Open Journal of Physical Chemistry, 2011, 1, 45-54
doi:10.4236/ojpc.2011.12007 Published Online August 2011 (http://www.SciRP.org/journal/ojpc)
45
Thermal Degradation Studies of Some Strongly Acidic
Cation Exchange Resins
Pravin U. Singare*1, Ram S. Lokhande2, Rupa S. Madyal3
1Department of Chemistry, Bhavan’s College, Andheri, Mumbai, India
2Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz, Mumbai, India
3Department of Chemistry, South Indians’ Welfare Society College, Sion, Mumbai, India
Received April 19, 2011; revised June 13, 2011; accepted July 22, 2011
Abstract
The thermal degradation of some sulfonic cationites namely Amberlite IR-120, Indion-223 and Indion-225
was investigated using instrumental techniques like thermal analysis (TG) and Scanning Electron Micros-
copy (SEM). Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the resins degrada-
tion steps. The sulfonic cationites undergo degradation through dehydration, followed by decomposition of
sulfonic acid functional groups liberating SO2. The thermogravimetric analysis of above cationites at higher
temperature up to 520˚C, show mass loss of 61.61% and 25.43% respectively for Indion-223 and Indion-225,
while Amberlite IR-120 cationite get burned off completely.
Keywords: Sulfonic Cationites, Thermal Degradation, FTIR, SEM, Nuclear Resin, Thermal Analysis
1. Introduction
Ion-exchange resins are produced and commercialized in
a wide range of formulations with different characteris-
tics, and have now a large practical applicability in vari-
ous industrial processes, such as chemical, and nuclear
industry for treatment of liquid waste [1-16]. For their
versatile properties, the cationic resins are used both in
the ion exchange area and in the heterogeneous catalysis
field [17]. These resins exhibit a high exchange capacity
and an excellent osmotic shock resistance. So, the cati-
onic resins, produced with a high degree of purity, be-
came important as catalysts in various food technologies
[18] and for purification in heavy-water moderated nu-
clear reactors in nuclear industries [19-21]. In many
cases their use is limited by the relatively low thermal
stability [22]. Hence, knowledge of the thermal behavior
of cation exchange resins is necessary. Abundant data
exist on the thermal degradation of anion exchange res-
ins [23-25] and on carboxylic cationites with low acidity
[26-27]; literature seems to offer relatively poor informa-
tion on polystyrene-divinylbenzene sulfonic cationites
[28-33]. Therefore, in the present investigation thermal
degradation of strongly acidic sulfonic cationites was
performed to understand the degradation steps and to
compare the relative thermal stability.
2. Experimental
2.1. Materials
The following commercial cationites were used:
· Strongly acidic gel-type resin with sulfonic acid
functionality based on styrene-divinylbenzene matrix:
Amberlite IR-120 (Rohm and Haas Co, USA).
· Nuclear grade strongly acidic gel-type resin with
sulfonic acid functionality based on styrene-divinyl-
benzene matrix: Indion-223 (Ion Exchange India Ltd.,
Mumbai).
· Strongly acidic gel-type resin with sulfonic acid fun-
ctionality based on styrene-divinylbenzene matrix:
Indion-225 (Ion Exchange India Ltd., Mumbai).
The details regarding the physical properties of catio-
nites used are given in Table 1.
The soluble impurities of the resins were removed by
repeated soxhlet extraction using water and occasionally
with distilled methanol to remove non polymerized im-
purities. The resins were then dried over P2O5 in desic-
cators at room temperature.
2.2. Thermal Analysis
The thermogravimetric experiments were performed on a

46 P. U. SINGARE ET AL.
Table 1. The main characteristics of the investigated catio-
nites.
Cationites
Exchange
Capacity
(mEq./mL)
Particle size Moisture
Content (%)
Maximum
Temperature
Stability ˚C
Amberlite
IR-120 1.9 16 - 50 mesh 45 121
Indion-223 1.8 0.3 - 1.2 mm 53 120
Indion-225 2.0 0.3 - 1.2 mm 50 120
DTG-60H, (Shimadzu, Japan) thermal analysis system
between 30˚C - 550˚C using aluminum cell (6 mm in
diameter and 2.5 mm in depth). The measurements of
resin samples were carried out in nitrogen flow (50
mL· mi n –1) at heating rate (β = 10 K·min–1). The mass of
resin sample used was ~5 - 20 mg. In order to character-
ize the decomposition steps of the investigated ion-ex-
change resins, FTIR and Scanning Electron Microscopy
(SEM) were used in addition to thermal analysis.
