TAP CHI HOA HQC T.49(2), 162-165 T H A N G 4 N A M 2 0 1 1
NGHIEN CLPU TJNH
C H A TVA CAU TRUC CUA VAT LIEU COMPOZIT POLYETYLEN/PE-g-AM/CaCOa
Thai Hoang, Vu Minh Due, Nguyen Vu Giang, Do Quang Tham Vi?n Ky thugt nhi?t dai, Vi?n Khoa hgc vd Cdng ngh? Vi?t Nam
Din Tda sogn 5-3-2010
Abstract
The composites of PE/CaCOs with and without PE-g-AM compatibilizer were prepared by melt mixing in a Haake Rheomix 600p. The Haake torque (could be called as the relative melt viscosity) of the composites was recorded while mixing by Polylab V 4.1 software. The mechanical properties of the composites were tested by a WMF instrument, dielectric properties were measured by using a TR-IOC dielectric loss measuring set and volume resistivity was measured by IV method using a TR-8401 DC instrument with applied voltage of 1000 V. The mophological structrure of the composites was studied by scanning electron microscopy (SEM). The results showed that CaC03 and PE-g-AM increased relative melt viscosity of the composites, this proved that PE-g-AM enhanced the adhesion between CaCOs and PE matrix while melt mixing them. The mechanical properties of the PE/CaCO-, composites strongly decreased with increasing CaC03 contents. But by adding PE-g-AM, the mechanical properties of the PE/CaCOs composites were improved significantly, especially in tensile strength. PE/CaC03 and PE/PE-g-AM/CaC03 composites had good electrical insulation properties, such as high resistivity and very low dielectric loss. The PE-g-AM compatibilizer played an important role for the enhancement of dispersity of CaC03 in PE matrix, reducing agglomeration of CaCOs particles in PE matrix.
1. MO DAU
Trong sd cdc polyme, polyetylen (PE) dugc sOr dung nhieu nhdt trong cdc ngdnh nhu sdn xuat bao bi, dd gia dyng, vdt lieu cdch dien, xdy dung, sdn xudt dtd... bdi chiing cd nhirng uu the vugt trgi nhu de gia cdng, do bin ca ly, bin hda chat cao ban... so vdi mdt so cdc vdt ligu polyme khdc [1,2]. D I tdng cudng mgt sd tinh chdt vd gidm gid thdnh sdn pham tir PE, ngudi ta dua cdc chdt dgn vd co vdo vdt ligu polyme nhu CaCOs, Si02, talc, thgch cao ... [3 7].
Tuy nhien, do bdn chat vd cgc tinh ciia chat dgn vd CO vd PE hodn todn khdc nhau nen khd ndng tuong hgp giira chiing rat kem. Cdc tinh ndng co ly ciia vgt ligu compozit suy gidm rat nhanh vd gdy khd khan cho vigc gia cdng. Nhdm tang khd ndng tuong hgp giira polyme vd chat dgn can sir dyng chat tuong hgp, biln tinh polyme hogc chat dgn [1 6]. Cdc chat dgn vd co, ddc bigt la CaC03 cd thi dugc biln tinh bdng vigc phu Ien bl mat mgt Idp vd, thudng Id cdc axit hiru co. Dilu nay tgo cho CaC03 biln tinh ddng vai trd nhu mgt chat dgn hda hgc vi kha ndng lien kit tot ban vdi cdc polyme [3].
Cdng trinh ndy nghien ciru su dyng CaC03 da dugc bien tinh bl mat bdng axit stearic phdn tan vdo nIn PE, cung nhu vai trd cua chat tuong hgp PE ghep anhydrit maleic (PE-g-AM) din tinh chat co ly, do nhdt chay tuong ddi, tinh chat dien vd hinh thdi hgc cua vat ligu compozit PE/CaCOs.
2. THUC NGHIEM 2.L Nguyen lieu
Polyetylen ty trgng cao (PE) dgng hgt sdn phdm ciia hang Exxon Mobil (A-rdp Xeut), ty trgng 0,95 g/cm\ chi sd chdy 8 g/10 phut d nhiet do 190°C vd tdi trgng 2,16 kg.
Chdt tuong hgp: polyetylen mgch thdng ty trgng thdp ghep anhydrit maleic (PE-g-AM) - d dgng hgt, hdm lugng MA ghep vdo PE Id 0,4%).
