Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles
Thermal decomposition of polyvinylpyrrolidone (PVP) in bulk and adsorbed on ultra-fine silica surface was studied as a model of thermal transformation of anthropogenic environmental pollutants on the surface of atmospheric micro-particles, Three stages of polymer decomposition with maxima at 150, 28...
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| Date: | 2001 |
|---|---|
| Main Authors: | , |
| Format: | Article |
| Language: | English |
| Published: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2001
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| Online Access: | https://surfacezbir.com.ua/index.php/surface/article/view/72 |
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Surface| _version_ | 1869291161631326208 |
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| author | Pokrovskiy, V. A. Bogatyrov, V. M. |
| author_facet | Pokrovskiy, V. A. Bogatyrov, V. M. |
| author_institution_txt_mv | [
{
"author": "V. A. Pokrovskiy",
"institution": "Інститут хімії поверхні НАН України"
},
{
"author": "V. M. Bogatyrov",
"institution": "Інститут хімії поверхні НАН України"
}
] |
| author_sort | Pokrovskiy, V. A. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2018-11-27T09:42:39Z |
| description | Thermal decomposition of polyvinylpyrrolidone (PVP) in bulk and adsorbed on ultra-fine silica surface was studied as a model of thermal transformation of anthropogenic environmental pollutants on the surface of atmospheric micro-particles,
Three stages of polymer decomposition with maxima at 150, 280 and 360°C were observed for bulk samples of PVP of average molecular mass about 10 000. Pyrrolidone (m/z 85) was the main product resulting from elimination of side groups in main polymer chain. Rupture of main chain itself resulting in elimination of vinylpyrrolidone (m/z 111) was the main process at high temperature and occurred in single stage with maximum at 360°C.
Thermal decomposition of PVP thin layers on the surface of ultra-fine pyrogenic silica was also studied. Samples were obtained by adsorption of PVP on Aerosil A-300 surface and contained 5.8, 16.9 and 29.3 mass % of polymer. Unlike to silica-free samples, only two maxima of 85 m/z elimination (at 120 and 360 °C) were observed, majority of pyrrolidone being produced during the high-temperature stage. Details of polymer decomposition depended essentially upon portion of adsorbed PVP. The conclusion was done that adsorption slows down the conformation exchange and effects the process of polymer decomposition. |
| first_indexed | 2025-07-22T19:30:03Z |
| format | Article |
| fulltext |
CI{ЕNIISORPTIONANDT'нЕRMALDЕсoNIPoSITIot{oF.
PoLWNуl,piккoLIDoNЕ ADSORBЕD BY Р\.ROGЕNIс
SILICA As N,IODЕL oF SURFAСЕ RЕAСTIONS oN
ATNIOSPIIЕRIС МIсRoРARТlсLЕs
V.A. Pоkrоvskiу аnd V.M. Bоga "vrov
Iпstittltе of Suфсе Сhеnlistry, Nаtioпаl Асаdеmу,, of Sсiепсеs
i,i. ioi,,,o', str' ]7, kуiv. l б1, 0з680 UKIaINЕ
t.}.:Hъ..."mроsition оf рoli,'l,inr{р1'гго.lidonе
(P\.P) in buik and a.lsoгbеd on ultгa-finе
siliсa surtЪсе was stuсtrеd a"s - .JoJ ог inЪгmai *u"iь,*uunn ol anthrоpogеniс еnviгоnmеntal
ffilh::::;.,,ЧlТ:,;:,x;1:'.'"ff'H;";li'жH'a at 15!,2^8О anсi]б0oС] ц'еrе obsегvеd
fоrbulk samрiеs oгpr.p.'uiu"J,Ь i,or..uiu, *l.' uьo..i tо ооо Pуrrоlirlоnе (miz 85) rvasthе
main pгoduсt геsulting tto*Ъri*inutiоn of sidе ;;й' i1 п1ai1|:ч.T.:'.huin Ruрtuге of main
сhainitsеlГLеsultinginеiiminatiоnolviпуtpупоlrdоnе(пl/zii1'lъ'a';thеrnairiproсеSsathigh
temреIaturе and oссuггеd in singlе stagе u'ith nraxinium at jб0"С
Тhегmal dесompоsrtion oТ pvp ihin lu;u.,, o,' th. ,u.Гo.. оf '-rltгa-finе руrogеniс siliсa was
aiso studiеd' Samplеs *е.е о.эtui,..с ьу uoso,|ii.,n oг в}'г o3 Aеrosil A-З0O suгfaсе and
сontainеd 5 8, 15 9 anо 29 3 mass 9,а оf pоiуmег L,hiikе tо "lillсa.tlее sarnplеs, onlу two maХlma
of 85 m/z еlimination (at 12О and 3бO "с; ,u.i. оbsеrlеd, majогitv of pупolidonе bеing
pгoduсеd during thе high-tеmpегatuге stagе, Б.i.li' of рolуmег .
