Vol. 16功能高分子學(xué)報(bào)No.12003年3月Journal of Functional PolymersMar.2003PMMA對(duì)聚氧乙烯β轉(zhuǎn)變的影響石軍**，王亞明2( 1.鄭州大學(xué)材料工程學(xué)院2.橡塑模具國(guó)家工程研究中心,河南鄭州450052 )摘要:對(duì)半結(jié)晶聚氧乙烯PEO)PMMA共混體系的DSC及動(dòng)態(tài)力學(xué)行為研究表明:PE0在和PMMA形成半結(jié)晶PE0/PMMA共混體系后其β轉(zhuǎn)變的峰溫沒(méi)有明顯移動(dòng);β峰只出現(xiàn)在淬火的半結(jié)晶PEO/PMMA共混體系中而在完全非晶的相容性共混體系以及退火的半結(jié)晶共混體系不出現(xiàn)在β轉(zhuǎn)變區(qū)對(duì)應(yīng)的模量反常地增大對(duì)應(yīng)的DSC曲線有明顯階躍?？梢?jiàn)半結(jié)晶PE0的β轉(zhuǎn)變并不象通常所認(rèn)為的源于PEO非晶區(qū)的玻璃化轉(zhuǎn)變。在接受半結(jié)晶PEO及半結(jié)晶PE0/PMMA共混體系的PEO結(jié)晶區(qū)存在結(jié)晶-非晶中間相觀點(diǎn)的基礎(chǔ)上，認(rèn)為β轉(zhuǎn)變?cè)从赑EO結(jié)晶區(qū)結(jié)晶-非晶中間相的玻璃化轉(zhuǎn)變過(guò)程。關(guān)鍵詞: PE0/PMMA ;β轉(zhuǎn)變;結(jié)晶-非晶中間相中圖分類號(hào): 0631. 2文獻(xiàn)標(biāo)識(shí)碼: A文章編號(hào): 1008- 9357 2003 )01 - 0069-04聚氧乙烯(PEO)是半結(jié)晶高聚物結(jié)構(gòu)簡(jiǎn)單具有良好的柔性、潤(rùn)滑性、粘合性及很低的生物毒性,在食品、醫(yī)藥等方面得到廣泛應(yīng)用。PEO和許多化合物具有很好的相容性。PEO與聚甲基丙烯酸甲酯( PMMA )的共混物是近年來(lái)研究較多的體系之一,研究主要 集中在相容性及PEO熔點(diǎn)附近的結(jié)晶行為等方面1-5]。Ishida等人[6的研究表明半結(jié)晶PEO樣品在-40cC附近會(huì)出現(xiàn)-一個(gè)β峰而單晶樣品則沒(méi)有這個(gè)峰。Ishida等人把觀察到的β轉(zhuǎn)變峰解釋為半結(jié)晶PEO非晶區(qū)內(nèi)鏈段運(yùn)動(dòng)的結(jié)果。類似的β轉(zhuǎn)變峰在聚偏氟乙烯( PVDF )中也觀察到了Saito 等人[7通過(guò)在PVDF中引入完全非晶的PMMA通過(guò)介電研究表明這個(gè)β轉(zhuǎn)變峰應(yīng)該源于PVDF中的結(jié)晶-非晶中間相而不象通常所認(rèn)為的那樣來(lái)自半結(jié)晶PVDF非晶區(qū)內(nèi)鏈段運(yùn)動(dòng)。本文采用DSC、及動(dòng)態(tài)力學(xué)手段研究了在PEO中引入PMMA后對(duì)其β轉(zhuǎn)變的影響。1實(shí)驗(yàn)部分1.1材料PEO :平均分子量為18x 103 ~ 20x 103 ,日本進(jìn)口分裝上?；瘜W(xué)試劑廠。甲基丙烯酸甲酯:AR級(jí),旭東化工廠使用前經(jīng)NaOH水溶液洗脫阻聚劑對(duì)苯二酚再用蒸餾水洗至中性無(wú)水硫酸鈉干燥3h后減壓蒸餾。重結(jié)晶的偶氮二異丁腈( AIBN)1.2樣品制備將PEO溶于甲基丙烯酸甲酯單體加單體重量0.1%的AIBN攪拌均勻加熱至70 C預(yù)聚合至體系相當(dāng)于二倍甘油粘度倒入玻璃模板中在40 C恒溫30h升溫至80 C維持2h再升溫至100 qc維持2 h最后緩慢退火取出板材。1.3 分子量測(cè)定在索氏提取器中用甲醇抽提PEO/PMMA48H(水浴溫度控制在759C左右)以.上將得到的PMMA在真空干燥箱中干燥-周以上。中國(guó)煤化工在烏氏粘度計(jì)中測(cè)定PMMA的粘度水浴溫度為(2:MHCNMHG氯仿。純氯仿溶劑的收稿日期2002-07-08基金項(xiàng)目河南省高校青年骨干教師項(xiàng)目(2001年)作者簡(jiǎn)介:石軍1971- )女河南鄭州人博士生,講師從事高分子化學(xué)及物理研究。E-mail : shjumn @ zou edu. cn , TEL :0371 -776352370 .石軍，王亞明流出時(shí)間t。 為43.83。用一點(diǎn)法計(jì)算粘均分子量。得到的純PMMA的M, = 1. 613x 10°，從共混物中抽提的PMMA的M,約為2.458x 106 ~2.576x 10%。