TAP CHI HOA HOC T. 50(2) 245-248 THANG 4 NAM 2012
NGHIEN CLPU QUA TRJNH T 6 N G HOP HAT NANO Cu TRONG NHU'A PE
La Due Duong', Nguyen Thi Hoai Phuong', Phan Xuan Tra^g^ Doan Thj Ngai' ' Vi^n Hda hgc - Vgt li^u, Vi^n Khoa hgc - Cdng nghe Qudn su
^Vijn Hda hgc mdi truong Qudn su. Bg Tul^nh Hda hgc Den Tda soan 24-2-2012
Abstract
In situ synthesis of copper-containing nanoparticles in polyethylene matrix by the method of thermal decomposition of (CHjCOO)2Cu.H30 was presented. Average dimensions, crystalline structure and size distribution of copper- containing nanoparticles were determined by transmission electron microscopy (TEM) and X-Ray diffraction. Effects of wt% of Cu to size of nanoparticles, composition and crystalline structure were investigated in detail. !t was shown that when copper concentration of lower 6 wt%, the nanopartilcs are mostly CuO and CU2O particles. When the sample containing copper concentration of higher 6 wt%, the nanoparticles contain CU2O and metallic Cu, With the sample containing 8 wt% of copper, the obtained Cu^O and Cu nanopartilcs are uniform with average sizes of 10 to 30 nm.
Keywords: Copper-containing nanoparlicle, copper-containing PE matrix.
1. MO DAU
Trong nhung nam gdn ddy, vi?c ch^ tao cdc vdt li?u polyme tien tiln cd chua hat nano kim loai ludn thu hijt dirge rdt nhieu mdi quan tam tu phia cdc nha khoa hpc [1], Nhung vat lieu nay cd the dugc ting dung trong rat nhieu ITnh vuc khde nhau nhu: bdo ve an raon, mdng chdng ndm mdc, trong ITnh vuc quang hoc, cam bien... nhd vao cdc tinh chat hda hgc vd vat ly tm viet cija chung. Vdt lieu polyme chiia kim loai CO the dugc che tao bang rat nhieu cdc phuang phdp khac nhau nhu: phdn tan co hgc, phuong phap khu, phircmg phap polyme hda, phuong phap phdn huy nhiet, phuong phap I^nh sau, phuong phdp quang hoa.
Vffi nhung iru dicm nhu che tao dirge cdc hat tiaiio CO kich ihuac nhd, phdn bo dong deu trong
"lang polyme va thiCn bj cdng nghe tuang doi don
^lan, phiroiig phap phan hiiy nhiet da duac irng dung fong rai trong vice che tao vat lieu polyme chua nano kim loai [2], Vat lieu polyme chua nano Fe duac che l3o thanh cong co kich cd tir 2-10 nm vdi thanh phan va cau true tirong doi phirc tap, phu thuoc vao ham IfOTigcLia Fe trong polyme va ban chat ciia pol>me Trong khi do, Kaushik M vd cdc dong nghiep [3] da cjie tao dugc vat lieu compozit poI>nie-nano kim loai 'If Cu va poly(o-toluidinc), vdi kich thudc ciia cac hat
"ano Cu khoang 2-5 nm...
Dong va cac oxit ddng da dugc biet den va irng
^"8 kha rong rai trong cac loai son chdng an mon
•"Ofg moi trudng khi hau bien. Ddng ciing da dugc
^^ung nhu mot tac nhan chong nam mdc trong
mot nhdm cac nhd nghien ciiru tai phdng thi nghiem Lucent Bell da phdt minh ra kha nang khu khi an mdn rdt hi?u qud ciia cac hat Cu d kich co nano, md ra mgt xu hudng mdi trong cdng nghe bdo quan vat lieu khdi tdc dgng dn mdn. Tuy nhien, viec dua cac - hat Cu d kich co nano vdo cac vat lieu ma van giiJ dugc thanh phdn, cdu true va cac tinh chat uu viet ludn Id mgt bdi todn khd ddi vdi cac nhd khoa hgc.
Trong nghien cuu ndy, cdc hat nano Cu va CuiO dugc che tao bdng phuong phdp phdn huy nhiet cdc hgp chdt chua Cu trong nhua PE. Thanh phdn, cdu triic vd mgt sd tinh chat ciia chiing dugc nghien ciru bang cdc phuang phdp hda Iy.
2. THUC NGHIEM 2.1. Nguyen vat lieu va hoa chat
Cdc hda chdt vd dung mdi sir diing trong qud trinh tdng hgp Id hda chat tinh khiSt. Vdt lieu nano dugc tdng hgp bdng phuong phap phdn hiiy nhi?t.