dесompоsition dеpеndеd
еssеntialiу uoon oon'on,;i,^;';Ь;;;lir, if;..*.tu'ion,".' don. ttrat adsоrption slows down
thе сonfoгпration еxсhangе and еffесts thе ргс-lсеss of polупrеr dесоmposrtion,
lntroduсtion - f ^аЬ ^.*^onЬprc Тhel. hai.е
Aеrosolsaгеliquidоrsolidрaгtiсlesthatarеpгеsеi1t-in.Еarthatmosphеrе.Thеуhavе
diamеtегs fгom l nm to ovеI than 1O '..,
*u,i oiiй.i, *u'' bеing in-thе sizе rangе Гrom about
0.1 to 2'5 mсm' Thеу огiginatе frorrr a *io* uu,i!tу: оJnаtural anianthгopоgеniс proсеssеs that
ехhibit a largе,p.tiui"-"i t;;p;;;i',.,iuьiti,у ihе. pгoduсtion mесhanisms aге: (1) dirесt
injесtion of paгtiсlеs i" ,h. ;;;Ь;ph..., mostlу ч,.l:Ь.':l"^ijj::::'.'
геsulting in so-сallеd
primary (and сoarsе,.n.,i,, 1 mй aегosоls) and'(2) transfoгmatiоns of inoгganiс and organlс
gasеous ргесuгsoгs 'nto.,..onou.у
(and finе, . t*.'i aегоsols. Aеrosols рleу an impoгtant rolе
inatrnosphеriссhеmrstry,havееffесtsonьu'unandanimalhcalthandwеlfaгеаnda]so
influеnсе сlimatе' Rесеntly, rеnеrvеd intе.еst''i t.йlrеalth гisks of aеrosols had bееn gеnегatеd
bv thе fi:rding .o,,.luiй,Ь.i*..n inсгеasеd пroпality and thе сonсеntration oГ finе aiгboгnе
;;;t;;i;;;tгopофn arеas in thе Unitеd Statеs [1].
Inadеquatеlу .";;,;il; aе,u,oi pottutiоn oi iьЁ вu,tь'' atnrosрhеrэ bу pтoduсts оf human
industгialaсti\,ityhadalrеadусausеdsоmеunprеdi.lubl:.ol::.1::::".*duеюshiftofnaturailу
оссuгring wеll-balanсеd сhеmiсal геaсtions in сompiеtеlу urrехpесtеd waуs. Aеrosols and dust
miсгo-paгtiсlе, or inоu,-t.iui oгigin providе^suгfaсеs fo' hеtегogеnеous геaсtiоns involving stagеs
of adsoгption oг inaпtаuur .J,opЬuna, г,o,]1-'i. gu, рl]as." and .Jеsorрtiоn рroduсts, oхidе
miсгo.paгtiсlе, оa,ьoni,iТbу thе pгoducts оf сomБustiЬn aге thе main dust pollutants of thе
atmosрheге in inсustria]'i.J, ,"r1.i. thе .oai is_a fi.,.t Тhough thе еffесt of suсh dust miсro.
oaгtiсlеs on thе human organisп-r has nоt ь. ,,uj,.J in аеtuit, itls сlеаr that сhеmiсal геaсtions of
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сoal is а fuе1 lhоugh tirе еi}Ьсt of suсh dust miсrо-рartiсlеs on thе human oгganism has
not bе studiеd rn dеtaii, iт is сlеaг that сhеmiсal геaсtions of biоlogiсally nеutгal
сomрounds оn thе surfaсе оf сaгbonizеd оxidе рaгtiсlеs may rеsult in thеiг сatalytiс
tгansГoгmations into toхiс сompounds. Dеspitе thе largе bodу litеraturе on the
invеstigation of aгоmatiс propeгtiеs and thеir rеaсtiоns a lot of quеstions on thе
mесhanisms оf tгansformation оf suсh сompounds геmains.
