TAP CHI HOA HOC T. 51(1)67-71 THANG 2 NAM 2013
CH^ TAO VA K H A O SAT TINH CHAT CUA NANOCOMPOZIT CLAY-EPOXY
Le Minh Dire'", Mai Thi Phuong ChiS Vu Quoc Trung^
'Trudng Dgi hgc Bdch khoa, Dgi hgc Dd Ndng
^Tnrdng Cao ddng Cdng ngh?, Dgi hgc Dd Ndng Khoa Hda hgc, Trirdng Dgi hgc Suphgm Hd Ngi
D i n Tda sogn 25-10-2012
Abstract
Montmorillonite organoclay (MMO) was incorporated into epoxy resin by mechanical agitation and sonication process. Optical microscopy was used to analyse the oplical homogeneity of dispersions. The properties of nanocomposite organic material were tensile strength, elongation at break and flexural strength. Wiih 2% of MMO tensile strength and elongation at break could gel optimum value. However, its strength values decreased when the neight percent of MMO increase to 3%. The flexural strength would be decreased with increasing the amount of nano clay in composite. The diffusion coefficient (D) could be calculated from the obtained data when dipping the composite sample in seawater and tap-water. They would be decreased with large amount of nanoclay in the sample.
Keywords: Nanocomposite, nanoclay, montmorillonite, epoxy, diffusion coefficient.
1. MO DAU
Hien nay, viec sir dung vat lieu td hgp polyme cau triic nano dugc ung dung rat rgng rai do nhu'ng dgc tinh ca hgc, hda ly tdt. Tuy vay, cac cau tir gay an mdn nhu oxi, nudc, cac ion gay pha buy vat lieu (Cr, H^, SOj'") van cd the khuech tan qua Idp phii.
De nang cao tinh chat che chan, bao ve cua Idp phii polyme nhieu loai phu gia, logi chat ddn vd ca, hiru CO da dugc nghien cuu de cai thien tinh chat nay ciia ldp phli [1-4].
Nanocompozit cd the dugc che tao tren nen kim loai, vd ca hoac hifu ca. Gan day, ngudi ta quan tam den nanocompozit tren ca sd mang ludi polyme duac gia eudng bdi nanoclay, dng nano cacbon, sgi nano cacbon, hgt vd ca nano nhu Ti02, Si02,...
Nanoclay dugc nhieu tac gia lira chgn lam chat dpn de bien tinh Idp phu hiJu ca vi khoang set san cd d Viet Nam nhu d Nha Me (Binh Thuan), Di Linh (Lam Ddng)..., re tien, cd kha nang nang cao tinh chat ca hgc ciia nhya nen.
Mac dil da cd nhieu nghien ciiu tap trung vao he clay nanocompozit nhung cac nghien ciru phat trien vin cdn dugc tilp tuc nham md rdng kha nang ung diing ciia logi vat lieu nay. Trong nghien cu:u nay, ldp phli nanocompozit tren nen nhua epoxy vdl khoang set kich thudc nanomet (nanoclay) dugc chi
tao va khao sat. Dac biet da linh loan dugc cac he sd khuech tan cua nudc vao ben trong vat lieu.
2. THUC NGHIEM
Nhya Epoxy thuang mai EP thudc loai nhua Epoxy Bisphenol A xuat xir tir Trung Qude. Chat ddng ran logi DETA (diethylen triamine) sir dung vdi ty le DETA/Epoxy = 20/100. Nanoclay la loai Benlonile Nha Me dugc san xuat tai Viet Nam bdi cdng ty TNHH Minh Ha, d dgng bgt, cd ty sd Si02/(A[203+Fe203) dao ddng tir 4,36-5,54 thudc loai benlonile kiem (Sodium Montmorillonite).
Nanoclay nay dugc bien linh bang silane. Thanh phin khoang chat chii yeu ciia benlonile Nha Me (dya theo kit qua phan lich Ranghen) dugc the hien d bang 1.
Bdng 1: Cac thdng sd ky thugt ciia nanoclay Ten khoang chat
Montmorillonite lllite Kaolinite Clorite Thach anh Felspat Gotit Canxit
Thanh phan, % 49-51
7-9 13-15
6-8 7-9 4-6 4-6
TCHH, T.51(l), 2013
Mdt sd thdng sd vat ly ciia nanoclay:
+ khdi lugng phan tir (g/mol): 540,46: 540,46.
+ Do cirng Mobs d 20°C: 1,5-2,0: 1,5-2,0.