Chat dgn CaCOs dugc cung cap bdi cdng ty Minh Dire, bien tinh bl mat bdng axit stearic, kich thudc hgt 3-10 pm; dign tich bl mat rieng 7 mVg; ty trgng 2,71 g/cni^
2.2. Che tao mau
Cdc mau polyme compzit PE/CaC03 cd vd khdng cd PE-g-AM dugc trgn trong mdy trdn ngi Haake (Dure) d nhigt dg 170°C trong thdi gian 5 phut, tdc dg quay cua true 50 vdng/phut. Hon hgp thu dugc sau qua trinh trgn dugc djnh hinh tren may ep thuy luc d 170°C trong thdi gian 3 phiit dudi dp luc 10 - 12 MPa thanh cac tam day 1-1,5 mm, sau dd dugc ldm ngudi den nhigt do phdng d dp luc 5 MPa.
Mau dugc bdo qudn d dieu kien chudn it nhdt 24 gid trudc khi xdc djnh cac tinh chat vd cau true.
162
TCHH, T. 49(2), 2011 Thdi Hodng vd cdng su 2.3. Phuo'ng phap va thiet bi nghien ciru
Do nhdt chdy tuong doi ciia vat lieu dugc ghi bdng phdn mem Polylab 4.1 kit ndi vdi mdy trgn Haake trong qud trinh che tgo mau, theo tieu chudn ASTM D 2538, tgi Vign Ky thugt nhiet ddi.
Tinh chat co ly cua mdu dugc xdc dinh tren mdy WMP cua Dire d nhigt dg phdng vdi toe dg keo 100 mm/phut, theo tieu chuan ASTM D638, tgi Vign Ky thugt nhiet ddi.
Xdc djnh hinh thdi cau true cua vgt ligu compozit bdng kinh hien vi dien tu quet SEM (Jeol- 5300 Nhdt Bdn), tgi Vign Ky thugt nhigt ddi.
Hdng so dien mdi vd tang gdc tdn hao dien mdi dugc do tren thilt bi TR-IOC (ANDO Nhdt Bdn) theo tieu chudn ASTM D150 d tdn so 1 KHz, tgi Vien Ky thudt nhiet ddi.
- Dien trd sudt mat vd dien trd sudt khdi dugc do bdng phuang phdp IV, theo tieu chuan ASTM D257 vdi he 3 dien cue vd thiet bj do ddng mgt chieu TR8401 ciia hang Takeda (Nhdt Bdn), dien dp 1 chieu 1000 V, do dm mdi trudng do khodng 70%, tgi Vien Ky thudt nhigt ddi.
3. KET QUA v A T H A O LUAN
3.L Anh hudng cua CaCOj va PE-g-AM den do nhdt chay tuong doi cua PE
Dg nhdt chdy tuong doi ciia PE ban dau vd compozit PE/CaC03 dugc khdo sdt thdng qua gidn do md men xodn theo thdi gian trgn. Hinh la trinh bay md men xodn ciia PE vd compozit PE/CaC03 vdi hdm lugng CaC03 la 10, 15, 20 % (theo tong khoi lugng). Tir hinh 1 cd thi nhgn thay pic ngp lieu (md men xodn dgt Idn nhdt) cua tat cd cdc mdu d khodng 0,5 phut. Khi PE mIm dan vd ndng chdy, md men xodn giam dan vd dgt gid trj khd on djnh sau khodng 4 phut trgn (khi PE ndng chdy hodn todn).
Md men xodn on djnh ciia nhua PE ban ddu cho gid trj thap nhdt vd tdng ddn khi tang hdm lugng CaCOs trong hdn hgp (hlnh nhd phdng to su khdc biet md men xodn on djnh cua cdc mdu). Dieu ndy cd the dugc bilu: cdc hgt vd co CaC03 da Idm gidm tinh linh dgng ciia cdc phdn tu PE trong qud trinh ndng chdy, do dd gia tdng do nhdt ciia hdn hgp ndng chdy [4].
r^
•wa o
<o
PE/CaC03 PE/CaC03 PE/CaC03 PE
80/20 85/15 90/10
-^PErt>E-g-AM/CaC03:80/5/15
•*PE/CaC03:85/I5
^ P E
6 5.8 5.6
""•---*
4 4.5 5 .,
5 0 1 2 3 4 5
Th5i gian tr9n (phut)
(b)
Hinh 1: Anh hudng cua hdm lugng CaC03 vd PE-g-AM den do nhdt chdy ciia PE
1 2 3 4
Thoi gian tr9n (phut)
(a)
Hinh lb trinh bdy kit qud nghien ciru tinh chdy nhdt cua compozit PE/CaC03 85/15 khdng cd vd cd 5% PE-g-AM (so vdi tdng khdi lugng mdu). Khi sir dung chdt tuong hgp, mdmen xodn cua hdn hgp PE/PE-g-AM/CaC03 (80/5/15) ldn ban ddng kl so vdi mdu khdng sir dyng chat tuong hgp vd PE ban dau. Dieu ndy chung td rdng da cd su tuong tdc giiJa cdc hat CaC03 vd PE nhd cd chat tuong hgp PE-g- AM, do dd Idm tdng khd ndng phdn tdn vd bdm dinh cua CaCOs vdi nIn PE.