1.4 DSC 及動(dòng)態(tài)力學(xué)實(shí)驗(yàn)在PE公司生產(chǎn)的DSC儀上進(jìn)行DSC測(cè)試升溫速率為20 C/min。動(dòng)態(tài)力學(xué)實(shí)驗(yàn)在多功能內(nèi)耗儀上進(jìn)行,試樣有效尺寸約為30x4.5x2.0 mm3強(qiáng)迫振動(dòng)模式升溫速率約2 C/min測(cè)量溫度約- 100~75 C測(cè)量頻率0.1~1 Hz。 其中淬火樣品是在80 C退火2 h然后用液氮淬火退火樣品是在55 C退火48 h。2結(jié)果及討論0.50圖1~圖3是PEO及其與PMMA的共混物在不同熱歷史了條件下的DSC曲線。退火試樣在60C以上均能觀察到--個(gè)吸熱峰峰高隨PEO含量的減少而降低,當(dāng)PEO的含量為30%意o2s5時(shí)觀察到的吸熱峰已經(jīng)很微弱淬火能使吸熱峰降低并移向旨低溫，當(dāng)PEO的含量為30%時(shí)吸熱峰已基本消失。文獻(xiàn)1-5]葛中比較統(tǒng)一的認(rèn)識(shí)是:在PEO的熔點(diǎn)( Tm約為65 C)以上，。 上PEO與PMMA在任意組成范圍內(nèi)形成均相共混物,在PEO的熔130210290/K37050點(diǎn)以下，當(dāng)PEO的含量超過(guò)20%時(shí),PEO/PMMA共混物形成兩Fig. 1 DSC curves of PEO.相體系:即PEO結(jié)晶相,以及PEO的非晶部分與PMMA形成的a : quenched sample ; b : annealed sample相容性非晶相。益0.2501301045'1302937450T/K .T1KFig.2 DSC curves of PE0/PMMA ( 40/60 )Fig.3 DSC curves of PE0/PMMA( 30/70 ).a : quenched sample ;b : annealed sample從DSC圖還可以看出淬火的半結(jié)晶PEO試樣在-40C左右可明顯觀察到熱容C,的階躍這和Ishida等人6用介電譜儀觀察到的β轉(zhuǎn)變峰的峰溫接近。隨PEO組分含量的減少,Cp階躍的幅度逐漸減小,但階躍的溫區(qū)沒(méi)有明顯移動(dòng)當(dāng)PEO的含量為30%時(shí),C。的階躍已經(jīng)很微弱。而對(duì)于退火的半結(jié)晶PE0、PE0/PMMA( 40/60和PE0/PMMA( 30/70 )試樣在- 40 C則沒(méi)有觀察到C,的階躍。圖4~圖7是淬火試樣的內(nèi)耗以及模量的溫度譜。圖8~圖9是退火試樣的內(nèi)耗以及模量的溫度譜。對(duì)于淬火的半結(jié)晶PE0/PMMA( 40/60 )及( 30/70 )試樣在- 40 C附近均能觀察到明顯的β峰(不包括PMMA的次級(jí)轉(zhuǎn)變PpNA峰) β峰的峰位基本不隨" 中國(guó)煤化工PMMA組分的增大而迅速降低在PEO/PMMA( 20/80 )中則完全消失。在出現(xiàn)THCNMHG反常地升高。對(duì)于退火的PEO/PMMA( 40/60 )及( 30/70 )試樣則觀察不到上述的β峰劉應(yīng)的保重也沒(méi)有反常的增大。β峰附近的峰很寬這是β峰、PE0/PMMA非晶相的玻璃化轉(zhuǎn)變、以及PI峰疊加的結(jié)果。從模量的大幅降低可見(jiàn)60 C左右是PEO/PMMA非晶相的玻璃化轉(zhuǎn)變區(qū)。PMMA對(duì)聚氧乙烯β轉(zhuǎn)變的影響1.001.00 CEe-0一 1H:PEO/PMMA0.1(3070)y 0.10要0.10(40/60)quenched somplequenched sanple。0.010050一0.010.-0.01.100-50F1PCFig. 4 Internal friction and modulus against tem-Fig. 5 Internal friction and modulus against tem-perature for quenched PEO/PMMA ( 40/60 )perature for quenched PEO/PMMA ( 30/70)sample1.00-quenched sample-o- 1化- o-0.tHzBousPMMA| 0.101a.10-PMIMA-0- 0.1H2PEOIPMMA(20/80)0.10T/C1CFig. 6 Interna! friction and modulus against tem-Fig. 7 Internal friction and modulus against tem-perature for quenched PEO/PMMA ( 20/80 )perature for quenched PMMA samplesatple1.00f- 0- 