Ionic liquids as convenient latent hardeners of epoxy resins

Ionic liquids as convenient latent hardeners of epoxy resins

PoLTMERY 200]
18, nr
11
1Ż
833
KITZYSZTOF KO\'\'ALCZYK, TADEL SZ SPYCHAi)
Technica] Univ€rsjĘ' oi szczecin, Pol)'ncr lns titu tc
ul. Pulaskiego I0,70-332 Szczccin
Ionic liquids as convenient latent hardeners of epoxy resins
RĄPID COMN4L}IICA'TIoNS
Summary
(BN{ITF) rvas
- l-Butyi'3'mcth)'limidazolium tetrafluoroborate
used as a ionic liquid haldener of th€ EPidian 6 dian ePoxy lesin'
Eflect oI
('C
BMITF (0.5-5 phr) and hardcning timc at 190
on ciosslinking ol dre resjn
was dcicrmincd or thc basis ofglass transition temp erature (7,,) values.ln1'estigatims wcrc pcrformcd using DSC, FTIR, DNITA and rheomciry. ts\4lTf
9holvs features of a ]atent hald€n$ anc1 cou]d fincl aPplicai('1 c 8' in adhe
s;ve, cast ar1d coaiing cońPoSiiions.
Key words: culjng agcnt, ]-buiY1-3-n1cthv1in1idazo]jum teilaflr.roroborai€,
cpox}' Iesin, latent ]rald€n€ł
closs]inłing'
The crosslinkjng proccsses oi cpoxy rcsins can bc
c]assified as addition or ionic poh''m€rizatiolr
reactions'
The mosi importani jonic polvnerizaiion caialysis inchdc Łcrtjarv amjn€S (causjng ihc anionic polvmeriza-
tion of cPory cottpounds) and thc addlcŁs of tll
fluoroboratc !v1th amines (thcse soiid. crvstalllnc adducts initiate cationic pol_vmerization oI epoxies) tll.
H'\c'.l l ęe'le.on-d'l 'Llt:e- f'i ]'o''.;eri'._
tion ofthe lattd rvith cpoxy resins durinB application.
lmidazo]c dcrivativcs fornl a sp€cific glouP of cpoxv
hardeners 11, 21. These liqujd compoun.ls contain nitro
gen aioms] tcltiary (likc tcltiaĄ' anincs), oI Śccondaly
(likc sccondarv a ines) arld ihe curing process reflecis
'l] o] ' |.I\ ]]'' ''l''''' 4f
sPect]r.€])''
|
]l; ńf i 'Lrri.jr.
lc_
htcrcst ls in.reasing rcccnilv in using ionic liqujds as
a n€dia of valious chcmiĆal lcaĆtio11s |3_5l' ]onic liquids offering some beneilcial features as compared to
.onvcniionai soh'enŁs hal.€ begun to b€ used also as an
envjIonment fol Pl]vmclization lcaĆi1ons [6_8]' A]kvlmei}r'limidazolium tctrafluoroboratcs arc an cxample
[:]'""
cHl
of thc lonjc liquids group, and their structurc
prcscntcd in Formula (l)
0l
oul aim n1i}js ]r'ork \Ą.as th€ ansl'€r to ih€ !]Uesiion
lvhether such typc of liquld salts coulcl bc uscd as cficc
iive ePox)' r€sins ]laI.1€n€rs?
EXPER]l\ł!NT^l
Materials
EPox)' .€sjn: bisphenol Ą baseci, 1ol' rnolecu].i
l'ej8ht cpoxv Iesin EPidian 6 (Ló) (epoxv equ]r'alent
lr'eight 185, I'iscosii\' 15 000 mPa s at 25 t'C) tuom Or'
ganika-Sarzyna, Nor,r.L Sarzl'l1a.
Harden€r (ioni. 1ic]rrid)] 1-bu
i}'l'3- c Łhy1i i.1azo1iu i€tlat]uorobofatc (Bx{lTF), Purit,v ż 979,, o
]eculaI ł.ci8hi 226'03 g/mo]' pIodr.]ci aron1 ]rluk.
Ch€mie'
Methods
Inieraction of E6 1{iih BNIITF hab bccr, rnvcsiigaicd ai
ambieni tempcratlrrc and durnrg hcating co posiilons
'lvith differeni contents of the components.
