乙烯-醋酸乙烯共聚物的流變性能

第23卷第6期高分子材料科學(xué)與工程Vol. 23.No.62007年11月POLYMER MATERIALS SCIENCE AND ENGINEERINGNov. 2007乙烯-醋酸乙烯共聚物的流變性能李新法'，黃靈閣'，胡宏偉2,蔣愛(ài)云'，孟程程',牛明軍'，陳金周'(1.鄭州大學(xué)材料科學(xué)與工程學(xué)院，河南鄭州450052; 2. 河南金田地農化有限公司,河南鄭州40000)摘要;利用XLY-1型毛細菅流變儀測試了己烯-醋酸己烯共聚物(EVA)的表現黏度、粘流活化能、非牛頓摺數等流變參數，討論了剪切迷卑、剪切應力和溫度等對己烯-醋酸乙烯共聚物熔體的表觀(guān)黏度的影響,研究了粘流活化能與剪切速率的變化規律。實(shí)驗結果表明,乙烯=醋酸乙烯共聚物熔體的表觀(guān)黏度隨溫度的升高而降低;粘流活化能AE隨剪切速率的增大而減小。在實(shí)驗溫度苑圍內,EVA熔體的表觀(guān)黏度隨剪切迷率和剪切應力的增大而降低,其非牛頓指敷n小于1,說(shuō)明EVA熔體為假塑性流體。關(guān)鍵詞:乙烯-醋酸乙烯共聚物;流變性能;表觀(guān)黏度中圍分類(lèi)號:0631.2*1文獻標識碼:A文章編號100555<20006-0124-030由于EVA具有優(yōu)異的耐屈撓性、耐低溫擠出,電子記錄儀自動(dòng)記錄擠出速度和溫度。性、抗沖擊性和耐環(huán)境開(kāi)裂性等特點(diǎn),因此,被1.4流變數據處理廣泛用于模塑制品、熱熔膠、增韌改性劑、涂料.1.4.1剪切應力(t_):及織物加工等方面(1.2]。然而有關(guān)其基礎研究卻r. = Op R/2L(1)不多見(jiàn)0.0,至今尚未見(jiàn)到對EVA流變性能的1.4.2表觀(guān)剪切速率(Y.):研究報道。為此,本文利用XLY- 1型毛細管流y. = 4Q/xR*(2)變儀測試了EVA的表觀(guān)黏度、粘流活化能和非1.4.3表觀(guān)黏度(n.):牛頓指數等流變參數,并系統研究了其流變性n.= r./9.(3)能,從而為其成型工藝條件的合理確定,成型機1.4.4非牛頓 指敷(n):由冪律方程τ.= K%,械及模具的設計和提高制品質(zhì)量提供了重要的兩邊取對數得理論依據。.lgτ.=lgK +nlg9.(4)以lgτ.對lg%作圖,在一定范圍內可得一直1實(shí)驗部分線(xiàn),由直線(xiàn)斜率可得非牛頓指數n。1.1 主要原料乙烯=醋酸乙烯共聚物(EVA):醋酸乙烯式(1)~(4)中:Op- -作用在毛細管兩端的壓力降;R- - 毛細管的半徑;L-一毛細 管的長(cháng)含量28%,上?；ぱ芯吭荷a(chǎn)。度;Q一從毛細管擠 出的容速;K一-流 體的1.2 實(shí)驗儀器毛細管流變儀:XLY-I型,吉林大學(xué)科教稠度系數。儀器廠(chǎng),毛細管長(cháng)徑比為40,未做人口校正。1.4.5乙烯~醋酸乙烯共聚物 的粘流活化能:乙烯-醋酸乙烯共聚物熔體的流動(dòng)行為服從Ar-1.3實(shí)驗方法將一定量的EVA試樣放人一定溫度下的rhenius方程:7.= A exp(OE/RT)(5)毛細管流變儀的料筒中,壓實(shí),恒溫7min,然后式(5)中:OE-粘流活 化能;R一-氣體常在恒定溫度和壓力下將EVA熔體從毛細管中中國煤化工收稿H期2006-07-12;鉛訂日期:2007-05-08若金項目:阿南省自然科學(xué)基金資助項目(0311060500DHCNMHG聯(lián)系人:李新法,主要從事高分子復合材料研究,E-mailslixinfa@zu.edu.cn'第6期.李新法等:乙烯~醋酸乙烯共豪鈞的流變性能125數;T-絕對溫 度。2.2EVA表觀(guān)黏度與剪切速率的關(guān)系以In,對1/T作圖,可得一-直線(xiàn),由直線(xiàn)斜EVA在120 C~180 C的表觀(guān)黏度與剪切率可求出EVA的粘流活化能OE。速率的關(guān)系見(jiàn)Fig.2.由Fig.2可見(jiàn),在實(shí)驗溫度范圍內,EVA的表觀(guān)黏度均隨表觀(guān)剪切速率的升高而降低,即出現了剪切變稀現象。這主要是因為當剪切速率增大時(shí)，流動(dòng)時(shí)間比松弛時(shí)間短,分子鏈來(lái)不及松弛收縮或已取向的分子鏈只收縮了一部分，從而減小了收縮所產(chǎn)生的流動(dòng)阻力,故表觀(guān)黏度降低;此外,表觀(guān)剪切速率的增大使影響流動(dòng)的纏結點(diǎn)更容易解纏,這也↓是EVA表觀(guān)黏度降低的主要原因之一。lgIr.(s')|Flg. 1 Rbeologlcal curves of EVA1:130比12;140Cr3:150C:4,160C;5; 170 c三王5lg|r.IP.1IFlg.3 The relatoaship betwen 7. and T. tar EVA1120 C+2: 130C13, 140C141 150 C15i160C16.170C.7.180ClgIs.1s"ll2.3EVA表觀(guān)黏度與剪切應力的關(guān)系Flg.2 The relhtionshlip belween n andy. for EVAEVA在120 C~180 C表觀(guān)黏度與剪切應1120 C12; 130 C13t 140C14s 150 C;力的關(guān)系如Fig.3所示.