TAP CHi H 6 A HQC T. 50(4) 502-506 THANG8NAM2012
K^T Hap TRO BAY BI^N T I N H S I L A N VA OXIT S A T TRONG CH^ TAG
MANG SON EPOXY B A O VE C H 6 N G A N M 6 N T H ^ P CACBON
To Thi Xuan Hdng, Trjnh Anh Triic, Ph^m Gia VQ, Nguyen Thiiy Difong, VQ Ke Oilnh, Bill van Trudc
Vien Ky thugt nhiet d&i, Vien Khoa hgc vd Cdng nghe Viet Nam Din Tdasogn 18-5-2012
Abstract
Fly ash, a by-product of the Pha Lai thermo-power plan, was modified by 2-aminoetyl-3-aminopropyl- trimetoxysilane. Epoxy coatings containing silane modified fly ash and iron oxide were prepared and applied on caitwD steel. Structure of modified Hy ash was analyzed by infrared spectroscopy and scanning elecUonic microscopy.
Corrosion protection of epoxy coatings was evaluated by electrochemical impedance spectroscopy and adhesion measurements. The results obtained showed that particles of modified (ly ash were coved by organic film fomied by silane. Corrosion protection of epoxy coatings depends on ratio of fly ash and iron oxide. Epoxy coatmg containing modified fly ash provides higher corrosion protection than epoxy coating contaimng iron oxide. Epoxy coating with ration of fiy ash and iron oxide of 20/10 has higher corrosion protection compared to coatmgs with ration of fly ash and iron oxide of 10/20.
Keywords: Fly ash, corrosion protection, epoxy coatings.
l . M d D A U
Tro bay, la san phdm phy ciia cdc nha may nhi?t dien, cd thdnh phdn chinh Id SiO:, AI2O3, FezOs, vi vay dd cd nhieu nghien cdu sii" dyng tro bay trong che tgo zeolit, xi mang, polyme compozit. Tro bay thudng dupe bien tfnh bang cac hpp chat hOu co nhu: silan huu co, axit stearic, stearat, titanat [1-41.
Tro bay dgng microsphere dupe sir dyng nhu chat dpn trong Idp phit hiru co, nhdm tdng cudng tfnh chat chdng an mdn vd chdng chdy cua Idp phii [5].
Cdc ket qud nghien ciru ciia Tiwari S. vd cpng sy cho thdy tro bay da cdi thi?n dp bin dn mdn, ben vdi cac mdi trucmg hod chat vd dung mdi hifu cp cua mang son epoxy [6]. Tro bay dupe sir dyng ldm chit dpn cho son nhu tuong chong chdy tren co sd nhya vinyl acrylic, ham lupng tro bay trong khoang 24-50% [7].
Mdng son epoxy-nhya than dd vdi hdm lupng tro bay tren 20% dupe che tgo dl son ben trong dudng dng nude thai [8, 9]. Chiing tdi dd nghien cihi dnh hudng ciia tro bay biln tinh silan din khd ndng bdo ve chdng dn mdn mang son epoxy [10]. Cac ket qud thu dupe cho thay fro bay biln tinh bdng silan da cd tac dyng tang dang kl khd ndng bao v? chong dn mdn cung nhu dp bdm dfnh ciia mdng epoxy.
De tang khd nang irng dyng ciia tro bay va che xao cac h$ son bdo v? chong dn mdn cua tuoi thp
cao, trong cdng trinh nay chung tdi nghien cim mdng son bdo v^ epoxy tren co sd ket hpp tro bay bien tinh vdi oxit sdt. Tro bay biln tinh dupe phan tich bdng pho hong ngogi vd kinh hien vi di$n tiir quet, khd ndng bdo v$ ciia mang son dupe ddnh gid bdng phuong phap tdng trd di^n hda vd do tfnh chat co ly ciia mdng son.
2. THU'C NGHIEM 2.1. Nguyen ll^u
- Tro bay sii dyng Id logi tro bay cua nha may Nhi?t di?n Pha Lgi cd ham lupng SiO'+ Fe20j tren 86 %.
