Document RjvK2aDpazpMjDoMa5XRqOqDa
B.P.GOODRICH CHEMICAL COMPANY AVON LAKE DEVELOIWENT CENTER
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Staff Technical Report No. 63
RESIDUAL MONOMERS & LOW TEMPERATURE DEGRADATION PRODUCTS FROM GEOR 351 & GBON 352 LATICES
by L. B. Crider
Distribution: Avon Lake R. J. Wolf C. H. Lufter R. G. Duke Technical Council C. L. Wheelock E. J. Leeaon
Geo. Antifinger Geo. Gateff R. Kreager
J. W. Ryan
E. G. DeCaplta E. A. Collins l>. Chandler CTF File (2)
Date Completed: Date Issutd:
June 25 196U (LBC-31-6U)
Brack*vllle
J. i. Shipman
L. Jlaenex
Cleveland R. D. icott - A. Vittone C. H. Alexander D. Kent
Louisville S. 3. Michels R. R. Taylor
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SUMMARY 4 CONCLUSIONS
The previous Identification of 0.5 wt. it methyl chloride in & *>&*
coagulated sample of Geon 350X11 raised some questions as to the origin .rn*
methyl chloride and the effects of this material on the measurement of rcsiT.%1
vinyl chloride monomer in Geon 351 and Geon 352 latex.
The results from our current study shows that chloromethane ar.d chlorcethane are decomposition products from Geon 351 (\'CI-methylacryua*.'r copolymer) and Geon 352 (VCl-ethylacrylate copolymer) respectively. Tr. i *.r. cases the decomposition begins at about 125 degrees C. ar.d is quite prcnc-occd at 150 degrees C. A degradation mechanism has been proposed bead on a cornsir.ed riass spectrometer-infrared study.
The mass spectrometer method for the analysis of vinyl chloride monomer in Geer, latices gives results that are about 2X those obtained by the standard stripping method. Samples of stripped latex from Louisville storage were tested by both methods and gave the following results:
Vinyl Chloride Methyl Chloride Ethyl Chloride
Stripped
Geon 351
M. S.
Standard
Method Wt. i
Method KTT
0.99 o.ou
--
0.45
Stripped
Geon 352
M.S.
Standard
Method
Wt. $
Method Wt. ?
0..6.o
0.25
0.01
The differences between the two methods have not been resolved but are believed to be due to the use of high vacuum and beat to extract the monomer in the mass spectrometer method while the standard procedure used steam stripping of the latex and a subsequent collection of the monomer fraction in n cold trap.
IHTKQUJCTIOII
Zt has been previously reported (1) that the two low temperature transitions which were observed In a differential thermal analysis of Geon 350X11 (VC1-methylacrylate copolymer) were due to the presence of methyl chloride in the latex. A mass spectrometer analysis obtained from a freese coagulated sample of this same latex
showed 0.3$ sMthyl chloride. It was suggested that the unexpected presence of this
quantity of methyl chloride in the dried latex must be due to decomposition of the polymer which could occur through the elimination of HC1 and a subsequent attao* of the ester group. The purpose of the current investigation was to determine the source of the methyl chloride and to measure the amount in a typical lot of production material.__________________________ ________________________ __
(1) Crider, L. B., "Volatiles in Qeon 350X11" Memo Report to E. J. Leeson, Dec. 12. 1963 (LBC-5^-63)
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DISCUSSION A RESULTS
A further study of the volatile product* In Louisville Geor: 351 a
Ceon 352 confirms that methyl chloride and ethyl chloride are degradation products from
VC1*methylacrylate and VCl-ethylacrylate copoxymera respectively. Mass spectra were
obtained from samples of freeze coagulated latex at temperatures of 100 degrees C.t
125 degrees C., 150 degrees C. and 200 degrees C. The results of this study shows
that trace amounts (100 ppm.) of methyl chloride and ethyl chloride are evolved on
heating the latlces at 125 degrees C. in vacuum for 5 minutes. At 150 degrees C.
O.Uo 1.50the decomposition rates are Increased to yield
methyl chloride and
ethyl chloride in 5 minutes and at 200 degrees C. these same yields are increased
to 6.76 and 3*195l respectively.
A summary of the results obtained from this study is given in Appendix I and Appendix II. It should be noted that the degradation products from the 351 latex (App. I) also Includes, in addition to methyl chloride, appreciable amounts of methanol and aroamtlc hydrocarbons. The decomposition of 352 latex yields, in addition to ethyl chloride, sizeable amounts of ethanol and acetaldehyde along with smaller quantities of acrylic acid and aromatic hydrocarbons.