2.3. FTIR Spectra
FTIR spectra (in 4000 - 450 cm–1 range) of thermal de-
composed samples, up to the characteristics mass-loss
steps temperatures, were recorded in KBr pellets (2 mg
cationite/200 mg KBr) using a FTIR PerkinElmer 1750
spectrophotometer.
Since in the thermal analysis, the major weight loss
was observed between 200˚C - 400˚C, the resin samples
were heated in an oven for 3h at 10˚C higher tempera-
tures above the maximum operating temperature, and
also at 200 and 400˚C. The thermal degradation of resin
was studied by comparing the spectra of fresh and heated
resin samples.
2.4. Scanning Electron Microscopy (SEM)
The thermal degradation studies of ion exchange resins
was also studied by examining the surface morphology
of fresh resin samples and samples heated at 400˚C using
JSM-6380LA Scanning Electron Microscope (Jeol Ltd.,
Japan).The powders were precisely fixed on an alumi-
num stub using double-sided graphite tape and then were
made electrically conductive by coating in a vaccum
with a thin layer of carbon, for 30 seconds and at 30 W.
The pictures were taken at an excitation voltage of 10 -
15 KV and a magnification of ×100 and ×130.
3. Results and Discussion
3.1. Characterization and Thermal Degradation
Study of Amberlite IR-120:
3.1.1. TGA Analysis
Figure 1 represents a dynamic weight loss profile of
Amberlite IR-120 from room temperature to 550˚C.
Thermogravimetric curve of Amberlite IR 120 shows
22% weight loss up to 200˚C due to moisture content and
the weight decreased gradually till 400˚C. Above 400˚C
whole compound burned off completely and weight loss
measurement was not possible.
3.1.2. FT IR Analysis
Figure 2 shows the IR spectrum of the fresh resin sam-
ple Amberlite IR-120. The bands at 2923 and 2876 cm–1
are due to the aliphatic C-H stretching absorbance of
methyl group in the main chain and in aromatic rings and
of methylene group respectively. SO2 asymmetric stre-
tching at 1382 cm–1. Strong band at 1652 cm–1 indicates
aromatic C=C bond. The four sharp peaks at 1009 cm–1
,
1037 cm–1, 1126 cm–1, 1186 cm–1 are due to SO3 sym-
metric stretching. The peaks at 1500 - 1600 cm–1 are due
to deformation and skeletal vibrations of C-H in DVB.
Bands appear at 2366 cm–1 which may be assigned to
O-H stretching vibration originating from the polymer.
At 200˚C, the 21% weight loss was observed without
any loss of peak in the IR spectra. At 400˚C IR investi-
gation indicates that the peaks in the region 1500 - 1000
cm–1 either shows a general broadening or no longer ex-
ists (Figure 3). Non-existence of the SO unit was con-
firmed by the absence of the peaks from 1500 - 1000cm–1,
with decomposition of the functional group i.e. sulfonic
portions of the ring. But slight broadening of the band is
observed at 1652 cm–1 for aromatic C=C bond remained
unchanged. This corresponds to the few chain scissions
in the DVB matrix.
3.1.3. SEM Anal ysi s
Figure 4, shows the surface morphology of Amberlite
IR-120 resins at room temperature indicating plane sph-
erical structure. At 400˚C, resin show large cracks and
thread like appearance on the surface (Figure 5).
3.2. Characterization and Thermal Degradation
Study of Indion-223:
3.2.1. TGA Analysis
Thermogravimetric curve of Indion—223H+ shown in
Figure 6. The 30% weight loss up to 200˚C can be at-
tributed to moisture content. The second major weight
loss begins at 270˚C and ends at 400˚C, which might be
due to slow degradation of side chain and loss of sul-
phonic functional group. The mass loss from 400˚C to
521˚C was gradual which might be due to degradation of
styrene/DVB matrix.
3.2.2. FT IR Analysis
T
he IR spectrum of Indion-223 in the 3700 - 400 cm−1

P. U. SINGARE ET AL.
47
Figure 1. TG curve of Amberlite IR-120.