- Epoxy siir dyng la logi X75 vd chat ddng rdn la PA66 ciJa Thdi Lan.
- Dung moi su dyng Id logi hon hpp toluen, xylen, butanol.
- Silan su dyng Id 2-aininoetyl-3-aminopropyl- trimetoxysilan cua Merck (Due).
- Oxit sdt sit dyng la logi thuang phim ciia Trung Quoc.
2.2 Biln tinh tro bay bfing silan
2-aminoetyl-3-aminopropyltrimetojQ' silan dupe 502
TCHH, T. 50(4), 2012
thuy phdn trong hdn hpp cin nude d nhift dp 80°C trong 30 phut, tro bay dupe cho tii tir vdo dung djch silan da thiiy phdn, phdn iing dupe tiln hanh trong 4 gid d SOT. Nong dp silan biln tinh Id 3% so vdi tro bay. Sdn phim tro bay biln tfnh dugc lpc, rira nhilu lan bdng nude cit va say d lOCC trong 24 gid.
23. Chi t^o son epoxy chu-a tro bay bien tinh Son epoxy chua tro bay biln tfnh va oxit sdt vdi cac ti 1^ khac nhau dupe chi tgo bdng phuong phdp nghien bi. Ham lupng tro bay vd oxit sdt ttrong cdc mdu son dupe trinh bdy trong bdng 1. Hdn hpp bpt mau, epoxy dupe nghien trong dung mdi bdng cii nghien bi trong 48 gid. Chit ddng rdn PA66 dupe trpn vao son epoxy trudc khi son. Ti I? epoxy/ddng rdn la 10/8.
Bdng J: Ham lupng tro bay vd oxit sdt trong cdc mau son epoxy
Mlu Ml M2 M3 M4
Tro bay bien tinh silan, %
0 10 20 30
Oxit s5t,
%
30 20 10 0 2.4. Che tao mau
Mdu thep dupe stir dung la thep CT3 cd kich thudc 100x150x2 mm. Mdu thep dupe bdo qudn ngam trong ddu. Mdu dupe nia sach diu bdng xa phdng, lau vd sdy khd, sau dd tiln hanh tdy gi bdng dung djch axit HCI rdi bdng kilm, riia sach bdng nude, con va sdy khd. Mang son dupe tgo tren mdu thep bdng mdy tgo mdng li tdm. Dp day mdng son sau khi khd la 40 pm.
2.5. Cac phinmg phap nghien ciiru
- Phd hdng ngogi dupe do tren may Nexus 670 ciia hang Nicolet tgi Vipn Ky thudt nhi?t ddi.
Anh kinh hiln vi di^n tii quet dupe chyp trSn may SEM Hitachi 4800.
- Phd tdng trd dupe do tren mdy AUTOLAB P30. Cdc phep do dat d chi dp quet t^r dpng trong dai tan sd tu 100 kHz din 10 mHz. So dodo tong trd la he 3 di8n eye: di$n c\rc lam viec Id mdu thep phii mang son dupe chyp dng PVC hinh try cd chiia dung dich NaCI 3%, dien tich tilp xue cua bl mgt mau vdi mdi trudng xdm thyc la 28 cm^, di?n eye so sanh id di?n cue calomen bao hda, di?n eye doi Id dien eye platin.
Td Thi Xuan Hang vd cgng su - Dp bam dfnh ciia mdng son dupe do bdng mdy ADHESION TESTER model 525 cua hang Erichsen theo tieu chuan ASTM D-4541.
- Dp ben va dap cua mdng son dupe do tr8n may Erichsen model 304 theo tieu chuin ISO D-58675.
- Cdc mdu son dupe thii nghiem gia tic trong tii mil muoi. Dilu ki^n thii nghiem: nhi^t dp: 35±2''C;
dung djch NaCI nong dO 50±5 g/1. Be mat mdu dupe theo ddi danh gid trong thdi gian thii nghi?m.