Мass spесtгomеtry is a mеthod of сhoiсе in thosе studiеs sinсе it pгovidеs idеal
ехpегimеntal pгеssurе. tеmpегatuге and ionization сonditions foг thе simulation оf rеal
pгoсеssеs in thе аtmоsphеrе, Соrnmon iritеrеst in thе apрliсation of thе dеvеloped
powегful mass spесtromеtriс tесhniquеs to the uгgеnt prоblеms of thе Еaпh sсiеnсе whiсh
гelatе to pоllutron сontrоl of human еnviгоnmеnt has bгcught tоgеthег Swiss and
Ukrarnian rеseaгсh tеams in thе fгaтnеrvоrk of thе pгojесt ..Сhеmisoгption
and
dесompositiоn of tохiс сomроunds on охidе miсro-paгtiсlе suгfaсеs'' со-oгdinatеd by
Ргof' Rеnatе Zеnobi' Неad оf Analуtiсal Сhеmistry Dерaгtmеnt ЕTH, Zr.rriсh' Rеsults
obtainеd in this pгojесt pгori,ltltеd fuттhег inrеstigation of surflaсе геaсtioгrs оn thе suгfaсе
of ultra-finе рaгtiсlеS modеiins atmоsphегiс aегosols L:- i l ] аnd lеad authoгs to
undегsianding thе nесеssity с-lf invеstiеation оf thегmal dесompоsitiоn of рolуmеr systеms
adsorbес] оn thе ultra-finе oхidе suгГaсе'
P\P w,as с:hоsеn as a rnodеl systеm. Thrs рolymег is known to рossess a sеt of
phуsiсo.сhеmiсal pгopепiеs prоviding its еffiсiеnt intеrасtiоn with siliсa suгfaсе. on thе
othеr sidе, it is usеd in рhaггn,зсеutiсs iIldustry as a сomponеnt оf mеdiсinеs' lt stimulated
ouг intегеst to studiеs оn thегmal tгansfoгmatiоn оf P\,Р in sub-mоlесulaг laуеrs of PVP
on ulra.finе siliсa'
Ехperimеntal
Меdiсal РVP prоduсеd by кSintvital>' Russia, was usеd in prеsеnt studу. Aveгagе
molеcular mass was l070О Dalton P\? produсеd bv К-15' Fluka and anothеr batсh oГ
PVP pгoduсеd by <Sintvital>, Russia' и,еrе usеd as rеfеrеnсе samplеs Pугogеniс siliсa
was Aегosil A-300, with suгfaсе areaЗ2О m,/g, produсеd bу <Khloгvinyl>, Ukrainе.
Тhе proсеduге of samplе prеparation was as fоllows 10o% aquеous solution of P\{P
in distillеd ц.atег was prеpaгеd as ц,еli as dispегsiоn of siliсa Thе сalсulated amоunt of
P\P solution was addеd tо dispегsion. thогoughlу mixed, and aftег onе-houг.pausе
deрositеd as a thin la1'ег on glass suгfaсе. Thеn samрlеs ц,eге dгiеd at thе tеmpeгatuгe
80 "С fог 4-5 houгs, Thе produсt w,as thеn disрегsеd and additiоnallу tгеatеd foг 1 houг at
thе tеmpегatuге 80 .C.
Caгbon сontеnts \\,as mеasurес! bу ехpгеss ana|у,zеr .\N.7529, Russia, by buгning
3amplе-s in oxуgеn fluх at 800 "с' Sресifiс suгfaсе агеa оf thus pгерaгеd samplеs was
еstimatеdbу 1oв, tеmpегatuге argon dеsoгрtion.
IR speсtгal mеasuгеmеnts wеге сonduсtеd on N{-80 aрparatus (Kaгl Zеiss, Jеna),
Spесtгa оf individual P\T samplеs wеге mеasured bеing prеlinrinaгilу pгеssеd with KBr
(2.5 пg of P\? in ЗC0 mg oГKBг); siliсa-соntaining samplеs u,егe pгessеd at 30 atm to
obtаin pеllеts of dеnsitу 12-15 mglcm,,
Тhегmal dесomposition of adsoгbеd polymеr in oхуgеn.fгее atmosphеге was
analуzеd aссording tо thе ргoсеduге dеsсгibеd pгеviously Г2, 11] Samplеs of about 1mg
wеight r,vеге plaсеd in a quaпz-mоl1'bdеnurn tubе, еvaсuatеd at 1O.'Pa anсJ thеn attaсhеd
to thе in|еt sYstеm of a \{Х.7-з04 (Ukгainе) mass spесtrоmеtеr. Thе геaсtoг.to.mass
spесtгomеtеr intегfaсе inсludеd a high-vaсuum r'alr,е rvith an оrifiсе of diamеtеr 5 mm
and tlrе inlеt ttlhе of 20 сm !сngth' rvhiсh rr'а.i kерt аt l50 "С Тhе гсасtion sрaсе was opеn
in thе i.;n-stlrrгсе diгссtion. and a: thе hеating ratе usеo (аbout о l K s') thе obsегvеd
intеnsil}' tlt.:hе iоn сuггеnt t\,as ехресtеd tо bе propoгtional tо dеsoгption ratе so that
diffi"rsiоп inhibition might bе nеglесtеd Wе assumеd that quаsi.statiоnaгy соnditions wеге
aсhiеvеd rvhеn thе shapе and position оf dеsогption pеaks cid nоt dеpеnd on thе
349
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ш '..
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hLL :
l .-l
!'ii
i
Rеsults and disсussion
Good solubilitу оf polymеr in watег allows obtaining watеr dispегsions siliсa-P\? in widе
rangе of сomponеnt гatios, Pгеsеnсе of silanol groups on thе siliсa surfaсе as wеll as tегtiary
nitrogеn and сaгbonуl gгoups in polуmег molесulе providеd foг strong adsoгption intегaсtion. It
also has bееn shown that in thе hybrid PVP-siliсa matетial thе hydгogen bond formation has
bееn obsеrvеd binding silanol and сarbonуl gгoups.