由Fig.3可見(jiàn),隨剪切應5, 160 C16.170 C17; 180 C力的增大,EVA熔體的表觀(guān)黏度降低.這主要是因為剪切應力的增大,使影響熔體流動(dòng)的纏2結果與討論結點(diǎn)容易解纏,從而表觀(guān)黏度降低。2.1 EVA 的流變曲線(xiàn)由Fig.3還可看到,隨剪切應力的增大,其EVA在130 C、140 C、150 C、160 C表觀(guān)黏度變化較小,剪切應力增大近兩個(gè)數量和170C的流變曲線(xiàn)如Fig.1所示。由Fig.1可級,表觀(guān)黏度降低不到一個(gè)數量級,這說(shuō)明求出不同溫度下EVA的非牛頓指數,結果見(jiàn)EVA熔體的表觀(guān)黏度對剪切應力的敏感性較Tab. 1.由Fig.1和Tab.1可見(jiàn),EVA熔體在120 C小。這主要是由于其分子量較小或熔體流動(dòng)速~180 C溫度范圍內,其非牛頓指數n均小率較大所致。于1.說(shuō)明EVA熔體為假塑性流體;而且隨著(zhù)溫2.4表觀(guān)黏度與溫度的關(guān)系由Fig.2、Fig. 3、Fig. 4和Fig. 5可見(jiàn),EVA度的升高,其非牛頓指數x增大,說(shuō)明EVA熔熔體的表觀(guān)黏度隨溫度的升高而降低.這是因體的非牛頓性隨溫度升高而減弱。為溫度升高,分子鏈的熱運動(dòng)能增大,分子鏈間Tab.1 Non- Newtonian index(n) of EVA的距離中國煤化工于分子鏈的1(() 12030 140 150 160 170 180相對滑YHCNMHG黏度降低，0.680.70 0.71 0.72 0.74 0.75 0.76流動(dòng)性提高,對成型加工比較有利。126高分子材料科學(xué)與工程2007年3所示。Tab.3 The relationship between OE andT. for EVA力2τ.(MPa) 6.130 12.28 36.75 73.50 196.0oE (kJ/mol) 94.20 93.50 93.00 91.50 91. 40由Fig. 4和Fig. 5可見(jiàn),隨溫度升高,EVA熔體的表觀(guān)黏度降低,服從Arrhenius定律。由+x 10Yk*)Tab.2和Tab.3可見(jiàn),隨著(zhù)剪切速率和剪切應力的增大,EVA的粘流活化能減小,但剪切速率Fig4 The relatlosbilp betweea n and 1/T forEVA ,比剪切應力對粘流活化能的影響明顯.1 100o-15 2; 316.2s-'; 3; 1000s-1;4 1778s-1;51 3162 s-13結論(1)EVA在實(shí)驗條件下為假塑性流體,其表觀(guān)黏度隨著(zhù)剪切應力和剪切速率的增大而降低,非牛頓指數n小于1,且隨溫度的升高而增大.(2)EVA熔體的表觀(guān)黏度隨溫度升高而降低,在實(shí)驗條件下,其恒剪切速率下的粘流活化能為21.06 kJ/mol~ 38.29 kJ/mol,恒剪切應力下粘流活化能為91.40kJ/mol~94.20kJ/2.224 23mol.一x 10'K)FIg.5 The reatioasblp betwee n and 1/T tor參考文獻;EVA[1] 夏成林(XIA Cheng-lin), 賀均林(HE Jun-lin),黃詩(shī)1。6. 130X10Pas 2; 1. 228X10Pa; 3, .(HUANG Tao),等.高分于材料科學(xué)與工程(PolymerMaterials Science & Enginering), 1988. 4(2); 33~3. 675X10*Pa1 4 7.350X 10*Pas 5;381. 960X10'Pa[2]胡繼文 (HU Ji-wen),孫友德(SUN You-de).高分子Tab.2 The relationship between oE and材料科學(xué)與工程(Polymer Materisls Science & Eagi-y. tor EVAneering), 1993, 9(1); 42~46.六(s-1)00316.2 10007783162[3] 李新怯(LI Xin-fa), 牛明軍(NIU Mingijun),陳金周(CHEN Jin-zhou),等.離分子材料科學(xué)與工程(Poly-OE (kJ/mol) 38. 2929.67 27.18 22.97 21. 06ner Materials Science & Engineering). 2003, 31(4);103~ 105.2.5 EVA 的粘流活化能[4] 李新法(LI Xin-fa), 牛明軍(NIU Mingijun),陳金周EVA的表觀(guān)黏度與溫度的關(guān)系如Fig.4和(CHEN Jin-zhou),等.高分子材料科學(xué)與工程(Poly-mer Materials Seience & Engineering). 2002, 30(2); 20Fig.5所示。由Fig.4可求出EVA的恒剪切速率~21.下的粘流活化能OE,如Tab.2所示;由Fig.5可(下轉第131頁(yè),t0 be cninued on P. 131)求出恒剪切應力下的粘流活化能,結果如Tab.