Polyme sOr dyng trong qud trinh tdng hgp ndy la nh^ra PE cd khoi lugng phan tu cao (HOPE) vdi nhigt do ndng chdy 130°C dugc mua tir hang V&A Clia Hdn Qudc. Hat kim loai dugc che tao tir muoi ddng (II) acetate, Cu(CHiC00)2 (nhiet do phan huy tai 248°C, mua tir hang Xilong, Trung Quoc), bdng phuang phap phan hiiy nhiet tai nhiet dg cao hon nhiet do ndng chdy cua ddng axetat.
2.2. Quy trinh tdng hop
Quy trinh tong hgp nhua PE chira nano Cu dugc 245
TCHH, T. 50(2), 2012
thyc hien nhu sau: Dung djch dong axetat trong dung mdi hiTu co dugc nhd vdo binh phdn tmg chira lOg nhya PE ndng chay trong 100 ml dau chdn khong, dudi dicu ki?n khuay manh d 250-300"C trong 2 gid. Khi Ar dugc s\ic vao trong binh phdn ling de t^o mdi trudng khi tra va dc tdch nhanh cdc ligands va dung mdi tir binh phdn iing. Sdn pham thu dugc cd d^ng nhu parafin, lugng dau du dugc tdch bdng benzen trong thiet bj chiet Soxhlct. Sau dd sdn pham dirge Iam khd trong mdi trudng chdn khdng vd bao quan trong khdng khi. San pham thu dugc d d^ng bgt. mdu nau dd, Mdu dugc che t^o dudi d^ing mang hinh chiJ nhdt 10^15 cm, day 0,5-2 mm, diing de do dac kicm tra cdc tinh chat ciia compozit. Mau dugc tdng hgp c6 ham lugiig dong thay doi tir 1,5- 12% khoi lugng so vdi nhya PE.
2.3. Cac phuong phdp nghien cuu
Thanh phan pha vd thdnh phan nguyen to dugc phdn tich tren thiet bj nhicu xa tia X X'Pcrt Pro dugc ghi vdi andt Cu, tia birc xa CuKu, goc qudt 20 tu 15-80° vd thiet bj phd phdn tdn nang lugng (EDX) 6490 (LA). Kich thudc hat nano Cu dugc kicm tra tren kinh hien vi dign tir phat xa (TEM, EMLAB- NIHE). Nhi?t dg ndng chdy ciia compozit PE-Cu dugc do tren thiet bi phdn tich nhiet NETZSCH STA 409 PC/PG. Ngoai ra mdt s6 tinh chdt vat ly hda khac cung dugc do dac vd kiem tra.
3. KET QUA VA THAO LUAN
3.1. Su hinh thdnh nano Cu trong PE ndng chay Ca che hinh Ihanh hat nano Cu trong nhya PE ndng chay dugc bieu dien trong hinh sau (hinh I).
Hii Cu duoc »n
lonjiiong mui^ P-
@ .
Hlnh 1 • Sy tao thanh h^t nano Cu trong m?ng nhya PE tir dung djch CUACH2O Qua trinh hinh thanh Cu tir sy nhi?t phan ciia dung djch dong axetat trong nhya PE ndng chdy thudng xay ra tai cdc Id hdng trong mang ludi ciJa PE. Sy nhi?t phan ciia CUACH2O trong mdi trudng khi tro thudng trai qua 2 giai doan [4]:
+ Giai dogn 1 (25 - 225"C): Khir nirac
La Dire Duang va cgng su
(CIl,COO)2Cu.H20-^(CH3COO)2Cu + H2O (1) + Giai dogn 2 (225 - 325"C): Nhi^tphdn 6n(CH3COO)2Cu ^ C u + Cu20 + 3n
(Sdn pham khde) (2) Cdc sdn pham khac d day bao gom: axeton
(CHiCIIiCO), axit axetic (CH3COOH), andehit (Cl I3CHO), metan (CH4), CO2 vd H2. Khi md nhi?t dg ldng tren 325''C sdn pham chu yeu tao thdnh la CuO.
Sy phdn hiiy nhigt ciia CUACH2O thudng chi dien ra tji cdc 16 hong trong mang ludi ciia nhya PE, moi 16 hdng ddng vai trd nhu mgt binh phan irng d kfch cd nano. Khi mdi gigt dung djch chiia CUACH2O dugc dua vao trong dung djch PE ndng chay nd sc tim den mgt 16 hdng cdn trong. Khi dung djch CUACH2O d^t dfin trang thai qua bao hda, su hinh thdnh hgt bdt dau vdi sy tao mam ddng nhdt.