Propепiеs of P\?-siliсa samplеs synthеsizеd in aссoгdanсe with prеviously dеsсribеd
procеdurе arе summarizеd in Тablе i.
Tablе 1
Сhaгaсtегistiсs PVP.silica samplеs
Samplе numbеr
Contеnt ofсarbon
Сontеnt of PVP (wеight %)
Сontеnt of PVP (mmolе/g))
Surfaсе area.m,lg.
3.8
5.8
0.52
258
1 1.0
16.9
15?
183
190
29.з
2.64
65
,""--ъс-q}Juи*vw
I
,N
^./ \^---_O
H.'с'\ I
H2с
-
сH2
Sсhеmе I. Еlеmеntary link of polyvinylpyгrolidone
Thе numbег of еlеmеntary links in Samplе 1 (sее Tablе 1) was сhosеn to be еqual to thе
numbеr of silanol groups on ultra.finе siliсa surfaсe. But' as all thе links of polуmeг саnnot bе
distгibutеd unifoгйly thгoughout thе suгfaсе, IR spесtra showеd thе pгеsеnсе of fтее valеnсе
Sio-H bonds (3750 сm.'), not bound with сarbonyl groups of P\T. Inсrеasе of polymег amount
in Samplеs 1-3 rеsultеd in inсгеasе of сaгbonyl gгouр linе intensity of IR spесtеr and,
simultanеously, in dесrеase of Sio.H linе intеnsity up to its сompletе disappeaгanсе. Sсhеmе II
below illustгatеs thе probablе mесhanism of intегaсtion of еlementary link with silanol group of
thе ultra-finе siliсa surfaсe.
It is сleaг from thе tablе that spесifiс surfaсе aгеa of the samplеs PVP dеpеnded upon
amоunt of рolymer on thе siliсa surfaсе' Whilе amount of polуmег inсrеasеd, Sio2 paгtiсlеs
bесamе largег and suгfaсe arеa dесreasеd.
Thе molесular mass of P\{P used in prеsеnt study having avrragе molесulaг mass was
10700, whiсh сorгespondесJ to appгoхimatеly 94 еlemеntary links shown (sее Sсhеmе I), pius
tеrminal gгoups
350
.:..? in widе
:- :) teгtiary
rт::::сtion. It
:r-:tion has
' :эsсribеd
rt-:еd upon
!'. : :aгtiсlеs
l.iU - зss was
пе-: I), plus
: .:.зl to thе
ro. :зnnЬt be
A.:.= valеnсе
$t -.: amount
i ;::tеr and,
в S:hеmе II
k . *егoup of
,,с(**сl.l
i-\
' or'c--'"/
,'14'o-
J,.ZГr
Sсhеmе П' Adsоrption oГеlеmеntary link on silanol gгoup
T*'o mass spесtгa of adsorbеd P\T deсomposition arе pгеsеntеd in l-,to I
l_
l, arb, u
I
2 881
l;щi lя a
1l
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I
il 30
1!!J l ll?д
1 I, i--142 ,85
'"1 ill iiot 1
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-1i il r.' '!_ i. [ * _ _. _r,2! 4з Б] 80 ]с: ]20 ]40 ]80 2m trg.
mlz
Fig.1. Typiсal mass sресtгa of adsoгbеd polymеr dесomposition at сharaсtеristiс
tеmpегaturеs of about lз0 (a) and 360 "С (b) сoпеsponding to low-tеmpегatuге and high-
tеmpеratuге maхimum ratеs, as it is shown in Fig. 2 (а, b, c) bеlow.
In Fig 2. thегmograms aге prеsеntеd of pyrтolidone (at 85 m/z) and vinylpyггolidonе (at
111 m|z) dеsoгption in thе wholе temрегatuге intеrval foг siх samplеs, thгее of whiсh (a, b, c)
arе siliсa-PVP mixturеs with diffегеnt гatios of сomрonents, thrее othеrs (d, e, f) are bulk PYP
samplеs of diffеrеnt oгigin'
|, aгb.u
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О 12o 24o з60 480 6о0
тemperatuгв' oc
Таt
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0 12o 24o 360 480 60о
Тemperafurа, oC
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4 0i
|, eгb,u ] 9
^^l:l t,'4ot 1 '
20] ,/r,."]
z-У,Y'ц*.0 1ю 240 з60 480 600
Твmperatuгe, oC
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1 -1 2ool i" t\I /\ i^
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''*rt/
\| -1 , ,*-/ , *,*-*-
o 120 24o 360 480 60о
Тemрrature, oC
2A
10
Fig. 2. Тhеrmogгams of pугrolidonе (1, rt/z = 85) and vinylpyггolidonе (2, пt/z |||)
rеsultingfromP\?dеstruсtion: a-Samplе1;b.Samplе2; о-Samplе3; d-<Sintvito,Russia;
e - K-15, Fluka; f - anоthег batсh of кSintvitu, Russia.
