Ｏ−６ＴＧ−ＭＳを用いた臭素系難燃剤を含む耐衝撃性ポリスチレンの熱分解挙動の検討
Investigationofthethermaldecompositionofflameretardedhigh‑impactpolystyrenebyTG‑
M
S○正GrauseGuido（東北大学）学柄木田大樹（東北大学）正亀田知人（東北大学）
正BhaskarThallada（IndianlnstituteofPetroleum）正吉岡敏明（東北大学）

GuidoGrause,
Daiki
Karakita,
TomohitoKameda,
ToshiakiYoshioka,
ＴohokuUniv
er
sityT
halladaBhaskar,Indianln
stituteof
PetroleumThedeg
radationofseveralsample
sof
hig
h‑impactpolystyrene（1通S）
containingtheflameretardantsdecabromodiphenylether（DPE）
anddecabromodibenzyl（DDB)
，
respe
ctiv
ely，
w
asinv
cst
i
g
ate
dbythe
mnog
rav
i
metr
ycou
pledw
ithmassspe
ctroscopy（TG‑MS).
Additionally,ｔｈｅｅ砿ctofanti
monyoxide(Sb203)
w
aseXamined､
Variousbrominatedcompoundswereobserv
eddu
r
ingt
he
deg
r
adationofthcf
lameretaI
dant、
Brominatedbenzenes，
phe
nols，
anddibenzofUranswereobtainedfromDPE，w
hilebrominatedtoluenesw
eredctectedinthepresenccof
DDB､l‑Bromo‑
1‑phcnylethaneasaadditionproductof
HBrandstyr
enew
aspresentinanysample･
Thcriseinthefbr
mationofradi
cals
cause
dachangeinthe
mechanis
mofthepolystyrenedeg
r
adat
ion．

K
砂
恥
rf
s:
1
匹
S,
B
m
minatcdF
lame
reta
『
dant,
Polybrominateddibcnzofilrans,
Polybrominatedphenanthrenes
1．Introduction

applications・Brominatedflameretardantsareofienusedibrthis

TGA‑experiments，TheproductoilwasqualitativelyanalyzedbyGC/ＭＳ（ＨＰ6890/I悪5973）andquantifiedbyGC‑FID（GLScienceGC390)．Brominatedcompoundswereanalyzedby

pur
pose､
Duringrecycling,
however,theyimposcahighriskofreleasinghazardouscompoundswhenthermallytreated，

GC‑ECD（ＨＰ6890)．Ｔｈｅｓａｍｅｔｙｐｅｏｆｃｏｌｕｍｎ（GLSciencelnertCap5MS/Sil)
wasusedfbrall
GCanalyzes．

Flameretar
dantsareanecessar
yadditiv
efbr
manyplastic

Carcinogcnsubstances，ｓｕｃｈａｓｂｒｏｍｉnateddibenzodioxinsand

dibenzofUrans，arereleasedFurthermore，thcdegradation
pathwayofthepolymerischanged，alteringtheproduct

Table1．Samplccomposition
DPE‑Sb(0）DPE‑Sb(5)DDB‑Sb(0）composition，Inthiswork,wcinvestigatcdthcefY1ectoftheflameretardantonthepyrolysisbehav
iorofhigh‑impactpolystyrene（HIPS)，
andthedegradationoftheflameretardantsdecabromo
diphenylether（DPE）anddecabromodibenzyl（DDB）ｉｎｔｈｃ
ｐにsenceandintheabsenccofantimonyoxide(Sb203)．

】l】卜Ｓｂ２０３５ｗｔ％】ｌ】卜Thethermaldegradationthe
Sb203freesamplesDPE‑Sb(0）andDDB‑Sb(O）ｓｔａｒｔｃｄａｔａｂｏｕｔ３００ｏＣ（Fig.２)．Thcdegradationproceededintwosteps，v
isiblebytheshouldcrattachedtothe
maindegradationstep・
ThedegradationoftheSb203containingsamplesDPE‑
Sb(5)andDDB‑
Sb(5)
star
te
databoutthesamete
mpe
r
atu
r
c，
how
ev
e
r,the
de
g
r
adat
ion
r
ate
w
asint
he
be
g
i
nnin
g
st
r
ong
ly
accelc
r
at
e
d，
r
esu
ltmg
iｎ
ａｎｅａｒ
ｌｙ
ｍａｘｉｍｕｍａｔ３３０ｏＣａｎｄａｓｅｃｏｎｄｍａｘｉｍｕｍａｔａｂｏｕｔ４００ｏＣ，
whichmightbeidenticaltofirstdegradationstepoftheSb203Fortheseexperiments,ＨＩＰＳｗａｓｂｌｅｎｄｅｄｗｉｔｈＤＰＥａｎｄＤＤＢ，
respectively（Fig.１).Ｓｂ２０３ｗａｓａｌｓｏａｄｄｃｄｔｏｓｏｍｅｓａｍｐｌｅｓ、
ThecompositionofthesamplesusedｉｓｓｈｏｗｎｉｎＴａｂｌｃｌ・
TheTGAmeasurementwasperfbrmedwithaSeiko
TG/TDA6200overatemperaturerangeofbetween50and