3. KET QUA VA T H A O LUAN
3.1. Phfin tich cau triic cua tro bay bien tinh bSng silan
3.1.1. Phd hdng ngogi
Tro bay ban dau vd tro bay bien tfnh bdng silan d ning dp 3% dupe phdn tich bdng phd hong ngoai.
Pho hong ngogi cua tro bay ban dau, silan vd tro bay biln tinh silan dupe trinh bay tren hlnh 1.
4000 3500 3000 2500 2000 1S00 1000 500 S6 song (cm-')
Hinh I: Phd hdng ngogi ciia tro bay ban ddu (a), silan (b), va tro bay bien tinh bang silan (c) Tir hinh 1 nhgn thay pho hong ngogi ciia tro bay ban dau cd cac pic dgc trung cho lien kit -OH va Si- O tgi 3438 cm"' vd 1070 cm"'. Nhu vgy vdi su cd mgt ciia nhdm -OH, cho kha ndng biln tinh gdn silan tren bl mgt tro bay. Pho hong ngogi ciia 2- aminoetyl-3-aminopropy1trimetoxy silan cd cdc pic ddc trung cho lien ket ciia -NHj tgi 3292 cm'' va 1581 cm"', pic dac trung cho nhdm hydrocacbon tgi 2940 cm"' va 2840 cm , pic dgc trung cho lien ket Si-O-C tgi 1080 cm'. Pho hdng ngogi cua tro bay bien tinh silan cd cdc pic ddc trung cho lien ket -OH vd Si-O tgi 3438 cm" vd 1041 cm''. Ben cgnh dd ta thiy tro bay biln tfnh silan cd cac pic dac trung cua lien kit tgi 2916 cm"' va 2845 cm"'. Cdc kit qua ndy the hi?n sy cd mgt ciia silan trong tro bay bien tfnh.,
TCHH, T. 50(4), 2012
Bdng 2: Cdc pic ddc trung ciia pho hon^ ngogi cua tro bay ban dau vd sau khi biln tfnh bdng silan Iro bay
ban dau, cm"' 557 1070
3434
Silan, cm''
1080 1581 2940;
2840 3292
Tro bay bien tinh silan, cm'' 1041
2916; 2845 3439
Li€n ket djlc trirng Al-0 Si-0 Si-O-C -NHi -CH2 -NHj -OH 3.1 2 Kinh hien vi dien tir quel
Hinh thdi hpc cua tro bay ban dau vd sau khi bien tinh dupe phdn tfch bdng kfnh hien vi diC'n tir quet. Anh kfnh hien vi di?n tii qu^t ciia tro bay ban dau vd sau khi bien tinh bdng 3% silan dupe trinh bay tren hinh 2. Qua hinh 2 nhgn thay tro bay cd dgng hinh cdu, kich thudc ciia tro bay nhd hon 10 pm, be mat hgt tro bay mjn. Tro bay sau khi biln tfnh cd kfch thudc tuong ty nhu tro bay ban diu, quan sat thiy cd cdc hgt tro bay hinh cau va cd hat khdng cd dang khdng phai hinh cdu. Be mdt hgt tro bay cd Idp hiiu co bao bpc, the hipn sy cd mdt ciia silan bdm tren be mgt tro bay.
Ket hgp trg bay bien tinh silan vd.i 3.2. NghiSn cihi che t^o m&ng son epoxy ch6a tro bay bien tfnh kit hgrp oxit sfit
Mdng son epoxy chura tro bay biln tfnh vd oxit sit d cdc ti 1$ khdc nhau dupe tgo tren nIn th^p (xem bdng I). Khd ndng bdo v$ ching dn mdn ciia mdng son dupe ddnh gid bdng phuong phdp tong trd d i ^ hda, do dp bdm dfnh vd d$ ben va dgp cua mdng son.