Quantitativе mass spесtromеtгiс data for tеn main сompоnеnts of mass spесtra on thеrmal
dесomposition of Samplеs l.3 and bulk PVP at two tеmpегatuгеs оf maхimum гate of polуmer
dесomposition aге summaгizеd in Тablе 2.
As it is sееn from pгеsеntеd data' thе thегmal dесompоsition of P\T thin layегs was
studiеd on thе suгfaсе of ultra-finе pyrogеniс siliсa in сomparison with oхygеn-free thеrmolysis
in сondensеd state. Samplеs l-3 wеrе obtainеd bу adsoгption of P\T with avеragе molесular
mass about 10 000 on Aеrosil A.300 suгfaсе and сontainеd 5'8' 16.9 and 29.3 mass 0k of
polymeг, At lеast thгее stagеs of deсomposition werе obsеrvеd foг bulk, siliсa-frее P\rP, whiсh
геsultеd in formation of pyrгolidonе (m/z 85) as thе соnsеquеnсе of еlimination of sidе gгoups
fгom main polymег сhain' Тhis ргoсеss oссuггеd in thе wholе tеmpегatuге interval of
dесomposition and dеmonstгatеd maхima at 150' 280 and 3б0"с. Dеpolуmегization of main
120 240 360
Temрerаtura, oC
з52
Тabiе 2
Теn most intеnsе сomponеnts of mass spесtгa obsеn,еd
systеms and bulk P\,? at tеmpеratuгеs of maхimum гatе
intеnsity and most signifiсant linе aге pгintеd bold'
in ТPD ехpегimеnts of PVP.siliсa
of polymег dесomposition. Watеr
Samplе PVP 1
Т.,- oС 1з2
rn/z 28
% 100
30
49.2
85
41.5
40 44
16,I 15.4
27
1з.8
u1 HzO
564
42 4I
4]l5 40.0
56
6.9
Тn'"* oC 5>t
m!z
"k
28
100
30 4t 16ЧL 56 2't
48.9 2676.\ 65.9 б4.8
85
52.3
40
18.2
.+J
14.8
lll
12.5
HzO
103
/.J
I 216
Samolе PVP 2т .. t2l
NUz
%
28 Аa
an?
85
1'' 1
41
'7 1.6
40
19.9
56
14.8
lll HzO
129
84
142
30
100 98.9
29 27
,s n )r 6.
Т,,",. "С 368
\1,2
atЬ
26
t00
30
72О
42
624
41
591
56
54.з
ltJ
296
27
1^ 1
Э/
20.4
l1l
12.9
HzO
50.5
29 85
49 5 4r.9
\.r,'z 2g
% 1О0
30
у| э
А.
780
85
1 66.6
40
20.7
56
t4.7
HzO
129
an
^1
)64 111
84
I Z.O
111
oС
М/z
%
28
100
56
7 4.1
з0
.72'з
a1 чэ
20.1
40
19.6
1tl
18.7
Еzo
45.5
А 1 Аna I aL
62.5 6З.4
85 29
37.5 з2 |
)-r-
4t 85 27 29 40 3i 56чz
6з '9 62.8 59.9 з0'2 22'1 |7,4 1'6 2 14.0
HzO
23.3
T."* oС 39з
l п/z l11)
1;i,,, Russia;
эn thфmal
l эf polymеr
: laуеrs was
: :hermolysis
:е molесulaт
mass 7o of
Р\fP, whiсh
: sidе groups
intеrval of
сf main
NUz 28 56 41 27 42 57 29 з0 39 l11 85 Hzo
ss9/o 100 88 5 41.6 40.7 39 8 32 7 27 4 26.5 25.'7 20,3 ll.5 1.1
сhain геsulting in formation of vinylpyгrolidonе (кtlz \11) oссuпеd in onе stage at tеmpеratuге
highег than 300.C and pгovidеd at this tеmpегatuге main сontгibution to mass spесtra'
Unlike to siliсa-freе bulk samрlеs, only two stagеs of 85 rnlz foгmation wеге obsеrvеd for
P\.P adsoгbеd on siliсa suгfaсе, thеiг maхima bеing loсated at about 120 and збOoс' In adsorbеd
;tatе lhе majoгity of pyпolidonе was pгoduсеd in thе pгoсеss of thе high-tеmpегaturе stagе. For
;iliсa-P!? samplеs, diffегеnt to bulk samplеs, ruрturе оf main сhain rеsulting in foгmation of
".inylpуггolidоnе (rn/z l 1 1) rvas not thе main pгoсеss obsегvеd at 360oC.
