第32卷第2期北京化工大學(xué)學(xué)報(bào)Vol. 32, No.22005年JOURNAL OF BEIJING UNIVERSITY OF CHEMICAL TECHNOLOGY2005聚丙烯接枝乙烯醇結(jié)晶性能的研究譚琳1.2周寒2侯金順2楊萬(wàn)泰1,2*(北京化工大學(xué)1.教育部可控化學(xué)反應(yīng)科學(xué)與技術(shù)基礎(chǔ)重點(diǎn)實(shí)驗(yàn)室; 2.材料科學(xué)與工程學(xué)院，北京10029)摘要:用DSC研究了PP,PP-g-VAc和兩種不同醇解率PPgVOH的非等溫結(jié)晶行為,以Reziorny修正的Avrami方程進(jìn)行了動(dòng)力學(xué)分析,用偏光顯微鏡觀察了接枝物球晶形態(tài)的變化。研究結(jié)果表明:VOH接枝鏈可以有效地促進(jìn)PP異相成核,導(dǎo)致Avrami指數(shù)n隨醇解率增加而降低,結(jié)晶溫度顯著增加,結(jié)晶熱焓增加;同時(shí),由于VOH引入支鏈,降低了分子鏈的規(guī)整性,限制了PP排入晶格的速率,致使半結(jié)晶時(shí)間t/和結(jié)晶速率Ze常數(shù)降低。試樣的偏光顯微鏡觀察表明, PP-g-VAc的醇解率增加,球晶數(shù)目增多,直徑減小，完善程度降低。關(guān)鍵詞:聚丙烯;接枝;聚乙烯醇;結(jié)晶;結(jié)晶動(dòng)力學(xué)中圖分類號(hào): TQ325.14聚丙烯(PP)屬非極性材料,具有較低的表面能同醇解率P-g-VOH的非等溫結(jié)晶過(guò)程,并與PP和較低的內(nèi)聚能,為此,對(duì)PP進(jìn)行接枝改性,合成進(jìn)行了性能對(duì)比。用偏光顯微鏡觀察了試樣的結(jié)晶出極性化和官能化的PP,已成為近些年來(lái)科學(xué)工作形態(tài)。這些接枝鏈對(duì)接枝底物結(jié)晶性能的影響規(guī)律者關(guān)注的熱點(diǎn)。文獻(xiàn)報(bào)道[1-5], 用馬來(lái)酸酐(MAH)、與其物理機(jī)械性能、加工流變性能密切相關(guān)。丙烯酸(AA)、甲基丙烯酸( MMA)及其酯類等接枝1實(shí)驗(yàn)部分PP,可有效的引入極性基團(tuán)。而醋酸乙烯酯(VAc)與丙烯酸酯類比較,其毒性、刺激性和成本較低,作1.1 原料為接枝單體,在PP主鏈中引入酯基[6],可改善PPPP,多孔型,齊魯石化公司生產(chǎn), 230七下2 160g的印染性、吸濕性與極性聚合物的相容性,還可通過(guò)測(cè)定其熔融指數(shù)為0.70 g/min,丙酮抽提12h后使醇解制得PP-gVOH。PP-gVOH可有效改善聚合用。物的表面性能[7],亦可作為PP與Nylon、 淀粉等高1.2 PP-g-VAc 和PP.g-VOH的制備極性材料的相容劑。此外,鑒于PP_g-VOH具有阻以水為懸浮介質(zhì), BPO為引發(fā)劑,并加入少量氧性、可生物降解性[8]等特性,故認(rèn)為其作為接枝分散劑，在高壓反應(yīng)釜中通過(guò)固相懸浮接枝制備單體,還將賦予PP以新的功能。PP-g-VAc[12],產(chǎn)物經(jīng)丙酮抽提24 h純化后,質(zhì)量法接枝鏈對(duì)接枝底物結(jié)晶性能的影響較為復(fù)雜。測(cè)定接枝率(Pc)。多孔PP-g-VAc粒子經(jīng)非均相皂一方面,接枝鏈的引入降低了主鏈的規(guī)整性;另一方化工藝制備PP-g-V0H[12],其中NaOH為催化劑，面,某些極性接枝鏈增加了大分子之間的相互作用，低級(jí)醇/高級(jí)醇互配體系為反應(yīng)介質(zhì),通過(guò)質(zhì)量法測(cè)降低了成核界面自由能,增加了成核速率,又將提高定醇解率(Ps)。文中PP-g-VAc接枝率為8.3%;聚合物總的結(jié)晶速率。已有文獻(xiàn)對(duì)PP接枝甲基丙PP-g-VOH 1#和PP g-VOH2#為PP-g- VAc(Pc=烯酸縮水甘油酯(GMA)[9]和馬來(lái)酸酐( MAH)及其.8.0% )皂化制備得到,醇解率分別為10%和35%。離聚物10-11]等的結(jié)晶行為進(jìn)行了系統(tǒng)研究,但是1.3非等溫結(jié)晶行為PP-g- VOH結(jié)晶性能的研究至今未見(jiàn)文獻(xiàn)報(bào)道。本將樣品由室溫以80C/min升溫到160C,恒溫文采用DSC方法系統(tǒng)研究自制PP-g-VAc和兩種不5min,以消除熱歷史。隨后,以一定的降溫速率(20,中國(guó)煤化工”，記錄該過(guò)程的熱收稿日期: 2004-05-14焓變Fi量80 mL/min,樣第一作者:男,1979年生,碩士生品4CNMH(C型DSC研究試樣的*通訊聯(lián)系人非等溫結(jié)晶行為。