4310
GENESUMRELL, P. G . CAMPBELL, G . E.
bar which had an ASTM heat distortion of 110'. By comparison, a bar of poly-(methyl methacrylate), molded from polymer with an intrinsic viscosity of 0.72 and S.P. 144O, had an ASTM heat distortion of 102". Isopropyl Thiolmethacrylate Homopolymer.-A sample of 59 g. of isopropyl thiolmethacrylate was heated a t 80" for 11 days without a catalyst, giving a transparent waxy solid. Gelation had occurred in 3 days. The material exhibited swelling in a variety of organic solvents, including chloroform, carbon tetrachloride, benzene, acetone, dimethylformamide and dimethyl sulfoxide. However, the major part of it did not dissolve. The entire mass (after evaporation of solvent) was treated with methanol, giving 37.5 g. (63%) of white solid which had S.P. 127'. T h e unpleasant odor of the monomer was not completely removed. Another sample of 15 g. of this monomer was heated a t 60" without a catalyst for 72 hours, giving a clear soft gel. This material also displayed swelling in chloroform, giving a jelly-like mass when allowed t o stand with 900 ml. of the solvent. T h e polymer was distributed throughout the 900 ml. of chloroform, giving a gel which was too thick for pouring. A third sample (15 g.) of this monomer was heated a t 60' for 12 hours without a catalyst. The still fluid material was dissolved in 50 ml. of chloroform and poured with stirring into 250 ml. of methanol, giving 3 g. (20%) of white powdery material which had an intrinsic viscosity of 0.54 and S.P. 140'. This precipitated polymer was free of the odor of the monomer. &Butyl Thiolmethacrylate Polymers.-A sample of 62 g. of t-butyl thiolmethacrylate was heated at 60' for 4 days with 0.1 7, of azodiisobutyronitrile. Gelation occurred in 12 hours. T h e material dissolved readily in 1200 ml. of chloroform. Precipitation from 6000 ml. of methanol gave 41 g. (667,) of white, odorless powder. Thisomaterial had an intrinsic viscosity of 0.24 and S.P. 193 . Compression molding gave a clear brittle specimen which did not exhibit surface flow when heated in steam a t 121'. This monomer copolymerized readily with methyl methacrylate giving clear copolymers up to about 40 weight per cent. of the thiol ester. Larger amounts of thiol ester gave hazy and increasingly brittle materials. On one run, a mixture of 5 g. of t-butyl thiolmethacrylate and 45 g. of methyl methacrylate was heated a t 60' for 5 days without a catalyst. Precipitation gave 36.7 g. (73%) of copolymer which had a n intrinsic viscosity of 1.63 and S.P. 154'. Compression molding gave a clear tough bar which had an ASTM heat distortion of 112°.8 (8) T h i s material analyzed for 2.16% sulfur, indicating t h e incorporation of 10.7% of t h e thiol ester in t h e copolymer.
[CONTRIBUTION FROM
THE
H A M AND
c. H. SCHRAJIM
Vol. 81
Pentachlorophenyl Thiolmethacrylate Homopolymer.-A sample of 10 g. of pentachlorophenyl thiolmethacrylate was heated a t 105" for 48 hours with 0.5% of azodiisobutyronitrile, giving a yellow transparent solid which was quite brittle. This material was treated with 800 ml. or chloroform for several days, with no swelling and little solution occurring. Filtration gave back 6.5 g. of undissolved polymer which did not soften a t 250', the upper limit of our apparatus. An attempt t o dissolve 0.1 g. in 100 ml. of chloroform failed. Compression molding gave a clear brittle specimen which did not show surface flow when heated in steam a t 121'. Cross-linking of Poly-(methyl Methacrylate) Using Methvl 2-Methvl-3-thiomethoxvthiolpropionate.--Several runs were carried- out in which methyl methacrylate was heated with a catalyst under varying conditions with l - l O % by weight of the methyl mercaptan addition product of methyl thiolmethacrylate, yielding insoluble polymers. When such experiments were carried out without a catalyst, the addition product proved t o be an effective inhibitor t o polymerization. The following run is illustrative of such runs: A mixture of 20 g. of methyl methacrylate, 0.2 g. of the addition product and 0.02 g. of azodiisobutyronitrile was heated for 24 hours a t 50'. The resulting solid was allowed t o stand with 700 ml. of chloroform for several days. I t soon swelled to several times its original size, giving a soft gel which did not further change. T h e supernatant chloroform was decanted and the gel stirred in a blender with methanol. The precipitated white solid was further washed with methanol and dried. It amounted to 14 g. (70%) and had S.P. 153'. An attempt to dissolve 0.1 g. in 100 ml. of chloroform gave swelling of the individual particles, but solution did not occur. In another similar experiment, carried out a t the same time under identical conditions, the amount of addition product was reduced t o 0.07 g. This polymer was readily soluble in 400 ml. of chloroform. Precipitation in methanol gave 17 g. (85%) of polyme: which had an intrinsic visA control, in which the cosity of 2.08 and S.P. 152 addition product was omitted, gave 18 g. (90%) of .poly(methyl methacrylate) which had an intrinsic viscosity of 3.70 and S.P. 144'. Thus, a t the lower concentration, the mercaptan addition product acted a s a chain transfer agent, reducing the molecular weight of the polymer, but did not cross-link it.