353
lt is tо bе notеd also that, diifеrеnt to dесоmposition ofl bulk P\{Р, thегmal
dесоmposition oГ P\P on thе silica suгfaсе геsultеd in сarbonization. Aftег vaсuum
trеatmеnt at 600 "С samplеs bесamе blaсk'
Тhе thеrmal dесompositiоn in all samples is similaг as foг molесular ion of
vinуlpугrolidonе (1lii rrl/z) This ioп apреars mainly at thе last high-tеmpегatuге stagе
and is synсhronizеd with othег pгoduсts of high tеmpегatuге P\P dесomposition.
It is intеrеsting to notе that ratiо of maхima intеnsitiеs 85 rrtlz (high-
tеmpегaturе/low tеmрегatuге) was thе greatеst foг samplе 1 whiсh сontains thе least
amoЦnt of adsorbеd pol1'mеr. And thе гatio dесrеasеd whilе thе amount of pоlymeг
inсгеasеd. Also dесгеasеd тhе геlativе amount of othег dесompositiоn pгoduсts and
геaсhеd minimum for bulk samplеs. For ехamplе, for thе iоn at 41 rnJz the high-
tеmpеraturе/low tеmpеratuге гatio was 7.1, 3.4, and 3.0 foг thе samplеs 1-3 and was еqual
to 2'7 for thе bulk samplе
It was obsегvеd that mесhanism of thermal dеstruсtion of polymег at high-
tеmpегatuге also dереndеd uроn thе amоunt oГ аdsoгbed P\P Thе rеlativе оontгibution
of pyггolidonе in dесоmposition pгoduсts inсrеasеs with thе inсreasе of rеlativе amount of
adioгbеd рolуmег, It mеans тhat in thin adlaуег thе ruptuге of pугrolidonе ring fгоm main
1-nu..o,oi.сulaг сhain is most pгоbablе. Inсгеasе of fiее pоlуmеr in thе mixtuге provides
inсrеasе of vinуpуrгolidonе in thе (lll m/z) in mass spесtгa as a rеsult of dеstruсtion оf
main рolуmеr сhain, so that thе гatio Iвs/Irrr bесomеs lеss than unit for bulk рolуmеr'
Тhе obsегvеd dеpеndеnсiеs is most obvious from Fig 3 in whiсh гatios of
intеnsitiеs for rn]z 85 and rтlz ill arе pгеsеnted at high-tеmperaturе maximum of
dесomposition as a funсtion оf PVP amount in pyrogеniс siliсa prеsеntеd in mass 0% of
thе mixtuге.
П=t-
40 60
PVP, %
80 100
Fig. 3. Rеlativе intеnsitу Iвs/lrrr at high-tеmpеratuге mахimum as a funсtion of mass-
p",...nt of P\P in thе miхturе pоlymeг-siliсa for thгее ratios of PVP-siliсa is
pгеsеntеd (Samplеs i' 2, 3) Pоint..bulk,'сorгеsponds to bulk PVP samplе.
Fог polymегs оf vinу1 сontaining sеriеs (polyvinyl еster, polyvinуl aсеtatе,
po1yvinyl Ёьtoгiое; dесomроsition in bulk staгts with ruptuге of sidе bonds in main
pory'.i сhain, as ii is shorvn in Sсhеmе III Foгmation of hydгogеniс bond bеtwееn C=o
i,oup una silanolof thе siliсa suгfaсe maу block foгmation of suсh a сomplеx and pгеvеnt
Ьom formetion руrгоlidonе as a produсt of po1уmег dесomposition,
354
5
:4
\:
{3
aо
s2
lal
lm --..Summarizing
obtainеd геsults, it should be statеd that thеrmal dесomposition oГPVP in adsorbеd statе was сhaгaсtегizеd by dесгеasеd numbег of deсomposition stagеs in
сompaгison with bulk samplеs. Adsoгption of P\? on thе siliсa suгfaсе impеdеd thе
H"д
a*
.-- -\WНC H
li
,Ntt .r'.О,/' 'a'(7
\/\_,/
H.i.Ё
-_:>
..:|\^/мпU
-+T,| ^ lt
| ,,
*\.--o I I N-*,-y'o
li / i.---*\ iL"j"
&
(:'
Sсhеmе lII. PossiЬlе mесhanism of dеstruсtion of pоlуmеr main сhain.
ruptuге of pуггolidonе сyсlеs fгогп main polymег сhain at low-теmpегatuге stagе.