E- mail: yangwt@ mail. buct. edu. cn采用修正Avrami方程的Jeziorny法[13]研究PP第2期譚琳等: 聚丙烯接枝乙烯醇結(jié)晶性能的研究及其接枝物的非等溫結(jié)晶動(dòng)力學(xué)。等溫結(jié)晶條件枝鏈。下，根據(jù)Avrami方程.2.2 PP 及接枝PP的DSC非等溫結(jié)晶行為1-X.=exp(- Zt")(2)圖2為PP和PP-g-VOH1#試樣不同降溫速率式中, x,-結(jié)晶時(shí)間t時(shí)刻的相對(duì)結(jié)晶度, n-下的 DSC譜圖，PP.g-VAc和PP.g-VOH 2#試樣譜Avrami指數(shù),反映高聚物結(jié)晶成核機(jī)制和生長(zhǎng)方圖從略。由圖2得到結(jié)晶起始溫度(T。)和結(jié)晶焓式，z,-結(jié)晶速率常數(shù),與結(jié)晶溫度有關(guān)。(OH),結(jié)果列于表1中。由式(2)可得In[ -ln(1- X,)]=In Z + nInt .(3)PJeziorny利用公式(4)進(jìn)行時(shí)溫轉(zhuǎn)換T=(To- T)/R(4)式中,t為結(jié)晶時(shí)間,To和T分別為起始結(jié)晶溫度和結(jié)晶溫度, R為降溫速率。降溫速率PP-g-VOH I"通過(guò)式(3)對(duì)實(shí)驗(yàn)數(shù)據(jù)做線性回歸,直線斜率為1-5 C/min2-10 C/minn、截距為InZ。當(dāng)X, =0.5, t1/2 = (In2/Z.)"",3-15 C/min4- 20 C/minJeziorny考慮到非等溫結(jié)晶特點(diǎn),對(duì)速率常數(shù)Z。用降溫速率常數(shù)R來(lái)修正，即6081007CIn Zc=ln Z/R .(5)圖2 PP 和PP_g-VOH不同降溫速率下的DSC譜圖式中,Z。為非等溫結(jié)晶的速率常數(shù)。Fig.2 DSC thermograms of PP and PP-g-VOH at1.4結(jié)晶形態(tài)(POM)different cooling rates取少量試樣在熱臺(tái)上(180C)熔融壓片,迅速降溫到106.5C(DSC研究得到的最佳等溫結(jié)晶溫表1 PP, PP-g-VAc和PP-g VOH的非等溫結(jié)晶動(dòng)力學(xué)參數(shù)度),恒溫1.5h,在偏光顯微鏡(西德萊茨公司)下觀Table 1 Parameters of non- isothermal crystallization for察結(jié)晶形態(tài)。PP, PPgVAc and PP-g-VOH2結(jié)果與討論樣品R/(C/min) TJC n tin/min SH/J Z。5104.75 3.53 1.89 64.38 0.592.1 PP-g-VAc, PP-g-VOH的結(jié)構(gòu)表征l0101.15 4.00 1.02 64.71 0.95用紅外光譜對(duì)本文研究的PP-g-VAc和PP-g-PI99.13 4.25 0.74 64.75 1.06VOH結(jié)構(gòu)進(jìn)行了表征,如圖1。PP-g-VAc 在1740、2097.51 4.16 0.60 64.56 1.091240cm~I出現(xiàn)了酯基的特征吸收峰,證明VAc已108.24 3.432.25 55.38 0.53經(jīng)接枝到PP主鏈上;PP-g-VOH在3340 cm~'出現(xiàn)10106.59 3.65 1.33 55.01 0.87羥基特征吸收峰,且隨醇解率增加而增強(qiáng),同時(shí)酯基PP-g-VAc104.23 3.98 0.96 55.05 0.99吸收峰減弱,證明了羥基通過(guò)醇解反應(yīng)已經(jīng)引入接100.27 4.14 0.8 55.10 1.02PP116.49 3.58 2.46 56.85 0.47PE:VAc、PP-g-VOH114.03 3.671.4556.76 0.83PP-gVOH m115111.88 3.73 1.09 56.60 0.95PP-g-V0H2n110.15 3.63 0.87 56.52 1.00118.89 3.13.0262.67 0.47PP_g-VOH 10117.98 2.91 1.57 62.83 0.84中國(guó)煤化_-1.19 62.92 0.944000 3500 3000 2500 2000 1500 1 000500二0.933 62.28 0.99o/cm-:TYHCNMHG圖1 PP, PP-g-VAc 和PP-g-VOH的紅外光譜(FTIR)Fig.1 FTIR of pure PP, PP-g-VAc and PP-g VOH將DSC譜圖轉(zhuǎn)換為相對(duì)結(jié)晶度X,與時(shí)間t的40●北京化工大學(xué)學(xué)報(bào)2005年關(guān)系,見(jiàn)圖3。