3 2 I Do tdng trd dien hda
Tfnh chit bdo v$ ciia mdng son trudc hit d u ^ ddnh gid bdng phuong phdp tong trd di^n hda. Phi ting trd ciia cdc mlu th^p phu mdng son dupe do theo thdi gian ngdm trong dung djch NaCI 3%.
Hinh 3 trinh bdy phd tong trd cua cac mlu sau 16 ngdy ngdm trong dung djch NaCI 3%. Tir kit qua do nhgn thiy sau 16 ngdy ngam, pho tong trd cua cdc mau dd xuit hi^n 2 cung, dilu ndy chung td chit di^n li dd tdi be mdt kim logi. Tuy nhien, trir mlu M2, cung thii 2 d tan so thip ciia cdc mdu chira xac djnh. Cung thir nhit d tin so cao d$c trung cho cac tfnh chat ciia mdng son, cung thir 2 0 tan so thap ddc trung cho cdc qud trinh dn mdn tren bl mdt kim loai.
0 15 trf 3 l r f 4 5 trf 6 It
- S '•'"^
S l r f 1 IO" 1 Slrf 210*
4itf Birf eirf
B i r f 161(f 2 4 i c f 3 2 l t f
Phdn Vnxfc (£Icm>) Hinh 2: Anh kinh hiln vi di?n tit quet ctia tro bay
ban ddu (a) vd tro bay biln tfnh bdng 3 % silan (b)
Hinh 3: Pho tong trd sau 16 ngay ngam trong dung djch NaCI 3% cua cdc mdu Ml (a); M2(b)i
M3 (c) vd M4 (d)
504
'X60<4> 30I0 TCHH, T. 50(4), 2012
Cdc kit qud tren hinh 3 cho thiy, sau 16 ngdy ngam vdi cdc mau MI, M3 vd M4 chira c6 qud trinh dn mdn trSn b l mdt kim lo^i. Gid tri tong trd ciia mlu M4 cao nhat sau dd din mdu M3 vd MI, mlu M2 cd gid trj tdng trd thip nhit. Cdc kit qud tren cho thiy khi ham lupng tro bay cao 20-30 % gid trj di§n trd mang cao hon hdn mdu M2, chua 20%
oxit sdt + 10% oxit sit.
Tii phd tong trd, gid trj di?n trd mdng (Rf) vd modun tdng trd tgi 10 mHz (Ziomuz) cua cdc mau son dupe xac djnh vd theo ddi theo thdi gian ngam trong dung djch NaCI 3%. Gid trj Rf d$c trung cho khd nang che chdn ciia mdng son, gid trj Rf cdng Idn thi kha nang che chdn cdng Idn. Gid trj ZiomHzd^c tnmg cho kha nang bdo v? chong dn mdn cua mdng son.
Gia hi ZiomHi cao thi khd ndng bdo v? chong dn mdn cang cao.
Hinh 4 bieu dien sy thay ddi di$n trd mdng va modun tong trd tgi 10 mHz ciia cdc mdu theo thdi gian ngdm trong dung djch NaCI 3%.
IhM gian nsAm trang dung djch NiCl 3% (ngiy)
Hinh 4: Su biln ddi gia trj Rf (a) vd Z,o mHz (b) ciia cdc mlu theo thdi gian ngdm trong dung djch
NaCI 3%
Quan sdt do thi tr6n hinh thay rdng di?n trd milng, Rf ciia cdc mlu son ban diu cung khdc nhau
% khdng nhieu. Cac mlu M3 va M4 cd gia tri Rr rao hon 2 mlu cdn Igi. Dilu nay cho thdy kha ndng t^ie chdn cfia mang son phy thupc vdo ti I9 ciia tro I'ay va oxit sdt. So 2 mdu Ml chi chua oxit sdt vd
Td Thi Xuan Hang vd cgng su mlu M4 chi chiira tro bay ta thiy mlu M4 cd gia trj Rf cao hon thi hi^n tro bay cd tdc dyng tang khd nang che chdn ciia mang son cao hon oxit sdt. Kit qud ndy cd the dupe gidi thich do tro bay dupe biln tfnh silan, nen phdn tdn tot hon va cd thi cd kien kit vdi epoxy nen tdng dp ddc xit cua mang son vd tang khd ndng che chdn cua mdng son. So 2 mdu chiira hdn hpp hpp tro bay bien tinh vd oxit git, mdu M3 cd gid trj Rfcao hon mlu M2. Dieu nay cho thay tdc dyng ciia t l hpp tro bay biln tinh vd oxit sdt phu thupc vdo ti If ciia 2 logi pigment vd d ti 1§ ndy, ti I9 tro bay/oxit sat la 2/1 cho mang son cd hl^u qua bao v?cao hpnti 1^ 1/2.