700oCataheatingｒａｔｅｏｆ５Ｋｍｉｎ.
'，ｕｓｉｎｇｌＯｍｇｏｆｓａｍｐｌｅ・

fiecsamples,ＴｈｅｐｒｅｓｅｎｃｃｏｆＳｂ２０３雁sultedinanaccelerated

Ｔｈｅｈｅｌｉｕｍｆｌｏｗｗａｓｓｅｔｔｏ２００ｍｌｍｉｎ､lｉｎｏｒｄｅｒｔｏａｖｏｉｄ

dcgradationofboththeflameretardantandIⅡＰＳ.Ａcloserlook

ｃorrosion，causedbythediirUsionofHBr，releasedduringthe
dccompositionofflamerctardedInPS・ＴｈｅｇａｓｗａｓａｎａｌｙｚｅｄｂｙＭＳ(ＨＰ5973).ＴＧａｎｄＭＳｗｅｒｅｃｏｎｎｅｃｔｅｄｂｙａ５ｍｓｔａｉｎless００００

atthcdcgradationofDPE‑Sb(5)ataheatingrateof5Ｋｍｉｎl
byTG‑MSrevealsthatstyreneandｉｔｓｄｉｍｅｒｓａｎｄｔｒｉｍｅｒｓｗｅｒｅ
１誤︾彦閉ｃ目星智彦

steelcapillary（FrontierLabo，UADTP‑5M）withaninnerdiameterofO,２５ｍｍ,heatedat300oC】Ｆ１4.‑、ｈⅡＢｒＢｒＢｒＢｒＢｒＢｒＢｒ

１００２００３００４００５００６００

Ｄｅｃａｂｒｏｍｏｄｉｐｈｅnylether(DPE）Decabromodibenzyl(ＤＤＢ）

Temperature（｡C）

Fig.
１．
Ｆ
１ａｍｅ
Ｉ℃tardantsusedint
heseexpenments

Fig.２.ＴＧＡ/DTGofHIPSandflameretardedHIPS

２
１

属Ｅへま︒Ｐ色《》｡｡亘《三￨:L賊蕊
。

】F1｡̲母ｈＩＩ

００００００００００●６●４●２●０●
８

Ｔｈｅｓａｍｅｈｅａｔｉｎｇｐｒｏｇｒａｍｗａｓｕｓｃｄａｓｆｂｒｔｈｅ

５Evolv
ingproductswereidentifiedbypyrolysisexper
imentscarTiedoutinaquartzgIassrcactor，ｕｓｉｎｇ５００ｍｇｏｆｓａｍｐｌｅ・Ｂｒ

ＤＰＥ１３ｗｔ％
ＤＤＢｌ３ｗｔ％

３．ＲｅｓｕｌｔsandDiscussion

２．Experimental。
．
薯ＤＰＥＩ３ｗｔ％

DPE‑Sb(5)triphenylpentane，arelesscommonfbrthedegradationofpolystyrene，butcanbecxplainedbytheextraordinaryＢｒ｡
ケン･『?
'。

conditionsinthepresenceofaflameretardant・。

。
.
『◎廓｡
，GC‑ECDrev
ealedthepr
esenceofvariousbrominatedor
ganic
compoundsｐｒｅｓｅｎｔｉｎｔｈｅｐｒｏｄｕｃｔｏｉｌｏｆｆｌａｍｅｒetardedHIPS。

④目阿石屋︒全く

anerthethermaldegradation（Fig.３)．DPEreleasedmorebrominatedcompoｕｎｄｓｉｎｔｈｅｐｒｅｓｅｎｃｅｏｆＳｂｚＯ３ｔｈａｎｉｎits
absence・ＷｈｅｎＤＤＢｗａｓｕｓｅｄａｓａｎａｍｅｒｅｔａｒｄａｎｔ，thevicev
ersae
鮭ctw
asobserv
ed・
AccordingthedifIbrentstr
uctur
eso
f
thcflameretardantsused，thechromatogramsshowed
si
gni
fi
cantdi鮭renccs､
Whi
lcDPEfbr
medbromi
natedphenolsanddibenzofUrans，brominatedphenanthrcneswercobscrvedfromthedegradationofDDB・cL‑Ethylbenzene，
however，ｗａｓｆｂｕｎｄａｓａｐｒｏｄｕｃｔｏｆｂｏｔｈＤＰＥａｎｄDDBcontainingHPS，sinceitisnotderiv
eddirectlyfiromthedecompositionofa〕I】H‑5i卜

nameretardant，butresultedhomthereactionofHBrwith
styrene・ThcpathwayofthedegradationofflameretardedIⅡPS