3.2. Anh hudng cua ham lugng CaCOa va PE-g- AM den tinh chat co ly cua PE
Tren hinh 2 trinh bdy kit qud nghien cuu dnh
hudng ciia hdm lugng CaCOs cd vd khdng cd PE-g- AM den tinh chdt co ly cua PE. Mac du cdc hat CaC03 da dugc bien tinh (hiru co hod be mat) nhung khi phdi trgn vdi PE, khdng cd chdt tuong hgp, do ben keo dut ciia vat lieu cd xu hudng gidm vd gidm mgnh d cdc hdm lugng CaCOs ldn (15% vd 20%)).
Gid trj do ben keo diit gidm tir 22,8 MPa ciia PE ban dau xuong cdn 16,5 MPa khi hdm lugng CaCOa 20% (hinh 2a). Do ben keo dut cua vat lieu compozit PE/CaCOj tang khi cd 5% PE-g-AM. Do bin keo dut ciia vat lieu PE/PE-g-AM/CaCOs lan ban ddng ke so vdi vat lieu compozit PE/CaCOs tham chi cdn ldn hon so vdi nhua PE ban dau tuong ung vdi cac hdm lugng CaCOs 10 vd 15%). Khi tiep tuc bo sung them CaCOa (20 %) vao nIn PE/PE-g-MA, do bin
•163
TCHH, T. 49(2), 2011
keo diit cua vdt ligu compozit cd xu hudng gidm.
Dilu ndy cho thay khi hdm lugng CaCOa dua vdo nIn PE hodc PE/PE-g-AM Idn, trong vgt ligu xuat hign cdc khuylt tdt Idn, gidm tinh dong nhat [6].
Kit qud tren hinh 2a mgt lan nua cho thay vai trd cua PE-g-AM Idm tdng dg bdm dinh vd phdn tdn cua
Nghien ciru tinh chdt vd cdu true cdc hgt CaCOj trong nIn PE [1]. Dilu ndy cd the gidi thich bdi tuong tdc cua cdc nhdm phan cgc (C=0 vd C-O-C,) trong chat tuong hgp PE-g-AM vdi cdc nhdm C = 0 , -OH cua ldp axit stearic vd stearat canxi tren bl mat hgt CaC03, do dd, ldm tdng sg tuong hgp cua cdc hgt CaC03 vdi nen PE [3].
t
14 0
16 '- . C4J-.PE-I-AM KKtngctPK t AM
( li ?•/. PE-I-AM ---Kli«<n t6 PE-t-AM
5 10 IS l U m l u v n g C » C O , (%)
(a)
20 i S 10 15
l l i m lirong C a C O , (*/.)
20
(b)
Hmh 2: Anh hudng ciia hdm lugng CaC03 vd PE-g-AM den tinh chdt co ly cua PE Hinh 2b md td dnh hudng cua hdm lugng CaC03
vd chat tuang hgp PE-g-AM den do ddn ddi khi dirt cua PE. Dg ddn ddi khi dirt ciia PE deu gidm khi phdi trdn vdi CaC03 trong cd hai trudng hgp cd vd khdng cd chdt tuong hgp. Tuy nhien, trong trudng hgp thOr nhdt, nhd vai trd cua chdt tuong hgp nen khd ndng phdn tdn cdc hgt CaC03 ddng deu ban, mirc do CO cym tgo ddm cua cdc hgt vd co it hon [4], do dd do ddn ddi khi dirt ciia mdu cd PE-g-AM ldn hon so vdi mdu kh3ng cd PE-g-AM.