PP, PP-g-VAc譜圖從略。由圖3可結(jié)晶速率明顯下降。PP-g-VOH 成核速率大于PP,求得表征結(jié)晶速率的半結(jié)晶時(shí)間t1/2, 結(jié)果見(jiàn)表1。但結(jié)晶速率降低,這是由于接枝共聚物晶體生長(zhǎng)速100率降低起主導(dǎo)作用所致。-方面， 接枝鏈降低了主鏈的規(guī)整性;另-方面,由于接枝鏈間的相互作用較80|. 20C/mino- 15C/min- 159C/min強(qiáng),限制了分子鏈排入晶格的速率,故結(jié)晶總速率降-- 109C/min- 10C/min低。醇解度增加,接枝鏈的相互作用增強(qiáng),結(jié)晶速率→5C/min- 5C/min2PP-g-VOH I'PP-g-VOH 24進(jìn)一步降低。結(jié)晶速率常數(shù)Z。的變化規(guī)律進(jìn)一步證明, 接枝2468t/minVAc和醇解后, PP的結(jié)晶速率下降,如圖5所示。圖3 PP-g-VOH 相對(duì)結(jié)晶度與結(jié)晶時(shí)間的關(guān)系這與t1/2變化規(guī)律是-致的。Fig.3 Relation between relative degree of crysallization1.2and crysallization time-←- PP-g-PVAc圖4為PP-_g-VOH試樣的In[ -ln(1- X)]與-- Ps=10%0.9- --Ps-35%Int關(guān)系,其余試樣譜圖從略。由直線斜率和截距可求出n和InZ,以及Z,的非等溫修正值lnZe,結(jié)果N列于表1。0.62廠PgVOH1HPP-g-VOH2*●20C/min20C/minof. 15C/min●15C/min.10C/min, 10Cmin云-2|. SC/min59C/minyR/(C/min)圖5結(jié)晶速率常數(shù)z。與降溫速率R的關(guān)系Fig.5 Relation between crystallization rate constant-2.0 -1.0 0“ 101.5-2.0 -1.0 0Ze and cooling rate Rntn1在相同降溫速率條件下，PPg-VAc的n值較圖4 PP-gVOH的In[ - In(1 - X)]與Int的關(guān)系之PP略有減小,與其T。分析一致,表明接枝VAcFig.4 Relation between In[ - ln(1 - X,)] and Int后,成核作用有所增加,但不明顯。隨著PP.g-VAc由表1可以看出,相同降溫速率條件下，PP接的醇解,特別是醇解率較高時(shí),n值明顯減小,表明枝VAc后, T.溫度略有提高,再經(jīng)皂化, PP的T。溫接枝VOH,對(duì)PP異相成核作用顯著。度顯著提高,相差約10C,且醇解率愈高, T。溫度提探討接枝鏈對(duì)接枝底物0H的影響,必須除去高愈明顯。鑒于PP-g-VAc和PP-g-VOH接枝鏈都接枝鏈的質(zhì)量分?jǐn)?shù)?？梢约俣?在測(cè)試溫度范圍內(nèi)，屬極性聚合物,可有效地增加大分子之間的相互作接枝鏈的結(jié)晶焓為0J/g,扣除接枝單體質(zhì)量分?jǐn)?shù)，用，降低PP的成核界面自由能,增加PP的成核速PP的△H列于表2。PP接枝VAc后OH降低,醇率,故結(jié)晶溫度向高溫移動(dòng),且PP-g- VOH的接枝鏈解后AH增加,醇解率為35%時(shí),接枝PP的0H高對(duì)PP的成核更為有效。文獻(xiàn)報(bào)道[7.9), MAH, AA,表2去除接枝單體質(zhì) 量分?jǐn)?shù)后PP的結(jié)晶焓GMA作為接枝單體均可提高PP的成核速率和晶Table 2 Crytallization enthalpy of PP subtracting核密度,但St等非極性接枝單體則未發(fā)現(xiàn)這種作grafted monomer mass用,這些差異與接枝鏈的極性密切相關(guān)。本文的研0H/]R/(C /min)究結(jié)果表明極性較強(qiáng)的羥基較之酯基可以更為有效PP PP-gVA PP-g-VOH1# PP-g-VOH2#的促進(jìn)PP成核,進(jìn)一步證實(shí)了這一理論解釋的正6n 30_61.79 .68.12確性。中國(guó)煤化工61.7068.29由表1可知,在相同降溫速率下，PP, PP-g-VAcMHCNMHG61.5268.39和PP-g-VOH的t1/2逐漸增加,同時(shí)醇解率增加，2064.5660.0961.4367.70t1/2增大。