Clay da biln tinh dugc say d 105''C trong 2 gid.
Tao mau thyc hien nhu sau: can 80 g nhya epoxy cho vao coc Ihiiy tmh. Ham lugng nanoclay dugc tinh 1 %, 2%, 3% theo khoi lugng so vdi nhya epoxy (sai sd 0,01 g). Chuan bj chat ddng ran vdi ham lugng 20% khoi lugng so vdi nhya epoxy. Hdn hgp nhya va nanoclay dugc khuay trgn dong deu bang may sieu am trong thdi gian 1 gid d bien dg 40%.
Them chat ddng rSn vdi ty I? 20% so vdi lugng nhya epoxy, dd khudn, tgo mau. Mau dugc luu d nhipt do phdng trong vdng 24 gid, lilp den say d 70^0 trong 5 gid de mau ddng ran hoan loan. Sau khi say xong, mau dirge de ngugi d nhi^t dg phdng roi thao ra khoi khuon.
cac linh chat ca hgc dugc khao sat bao gdm:
+ Dg dan dai klii dirt, dg ben keo dirt theo lieu chuan ISO 37:2005 tren may Ihir nghiem keo Zwick ciia CHLB Dire.
+ Do ben udn theo lieu chuan ISO 178 tren may may thir nghiem keo nen INSTRON 5585 ciia My.
Cac phep do dirge thyc hien tgi Phdng Thu nghiem Ca ly - Trung tam Ky thuat Tieu chuan, Do ludng. Chat lugng 2, Thanh phd Da Nang (Quatcst 2).
3. KET QUA VA THAO LUAN
3.L Anh hudng ciia che dg khuay trgn den sir phan tan ciia nanoclay trong nhira epoxy
Hdn hgp nhya epoxy va nanoclay dugc phan lan bang hai phirang phap khuay ca hgc va sieu am.
Mang mdng dugc tgo tren tam kinh phang bang phuang phap phii quay (spin coaling). Phan bd cac hat set nano dugc danh gia bang quan sat tren kinh hien vi quang hgc. Ket qua thu duge the hien d hinh I.
Tu hinh la, cd the quan sat thay cd nhieu kcl tu tren mau. Khuay bang ca hgc, cac mach dai phan tu epoxy khdng the xam nhap vao cac ket tu va cung khdng the xen vao giu'a cac Idp nanoclay. Sd lugng va kich thudc cac ket tu giam nhieu khi lien hanh sieu am d bien do cao va thdi gian dai [5]. Vdi thdi gian sieu am 1 gid, dudng nhu khdng cdn cac kit tu niJa do da sd cac ldp nanoclay da dugc lach Idp dam bao cho cac mgch dgi phan tir ciia nhya epoxy chen vao giua cac Idp nanoclay (hinh lc). Dieu dd chung td su phan tan tdt ciia nanoclay trong nIn nhya epoxy. Tuy nhien, neu keo dai thdi gian sieu am ban nira (1,5 gid) thi mire dg phan tan nanoclay vao nhua cung khdng dugc cai thien (hinh Id). Liic nay, khdng khi di vao he cang nhieu, hinh thanh ldp bgt
Le Minh Due vd cgngj^
khi day tren be mat va ca trong hdn hgp, lam giam dg bin ciia san pham ddng ran. Ket qua ciia ph§n lich phd nhilu xg tia X, thi hi?n cac ldp ciia clay dugc tach ra va epoxy da chen vao cac Idp ciia nanoclay.
Hinh 1. Anh chyp duai kmh hien vi quang hgc cua hdn hgp, dg phdng dgi 1000 lan. Nhya epoxy va 2%
khoi lugng nanoclay sau khi: (a) Khuay ca hoc trong thdi gian 1 gid, (b) Khuay sieu am trong thdi gian 0,5 gid, (c) Khuay sieu am trong thdi gian 1 gid, (d)
Khuay sieu am trong thdi gian 1,5 gid
Hinh 2: Phd nhilu xg tia X ciia bdt clay (a) va compozit chua 1% clay (b) Nhu vay, sir dyng khuay bang sieu am la phuang phap hi$u qua dl pha vd cac ket tu trong h?
TCHH, T. 51(1), 2013
epoxy/nanoclay, thdi gian sieu am thich hgp la I gid.
3.2. Tinh chat eg hgc ciia nanocompozit vol cac ham lu^ng nanoclay khac nhau
Nanocompozit dugc che tgo vdi cac ham Iugng hgt nanoclay khac nhau 1, 2 va 3%i khoi Iugng. Cac tinh chat ca hgc cua mau nanocompozit dugc khao sat; dg ben keo dirt, dg dan dai khi dut, dg bin udn.