3.3. Nghien ciru hinh thai hoc ciia vat lieu compozit PE/CaCOs cd va khdng cd PE-g-AM
Hinh thdi be mat cua cdc mdu compozit
PE/CaC03 85/15, PE/PE-g-AM/CaCOj 80/5/15 dugc quan sdt tren dnh hien vi dien tOr quet (SEM) (hinh 3). Khi su dyng CaC03 bien tinh vd khdng cd PE-g-AM, CaC03 phdn tan khdng dong deu trong PE, cdc hgt CaC03 tap hgp thanh ddm vdi kich thudc Idn (10 - 20 pm) vd cd su tdch pha rd ret (hlnh 3a). Vdi su cd mat chat tuong-hgp PE-g-AM, CaC03 phdn tdn trong PE ddng deu ban, kich thudc nhd ban ( 4 - 1 0 pm) vd khdng cd su tdch pha rd ret (hinh 3b).
Dieu ndy cd the gidi thich bdi PE-g-AM ddng vai tro cua chdt hogt dgng be mat giiira 2 pha PE vd CaC03 vd cdi thien khd ndng tuong tdc be mat giira PE vd CaC03 [7].
I i
'A
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>M*ix' •—- •'"•"-'-^'-~'-• liritiff l*tir'tr- II •'*~iiii
r-.i
(a) PE/CaC03 85/15 (b) PE/ PE-g-AM/CaCOj 80/5/15
Hinh 3: Anh hien vi dien tir quet (SEM) cua vat lieu compozit PE/CaCOa, cd vd khdng cd PE-g-AM 164
TCHH, T. 49(2), 2011 Thdi Hodng vd cdng su 3.4. Tinh chat dien cua vat lieu compozit
PE/CaC03 cd va khong cd PE-g-AM
Nhieu cdng trinh nghien ciiu da chi ra rdng khdo sdt cdc tinh chdt dien Id phuong phdp trung gian hieu qud nghien ciiu cdu triic vat lieu polyme compozit, cho phep ddnh gid su tuong tdc, khd ndng phdn tdn giira cdc pha [9]. Cdc sd lieu d bdng 1 cho
thay dign trd suat khoi (pv) vd dign trd suat mat (ps) ciia vdt lieu compozit PE/CaC03, PE/PE-g- AM/CaC03 thap hon so vdi PE 1 bgc mu. Su gidm dign trd suat ndy Id do CaC03 thudng Idm tdng khd ndng xdm nhap cua hoi dm vdo vdt lieu. Tuy nhien, khi sir dyng them 5%) PE-g-AM, dign trd suat pv, Ps cua vdt ligu compozit PE/PE-g-AM/CaC03 cao ban so vdi vdt ligu compozit PE/CaC03.
Bdng 1: Anh hudng cua CaC03 vd PE-g-AM din tinh chat dign cua vdt lieu compozit PE/CaC03
Mdu PE
PE/CaCOj (85/15)
PE/PE-g-AM/CaC03 (80/5/15)
Pv (Q.cm) 4,4.10"'^
5,6.10^'' 5,8.10"'^
Ps 1,5.10^'"
1,7.10^'^
2,1.10^'^
e 2,10 2,11 2,20
Tg5 0,002 0,003 0,003 Hdng so dien moi (e) vd tang cua gdc tdn hao
dien mdi (tg8) ciia vat lieu compozit deu Idn hon so vdi PE nhung khdc nhau khdng ddng ke. Su tdng len cua hang so dien mdi ciia vat lieu Id do ban chdt phdn cue ciia CaC03 ldn ban so vdi PE. Tang cua goc tdn hao dien mdi ciia cdc vdt lieu deu rdt nhd (10"^). Noi chung, vgt lieu compozit PE/CaC03 vd PE/PE-g-AM/CaC03 diu Id vat lieu cdch dign tot [10].
4. KET LUAN
Su CO mat ciia CaC03 bien tinh vd chdt tuong hgp PE-g-AM Idm tdng do nhdt chdy ciia PE. Chat tuong hgp tang khd ndng bdm dinh cua CaC03 vdi PE trong qud trinh trdn ndng chdy. Tinh chdt co ly cua vat lieu compozit PE/CaC03 nhd ban so vdi PE nen. Khi su dyng chat tuang hgp PE-g-AM, tinh chdt CO ly cua vat lieu compozit PE/CaC03 da dugc cdi thien ddng kl, ddc biet Id do ben keo dirt. Chdt tuong hgp PE-g-AM tang khd ndng phdn tdn, hgn che su CO cum, su phan pha cua cdc hgt CaC03 trong nen PE. Vdt lieu compozit PE/CaC03 cd vd khdng cd PE-g-AM Id vdt lieu cdch dign tdt.
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Lien he: Thai Hoang
Vien Ky thuat Nhiet ddi
Vien Khoa hgc va Cong nghe Viet Nam 18 Hoang Quie Viet, Cdu Gidy, Ha Ngi
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