「クロマトグラフィーを主体とした高分子分析法における最近の話題」
日本分析工業株式会社

大栗 直毅1 ) Analysis of Polyester by a Combination of Curie-Point Heating
Techniques and Preparative Liquid Chromatography
Naoki Oguri※ , Akira Onishi※ , Sigeki Uchino※, Keiji Nakahashi※ And Xigao Jin※※Japan
Analytical Industry Co., Ltd., 208,Musashi Mizuho, Nishitama, Tokyo 190-12,Japan
Institute of chemistry, Chinene Academy of Siences, Beijing , 100080, China
A Curie-point heating technique has already been introduced to pyrolysis-gas chromatography, which was developed by
us. We analyzed the component of a mulli-component polyester completely by using a combination of the technique andpreparative HPLC. We used Curie-point pyrolysis-GC/MS, direct injection/ MS, headspace-GC/ MS and preparative
HPLC for this study. We could thus detcrmine the composition of the uncured polyester for manufacturing man-mademarble consisting of an uncured polyester prepolymer, a crosslinking accelerator, an acrylate copolymer as themodification agent and some additives (Surfactant and plasticizer). This analytical method is an available, convenient
way for compositional analysis of comple3t Polymers materials.
KeywordCurie-point pyrolysis, Curie-point direct injection probe, headspace gas chromatography, mass
spectrometry, preparative liquid chromatography, polyester

Pyrolysis gas chromatography-mass spectrometry(PyGC/MS) has recently become popular for polymer
analysis owing to its simplicity and capacity for providing
important compositional and structural information,
especially regarding multi-component materials. Oneof the advantages of this method is that all compositionsof the polymer(s), and additive(s) employed in thematerial can be investigated without any pretreatment. 1.2
0n the other hand, headspace-GC/MS is a powerfulmeasurement technique for volatile compounds insolids.3 Moreover, it is suggested that that data becompared with the Py-GC results for a distinction ofvolatile components from pyrolyzates on a pyrogram ofa multi-component polymer material. An on-line direct
injection/MS(DI/MS) technique could separate thepyrolyzates and volatile components of a polymer sample
according lo the mass on a liner scale with very highsensitivity., it thus enables a rapid analysis with athroughput of up to one sample per minutes.4.5 For
the most complex material system, fractional separationby preparative liquid chromatography is helpful,and sometime necessary, to. obtain pure fractions
and then identify them individually by Py-GC or
pyrolysis-DI/MS in order to determine definite mass
data.6 Due to the high heating speed (less than 0.2s ofthe temperature raise time), accurate temperature
reproducibility (±1℃) and a wide temperature range(l60 – 1040℃), the Curie-point heating technique has
successfully been applied to Py-GC/MS, DI/MS andheadspacc-GC/MS.2.3,7.8 In this work, all of themeasurements mentioned above were used tocharacterize a multi-component thermosetting polymer
system composited by the uncured unsaturated polyester
resin, curing agent modification agent and additives.
Experimental
SampleA set of uncured unsaturated polyester resin (BX-923,
Synthetic Resin Co. of Beijing, China) comprised twoparts (coded as part A and B), including a prepolymer,
reactive monomer, curing accelerator, modificationmaterial and additives in the sample. This polymer was
mi3ted with marble powder, and used for manufacturing
man-made marble.
Apparatus
Pyrolysis or headspace sampling was carried out using
a ModeJHP-3 Curie-point Pyrolyzer or a Model JHS100 Curie-point Headspace Sampler (Japan AnalyticalIndustry Co., Ltd.), which was combined with an on-line
Model QP-2000A C'C/MS system (Shimadzu Co.,
Japan). 1'he GC/MS was equipped with a highresolution, fused-silica capillary column (J&W Sci., DB1, 0.25mmi.d.X30m) coated with immobilizedpoly(dimelhyl silicone) of 0.25μm thickness, and aquadrupole mass spectrometer with an El ioniz1ation
source(70eV). A JD1 800 Curie-point DI Probe(Japan
Analytical Industry Co.. Ltd.) was inserted in a QP