Figure 2. IR spectrum of Amberlite IR-120 at room temperture.

P. U. SINGARE ET AL.
48
Figure 3. IR spectrum of Amberlite IR-120 at different tem-
perture.
Figure 4. Scanning electron micrograph of the surface of
the Amberlite IR-120 at room temperature.
Figure 5. Scanning electron micrograph of the surface of
the Amberlite IR-120 at 400˚C.
region is shown in Figure 7. FTIR spectral analysis
shows SO3 sharp symmetric stretching band at 1005 -
1126 cm–1. O-H stretching at 2364 cm–1. S-O stretching
at 668 cm–1. SO2 asymmetric stretching at 1382 cm–1.
C=C aromatic nucleus skeletal vibration band at 1500 -
1600 cm–1 and OH hydrogen bonded broad stretching
band at 3200 - 3500 cm–1. The band at 2900 cm–1 attrib-
uted to C-H stretching vibrations in the main chain and
in aromatic rings; the peaks at 1500 - 1600 cm–1 are due
to deformation and skeletal vibrations of C-H in Poly-
styrene/DVB.
FTIR investigation shows that that strong bands at 668
cm–1, 1019cm–1 and 1382 cm–1 which are related to SO
and 2364cm–1 stretching frequency of C-H units re-
mained upto 200˚C, but at 400˚C both the groups disap-
peared (Figure 8). This indicates that at 200˚C the 29.7%
weight loss is due to moisture, whereas 31.8% loss is due
to the functional group i.e. SO and breaking of C-H
bond.
3.2.3. SEM Anal ysi s
Surfaces of resins at room temperature (Figure 9) and at
400˚C (Figure 10) were examined by a Jeol JSM-
6380LA scanning electron microscope. It was found that
at 400˚C resin showed crack in the spherical structure
which supports breaking of polymer matrix at that tem-
perature.
3.3. Characterization and Thermal Degradation
Study of Indion-225:
3.3.1. TGA Analysis
Thermogravimetric curve of Indion-225 H+ is shown in
Figure 11. Thermogravimetric curve shows ~13% weight
loss up to 200˚C, corresponding to the moisture content.
Degradation of resin between 270˚C - 340˚C takes place
sharply and further gradually up to 521˚C which might
be due to decomposition of the sulphonic functional
group with rapid evolution of SO3 or SO2 showing mass
loss of ~12.5%.
3.3.2. FT IR Analysis
The IR spectrum of Indion-225 H+ in the 3700 - 400
cm–1 region is shown in Figure 12. FTIR spectral analy-
sis shows four sharp peaks at 1009 cm–1
, 1037 cm–1, 1126
cm–1, 1186 cm–1 are due to SO3 symmetric stretching. O-
H stretching at 2900 - 2400 cm–1. S-O stretching at 672
cm–1. C=C aromatic nucleus skeletal vibration band at
1550 - 1670 cm–1 and OH hydrogen bonded broad
stretching band at 3200 - 3500 cm–1. The sharp peak at
2900 cm–1 range attributed to C-H stretching skeletal
vibrations of C-H in Polystyrene/DVB.
The degradation occurs in a single step and mass loss
is 25% up to 521˚C. SO2 is the dominate product evolved
at 190˚C and 380˚C while water is also present during
the entire degradation pathway but in relatively small
amount. Loss of SO unit can also be confirmed by IR
investigation. The characteristic band for SO unit at 1009
cm–1
, 1037 cm–1, 1126 cm–1,1186 cm–1 are no longer exist
(Figure 13). The evolution of water occurs in the same
temperature regime as SO2, between 185 and 400˚C, as
spectrum at 200˚C shows broadened bands indicating
light decrease in SO content. This is likely due to the s

P. U. SINGARE ET AL.
49
Figure 6. TG curve of Indion-223.
Figure 7. IR spectrum of Indion-2223 at room temperature.

50 P. U. SINGARE ET AL.
Figure 8. IR spectrum of Indion-2223 at different temperature.
Figure 9. Scanning electron micrograph of the surface of
the Indion-223 at room temperature.
Figure 10. Scanning electron micrograph of the surface of
the Indion-223 at 400˚C.
formation of sulfurous acid by the process noted above.
Water is also evolved early in the degradation and this is
likely due to the loss of physically combined water as
has been observed for the other compounds [34].