Theo thdi gian ngam trong dung dich NaCI 3%
tdng, gia tn Rf ciia cdc mlu dlu gidm. Sau 36 ngay ngdm. gid trj Rf ciia mlu M3 vd M4 cao hon hdn mdu MI va M2. Mdu M4 cd gid trj dien trd mang giu d muc cao nhit, sau dd din mlu M3 vd mdu Ml, mdu M2 cd gia tri di?n trd mang thdp nhit.
Tir hinh 4b, nhgn thiy sy thay ddi gid trj Ziomm (d§c trung cho dp ben an mdn cua mang son) theo thdi gian cita cdc mdu son khac nhau. Tuong ty nhu gid tri di?n trd mdng, gia trj ZiomHzCiia cac mdu gidm theo thdi gian ngdm trong dung djch NaCI 3 %.
Sau 36 ngdy ngam, mdu M4, chiira 30 % tro bay biln tinh bdng silan cd gid trj di|n trd phdn eye cao hon 3 mdu cdn lai. Mdu M3 cd gid tri ZiomUzthap hon mau M4, nhimg cao hem nhieu mau Ml va M2.
Mau M2 CO gid tri ZIO^HZ thdp nhit.
Cdc ket qua do tdng trd cho thay khd ndng bdo ve chdng an mdn cua mang son phy thupc vao ti 1?
tro bay vd oxit sat, trong 4 mau son nghicn cihi mau son epoxy chira 30% tro bay bien tinh bang silan va mau chira 20% tro bay + 10% oxit sdt cd khd nang che chdn va bdo v? chdng an mdn cao hon mdu son epoxy chua 30% oxit sdt va mau chura 10% tro bay + 20% oxit sdt.
+ Tinh chdt co ly cua mdng son
Ben cgnh do tdng trd di?n hda, dp bdm dinh va dp ben va dap ciia cac mdng son cung dupe xdc djnh, cac kit qua dupe trinh bay d baiig 3. _
Cdc kit qud do bam dfnh cho thdy mdu son chi chira tro bay biln tinh (M3) cd dp bdm dinh cao hon mau son chi chiia oxit sdt (Ml). Dp bam dinh ciia mdu Ml va M4 tuong iing la 1,4 N/mm^ vd 1,7 N/mm2. Cac mlu M2 vd M3 co chijra tro bay va oxit sdt, cd dp bam dinh cao hon mlu Ml, dgt tuong ung Id 1,5 N/mm^ vd 1,7 N/mm^. Dieu nay cho thay tro bay biln tfnh cd tdc dyng lam tdng dO bdm dfnh cua mdng epoxy. Mdng son chiJa tro bay biln tinh cd dp bdm dinh cao hon mdng son ch^a oxit sat cd the dupe giai thich do su cd mdt ciia silan da tdng cudng lien kit ciia tro bay vdi epoxy, dong thdi silan tuong
TCH11,T 50(4), 2012
tac vai be mat thep lam tdng lien ket ctia mang son vai bo nuM thep.