2000A mass system up to the position where the sample
cell (9 mmX2mmi.d.) at the tip of the probe could beconnected to the ion source.8 The sample was wrappedin Pyrofoil with tight contact. The amounts ofsamples to be injected were less than 2μg, 0.1 mg and0.4mg for Dl/MS, Py-GC/MS and headspace-GC/MS,
respectively. The GC column temperature was initiallymaintained at 35℃ for 5 min, and then programmed to
300℃ at 8℃/min. From the carrier gas of helium,
50ml/min was split at a ratio of 50:1. The volatile
fractions of the headspace samples extracted at 220℃
for 10 min were transferred to an adsorbent, (Tenax) at-40℃, and then desorbed at 255℃ for 10s by
Pyrofoil with Curie-point heating. A Model LC-908,
preparative liquid chromatograph (HPLC) was equippedwith the series of columns(GPC) of Model Jaigel-IH and
JaigeI-2H and a refractive index detector (Japan
Analytical Industry Co., Ltd.). Chloroform was used as
the solvent (40kg/cm2, 3.8ml/min). The sample size
injected was 50 mg in 3 ml of the chloroform.
Results and Discussion
Resin and its additives
A total ion current (TIC) pyrogram obtained from PyGC/MS of the uncured resin (part A) pyrolyzed at
500℃, as shown in Fig.1. The structures assigned tothe mass signals of the pyrolyzates are listed in Table 1;
the identification was carried out mainly on basis of mass
spectral fragmentation patterns. The code numbers of

the pyrolyzate peaks in Fig. 1 corresponded to thenumbers in Table 1. Peaks 2 and 3 (with shorter
retention times) indicate unsaturated hydrocarbon andalcohol derived from the hexylene sequences in thepolymer chains. In particular, the α, w-diens are most
likely formed through the predominant pyrolysis
mechanism involving a cyclic transition state at twoneighboring ester linkages for the polyester (Scheme 19).
The 1, 5, and 7 peaks correspond to benzene, phthalicanhydride, and cyclohexenyl phthalale, respectively,
which were also the main peaks on the pyrogram of thepolyester synthesized by phthalic acid and hexenediol.10
A mostly characteristic pyrolyzate, dihexenyl phthalate
as the monomer (peak 11), was reflected on the repeat
units of poly(dihexenyl phthalate). The relationshipbetween the polymer structure and the pyrolyzates issummarized in Scheme 2. The presence of phenyl
benzoate (peak 8) and polycyclic aromatic pyrolyzates(peak 6, 9 and 10) on the pyrogram of the resin would becaused either by the secondary and tertiary thermal
processes of the polyester, or by a thermal decompositionof other aromatic component mixed with the polyester.
To distinguish the different conclusions, part A of thesample was separated and collected into two fractions (FI and F-2), as shown in Fig. 2, by preparative HPLC withhigh-performance columns; F-I and F-2 were thenidentified by Py-GC individually. The pyrogram of F-I
also showed all of the characteristic pyrolyzates ofpoly(dihexenyl phthalate) and reconfirmed the same
results mentioned above. The pyrogram of F-2,
performed at a relatively lower temperature of 220 ℃ for
3 s, is shown in Fig. 3. The sufficient decomposition of
F-2 in a weaker thermal environment indicated that it
could be a thermally labile compound. Some of theassigned pyrolyzates of F-I (see Table I) corresponded tobenzoic acid (peak 4) and phenyl benzoate (peak 8) and
implied the scission, elimination, and recombination of aaromatic peroxide. A rearrangement of the peroxidewith subsequent cyclization to polycyclic compunds(acenaphthene, methoxydibenzofuran and dihydronaphathaccnc, as peak 6, 9, and 10 on the pyrograms) has
also been considered to a significant extent.
Summarizing all of this information, F-2 was identified
as benzoyl peroxide (BPO), a crosslinking accelerator for
the unsaturated polyester. The decomposition
mechanism of BPO is shown in Scheme 3. In addition,a broadly exothermic peak with a maximum temperatureof l33℃ was observed in the differential scanningcalorimetry (DSC) profile of F-2,which was identicalwith the thermal decomposition behavior of BPO.
Finally, a weaker mass signal(peak l2) with a longer
retention time in Fig. I indicated the presence of a highaliphatic alcohol in the resin, implying that component asa kind of additives (a surfactant, perhaps),
Curing agent and modificalion agent
Figure 4 shows a TIC pyrogram of part a carried out
by Py-GC/MS, pyrolyzed at 500℃ for 5s, on whichsome acrylate monomer peaks, methyl acrylate (MA,peak I), methyl methacrylate (MMA, peak 2) andisohextyl methacrylate (HMA, peak 3), were identified.