3.3.3. SEM Anal ysi s
Figure 14 shows the surface morphology of the In-
dion-225 H+ at room temperature indicating plane sph-
erical structure. Similar to Indion-223 H+; Indion-225 H+
also shows crack on the spherical surface when heated at
400˚C (Figure 15)
4. Conclusions
From the FTIR analysis of three sulfonic acid cationites,
it was observed that the degradation takes place through
dehydration, followed by decomposition of sulfonic acid
functional groups. The thermal analysis shows that up to
200˚C, Indion-225 cationite shows mass loss of only
13%, as against mass loss of 21% and 30% shown by
Amberlite IR-120 and Indion-223 respectively. The
thermal analysis at a higher temperature up to 520˚C,
Amberlite IR-120 cationite gets completely burned,
while Indion-225 and Indion-223 shows total mass loss
of 25% and 62% respectively. Hence the thermal stabil-
ty of three cationites increases in the order of Amberlite i

P. U. SINGARE ET AL.
51
Figure 11. TG curve of Indion-225.
Figure 12. IR spectrum of Indion-2223 at room temperature.

52 P. U. SINGARE ET AL.
Figure 13. IR spectrum of Indion-2223 at different temperature.
Figure 14. Scanning electron micrograph of the surface of
the Indion-225 at room temperature.
Figure 15. Scanning electron micrograph of the surface of
the Indion-225 at 400˚C.
IR-120 < Indion-223 < Indion-225.
5. References
[1] R. Lokhande and P. Singare, “Comparative Study on
Iodide and Bromide Ion-Isotopic Exchange Reactions by
Application of Radioactive Tracer Technique,” Journal of
Porous Material, Vol.15, No. 3, 2008, pp. 253-258.
doi:10.1007/s10934-006-9077-z
[2] R. Lokhande, P. Singare and A. Patil, “Application of
Radioactive Tracer Technique on Industrial Grade Ion
Exchange Resins Indion-830 (Type-1) and Indion-N-IP
(Type-2),” Radiochimica Acta, Vol. 95, No.1, 2007, pp.
111-114. doi:10.1524/ract.2007.95.2.111
[3] R. Lokhande and P. Singare, “Comparative Study on
Ion-Isotopic Exchange Reaction Kinetics by Application
of Tracer Technique,” Radiochimica Acta, Vol. 95, No. 3,
2007, pp. 173-176. doi:10.1524/ract.2007.95.3.173
[4] R. Lokhande, P. Singare and A. Kolte, “Study on Kinet-
ics and Mechanism of Ion-Isotopic Exchange Reaction
Using Strongly Basic Anion Exchange Resins DuoliteA-
101 D and Duolite A-102 D,” Radiochimica Acta, Vol.
95, No. 10, 2007, pp. 595-600.
doi:10.1524/ract.2007.95.10.595

P. U. SINGARE ET AL.
53
[5] R. Lokhande, P. Singare and M. Dole, “Comparative
Study on Bromide and Iodide Ion-Isotopic Exchange Re-
actions Using Strongly Basic Anion Exchange Resin
Duolite A-113,” Journal of Nuclear and Radiochemical
Science, Vol. 7, No. 2, 2006, pp. 29-32.
[6] R. Lokhande, P. Singare and P. Karthikeyan, “The Ki-
netics and Mechanism of Bromide Ion Isotope Exchange
Reaction in Strongly Basic Anion-Exchange Resin
Duolite A-162 Determined by the Radioactive Tracer
Technique,” Russian Journal of Physical Chemistry A,
Vol. 81, No. 11, 2007, pp. 1768-1773.
doi:10.1134/S0036024407110088
[7] R. Lokhande, P. Singare and M. Dole, “Application of
Radiotracer Technique to Study the Ion Isotope Exchange
Reactions Using a Strongly Basic Anion-Exchange Resin
Duolite A-113,” Radiochemistry, Vol. 49, No. 5, 2007, pp.