Cdc mam ndy s5 Idn dan len, den mgt kich thudc nhat djnh, ciing vdi nong dg cdc hat du cao se xay ra qua trinh ket ty thdnh cac hgt cd kich cd nano. Tuy nhien, trong mgt so trudng hgp nhdt djnh, co che phdn ling cdn dien ra phuc tgp han nhicu.
Nhu-ng thi nghi?m \i dgng lyc hgc cua qud trinh phdn irng da chi ra rdng: sy ldn Ien cita cac hat dien ra ddng thdi tai rdt nhieu cdc 16 hdng trong todn bd mang PE; mdi logi nhya PE cd sd lugng va kich cd 16 hong khde nhau. Cdc 16 hdng ddng vai trd nhu mgt binh phan ung kich cd nano. Vd ben trong ehung hgt nano Cu dugc hlnh thdnh vdi hinh dang vd kich thudc nhdt dinh. Sy tao mam vd su Idn len Clia cac hgt cdng ddng nhdt, thi kich thudc hgt Cu va CU2O thu dugc cdng ddng deu.
3.2. Md ta cau true cua nhira PE chua nano Cu 3.2.1. Thdnh phdn vd cdu true cua nhua PE chua nano Cu
Cdu true tinh th8 vd thdnh phan nguyen td cua hgt Cu vd CUTO trong nhya PE dugc xac dinh bang sir dyng pho nhilu xg tia X (XRD) va phd EDX (hinh 2).
Tir pho tan sdc nang lugn^ tia X (hinh 2A) ta thay sy xudt hi^n ciia nguyen td Cu va O trong nhya PE. Cau trite tinh the va thanh phdn hgp chat cd mat trong nhya PE dugc xdc dinh bdng phd nhieu xg tia X (hinh 28). CJ hdm lugng Cu Id 6% khoi lugng trong nhya PE, cac pic thu dugc hoan toan phit hgp vai pic chuan cita pha CU2O lap phuang tdm khdi (cubic) vdi thdng sd mang a = 4,258 A (JCPDS, so 77-0199), cdc pic danh dau (*) tuong ung vdi cdc pic chuan cua pha nhua PE (JCPDS, so 053-1859).
Phd nhilu xa tia X d ham lugng Cu la 8%, ngoai cac pic thu dugc tucmg ung vdi cac pic chudn cua CuzO va nhua PE, ta con thu dugrc cac pic phu hgp vdl cac pic chuan ciJa pha Cu lap phuang tam khoi (cubic) vdi thdng so mgng a = 3,615 A (JCPDS, so 04-
TCHH,T.50(2),2012
Nghien cim qud trinh tdng hap.
0836). Ham linmg Cu trong PE dugc tang len den duyc voi liam luyng Cu la 11% cao hon so v*i cac 11% khoi lugng, ta thu dupe pho XRD hoan toan pic thu dug-c tai 8% khoi luong Cu trong PE diSu do phi hffp vcri cac pic chuan ciia Cu, CuiO va nh\ra chirng to dg tinh thS va mat dp Cu va CU26 4 11%
PE. Tuy nhien cuong do cac pic ciia Cu va CujO thu Cu cao hon so voi o 8% Cu.
Ivt JL^
B Q O O -
G O O D .
loao.
l O O D
AJJ»
• • Cu20
• Cu
•
S 11%Cu
e%cu
6%Cu
" 20 (Angle)
(A) . , (B) Hmh 2: (A) Phd tdn sac nang lugng tia X vdi 8%Cu trong PE;
(B) Phd nhilu xg tia X vdi ham lugng Cu trong PE Id: 6%, 8% va 11%
il ' A7c7; thuoc nano Cu trong nhua PE
Hlnh ilidi hgc vd kich cd ctia cdc hat nano Cu va Cu.O hinli thanh trong mgng PE bdng phuang phap phan hiiy nhiet dtrgc quan sat ky hon bdi hinh TEM sau khi hoa tan compozit PE-Cu trong toluen (hinh 3).
Hinh TEM vdi dg phdng dgi 15.000 ldn (hinh 3A) lan clio thdy nh&ng chdm den dugc coi la cac hat nano Cu va CuiO, nhiJng vimg mau xam nhgt lirong irng vdi nhya PE Dieu dd cho thay rang cdc hat Cu \a Cu20 cd kich cd nano dugc phdn tan deu dan va tach biet, khdng xdy ra sy ket tu giua cac hat.
Hinh thai hoc va kich cd ciia cdc hgt nano ndy dugc xac nhan ky hon bdi hinh TEM cd dg phdng dgi 120,000 1^ trong hinh 3B, vol kich thudc ciia cdc hat lir 10-30 nm.