Intегaсtion of P\P ц'ith silanol gгoups of siliсa suгfaсе impеdеd thе high-tеmp..uй
depolуmегization pгосеss геsulting in dеsoгption of vinylpyггolidonе. Тhе сonсlusion was
donе that adsoгption slоws down thе соnfoгпlаtion e*сhangе in P\|P, thus effeсting
еssеntially thе рathways of P\? thегmal dесomposition and displaсing еquilibrium tБ
highег thегmal stability of polymег сhains' Thir faсt should bе takеn into aссount in
еstimation oГ геaсtion рathways and гatеs on thе suгfaсе of soiid atmospheгiо
miсrоpaпiсlеs oГ industгial oгigin
Aсknowledgeпrеnts
Authoгs aсkлowlеdgе Prof Rеnato ZenoЬi Неad оf Analрiсal Chеmistry Depaгtmеnt of
ЕTH, Zuгiсh, Thе Pгojесt сo-oгdinator of thе SпNSF Grant 7t,кPJ048657 ..Chеmisoгption
and deсomposition of toхiс сompounds on oхidе miсro-paгtiсle suгfaсеs', гor ьеtpzut
disсussions and pегmanеnt intеrеst to thе pгеsеnt study'
Rеfеrеnсеs
1. An Association bеtwееn aiг pollutiоn and moпalitу in siх US сitiеs i D'W, Doсkеrv.
C'A. Pope, Х. Up еt al. //N. Еng. J Меd. - 1995 - V з2g -P. 1.|5З.\759.
2 Pokovskiy V.А Tеmpегatuге-pгogrammеd dеsoгption mass spесtгometгy (TPD МS)
of disрегsed oхides/i Adsoгptiоn Sсiеnсе & Tесhnologу _ lэсil,_ v.l4, N 5 _ P. 301 _
з1.|.
3. Tеmperatuге-programmеd dеsoгptiоn mass spесtгomеtry of chеmiсally modifiеd
dispеrsе oхidеs as modеls of industrial aегosols / V.A Pokovskiу, R. Zenobt'
V'M. Bogatyr'ov, V.М. Gunko // Еnviron. Sсi & Pollut Rеs. . 1998 - V. 5. N 3. -P.192
4 Thе ozonе-dеplеting volatilе oгganiс сompounds in Antагсtiс iсе / V.I. Bogillo, V A.
Pokrovskiу, o'V. Kuraеv, P F. Gozhуk // Еnviгon. Sсi. & Pollut. Rеs. - 1998.. V. 5'
N3 -P 136
5. Tеmpеratuге-pгogтammеd dеsoгption mass speсtromеtry of сarbonized siliсa suгfaсе /
V A' Pоkгovskiy, R. Leboda, V'V' Tuгov, D Charmas, J, Rусzkowski// Сarbоn _
1998 - N i7. - P. 10З9-1О47
6' Pokrovskiy V'A., Bogillo V'l', DаЬrowski A Adsorption and Сhеmisoгption of
3s5
oгganiс Pоllutants on thе Solid Aегosols Suгfaсе //Adsorption and its Appliсation
in Industry and Еnviгonmеntal Protесtion. - У. 2. (Studiеs in Surfaсе Sсiеnсе and
Catalуsis. . v l20B) - A. Dabrowski, Еd _ Amstеrdam: Еlseviег, l998. - P,5.71.6з4.
7 Pokгovskiy V A Tempеraturе.pгogгammеd dеsoгption mass sресtгometry ll
Pгoсееdings of thе 28. Intегnational Vaсuum Мiсгobalanсе Тесhniquеs Confеrепсе.
- Kiеl,, 1999. - P. 22-24.
8. Gunko V'V,, Lеboda R., Pokovskiy V.A. Pathways foг dесomposition of
phеnуlеthanol bound to siliсa suгfaсе i/ Polish J Chem - 1999 ' - У '
.7з
. - P. 1з45- l3 56
9 ТPD lv{S Invеstigation of Carbonizеd Siliоa Synthеsizеd from Phеnуlеthanolе /
V'A. Pokгovskiy, R Lеboda, B' Сharmas, C.J. Ryсzkorvski// In' matегial oil Pollution
InternationalСоnfегеnсе ( Poland, August 29 - Sеptеmbег 3' 1999) - P. 84 - 89.
10 Influеnсе of Caгbonization and Poгositу on thе Chaгaсtегistiсs of thе Interphasial
Laуеrs of thе Watеr in Aquеous Suspеnsions of Dispегsеd Paгtiсlеs / R. Lеboda,
V. A Pokrov skiу l l Мatегial oil Pollution International Confеrenсе. (Poland,
August 29 - Sеptеmbег 3, i999) -P .|1.75.
i i Pokovskiу V A Теmpегatuге-pгogrammеd dеsoгption mass spесtгometry llJouгnal
оf Тhегmel Anal1,sis and Caloгimеtгу - 2000' -У 62,-P,40'7-415.