Kit qua khao sat tinh chat ca hgc dugc the hi?n d hinh 3 va 4.
MIU epoxy nguyen chat cd dg bin keo dirt va dg dan dai khi dirt be. Khi dugc gia cudng bang nanoclay, mau cd dg ben keo dirt va dg dan dai khi dirt Idn han so vdi nhya nen epoxy. Khi dd, dg bin keo diift va dg dan dai khi dut cua mlu nanocompozit dgt eye dgi d ham lugng nanoclay 2%i. Tuy nhien, neu tang ham lugng nanoclay len 3% thi dg ben keo dirt va dg dan dai khi dirt ciia mau nanocompozit epoxy/clay lgi giam xudng.
- * - L l n M i i u f i n |
Che tgo vd khdo sdt tinh chdt...
ngoai va ngan ngira sy ldn ien ciia cac vet mit te vi tdn tgi ben trong epoxy ra be mat nen dg ben chiu tai trgng cua vgt ligu tang len [7]. Do vay, dg ben ciia cac mau nanocoposite epoxy/clay dugc cai thi^n.
Tuy nhien, vdi 3% khdi lugng nanoclay thi se tdn tai cac hgt nanoclay du. Luc nay, trong he se hinh thanh pha rieng biet, pha vd cau trite ddng nhat cua he epoxy/nanoclay. Dudi tac dyng ciia ngogi lye, irng suat se phan bd khdng deu trong khdi vat lieu iam eho do ben keo dirt va dg dan dai khi dut ciia mau giam [6]. Ddng thdi, khi trong mau nanocompozit cd chira ham lugng nanoclay ldn (3%) thi se gay khd khan cho qua trinh ddng nhat mau do dg nhdt tang cao trong thai gian ngan va bgt khi xuat hi?n nhieu trong san pham. Day chinh la nguyen nhan khien dg ben ciia mau giam. Mau nanocompozit tren ca sd nhua epoxy vdi 2% khdi lugng nanoclay cd dg ben keo dirt tang khoang 16,1% va dg dan dai khi dirt tang khoang 50% so vdi mau compozit epoxy nguyen chat.
Hmh 3: Anh hudng ciia ham lugng nanoclay den do ben keo dirt va dg ben udn ciia vat lieu
nanocompozit epoxy/clay Trong khdi epoxy nguyen chat, gi&a cac cau triic thudng tdn tai nhirng diem cku triic rdng (khuyet Igt). (} nhirng diem kit bd rdng nay, cac doan mach phan tir cd dg linh ddng Idn va lye tac dung tuang hd giira cac phan tu rat nhd. Dudi tac dung luc ca hgc, chang hgn luc keo dirt thi ung suat xuat hien trong khdi polyme khdng ddng deu nen polyme se bj pha buy vdi gia trj iyc khdng Idn lam [6]. Khi cac ket bd rdng nay dugc dien day bang nanoclay hoac mgch dgi phan tu epoxy chen vao giira cac ldp nanoclay, dg bin lien kit giira mgch dai phan tir epoxy vdi cac Idp nanoclay dugc tang len. Ngoai ra, nanoclay cdn cd tac dung lip day cac khuyet tat trong khdi vat li?u, ngan chgn su pha hiiy ciia cac tinh the tren bl mat epoxy bdi lye tac dung tir ben
Hmh 4: Anh hudng ciia ham lugng nanoclay den do dan dai khi dut ciia vat lieu nanocompozit
epoxy/clay
3.3. Tinh he so khuech tan nude vao nanocompozit
Qua trinh khuech tan nudc vao trong he epoxy tuan theo djnh luat Pick 2 [2-5, 8]:
3/ 3x'
Vdi c la nong dp nudc khuech tan, t la thdi gian, D la he sd khuech tan, x la chieu dai quang dudng khulch tan. Mdi lien he tren cd the dugc dan gian hda cho giai doan dau cua qua trinh hap thu nudc.
Khi dd, phuang trinh dugc bieu dien lgi dudi dang:
M, 4 M„ L4n -IDI
TCHH, T.51(I), 2013
M, la lugng nudc khulch tan vao vgt li?u polyme d thdi dilm t, JW„ la lirgng nudc hap thy d trgng thai can bang. Ve dd thi bieu dien sy thay doi khoi lirgng ciia mau sau khi ngam 30 ngay trong cac mdi trudng M|% theo can bgc hai ciia thai gian ngam t"^ ta thu dugc kcl qua d hinh 5.