The follorving insirumental techniques and appar.r
ius rvere use.1: (;) Diffclcntial scann1n8 Ćalolin1ctr\
(DSC) _ DSC'7, P€rkin E]mcr (temPeraturc Bradi.nt
5'rC/min), (ii) Rheological jn\.estigatjons rheometric
caPansion system, Ricon1ciljc ScicnŁifi. (Łcmpelnture
gladicni 5 oC/miĄ a platc_Platc s}'stcm, q = 50 mln, 3a|
I mm), (rii) Fourier-transform intuarecl spectroscop\,
been "'|.'
1!I]oń J]] correso.n.]en..] \h1Ń!; L.r add:.si!dr. !ra,l
'la.]cusŻ'sFY.h.i@Ps
Pl
POLINIERY 2003,48, ru 11-]2
(FT-IR)
N€xus FT_IR 1\ith C]oIden Gate (ATR),
Th€rno -Nicolci CorP' LL]ujd composiinDs fol FT-II.I
mcasrrrcmenis have b€€n plcparc.l in a small sanple jal
(.'' 5 B) and as a ihin film on Zinc coat€d si€el P]ates'
Bot} types of thc samp]es lr'ere h€ated at 190 oC and
FT-IR spectla takcn afŁer sońe time' H€ating tcmPeraiule se]ection was dcPendent on ihe Iate of cuńng process (crosslil*ing at Ioa.er temperaturcs takes much
more iime, plovid€d it takes P1a.c ai a]]) ('') D\,ITA
measured thc glass transiiion iemperaturcs (7.)
DN{TA moc1e]'\,1K II, P(llvmcr Laboratories (tempńtrrrc
Iangc 25_ł0 ']C, fr€quency 1 HZ). Sańples for DMTA
measulemcnŁs lvele obiained by curint ihc E6lBMTTF
composiiions ir1 thc PTFE mou1d.
RESULTSAND CO\CLUS]ONS
ai higher haldenel content (Fi8' 1a). Epox}'Ćom_
position with the highcsi BMTT| content (cff\'c 3) starts
io 8e1 ai about 235 oC' Ho1\revel, a small Positjv€ Peak js
obscrvc.l a! a tcmPeraiure range oI about 173 io 188 ,rC.
Serv€d
Celation poini tor E6/BNIITF s.iih 1 phr ol hardener
(culYe 2) is above 275 ''C; it js
Preceded b,v sma]]el PĆak
in the region of about 232 uC io 267 oC. The origin of
ih€se sma]l Peaks o1r lhconlebjc curves is unknolvn and
cannot be sinlPly exPlained' G€]ation icmPoaĘr.e IoI
s-"-siem lvith lh€ lowest B]VI]TF conient (culve 1) js
shified to hithcr va]u€s (b}.abott fclv .cntigr.
T a b ] e 1- Heat eilects oi thĆ ĆIoss]inking Pio.ess in t|c
!6/BMITaT'stcm _
lrot}..ńi.
Ionic liqlrid BlvllTF coul.l bc casilY mixed $,ith E6
PeJlr(s),
ic
Lnd
in
wei8hi Iatios' Addition of B]!,IITF io E6
(ai ihe Iange of'ń'cighi laiios from 0 5:100 to 5:l00) does
not change co]ol and viscositv of ih€ r€sin. Declease ln
gclation point temperaturcs of epoxy systems is ob
a l\ridĆ lanSe of
d es) '
Eó/Bl\]1TF
]5ó
Tlbl
H.lll\
!'Tlre
]tr€t||
L.
.
28]
la/BlvaTF
1001
!ór'B\1]Tl
t6t
2-.:l
2,i1r
,2011
211
278
i9:)
Al1 nrl.estigated compositions sho\. c\othermic
pcaks ai similar iemperature rangc.rr. 280,290'rC (Fig
1b, Table ]). Ho$/evel, ilr€ comPositmn with the highest
BMITF content has an additional €xoihermic Pcak nt
a ]o\Ą.el tcmPeratule (./7' 200'c _ culYe 3)' Th.
E6IBNIITF s'vsi€rns .ith highcl raŁios ol jonjc ]i!uj.]
(1 and 5 phl) cxhibit simi]ar tota1 cxothclmjc €llects
|-298 ]/ , i'.. about 67 ']; of ih€ €xothelmiĆ cffccŁ of
cpoxy comPosiijon 1vith thc lowcsi caialysi cont€nt
!.01 :
0|
r50
(0.5 ptu).