0.1Hz一一0.1Hz .PEOIPMMA BpuuPEO/PMMA p(40/60}4a.10苫-0.10 E是0.10f暑ounmaled sampleannealed sample100-10050° 1001T1CFig. 8 Internal friction and modulus against tem-Fig. 9 Internal friction and modulus against tern-perature for annealed PEO/PMMA ( 40/60 )perature for annealed PEO/PMMA ( 30/70 )如果半結(jié)晶PEO中β轉(zhuǎn)變過(guò)程如Ishida等人[6]所述的那樣源于非晶區(qū)的玻璃化轉(zhuǎn)變那么,在和PMMA形成半結(jié)晶共混體系后半結(jié)晶PEO的非晶區(qū)會(huì)和PMMA形成均一的非晶相,β轉(zhuǎn)變應(yīng)該大幅度地移向高溫這和本文的實(shí)驗(yàn)結(jié)果不符。因此在半結(jié)晶prO中!乃半結(jié)早DEO/PMMA共混體系中出現(xiàn)的β轉(zhuǎn)變并不象通常所認(rèn)為的那樣來(lái)自于半結(jié)晶PTH中國(guó)國(guó)煤化二等人[7對(duì)PVDF/PMMA體系的介電松弛譜的研究結(jié)果-致。依據(jù)鏈段在片晶表CN. M.HG[7認(rèn)為半結(jié)晶PVDF中出現(xiàn)的β轉(zhuǎn)變應(yīng)該源于半晶高聚物結(jié)晶區(qū)內(nèi)的結(jié)晶-非晶中間相。更進(jìn)一步半結(jié)晶PEO中出現(xiàn)的β_轉(zhuǎn)變究竟來(lái)自于結(jié)晶_非晶中間相什么樣的微觀過(guò)程呢?從本文淬火試樣在動(dòng)態(tài)力學(xué)測(cè)量中伴隨β轉(zhuǎn)變出現(xiàn)的模量反常增大我們似乎可以認(rèn)為在β轉(zhuǎn)變時(shí)中間相內(nèi)的PEO鏈段發(fā)生了運(yùn)動(dòng)形成微小的有序區(qū)域使模量增加。然而,如果真的發(fā)生了從無(wú)序到有序的72 .石軍，王亞明轉(zhuǎn)變對(duì)應(yīng)的DSC曲線上應(yīng)出現(xiàn)一個(gè)放熱峰而本文的DSC結(jié)果則是出現(xiàn)一個(gè)階躍。我們注意到淬火試樣DSC曲線上出現(xiàn)的C,階躍和典型非晶高聚物玻璃化轉(zhuǎn)變時(shí)C,的階躍很相象。因此我們認(rèn)為觀察到的β轉(zhuǎn)變過(guò)程還是應(yīng)該歸結(jié)為半晶PEO結(jié)晶區(qū)內(nèi)結(jié)晶_非晶中間相鏈段的玻璃化轉(zhuǎn)變過(guò)程。只是由于中間相既非完全非晶也非完全結(jié)晶,因此和完全非晶高聚物玻璃化轉(zhuǎn)變相比顯得很反常。這樣,可以將淬火試樣在動(dòng)態(tài)力學(xué)測(cè)量中伴隨β轉(zhuǎn)變出現(xiàn)的模量反常增大解釋為:中間相內(nèi)的非晶鏈段發(fā)生玻璃化轉(zhuǎn)變時(shí)并沒(méi)有象完全非晶體系那樣自由,而是受到少量的結(jié)晶成分的牽制，從而導(dǎo)致模量反常地增大在退火樣品中β轉(zhuǎn)變的消失,可以理解為在退火時(shí)處于亞穩(wěn)態(tài)的中間相轉(zhuǎn)變?yōu)楦€(wěn)定的形式中間相消失。3結(jié)論在半結(jié)晶PEO中引入PMMA形成半結(jié)晶共混體系后,PMMA 對(duì)PEO的β轉(zhuǎn)變沒(méi)有影響?？梢?jiàn)半結(jié)晶PEO的β轉(zhuǎn)變并不象通常所認(rèn)為的那樣來(lái)自于PEO非晶相的玻璃化轉(zhuǎn)變。參考文獻(xiàn):[1] Radhakrishnan S , Venkatachalapaly P D. Efet of casing solvent on the rslizatin in PE0/PMMA blends[J] Polymer , 1996 ,37( 16):3749 - 3752 .[2] Eastmond G C ,Schofield P , Saellariou P. Thermal properties of pol(C ethylene oxide )-pol;( methlyl methacrylate )blends and copolymers complesedwith sodium thiocyanate[ J]. Polymer , 1997 ,38(7):1753- 1761.