Dirang kinh tinh the trung binh ciia hgt Pt dugc tinh toan sg dung phuong trinh Debye-Scherrer [5]:
'$
KX
' BcosO (3)
(A)
tl. ,f (B)
Trong do: d li duong liinh tinh ihl, K la hSilj d ph\l thoc vao dang tinh till (0,89), A la buoc song ctia
"a X (1,54060 A), B la do rgng ciia pic tai vj tri gifta wa pic. Tir phuang trinh tren, kich thuoc trung binh Ma cac mat (111), (200), (220) trong tinh thi Cu va ("I).(Ill), (200), (220), (311) trong tinh th4CuiO 'i" a c gia tri 20 luong irng 43,593", 50,678°, '4,213° va 29,881°, 36,693°, 42,566°, 6\,55T', '•1,662° thu dugc trong bang sau (bang 1).
Hinh 3: Hinh TEM cua cac hjt nano Cu va CuiO;
(A) Dp phong d?i 15000 ijn; (B) Dp phong dai 120000 lan
D(ra vao linh toan a bang 1 nhan thjy kich thuoc trung binh cda cac m}t tinh th6 Cu va CU2O thu dupe kha dong d£u tir 15-25 nm a cac ham lucmg phan trSm Cu trong nh\ra PE khac nhau. K6t qua nay hoan toan phil hpp vcri kich thuac trung binh cua cac hat
TCHH, T. 50(2), 2012
Cu vd CU2O da dugc quan sdt trong hinh TEM d tren.
3.2.3. Tinh chat nhi^t ciia hat PE chira nano Cu
Tinh chat nhigt ctia nhya PE chu'a Cu va CU2O dugc xdc djnh bdi gian do phdn tich nhi^t DTA (hinh 4).
La Dire Duong va cgng sir Nhin vdo gian do phdn tich nhi?t (hinh 4) thay rdng nhict ndng chdy cita nhya PE chua 8% Cu la 120°C, gidm ddng kc so vdi nhya PE khong chira Cu (I29,5"C). Dieu nay dugc gidi thich Id do sy hi?n ciia cdc hgt nano Cu kim logi vd CU2O lam tdng kha ndng ddn nhigt ciia nhya PE, va do dd Idm gidm dicm ndng chay ciia compozit PE-Cu so vdi nhya PE ban dau.
Bdng I: Kich thudc trung binh ciia cdc mdt linh the Cu vd CU2O tinh theo cdng thirc Debye-Scherrer
STT
1 2 3
Ham lupng Cu trong nhua PE, %
6 8 I I
Pha tinh the d(Cu), nm
(111)
23 19
(200)
23 18
(220)
22 19
d(Cu20), nm (110)
15 23 16
(111) 19 24 16
(200) 20 22 18
(220) 18 19 17
(311) 18 20 17
Hinh 4: Gidn dd phdn tich nhi?t cua nhya PE va nhya PE chira 8%Cu
4. KET LUAN
Nhya PE chira hat nano Cu vd CujO dd dugc che tao thdnh cdng bdng phucmg phdp phdn hiiy nhi?t true tiep muoi Cu(CH3COO)2.H20 trong nhya PE ndng chay vdi mdi trudng khi Ar. Kich c& hgt Cu va CuiO thu dugc tuong doi dong deu tir 10-30 nm.
Compozit PE-Cu dugc tdng hgp voi 2,5 g Cu(CH3C0O)2.H2O nhi?t phan trong 10 g nhya PE d nhigt dg 250-300°C trong vdng 2 gid, c6 nhi?t dg ndng chay Id I20°C.
TAI LIEU THAM K H A O
1 N, Luigi and C. Gianfranco. Metal-Polymer Nanocomposiles, Wiley Interscience (2005).
E M. Natanson and Z. R. Ul'berg. Colloidal Metals and Metal-conlaining polymers, Kiev, 174 (1971).
I. D. Kosobudshii and S.P. Gubin. Metallic cluster in polymer matrices. A new type of metal-filled polymer, Vysolomol Soed., 27, 689-695 (1985).
J. V. Bellini, R. Machado, M. R. Morelli, and R. H.
G. A. Kiminami. Thermal, structural and morphological characterisation of free-dried copper (II) acetate monohydrate and its solid decomposition products, Materials Research, 5, 453-457 (2002).
D. D. La, C. K. Kim, T. S. Jun, Y. Jung, G. H. Seong, J. Choo, Y. S. Kim. Pt nanopartide-supporled mulliwall carbon nanotube electrodes for amperomelric hydrogen detection. Sensors and Acuators B., 155,191-198 (2011).
Lien ftp: La Due Duong
Vi^n Khoa hgc vd Cdng ngh? Quan sy So 17 Hodng Sam, NghTa D6, Cau Gidy, Hd Ngi Email: masterist83(^gmaiI.com.
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