Trong giai dogn dau (khoang 10 ngay dau), khoi lugng mau tang nhanh chii yeu la sy tham nhgp nhanh ciia cac thanh phan Ihap phan tir tir mdi trudng vao vat lipu. Sau dd, khoi lugng thay doi khdng dang ke. Sau khoang 28 ngay ngam trong mdi trudng nudc bicn, bat dau xuat hi?n nluTng vet nhd mau trang d cac cgnh va gde ciia mau chirng td da cd sy khuech tan ciia ingt sd chat tan lir vgt \'\gu compozit vao mdi trudng nudc bien gay ra sy mat mat khoi lugng mau. Nguyen nhan la do trong nude bien ton tai mgt sd thanh phan (cac logi muoi, cac ion kim loai...) lam cho nhya bj truong mgnh han va phan irng thiiy phan cd the xay ra mgnh ban trong mdi Irudng nudc may.
• EfKny ngiiyC - * Er-.^y^r^ nd I T E|..xyt.r^n»
chli
noclay
Le Minh Dire vd cdngsii doiin dau) va su khuech lan ciia chat tan (giai doan sau), Nhgn thay rang, trong giai doan dau, phan tram ih;iy tidi khoi lugng tuyen linh vdi tl/i. He sd khuech liiu cd the dugc linh loan lir do ddc ciia vimg luy^n liiili Ircn dudng cong hap thu nudc (ni = 4D"VL7t"^), V()i ill hi dg ddc ciui dirdng cong irng vdl viing tuyfn linh
I ir thing duimg cong hap thu d hinh 5 va ket qua linh liv so khuech liin d bang 2 va 3 cho thay, dp doc ciKi cnc dudng cong hap thu nudc giiim dan lir man cp()\> nguyen chat. cpo\y"t-l% nanoclay.
epoxy i3%nanoclii} v:i sau ciing )a L'poxy 12%iianoclay Hay nui each khac, luong niiiii)i.hi\ liong he lang. he sd khuech tan nudc giam.
Iii\ nhien. kin tang luang clay len 3% khoi lugng (hi dl) ddc ciia duang cong lgi tang len ird lai Dicu iiiiv CO Ihc do Ciic nguyen nhan sau;
Iking. - Hg sd khuech tan ciia nudc vao cac mau ompo/.il kill ngiim trong nudc may
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lir(,mfi nuac
hap Ihu 1.09 (1.79 0 44 0 51
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( i . l ! 5 6 0,3 15K 0 3156 0 1152
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0 067 11 l)4H IJ.Ii27 0.032
l i t 56 khucth lan
( e m ' s ' ) 2.439x10' 1.253x10' 3.960x10' 5.549x10'
. I . I . I I I I I I I I I
Hinh 5: Su thay ddi khdi tugng cac mau compozit khi ngam trong cac mdi trudng nudc may (a),
nudc bien (b)
Nhu vay, sy thay doi khdi lugng ciia cac mlu compozit sau khi xir ly ngam trong mdi trudng nudc bien la ket qua ciia 2 tac dyng: sy hap thu nudc (giai
kirii; 3 He so khuech tan ciia nudc vao cac mau compo/i! khi ngiiin irong nudc bicn
M i u
L p c > \ \ n g u ) CII c t i a l U.po\\ l " o r i a n o c k i y P.po\\ • 2 " o n a r i o c l ; i y [ : p o \ > • ? " o r i a i i o c l i i v
l u o n g n i / a c hap t h u
l . J J 0,S7 0 , 4 9 0 , 5 J
C h i e u d a y , c m
0 , 3 1 5 2 0 , 3 1 5 8 0 , 3 1 5 2 0 , 3 1 5 2
D o d o c m
0,082 0 , 0 5 3 0 03 0,034
He so khuech tan, cm'",s'' 3 , 6 4 4 x 1 0 ' 1,528x10"' 4,877x10"' 6,264x10"'
- kill phan lan nanoclay vao nhya epoxy bang pliijoni: phap ddng nhat sieu air thi cac Idp nanocla) se diuic tach ra khdi nhau lao dieu kien cho cac iiKich dLii phan lu epoxy chen vao giira cac lop n;inoel,i\ Khi do. do ben bam dinh giira mach dai phiiii iir epo\y vdi cac ldp nanoclay dugc cai thien Neo.ii ra, do nanoclay cd cau triic dang Idp nen co tiie dung nhu cac tam chan hiru hieu ngan can su tham nhap ciia cac Ihanh phan thap phan tii tir moi iruonsi \ao trong cau tnic vat lieu. Ben canh do. klia niing Lip day cac Id trdng trong mang ludi epoxy ciia
TCHH, T. 51(1), 2013
nanoclay cung gdp phin ngan can qua trinh khuech tan.