As is well known, acrylate polymers and copolymers
thermally degrade mainly to the correlative monomers intile absence of oxygen.l2.13 Based on that information, asolid sample of part B was reasonably deduced as being a
copolymer of MA, MMA and HMA. Otherwise, peak
4 and 5 on the pyrogram assigned lo a high aliphatic
alcohol and dioctyl phthalate (DOP) would reflect thethermal volatilization of some additives, which areconsidered to be a surfactant and a plastici2er in thematerial, respectively.
Pyrolysis-DI/ MS is a simple, rapid analytical pyrolysis
measurement technique without any chromatographic
separation process. Since the mass profiles of all
pyrolyzates are labeled on a linear mass scale, it is suitablefor fingerprint identification purposes.7.8 figure 5 is
theTIC pyrogram of part a pyrolyzed at 500 ℃ for3 s by

DI/MS. The corresponding mass spectrum indicatedthat the observed species was a co(MA-MMAHMA)polymer identified by the related monomer
fragments with m/z values of 86(MA), 100(MMA), andl70(HMA), respectively. Though the conclusion is thesame as that by Py-GC,since the throughput of up to one
sample was within a few minutes, the analysis is more
effective.
An important point remained regarding the previous
discussion, i.e. the monomer peaks of MA, MMA andHMA on both of Py-GC and Dl/MS pyrograms of thepart B must have originated from two considerable ways;
thermal pyrolysis of the copolymer to the corresponding
monomers or/and thermal volatilization of tile freemonomers dissolved in the copolymer.14 To confirm
that, headspace GC/MS was carried out at a purging
temperature of220oCwithin I min for both part B and amonomer-free co(MA-MMA)polymer for the same
sample size and condition. Since no significant peak
showed on the headspace chromatogram of themonomer-free copolymer, this indicated that nodetectable pyrolyzate formed al that temperature for the
purified co(MA-MMA)polymer. A headspace TIC
chrormatogram of part a at 225℃ is shown in Fig. 6, in
which the monomer peaks of MMA and HMA presented
with the obvious intensities are compared to the standard
copolymer. The results show that there were somereactive monomers (MMA and HMA) dissolved in the
copolymer as the crosslinking agents of the unsaturated
polyester. Therefore. it could be deduced that the
copolymer in part a acted as a modification material andan adsorbent for the reactive monomers.
In conclusion, all of the components in a set of uncured
unsaturated polyester system, including an unsaturated
polyester prepolymer, a crosslinking accelerator, an
acrylate copolymer as the modification agent and some
additives (surfactant and plasticizer) were well identified
by a combination of Curie-point Py-GC/MS, DI/MS,
headspace-GC/MS and preparative HPLC. A
flowchart diagram of the analytical measurements usedin this work is illustrated in Fig. 7. The results showedthat the Curie-point heating technique combined tomulti-chromatographic and mass spectroscopic methods
is an available and convenient way for the compositional
analysis of complex polymer materials.
The authors express their sincere thanks to Ms. H J. Hsu(Research Center. Eternal Chemical Co., Ltd., Kaohsiung.
China) for her useful help and discussions.