說(shuō)明接枝VAc特別是醇解后,聚丙烯的注:OH是以1g物質(zhì)來(lái)計(jì)算。第2期譚琳等:聚丙烯接枝乙烯醇結(jié)晶性能的研究于純PP。PP-g-VAc 接枝鏈破壞了分子鏈的規(guī)整球晶的細(xì)化程度增加。性,異相成核作用又不顯著,故結(jié)晶焓降低;醇解反應(yīng)將部分VAc轉(zhuǎn)化為VOH,由于VOH的成核作用參考文獻(xiàn)促進(jìn)^了PP結(jié)晶能力的提高,結(jié)晶焓增加。[1] Rengarajan R, Vicic M, Lee s. Solid phase graft copoly-2.3 PP 及接枝PP的偏光顯微鏡形態(tài)觀察merization. I . Effecet of initiator and catalyst[J]. J Ap-由圖6(放大倍數(shù)相同)可知,PP的球晶結(jié)構(gòu)完pl Polym Sci, 1990, 39:1783 - 1791善,直徑也較大;接枝VAc后球晶結(jié)構(gòu)也較完善,半[2] JiaD, LuoY, Li Y, et al. Synthesis and characteriza-tion of solid-phase graft copolymer of polypropylene with徑變化不大,表明VAc接枝鏈對(duì)PP成核作用不明styrene and maleic anhydride[J]. J Appl Polym Sci,顯;醇解后,球晶尺寸減小,完善程度明顯降低。PP-2000, 78: 2482 - 2487gVOH(2# )與PP-g-VOH(1# )比較,前者球晶細(xì)化[3] Lee s, Rengarejan R, Parameswaran V R. Solid phase和不完善程度更為顯著。graft copolymerization: Effect of interfacial agent[J]. JAppl Polym Sci, 1990, 41:1891 - 1894[4] 鄔潤(rùn)德，童莜莉，楊正龍.懸浮法合成聚丙烯接枝丙烯酸[J].功能高分子學(xué)報(bào), 2001，14: 85 - 895] Gupta BD, TyagiP K, Ray R Alok. Radiation inducedgrafting of 2-hydroxyethyl methacrylate onto polypropy-lene for biomedical applications. I . Effect of synthesisconditions[J]. J Macromol Sci ( Pure Appl Chem),1990, A27:831 - 841PPP-g.VAc[6] Singh R P. Surface grafing onto polypropylene-A surveyof recent developments[J]. Prog Polym Sci, 1992, 17:251 - 281[7] DengJ P, Yang W T, Ranby B. Surface photgraftingpolymerization of vinyl acetate (VAc), maleic anbydride,and their charge transfer complex. I. VAc(1)[J]. J Ap-pl Polym Sci, 2000, 77(7): 1513- 1521[8] Emo C, Andrea C, Salvatore D A, et al. Biodegradationof poly( vinyl alcohol) based materials[J]. Prog PolymPP-g VOH 1#PPg-V0H2#Sci, 2003, 28(6):963 - 1014圖6 PP, PP-g-VAc和PP-g- VOH的偏光顯微鏡照片[9] Yin H, Zhang Y, Yin J. Isothermal rytallization ofFig.6 Micrographs of spherocrystal by polarization microscopePP-_g- GMA copolymer[J]. J Appl Polym Sci, 1997, 63;1565 - 1569DSC研究已經(jīng)表明，PP接枝VAc經(jīng)醇解后,對(duì).[10]余堅(jiān), 何嘉松.聚丙烯接枝馬來(lái)酸酐及其離聚物的PP有明顯的異相成核作用。這與偏光顯微鏡觀察等溫結(jié)晶行為[J].高分子學(xué)報(bào), 1999(1); 87-92得到的結(jié)果完全吻合。[11] 余堅(jiān),何嘉松.聚丙烯接枝馬來(lái)酸酐及其離聚物的非等溫結(jié)晶行為[J].