356
|
| id | oai:ojs.pkp.sfu.ca:article-72 |
| institution | Surface |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2025-07-22T19:30:03Z |
| publishDate | 2001 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | surfacezbircomua/e8/02088b07f0b618202041ad9cb1eefee8.pdf |
| spelling | oai:ojs.pkp.sfu.ca:article-722018-11-27T09:42:39Z Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles Pokrovskiy, V. A. Bogatyrov, V. M. Thermal decomposition of polyvinylpyrrolidone (PVP) in bulk and adsorbed on ultra-fine silica surface was studied as a model of thermal transformation of anthropogenic environmental pollutants on the surface of atmospheric micro-particles, Three stages of polymer decomposition with maxima at 150, 280 and 360°C were observed for bulk samples of PVP of average molecular mass about 10 000. Pyrrolidone (m/z 85) was the main product resulting from elimination of side groups in main polymer chain. Rupture of main chain itself resulting in elimination of vinylpyrrolidone (m/z 111) was the main process at high temperature and occurred in single stage with maximum at 360°C. Thermal decomposition of PVP thin layers on the surface of ultra-fine pyrogenic silica was also studied. Samples were obtained by adsorption of PVP on Aerosil A-300 surface and contained 5.8, 16.9 and 29.3 mass % of polymer. Unlike to silica-free samples, only two maxima of 85 m/z elimination (at 120 and 360 °C) were observed, majority of pyrrolidone being produced during the high-temperature stage. Details of polymer decomposition depended essentially upon portion of adsorbed PVP. The conclusion was done that adsorption slows down the conformation exchange and effects the process of polymer decomposition. Thermal decomposition of polyvinylpyrrolidone (PVP) in bulk and adsorbed on ultra-fine silica surface was studied as a model of thermal transformation of anthropogenic environmental pollutants on the surface of atmospheric micro-particles, Three stages of polymer decomposition with maxima at 150, 280 and 360°C were observed for bulk samples of PVP of average molecular mass about 10 000. Pyrrolidone (m/z 85) was the main product resulting from elimination of side groups in main polymer chain. Rupture of main chain itself resulting in elimination of vinylpyrrolidone (m/z 111) was the main process at high temperature and occurred in single stage with maximum at 360°C. Thermal decomposition of PVP thin layers on the surface of ultra-fine pyrogenic silica was also studied. Samples were obtained by adsorption of PVP on Aerosil A-300 surface and contained 5.8, 16.9 and 29.3 mass % of polymer. Unlike to silica-free samples, only two maxima of 85 m/z elimination (at 120 and 360 °C) were observed, majority of pyrrolidone being produced during the high-temperature stage. Details of polymer decomposition depended essentially upon portion of adsorbed PVP. The conclusion was done that adsorption slows down the conformation exchange and effects the process of polymer decomposition. Thermal decomposition of polyvinylpyrrolidone (PVP) in bulk and adsorbed on ultra-fine silica surface was studied as a model of thermal transformation of anthropogenic environmental pollutants on the surface of atmospheric micro-particles, Three stages of polymer decomposition with maxima at 150, 280 and 360°C were observed for bulk samples of PVP of average molecular mass about 10 000. Pyrrolidone (m/z 85) was the main product resulting from elimination of side groups in main polymer chain. Rupture of main chain itself resulting in elimination of vinylpyrrolidone (m/z 111) was the main process at high temperature and occurred in single stage with maximum at 360°C. Thermal decomposition of PVP thin layers on the surface of ultra-fine pyrogenic silica was also studied. Samples were obtained by adsorption of PVP on Aerosil A-300 surface and contained 5.8, 16.9 and 29.3 mass % of polymer. Unlike to silica-free samples, only two maxima of 85 m/z elimination (at 120 and 360 °C) were observed, majority of pyrrolidone being produced during the high-temperature stage. Details of polymer decomposition depended essentially upon portion of adsorbed PVP. The conclusion was done that adsorption slows down the conformation exchange and effects the process of polymer decomposition. Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2001-06-10 Article Article application/pdf https://surfacezbir.com.ua/index.php/surface/article/view/72 Surface; No. 4-6 (2001): Chemistry, Physics and Technology of Surface; 348-356 Поверхность; № 4-6 (2001): Химия, физика и технология поверхности; 348-356 Поверхня; № 4-6 (2001): Хімія, фізика та технологія поверхні; 348-356 3154-8091 3154-8083 en https://surfacezbir.com.ua/index.php/surface/article/view/72/71 Авторське право (c) 2001 V.A. Pokrovskiy, V.M. Bogatyrov |
| spellingShingle | Pokrovskiy, V. A. Bogatyrov, V. M. Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_alt | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_full | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_fullStr | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_full_unstemmed | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_short | Chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| title_sort | chemisorption and thermal decomposition of polyvinylpyrrolidone adsorbed by pyrogenic silica as model of surface reactions on atmospheric microparticles |
| url | https://surfacezbir.com.ua/index.php/surface/article/view/72 |
| work_keys_str_mv | AT pokrovskiyva chemisorptionandthermaldecompositionofpolyvinylpyrrolidoneadsorbedbypyrogenicsilicaasmodelofsurfacereactionsonatmosphericmicroparticles AT bogatyrovvm chemisorptionandthermaldecompositionofpolyvinylpyrrolidoneadsorbedbypyrogenicsilicaasmodelofsurfacereactionsonatmosphericmicroparticles |