519-522. doi:10.1134/S106636220705013X
[8] R. Lokhande, P. Singare and A. Patil, “Application of
Radioactive Tracer Technique for Characterization of
some Strongly Basic Anion Exchange Resins,” Radio-
chimica Acta, Vol. 96, No. 2, 2008, pp. 99-104.
doi:10.1524/ract.2008.1465
[9] R. Lokhande, P. Singare and S. Tiwari, “Study of Bro-
mide Ion-Isotopic Exchange Reaction Kinetics Using a
Weakly Basic Macro Porous Resin Indion-860,” Radio-
chemistry, Vol. 50, No. 6, 2008, pp. 633-637.
doi:10.1134/S106636220806009X
[10] R. Lokhande, P. Singare and S. Parab, “Application of
Radioactive Tracer Technique to Study the Kinetics of
Iodide Ion-Isotopic Exchange Reaction Using Strongly-
Basic Anion Exchange Resin Duolite A-116,” Radio-
chemistry, Vol. 50, No. 6, 2008, pp. 642-644.
doi:10.1134/S1066362208060118
[11] R. Lokhande, P. Singare and V. Patil, “Application of
Radioactive Tracer Technique to Study the Kinetics and
Mechanism of Reversible Ion-Isotopic Exchange Reac-
tionusing Strongly Basic Anion Exchange Resin Indion
-850,” Radiochemistry, Vol. 50, No. 6, 2008, pp. 638-
641. doi:10.1134/S1066362208060106
[12] R. Lokhande, P. Singare and T. Prabhavalkar, “The Ap-
plication of the Radioactive Tracer Technique to Study
the Kinetics of Bromide Isotope Exchange Reaction with
the Participation of Strongly Basic Anion Exchange
Resin Indion FF-IP,” Russian Journal of Physical Chem-
istry A, Vol. 82, No. 9, 2008, pp. 1589-1595.
doi:10.1134/S0036024408090331
[13] R. Lokhande, P. Singare and A. Kolte, “Application of
Radioactive Tracer Technique for Characterization of
Strongly Basic Anion Exchange Resins Duolite A 101D
and Duolite A 102D,” Radiochemistry, Vol. 52,No. 1,
2010, pp. 81-86. doi:10.1134/S1066362210010182
[14] R. Lokhande, P. Singare and S. Tiwari, “Application of
82Br as a Radioactive Tracer Isotope to Study the Bro-
mide Ion-Isotopic Exchange Reaction in Strongly Basi-
cAnion Exchange Resin Duolite-A161,” Russian Journal
of Physical Chemistry A, Vol. 83, No. 8, 2009, pp.
1389-1394. doi:10.1134/S003602440908024X
[15] S. K. Samanta, T. K. Theyyunni, B. M. MISRA, “Col-
umn Behavior of Aresorcinol-Formaldehyde Polycon-
densate Resin for Radio Cesium Removal Fromsimulated
Radwaste Solution,” Journal of Nuclear Science and
Technology, Vol. 32, No. 4, 1995, pp. 425-429.
doi:10.3327/jnst.32.425
[16] International Atomic Energy Agency, “Advances in
Technologies for the Treatment of Low and Intermediate
Level Radioactive Liquid Wastes,” Technical Reports
Series, No. 370, IAEA, Vienna, 1994.
[17] B. Saha and M. Streat, “Cation Exchange Resin- Cata-
lysed Esterification of Acetic Acid with 2-(1-Cyclohex-
enyl) Cyclohexanone,” Catalysis Letters, Vol. 51, No.
1-2, 1998, pp. 121-127. doi:10.1023/A:1019084901133
[18] E. Dickinson and G. Stanisly, “Colloids and Foods,” Ap-
plied Science Publisher, London, New York, 1982, p.
220.
[19] International Atomic Energy Agency, “Operation and
Control of Ion Exchange Processes for Treatment of Ra-
dioactive Wastes,” Technical Reports Series, No. 78,
IAEA, Vienna, 1967.
[20] International Atomic Energy Agency, “Treatment of
Low- and Intermediate-Level Liquid Radioactive
Wastes,” Technical Reports Series, No. 236, IAEA, Vi-
enna, 1984.
[21] C. Simister, F. Caron and R. Gedye, “Determination of
the Thermal Degradation Rate of Polystyrene-Divinyl
Benzene Ion Exchange Resins in Ultra-Pure Water at
Ambient and Service Temperature,” Journal of Radio-
analytical and Nuclear Chemistry, Vol. 261, No. 3, 2004,
pp. 523-531. doi:10.1023/B:JRNC.0000037092.52163.3d
[22] Yu. Egiazarov, V. Radkevich, L. Kravchuk and A. Ivko,
“Thermal Stability and Activity in Hydrogen Oxidation
of Palladium Catalysts Supported on Fibrous Sulfonic
Cation Exchanger in the Hydrogen and Magnesium
Forms,” RussianJournal of Applied Chemistry, Vol. 77,
No. 9, 2004, pp. 1500-1504.
doi:10.1007/s11167-005-0059-8
[23] M. Hyder, S. Bartenev, L. Lazarev, V. Romanovskiy, S.