A degradation mechanism for both latices was developed baaed on the evolution of methyl chloride and methanol from Qeon 351 and ethyl chloride and ethanol from Geon 352. The proposed decomposition route is elucidated by a comparison of the Infrared spectra obtained from both latices before and after heat treatment at 150 degrees C. and 200 degrees C. (The X.R. work was done by J. W. Ryan). The heat treatment of both polymers resulted in oxidation which was shown in an absorption at 1770 cm*l (3.65 u). This absorption could result from the presence of an acid chloride, organic carbonate or n five amnbered lactone. The saaple examined at 150 degrees C. showed only very weak absorption at 1770 cm-I and a correspondingly pale color. The 200 degrees C. samples were very dark in color and had very strong absorptions at 1770 cm**, lone of the samples had absorptions characteristic of Mter, alcohol or free acid.
(i)
(II)
The combined mass specti ter and infrared data tends to support the
----------------- ----------------- *HCI-----------------:-----------------
ci I1
200 degrees C.
0 --- C-0 1I
`C^hVi HH
HH
Cl
ikis!
HH
* *
f H
200 degrees C.
ROM
Cl -- C-0 I
** H where R is methyl or ethyl
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The IR absorption at 1770 carl nay be attributed to the C0 in b-,*.h structures I and XI. The carbon-carbon double bond In structure II is evidencd by an absorption at 1640 cm*l.
With this background, the mass spectrometer procedure for the analysis of residual monomers In latex samples of this type was modified to use a sample Inlet temperature of 100 degrees C. to avoid any possible decomposition of the polymer. The undiluted latex sample la charged to the Instrument through a rubber septum using a micro -syringe.
Analyses were made for both the stripped and unstripped latex samples received from Louisville (L-3793, 5/22/6U). These results are given In Appendix I and Appendix IX. It should be noted that the values obtained by the mass spectrometer method for residual vinyl chloride monomer in the latex are about 2X those obtained by the standard testing procedure (Procedure Ho. 367):
Geon 351 Latex
Stripped
Stripped
Unstripped
vt. t
Wt. *
wt. i
By M. 8.
Proc. Ho. 387
By M. 8*
VC1
0.4$
1.13
Geon 352 Latex
VC1 Monomer
0.60
0.25
1.72
The results obtained from the unstripped 351 latex also shows an appreciable amount of methyl chloride which at this temperature (100 degrees C.) could not be present due to decomposition. By contrast, the unstripped 352 latex shove only a trace amount (0.01$) of ethyl chloride. The results from the unstripped 351 latex suggest that some methyl chloride may be formed during polymerisation.
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Volatile* from Oeon 351 Latex
--(i^uiiviiie$/;&)--
Geon 351 Latex 9100 degrees C.
H20 Methyl Chloride Vinyl Chloride Keat Loss
Stripped
wt. i
5^.61
o.o4
0.99 5TT6?
Unstrlpped
Wt. %
53-36 1.14
5^
Volatiles from Samples of Freese Coagulated 351 Latex
HgO Methyl Chloride Vinyl Chloride Methanol Aromatics
Stripped Latex
100 degrees C.
Vt. i
0.0062 nil nil nil
100 degrees C.
Wt. i
0.0068 nil nil nil
150 degrees C.
Wt. t
o.uo .0045
trace trace
.3200 degrees C,
Wt. * o.3t> 6.76 trace
0.27 0.15 8To4
Unstripped Latex
Methyl Chloride Vinyl Chloride Methanol Aromatics
100 degrees C. Wt. i 6.66U
0.0007
129 degrees C. wt. i
0.0129 0.0084
150 degrees C. Wt. f 0.50 0.0048 Trace Trace
APIBDZX X
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Volatile* from Oeon 152 Latex
-----(Loui'ivfir*
Ceon 352 Latex #100 degrees C.
Stripped wt. i
Unstripped
*t- %
h2o Ethyl Chloride Vinyl Chloride
Heat Loss
*5.15
0.01 0.60 55T75T
44.53 0.01
1.72 505
Volatile* from Saaple* of Freese Coagulated 352 Latex
HgO Ethyl Chloride Acrylic Acid Acetaldehyde Vinyl Chloride Arooatlcs Ethanol
Stripped Latex
#100 degrees C. 2.74 nil nil nil nil nil
nil
wt. t
#125 degrees C. #150 degrees C.
2.97
3.42
0.005*
1.50
0.0120
0.07
nil
0.03
0.0033
0.01
trace
0.25
0.0063
0.30
#200 degrees C.
1.38
3-19 0.03 0.l6
0.01
0.09 0.43
HgO
Ethyl Chloride Acrylic Acid Acetaldehyde Vinyl Chloride Araeetlc* Ethanol
2.5
all
nil
nil
ail ail nil
1
I
m
n
e
Unstripped Latex
Wt. %
#123 degrees C. #150 degrees C.
2.79 0.0030
0.0000
ail
0.0020 trace 0.0060
0.32 1.06 0.04 0.21 0.32 0.21
0.33
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