2) Multichannel Autosampler for Curie-Point Pyrolysis Capillary
Gas Chromatography
Naoki Oguri ※ and Akira Onishl
Japan Analylical Industry Co. Ltd. 208 Musashi. Mizuho. Nishitama.Tokyo l90-12. Japan

Toshihiko Hanai

int. Inst. of Technol. Anal.. Health Res. Fond., Inst. Pasteur de Kyoto 5F. Sakyo-ku. Kyoto 60, Japan

Xigao Jin

Institute of Chemistry. Chinese Academy of Sciences. Peking. 100080 China

Key Words:

I

Capillary GC
Curie-point pyrolysis
GC-MS
Multichannel autosampler
Summary
A multichannel autosampler which can automatically analyze
up to 20 samples in sequence has been developed for on-line
Curio-pout pyrolysis - capillary GC. The results obtained fromthe system show that the analysis of thermally labile samples
could be performed without either thermal degradation orreaction during th4 Waiting time before the final pyrolysis.The
reproducibilities of the relative peak areas and retention timesof the characteristic pyrolysates of a tricomponent copolymer
were significantly better than those obtained by manual sample
manipulation.
1 Introduction
Pyrolysis is used as a means o[ sample Introduction for the gas
chromatographic analysis of high molecular weight compounds.
the technique uses high temperatures to degrade the compounds
to a characteristic mixture of volatile monomers, oligomers andother pyrolysates. Curie-Point Pyrolysis - Capillary GC is a
powerful method for analysis of the composition and structure ofsuch non-volatile compounds as synthetic plastics [1]. Rubbers[2].
and paints [3].
In previous work. liquid. solid. and powder samples have been
Handled by wrapping in 50 μm thick Pyrofoil. Placed in a speciallydeveloped, magnetic. metal foil holder, and inserted Into (hepyrolyzer [4. 5]. Because pyrolysis can be effected by a number ofexperimental parameters. it should be performed as reproduciblyas possible. especially for quantitative analysis. For this reason
we have developed a multichannel autosampler which can handle
up to 20 samples without causing any degradation and/or further
polymerization inside the sample holder during the waiting time
before final pyrolysis This has solved a problem observed withanother autosampler [6] in which thermally labile compounds
could be degraded o[ polymerized before pyrolysis [7. 8]
The results from quantitative analysis of multi-component polym
ers has shown that as a result of the standardization of experi
mental conditions the reproducibility obtained using the autosampler is much improved in Comparison with manual sample
manipulation

2 Experimental
2.1 Instrumentation
A schematic diagram of the model JPS-220 multichannel autosampler and JHP-22 pyrolyzer is shown in Figure 1 .Samples areweighed and individually wrapped in Pyrofoil in a manner
ensuring good contact The Pyrofoil-wrapped samples (A) areplaced on a magazine (a). the purge valve (C) opened to replace
the air inside the equipment with carrier gas. and. after 1 min. thesix-port valve(D)turned to the sampling Position The first sample
is pushed by the injector (E) down to a pyrolysis chamber (F)where it is instantaneously pyrolyzed The pyrolyzates aretransferred. through(D). to a on-line GC column to chromatograph
A magnet (G) IS then lowered to retrieve the spent sample andreturned to the upper position A slide-way(I)is placed below themagnet and when the electricity supply to the magnet is switched
off the used sample (H) slides into the trap (J) The slide is thenreturned to its initial position The instrument is controlled byunit(K)
When gas chromatographic analysts of the first sample is complete. the foil magazine is moved forward, the second sample
dispensed Into the pyrolysis chamber by the plunger .and thesecond processing begins automatically. This sample introduction method is repeated up to 20 times from one magazine
In order to keep the carrier gas now rate Constant, during
operation the inlet gas pressure is controlled by a pressurebalancer (L) without this Pressure controller, It took more than
30 min to obtain the stable gas pressure which is Important for
production of reproducible pyrograms
2-2 Condition for Pyrolysis GC