.
Acknowledgments.-The authors wish to thank C. F. Hartman for technical assistance in this work, and Alfred Foulds for the sulfur analyses. PHILLIPSBURG, N. J.
RESEARCH LABORATORIES OF J. T. BAKERCHEMICAL Co.]
Preparation and Polymerization of Some New Aryl Methacrylates1 BY GENES U M R E L L PAUL , ~ G. CAMPBELL, GEORGEE. HAMAND CII.\RLESH. SCHRAMJI RECEIVED JANUARY 10, 1959
A number of new halogenated phenyl methacrylates have been prepared and polymerized. The relaticinship of softening points of the polymers t o structure of the monomers is discussed. Difficulties experienced in the preparation of the 2,D-disubstituted phenyl esters is discussed, and a method of preparation is described. This method involves a modified SchottenBaumann reaction in which methanolic sodium hydroxide is used instead of the aqueous reagent.
Although aliphatic esters of methacrylic acid have been extensively investigated, relatively few aryl methacrylates have been reported in the literature. We are aware of only two halogenated phenyl methacrylates having been previously prepared, ;.e., 4-chlorophenyl and 2,4-dichlorophenyl methacrylate. The possibility that halogenated ( 1 ) T h e antibacterial and antifungal properties of some of t h e mmpounds described in this paper are being reported elsewhere ( 2 ) T o whom inquiries for reprints should be sent. Southwest Research Institute, 8500 Culebra Rd., S a n Antonio F, Tex. (3) S. Patai, R I . Bentov and M. E. Keichmann, Tms J O I J R N A L , 74, 845 (1952).
phenyl methacrylates could be used in the preparation of flame resistant polymers prompted us to prepare a series of chlorinated and brominated phenyl methacrylates. Some of the properties of homopolymers of these materials are presented here. We found that even the monomers containing one or more bromines were quite resistant to burning. At least three chlorines were necessary in the aryl methacrylates and their homopolymers to give marked resistance to burning. The halogenated phenyl methacrylates all gave clear transparent polymers when heated alone or in the pres-
4311
POLYMERIZATION OF NEWARYLMETHACRYLATES
Aug. 20, 1959
TABLE I ARYLMETHACRYLATE ESTERS,CHa=C( CHa)COOR Yield,
h.1.p. or b.p., O C .
96-98 64-66 85-86 122-124 55-56 60-61 78-80
Mm.
8 0.3 1.3
8
n2
6 ~
1.5138 1.5246 1.5274 1.5295
% 89" 62" 82" 53"
-CalculatedC
61.08 61.08
7 -
H
Halogen
C
4.61 4.61
18.03 18.03
61.40 61.10
Found
H
Halogen
4.80 4.66
17.70 18.04
83' 8Gb 5gC 35" 61" 86" 83*
39.89 45.14 2.58 45.23 2.66 40.06 44.92 2.46 39.88 45.23 2.66 40.06 c 47.66 39.74 2.05 40.04 2.02 47.28 52.94 35.83 1.77 90-92 35.91 1.51 53.01 50.05 3 61 33.33 78-79 0.3 1.5483 49.81 3.76 33.15 37.77 2.55 49.97 63-65 37.53 2.52 49.95 29.98 1.84 59 99 IF 30.11 1.77 60.10 123-125 0.2 1,6020 21.78 1.08 71.74 138-140 31" 21.57 0.91 71.77 E . M. Filachione, J. H. Lengel and W. P. Ratchford, THIS JOURNAL, Method A. 6 Method B. C See Experimental. 72, 839 (1950), use a more involved method for this compound; they report b.p. 47-50' (0.2 mm.), n z O ~1.5147. e Lit.4 b.p. 142-146' (23 mm.). f Lit.4 m.p. 56'. 0.1
1.5504
(1
TABLE I1 HOMOPOLYMERS OF ARYLMETHACRYLATE^ Ester, grams
Polymer,
Softening
Conditions of polymerization
1 Temp., '(2. Time, days AIBN, yo 152 1.20 60 2 0.1 20 65 W S 0.52 60 2 .1 141 15 69 2-ClC& 65 2 15 0.13 125 9 72 3-CICaa 4.40 60 9 None 154 4-c1c& 20 40' 0.84 65 2 0.1 10 80 154 2,4-ClzCcHa 65 1 0.3 160 .60 2,4,5-c1ac&z 32 75 .42 75 7 None 24 1 2,4,6-C13CsHz 10 70 .3OC 95 1 0.07 237 7 86 2,3,4,6-C14CcH >2