Strelkov, G. Zachinyaev, E. Nazin, A. Aldochin, Y.
Glagolenko, A. Maliych and S. Rovniy, “Russian Studies
of the Safety of Anion Exchange in Nitric Acid,” Separa-
tion Science and Technology, Vol. 34, No. 6-7, 1999, pp.
1183-1194. doi:10.1080/01496399908951088
[24] M. Tomoi, K. Yamaguchi, R. Ando, Y. Kantake, Y.
Aosaki and H. Kubota, “Synthesis and Thermal Stability
of Novel Anion Exchange Resins with Spacerchains,”
Journal of Applied Polymer Science, Vol. 64, No. 6, 1997,
pp. 1161-1167.
doi:10.1002/(SICI)1097-4628(19970509)64:6<1161::AI
D-APP16>3.0.CO;2-Z
[25] P. Tulupov and N. Polyanskii, “Thermal Stability of An-
ion-ExchangeResins,” Russian Chemical Review, Vol. 42,
No. 9, 1973, pp. 754-771.
doi:10.1070/RC1973v042n09ABEH002730
[26] A. Chapiro and P. Seidler, “Preparation et Proprietes de
Quelques Membranes Semi-permeables Obtenues par
Greffage de Films de Polytetrafluoroethylene dans leur
Masse,” European Polymer Journal, Vol. 1, No. 3, 1965,

P. U. SINGARE ET AL.
54
pp. 189-205. doi:10.1016/0014-3057(65)90037-6
[27] D. Chambree, C. Iditoiu, E. Segal and A. Cesaro, “The
Study of Non-isothermal Degradation of Acrylic Ion-Ex-
Change Resins,” Journal of Thermal Analysis and Calo-
rimetry,Vol. 82, No. 3, 2005, pp. 803-811.
doi:10.1007/s10973-005-0967-0
[28] C. Iditoiu, E. Segal and D.Chambree, “Kinetics of
Non-isothermal Behaviour of Synthetic Cationites with
Low Acidity,” Journal of Thermal Analysis and Calo-
rimetry, Vol. 56, No. 1, 1999, pp. 407-417.
doi:10.1023/A:1010171222225
[29] C. Iditoiu, C. Popescu and D. Chambre, “Non-isothermal
Dehydration Kinetics of Some Cationites,” Journal of
Thermal Analysis and Calorimetry, Vol. 55, No. 3, 1999,
pp. 885-893. doi:10.1023/A:1010142102614
[30] M. Matsuda, K. Funabashi, T. Nishi, H. Yusa and M.
Kikuchi, “Decomposition of Ion Exchange Resins by
Pyrolysis,” Nuclear Technology, Vol. 75, No. 1, 1986, pp.
187-193.
[31] M. Matsuda, K. Funabashi and H. Yusa, “Influence of
Functional Sulfonic Acid Group on Pyrolysis Character-
istics for Cation Exchange Resin,” Journal of Nuclear
Science and Technology, Vol. 24, No. 2, 1987, pp. 124-
128. doi:10.3327/jnst.24.124
[32] S. Petterson and G. Kemmler, “Experience of Resin Py-
rolysis,” Waste Management, Arizona Board of Regents,
Vol. 2, 1984, pp. 223-225.
[33] L. Petrus, E. Stamhuis and G. Joosten, “Thermal Deacti-
vation of Strong-Acid Ion-Exchange Resins in Water,”
Industrial and Engineering Chemistry Product Research
and Development, Vol. 20, No. 2, 1981, pp. 366-371.
doi:10.1021/i300002a026
[34] B. Boinon, D. Ainad-Tabet and J. Montheard, “Thermal
Degradation of Poly Ortho Chloro Methyl Styrene and
Polymetachloromethylstyrene,” Polymer Degradation
and Stability, Vol. 28, No. 2, 1990, pp. 197-207.
doi:10.1016/0141-3910(90)90006-S