200
300
Fjg' 2 il]usŁraies FT_l]t sPecira for [ó/B\,1]TF conlPo_
sitions of a'eightraiio 100:1 alt€rvariousPc.()ds.rf
hedt-
j
f'
o.z:
.łll.8
Ź |).]4
ii
0
50
tno
]l0
20t 250
Tcnp.r.tur..'C
100
Fig 1. Rheo'netrr c rles h) dnLi DSC lhetnaSnffi (b).t
iBMIT I can|pasitbns'aith I\:ł i)1ls cDnten! of t]E hardenel )
E6
B],Ą]TF
n1
p]lr:1 0'5.2 1,3
5
Wercnumler. cr,
r
FiP\ 2 FT-IR spccfua E,|BMITF (1 |)1r') Ćanpasilio bcfal,:
heating (A) and dftct lltdtinł a! 19A "C t'ar: 0.5 l! (B),1 h C)
l:]n!1
15 11G
lc|1
Ćonprsilian
D)
POLIN,IERY 2003,48, nr
11
12
ing at190 oC. Thcmost important changes ofband inten
siiies ai 23ó0 cm i (characterisiic fol -N+H ions; sońe
]ll-hLm-l l.ll 'lllell'l- \.'l '.pp'j !J :1 l||:- '-Ó:oll J:
w€ll), 1720 ]740 cm-r (carbony1 grorrps) and
l07U-1150 cm'r (C-O-C stretching vibratiol$) lt'crc obseNed' lnĆIeases in the first til'o bands have been de
tecied duńng heaiing of ih€ r€sin/haldener sysiem, bui
ihev have decreased in cured epoxy co positions. Two
ol lhe lro.t i1'tFr'-i\. b"rds . 'lcr.t i \ \e.,( rg ur'e-Dr
.]'e l' ]t ol 070 l_]0 m łlo l200_ _27] crl oJnd'
Ćo1'lncĆtcd wiill .thcr boncis, cxPeĆted ln thc Pol)'mc'
ńzed €pox]r matelial'
T
a
TJ
l' ] e 2. !6/BM1T! dring tińe9 (teńP.
yallos ot tne clred.ompositions
190
''c) and resPeĆtive
T:i,
!a
/ tsi\,rr'lr
100:05
l5
"c
6;
20
!ó/B\IlT!
ĆonsideIed as conv€nient
B]VIITF induc€
of 'eight Iatios' ]nitiation of thc l:ross1inking
reactlon has a proper ratc at 190 "C. Also, r'ro viscositv
changc of Epidian 6/BMITF (1 an.t 5 phr) compositions
]Ą.ide range
stored for 6 monihs ai ambieni
ie
perature has beer
The BMITF and other' iol'liĆ ]iquids can b€ use.] as
hardeners for epoxy coatings, adhesives o. castcompositions and in other applicaiions l9l.
REFERENCES
1.
2'
BlÓicl Z', H€Itz Z., lrencz€k P: "Z)'\vjce ePoksy_
do1v€",
WNT, walsza1va 1982
Riccialdi F, Romanchick A' \Ą1, ]ou]]ie M.
Um Sci., Polyn Che L. Ed 19a?,,2t,1475.
łV€]tonT.]C}.'1 R'lj. 1999, 99, 2071
I'1.]
3'
4' Pelnak]'|?[Ć'1 Cł. '2000,79,150'
5' Fluka Chemie "Chem}'i]esj Gleen Ch€misir]'
6'
150
Cur€d Ćompositions Ćoitaining lowcr amounts of
BMITF (0.5 and 1 phr) indicate ]ow values of T" (b€]ow
100 "C); ord) T- of epoxy svsiem based on ihe highesr
amount of catalyst (E6ltsMlTF weight raUo 100:5)
I€aches 150 oc (l'ablc2)'
Presente.t data sho ' that ionic liqui{1s such as
l-buthyl-3-meihvlimjdazolium ietrafluoroboraie can be
lat€nt epox-v resin haldeners'
cPoxy rings ionic Po1i,mcriŻation ill a
/' 1ł]
(I()ni.
Lqulds)" 2001, 1
7),2 5.
Camicha€] A. ]., Ha.tdlcton D' M', Bon S A., Sed
clon K. P:Cneł. Cotu .2000,1237.
Bicdloi1T, Kubisa l'.: ''Po]vm€risation j! lonjc Li
quids", ELrropol)'mer Congress, Siockholm 2003,
(No
Book of Abstracts (Oral Prcscniations).
Vy8odskii Ya. S., Lozinskal'a E. L, Sh.iplov A. S,
l\.Ielnik O. A : "lonic Liquids a Nciv E.ologicallv
Friendly Rcaciion Media for Pol]'ner Synthesis"
9.
17l.
Ko\Ą,alcŻvk K', sp}'chaj T':
n
unyb|iskn rc9 hJ.
&L.i.iJ i
ll/12u0.1.