Bang J Dp bam dinh vd dp bin va ddp ciia cdc mdng scm
Mlu Ml M2 M3 M4
D$ b;^ni dinh, N/mm'
1,4 1,5 1,7 1.7
DO bin va d§p, kg,cm
180 180 180 180 Dp bin va d§p cua mdng mdng epoxy chii-a tro bay biln tinh va oxit sdt dlu dgt 180 kg.cm, nhu v§y, sy cd mdt ciia tro bay khdng dnh hudng din dp bin va dgp ciia mang epoxy.
+ Tim nghiem nm muoi
Kit qud thir nghiem mii muoi ciia cdc mau cho thay, sau 1000 gid thir nghi?m tren tit ca cdc mau deu chua xuit hi^n dilm gi, vdi cdc mdu EPI, EP2 da thiy xuit hi^n cdc dilm rpp, trong khi vdi cdc mdu EP3 vd EP4 be m$t mdu khdng he cd hi^n tupng rpp. Nhu vgy cac mau EP3 va EP4 cd dp bin mil mudi cao hon cac mlu EPI vd EP2. Cac kit qua thu nghiem cung phii hpp vdi ket qud ddnh gia bdng phuong phdp tdng trd.
4. KET LUAN
Da bien tfnh tro bay bdng 2-aminoetyl-3- aminopropyltrimetoxysilan. Ket qua phan tich bdng phd hdng n^oaf, va b'nh hiln vi dipn tu quet cho thiy hpp chdt silan dd bdm vd phu len bl ngt hgt tro bay. Da nghien cim che tgo Idp phii epoxy cd chiira oxit sat vd tro bay biln tinh d cdc ndng dp khdc nhau. Ket qud thu dupe cho thiy mdng son chua tro
Ket hgp tro bay biin tinh silan vd...
bay biln tinh cd khd ndng bdo vp chong Sn mdn cao hon mdng son chda oxit sdt. So cdc mdng son chiira ti 1^ tro bay vd oxit sdt khdc nhau (20/10 vd 10/20), mdng son chira ti 1§ tro bay cao hon cd khd ndng che chdn vd bdo v | ching fin mdn cao hon. Cdc kit qua ndy md ra triin vpng lirng dyng tro bay bien tfnh bfing silan trong Idp phii epoxy bdo v? chong dn mon cho th6p.
T A I L I $ U THAM K H A O
1. H. Demir, D. Balkose, S. Ulku. Influence of surface modification of filler and polymer on flammability and tensible behaviour of polypropylene-composites, htip .//c 1 sc v ier.com/locate/po ly depstab (2005).
2. N. A. N. Alkadasi, B. D Alkadasi, U. R. Kapadi, D.G. Hundiwale, EfTect of bis (3-triethyhoxy silylpropyl) tetrasulphtde on the mechanical properties of flyash filled styrene butadiene mbber.
Journal of Scientific & Industrial Research, 63, 287- 292 (2004).
3. US Patent 6139960.
4. US Patem 6242098.
5. i^ Elfving. Polym. Paint Colour J, 176 574(1986).
6. S TIWARI, M. SAXENA. Use of Fly Ash in High Performance Industrial Coatings. Bntish Corrosion Joumal, 34(3), 184-191 (1999).
7. US patent 4229329.
8 AWWA Manual M41. Ductile Iron Pipe and Fittings, AWWA, Denver, Co. (1996).
9. NACE T-6A TPC 2 Publication. Coatings and Linings for Immersion Service, NACE International, Second edition (1998).
10. To Thj Xudn HSng, Nguyin Tuin Dung, Trjnh Anh Tnic. Nghien cihi bien tinh tro bay bdng silan vd ung dyng trong che tgo mdng son epoxy bdo ve chong Sn mdn cho thep cacbon. Tgp chf Khoa hpc va Cong ngh§, 48(3A), 87-94 (2010).
Lien he: To Thi Xuan Hdng
Vi?n Ky thugt nhi?t ddi, Vi?n Khoa hpc vd Cdng ngh? Vi?t Nam 18 Hodng Quoc Vi^t, Ciu Giiy, Hd Npi
Email: [email protected].
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