporation; all other organic chemicals were purchased from Eastman Kodak Company. POLYMERIZATION CONDITIONS.Maleic anhydride and methyl methacrylate were heated a t 40" C. for 4 hours in the absence of air and in the presence of 0.570 benzoyl peroxide. The sirup was poured into glass molds using 0.125-inch thick strips of copolymer for spacers and bond paper adhered with polyvinyl alcohol for closures. Polymerization was completed by heating for 24 hours a t 40 O C. and 48 hours at 70" C. ESTERIFICSTION REACTION.Weighed pieces of the cast maleic anhydride copolymer were immersed in 16 ml. of liquid alcohol containing 0.1 gram of sodium carbonate in 4-ounce screw capped bottles. The caps were screwed on and the bott'les were heated 16 hours a t 70" C., the plastic pieces were removed, immersed in methanol for 45 hours at room temperature, dried, and reweighed. Weighed pieces viere also immersed in solutions containing 0.1 gram of sodium carbonate and 1 gram of alcohol in 20 ml. of heptane in 4-ounce bottles heated for 6 hours a t 70" C. The reacted pieces were rinsed with heptane, dried, and weighed. REACTIOX WITH AMINES. Cast sheets of copolymer 1 X 0.5 X 0.125 inch were immersed in solutions containing 5 grams of aniine in 95 grams of 50% aqueous methanol for 18 hours a t 25 ,, C. or in solutions containing 5 grams of amine in anhydrous methanol for 40 minutes a t 25" C. Amine salts were obtained when water was present and half amides when anhydrous conditions werc used. REACTIOX WITH METALSALTS. Cast, sheets of copolymer 1 X 0.5 X 0.125 inch were immersed for 24 hours a t room temperature in a solution containing 10 grams of potassium hydroxide in 90 grams of 80% aqueous met'hanol. The treated samples were immersed for 5 minutes in 10% aqueous methanol, then immersed for 30 minutes in a solution containing 5 grams of metallic cliloride and 1 gram of concentrated hydrochloric acid in 95 grams of 10% aqueous methanol and finally washed for 5 minutes in 10%; aqueous methanol and dried 12 hours a t 60 O C. ACKNOWLEDGMENT
This investigation constitutes one phase of a joint effort of the Industrial Research Institute of the University of Chattanooga and the Office of Naval Research under Contract N6ori-229. The assistance of D r . J. H. Coulliette in the construction of the testing instruments is greatly appreciated. LITERATURE
crrm
(1) Atmood, F. C., U. 8. Patent 2,418,688 (April 8 , 1947). (2) Carbide & C a r b o n Chemicals C o r p . , Brit. P a t e n t 542,874 ( J a n . 30, 1942). (3) I. G. Farbenindust,rie, French P a t e n t 763,027 (April 23, 1934). (4) Seymour, R.B., a n d B r a n u m , I., ISD.EXG.CHEW,41, 1479 (1949). ( 5 ) Stoops, W. N., and Denison, W. A., U. S. P a t e n t 2,324,739 (July 20, 1943). (6) Stoops, W.N., a n d Staff, C. E., U. 9. P a t e n t 2,375,960 (Mar. 1, 1944). (7) VOSS, A., a n d Dickhauser, E., U. S. P a t e n t 2,047,398 (July 14, 1936).
RECEIVED April 6 , 1948. Presented before the Division of Paint. Varnish, and Plastics Chemistry a t the 113th Meeting of the AAIERICAN CHEIITCAL SOCIETY, Chicago, Ill.