中國煤化工MYHCNMHG第6期胡小洋等;葭乙二醇及其衍生物改性生物醫用材料表面的血液相容性131[31] Lasseter T L, Clare BH, AbbottL N,e al. J. Am.Chem. Soe. , 2004, 126(33); 10220.Blood Compatibility of Biomaterial SurfacesModified with PEG and Its DerivativesHU Xiao-yang' , CHEN Hong'"', ZHANG Yan-xia'WANG Yi-feng', WU Zhong -kui'(1. School of Materials Science and En gineering, Wuhan University ofTechnology, Wuhan 430070, China; 2. Biomnedical Materials andEngineering Center, Wuhan University, Wuhan 430070, China)ABSTRACT :Poly(ethylcne glycol)(PEG) and its derivatives are accepted as a kind of ideal poly-mers to improve surface blood compatibility of biomaterials. Due to their excellent hydrophilici-ty, mobility, biological inertness , resistance properties of protein adsorption and cell adhesion,PEG and its derivatives are widely used in surface modification of biomaterials. In this article,the applications of PEG and its derivatives in surface modification to improve blood compatibilityof biomaterials were reviewed. Some techniques, ATR-FT-IR, Water Contact Angle, X-ray pho-toelectron spectrometer, Surface Plasmon Resonance , Ellipsometry, Western blot, protein La-beling technology, which are used to characterize PEG -modified biomaterial surfaces, were alsointroduced in this paper.Keywords: biomaterials; poly(ethylene glycol); surface modification; blood compatibility(上接第126頁(yè).continued from p. 126)Studies on Rheological Properties of EthyleneVinyI-Acetate CopolymerLI Xin-{a', HUANG Ling ge' , HU Hong wei', JIANG Ai-yun'MEN Cheng cheng' , NIU Ming-jun' , CHEN Jin-zhou'(1. School of Materials Science and En gineering, ZhengzhouUniversity, Zhengzhou 450052, China; 2 Henan JintiandiAgricultural Chemistry Co. L.DT , Zhengzhou 450000, China)ABSTRACT: The rhcological properties o[ ethylene vinyl-acetate copolymer (EVA) have beenstudied by means of XLY- 1 Rheometer. The effect of shear rate ,shear stress and temperatureon the apparent viscosity of the ethylene vinyl-acetate copolymer was discussed. Non Newtonianviscosity decreases with the increase of thc temperaturc. With increasing shear rate and shearstress, shear thining of the ethylene vinyl-acetate copolymer was observed clearly. Non-Newtoni-in index is less 1, and increases with the incrcase of the temperature, indicating a pseudoplasticnature of the mclt EVA.Keywords :ethylene vinyl-acetate copolymer; rheologica中國煤化工sityfYHCNMHG