3 Results and Discussion
The multichannel autosampler coupled on-line with the Curiepoint pyrolyzer and the capillary GC system may be used not only
for time-saving automatic measurements on a large number ofsamples. but also for tile highly accurate quantitative analysis ofthermally labile samples.

capillary column coated with a 0.25 pm film or immobilized
polydimethylsiloxane (DB1: J&W. Folsom. CA. USA).
Following pyrolysis. the column temperate was maintained at
50 ℃ for 3 min and then programmed at 10℃/min to 250 ℃ which
was held for 10 min. Helium was used as carrier gas; a total now
rate of 50 ml/min was split in the ratio 50:1. The identification of
the pyrolysates was performed with a directly coupled model
QP 2000 A quadrupole mass spectrometer (Shimadzu): ionization
was by EI at 70eV.
2.3 Samples
I
A commercial bisphenol A type epoxy prepolymer and modified
polyamide hardener were obtained from Konishi. A Toyolac 700
ABS resin. a copolymer of acrylonitrile (23 %). butadiene (13%).
and styrene (64 %) was obtained from Toray industries.

3.1 Analysis of a Thermally Labile Sample
Conventional autosamplers for pyrolysis GC are usually provided
with auxiliary hcatin9 in order to maintain the sample holder at atemperature Sufficient to prevent condensation of pyrolysates on
its inner wall [6] Because uncured epoxy resins are susceptible tofurther curing. even at low temperatures. When such samples aremounted in a conventional pyrolyzer they are often exposed totemperatures Which cause further Curing during the waiting
period before final pyrolysis: the degree of reaction depends on
the temperature. the waiting time. and the size of the sample.
etc.; these are. in turn. reflected in the specifically and the
reproducibility of the resulting pyrograms [8].
Since the sample magazine of JPS-220 is designed to be located
far from the pyrolysis chamber. such heating is not necessary.
This enables thermally labile samples to be analyzed reproduci-pyrogram from the uncured resine some of the monophenol
pyrolysate peaks had increased in size whereas that of bisphenol
A had. in contrast. decreased. These differences obviously
reflected the curing reactions of epoxy resin with amidehardener.
3.2 Reproducibility
The reproducibility of Py.GC analysts is Influenced by each of aseries of steps: One of the most critical is the sample handlingtechnique [9]. As already mentioned. the use of an. autosampler
enables reproducible Sampling handling: because of this anenhancement of the reproducibility and standadization of quantitatve analysis would be expected.
A tricomponent copolymer. an ABS resin. was analyzed quantitatively using both automated and manual sample introduction
systems. figure 3 shows the pyrogram of the ASS resin: theintensities of the monomer (A. B.and S). diner (AS. SA. and SS)
end trimer (ASA. ASS. and SAS) peaks represent the structural
specificity and composition of the copolymer.
The relative peak areas and retention times of the specificpyrolysates are Summarized in Tables 1 and 2. respectively. The
relative standard deviations (CV%) of the peak areas and retention
bly. Figure 2 A Shows the pyrogram obtained from a sample oftimes (t) are are listed in the tables and (in part) presented
the epoxy resin mixed with 4mlde hardener[ (1:1) at room
schematically Figure 4. The CV% and ti data show that thetemperture. No changes were observed in the pyrograms whenexperimental reproducibilities obtained using Ike autosampler
smples were stored in the sample magazine from 1 to 60 min.
were as much as 1.3 and 2.3 times better. respectively. than thosewhich indicates that the JIPS-220 is suitable for the analysis of obtained by manual sample introduction under the Same condi.
thermally labile samples.
tions.
The pyrogram of the epoxy resin cured at 150℃ for 60 min is shown
We consider that in addition to the completely uniform sample
in Figure 2 B : compared with theintroduction. pyrolysis. and chromatographic processing effectedby the autosampler control. there is another reason for this
Improvement: the removal of air by purging the pyrolyzer withcarrier gas. During manual sample introduction. air enters the4) Py-MS 法によりるブレンド コポリマーの分析