１０２０３０４０５０６０difYersstrongI
yfiromthatof
polystyrene（Fig.
４).
Polystyreneundergoesachainfissioninthefirststep，
fbllow
edbytheunzip‑mechanismasthcmainreactionpathway､２，３TosomeRetentiontime(ｍin）Fig.
３.
GC‑
ECDofthedegradationproductsofflameretardedHIPScontainingSb2
03
produccdduringthewholedegradationrange，Hyd『ogenbromideasanindicatorfbrthedegradationoftheflame
retardantwasonlyreleascdduringthefirststageofthedcgradation・obviously，thepresenceofSb203triggercdthe
decompositionoftheflameretardantatalowertemperatureextent,back‑
bitingreactionstakeplace,resultingindimer
sandtrimers、Inthepresenceofaflameretardant，themechanism
changesduetothehighconcentr
ationoff
ieebr
omincradi
cals・
Afierthedegradationoftheflameretardantmolecule，ther
e
sult
i
ngbr
omineradicalstransfbrtheradicaltothepolymer
cha
in，
ｉｂｒ
ｍｉｎｇ
Ｉ
四r，
Sincethesecondarymacror
adica
li
s
mor
e
stablet
hant
he
pr
i
mar
yone
，
ｉｔ
ｃ
ａｎｂｅ
ａｓ
ｓ
ｕ
ｍｅ
ｄｔ
ｈａｔ
ｓｏ
ｌｅ
ｌｙｔ
ｈｅ
ｓｃｃondarymacr
oradicalisfbr
med,whichcande
composebytherelcasinghighconcentr
ationsofHBr，
SbB
r
3，
ａｎｄw
ater
､
lT
he
degradationoftheflameretardantproceededbyaradical
mechaniＳｍ，andbromineradicalswerereleasedinhigh
con
centr
ations・R
adicaltr
ansferr
eactionsw
iththepolystyr
encchainresultedinHBrandpolystyrenetertiarymacromdicals・
Thechainfissionresultedinasecondarymarcoradical，releasingstyrenebyazippermecha､ism，andapolymerchain
withanunsaturatedchainend，whichmightnotundergo
degradationimmediately,ｂｕtbeingthesourceoftheincreased
productionofby‑productsductotheoddchainend
Besidesstyrene，styrenedimersandtrimers，whicharecommonproductsofthepolystyrenedegradation，by‑products
inhighyieldswereobservedduringthedegradationofflame
retardedlⅡPS，Products，ｓｕｃｈａｓｔｏｌｕene，a‑methylstyrene，
1,3‑diphenylpropane，andmethyl‑phenyl‑naphthalenecanalso
befbundunderthedegradationproductsofpolystyrene，but
theirfbrmationwerestronglyenhanced・Products，suchas
cumene，1,3‑diphenylbutane，diphcnylpentadiene，ａｎｄ

unzip‑mechanismTheothersideofthcchainisstabilizedasan

alkeneanddoesnotundergoafimherdegradationunti
lanotherr
adicaltr
ansfbrtakesplace､
Eachr
adicaltr
ans化rleavcsanoddchainend,whichresultsinproductsdi鮭renttothoseobtained
fiomthedegradationofpurelⅡPS．
４．Referencesl・ＪａｋａｂＥ,ＵｄｄｉｎＭＡ,BhaskarT,SakataY､2003.JAnalAppl
Pyrolysis
68‑
69:
832.
Ｌｅｖ
ｉｎｅＳＥ,
B
roadbelt
L
J､
2008.
PolymDegradStab93:
９４１
３.PolccMJ,OcampoM,QuirkRP,WesdemiotisC､2008.Ａｎａｌ
Ｃｈｃｍ８０:347●一ＣＨ−Ｃ‐

一Ｈ１ＰＳ〆．Ｃ‐‑−−−−−陰 １１１'、､' 1,1 ｗい!）li，

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剛卿−７４ﾏ"音到ざ−…て躯。

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唖2の睡耐犀
一一二二b…
箕B
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Ｆｉｇ､４.DegradationpathwayofH1PSandnameretardedHIPS2２