[3] Liau w B , Chang C F. Casting solvent ffee on ryallizaion behavior and mophology of pols( ethylene oxide ) pol( methyl methacrylate)[J]. JAppl Polym Sci , 2000 , 76( 11 ): 1627 - 1636.[4] Suvorova A I , Hassanova A H ,Tyjkova I s. Phase equilibium in blends of rytalline poly( ethylene oxide ) -amorphous poly( metlyl acrylate )orpol( methyl methacrylate )[ J]. Polymer Itemational , 2000 , 49(9): 1014- 1016.[5] Dionisio M , Femandes A C , ManoJF ,et al. Relaxation studies in PE0/PMMA blends[ J]. Macromolecules , 2000 , 33(3 ): 1002 - 1011.[6] McCrum N G. Anelastic and Dieletie Effects in Polymeric Solids[ M] London : John Wiley & Sons. Inc. ,1967. 555.[7] Saito H , Stuhn B. Dielectrie study of the crystal amorphous intephase in polx( vinylidene fluoride ) pol( methyl mehacylate )blends[J]. Poly-mer , 1994 ,35(3):475- 479.Effects of the Blending of Poly( ethylene oxide )with Poly( methyl methacrylate ) on its β -TransitionSHI Jun'，WANG Ya-ming?( 1. College of Matierial Engineering ,2. NERC of Advanced Polymer ProcessingTechnology , Zhenghou University , Zhengzhou 450052 , China )Abstract : The themal and dynamic mechanical studies for smi-rytalline pols( ethylene oxide ) pols( methyl methacrylate )( PE0/PMMA ) blends show that , the temperature of the dynamic mechanical β- transition of PEO remains invariant in its smi-crysallineblends with PMMA , and the β - transition is only found in the quenched semi- crytalline PE0/ PMMA blends and disappeared in the an-nealed semi- crystalline blends or the completely amorphous blends , meanwhile，an abnormal increase in modulus curves and a step in-crease in DSC curves are observed near the β - transition. It could be concluded that the β -transition of semicrystalline PE0 is not re-lated to the liquidlike amorphous phase. Based on recognizing the theory that a crystalline- amorphous interphase is existed in PEO crys-allites for both sin-crstalline PE0 and semi cytalline PE0/ PMMA blends and further sosterd that the β -transition is derived from中國(guó)煤化工the motions of chain segments in the process of glass transition which 0CcI; in PE0 rytallites.Key words: PE0/PMMA ;β -transition ; crystal-amorphous interphase:YHCNMHG