- CJ ham lugng nanoclay la 1% khoi lugng thi chua du de tao nen mgt he phan tan tdt ciia nanoclay trong nen nhya epoxy. Liic nay, thi tich ty do trong vgt li^u vin cdn Idn nen nudc khulch tan manh vao vat lieu. Tang ham Iugng clay len 2% khoi lugng thi vira dii de tgo nen mgt hf phan tan tdt, cd tac dung ngan can mgnh me su xam nhap ciia nudc vao trong vat lieu. Nhung d 3% khdi lugng nanoclay thi se ton tai cac hgt nanoclay du. Liic nay, trong h^ se hinh thanh pha rieng biet, pha vd cau tnic ddng nhat ciia he epoxy/nanoclay. Ddng thdi, khi trong mau nanocompozit cd chua ham lugng nanoclay ldn (3%) thi mat do lien ket ngang giam tgo dieu kien cho nude xam nhap vao cau true vat Ii?u [3].
Dp thay ddi khdi lugng trong mdi trudng nudc bien Idn hon trong mdi trudng nudc may la do trong nudc bien tdn tgi nhieu thanh phan (cac logi mudi, cac ion kim loai...) cd kha nang gay pha vd lien ket tren bl mat vat lieu, iam cho vat lieu bj truang mgnh hon va phan img thiiy phan cd the xay ra mgnh hem trong mdi trudng nudc may [3].
4. KET LUAN
Trong nghien cuu nay nanocompozit tren nen nhya epoxy vdi hat nanoclay dugc che tgo thanh cong bang phuong phap dan gian. Mau dugc kiem tra tinh chat ca hoc va nhan thay rang ham lugng hat nanoclay trong mau thuc su da cd nhirng anh hudng nhit djnh den tinh chat ca hpc ciia mau nanocompozit. Dp ben keo, udn, nen dupc cai thien vdi mpt ham lugng hat nanoclay nhat dinh. Ngoai ra, kha nang hiit nudc trong mdi trudng ciing dugc danh gia va tir do tinh loan dugc he sd khuech tan nudc vao vat lieu.
Che tao vd khao sdt tinh chdt...
TAI LIEU THAM KHAO
1 Bradley Siddans. Epoxy/Clay Nanocomposiles: Effect of clay and resin chemistry on cure and properties, Queensland University of Technology (2004).
2. Jang-Kyo Kim, Chugang Hu, Ricky S. C. Woo, Man- Lung Sham Moisture barrier characteristics of organoclay-epoxy nanocomposiles. Composites Science and Technology, 65. 805-813 (2005) 3. L. B. Manfredi, H De Sanlis, A. Vazquez Influence
of the addition of monlmortllonile lo the matrix of unidirectional gloss fibre/epoxy composites on their mechanical and water absorption properties.
Composites Part A, 1-28 (2008)
4 Lisardo Nunez, M. Villanueva, F. Fraga, M R.
Nunez Influence of IVater Absorption on the Mechanical Properties of a DGEBA (n=0)/l. 2 DCH Epoxy System. Joumai of Applied Polymer Science, 74,353-358(1999).
5. M. Nematollahi, M. Heidarian, M Peikar, S. M Kassiriha, N. Arianpouya, M. Esmaeilpour Comparison between the effect of nanoglass flake and montmorillonite organoclay on corrosion performance of epoxy coaling. Corrosion Science, 52, 1809-1817(2010).
6. Ngo Phu Tru. Ky thudt che bien \d gia cong cao su, Trudng Dai hoc Bach khoa Ha Noi, 157-161 (1995), 7, S.R, Ha, S.H. Ryu, S J Park, K Y. Rhee. Effect of
clay surface modification and concentration on the tensile performance of clay/epoxy nanocomposiles.
Materials Science and Engineering A, 448, 264-268, (2007).
8 T. Glaskova, A, Aniskevich. Moisture absorption by epoxy/montmorillonile nanocomposite. Composites Science and Technology, 69, 2711-2715 (2009).
Lien hi: Le Minh Dire
Trudng Dai hgc Bach khoa Da Nang 54 Nguyen Luang Bang, Thanh phd Da Nang Email: [email protected].