高分子學(xué)報(bào), 1999(5): 513 -3結(jié)論519PP-g-VOH對(duì)PP具有異相成核作用,使PP起譚琳. PPg-VAc. PP-gVOH的合成及性能研究始結(jié)晶溫度T。提高,結(jié)晶熱焓0H增加。醇解率較[D]. [碩士學(xué)位論文].北京:北京化工大學(xué), 2004高,Avrami指數(shù)n值減小,表明接枝VOH可以促[13] Jeziorny A. Parameters characterizing the kinetics of the進(jìn)PP異相成核。接枝后顯著降低了PP分子鏈的non- isothermal crysallization of poly ( ethylene tereph-規(guī)整性,故PP-g-VOH半結(jié)晶時(shí)間t1/2 和結(jié)晶速率中國(guó)煤化工Polymer, 1978, 19;常數(shù)z。明顯降低。經(jīng)醇解后, PPg-VOH試樣的球CNMHG(下轉(zhuǎn)第46頁(yè))晶細(xì)化,結(jié)晶結(jié)構(gòu)完善程度降低。醇解度提高,現(xiàn)象●46●北京化工大學(xué)學(xué)報(bào)2005年polymerization of polyacrylate superabsorbents[J]. J Appl [6] Raju MP, Raju K M. Design and synthesis of superab-Poly Sei, 2000, 75(6):808 - 814soebent polymers[J]. J Appl Poly Sci, 2001, 80(13):[5] Lee Wen-fu, Huang Yu-Lin. Super absorbent polymeric2635 - 2639materials X: effect of cationic structure on swelling be-[7] Bakass M，Moklisse A, Lallemant M. Absorption andhavior of crosslinked poly ( sodium acrylate co-cationicdesorption of liquid water by a superabsorbent polyelec-monomers) in aqueous salt solutions[J]. J Appl Poly Sci,trolyte:role of polymer on the capacity for absorption of a2001, 81(8):1827- 1837ground[J]. J Appl Poly Sci, 2001, 82(6):1541- 1548Synthesis and characterization of super absorbentammonium acrylate-acrylamide copolymerXIONG Rong-chun' BU Ai-hua' ZHAO xil+2 LI Fei-feilWEI Gang'(1.College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029;2. Beiing Research Institute of Chenical Industry, Beijing 100013, China)Abstract: The earth will be hardened and Na * will accumulate by using sodium polyacrylate. In addition, poly-acrylate has lower absorbency for ion. In order to resolve these problems, ammonium acrylate was used as a sub-stitute of sodium acrylate and acrylamide was introduced synchronously. A super absorbent polymer of ( ammoni-um acrylate- acrylamide) was synthesized by water solution polymerization. The influences of the kinds and con-tents of the components and the effect of different ions on the property of SAP were studied. The results showedthat when the pH value was between 9~ 10, crosslinker between 0.01 % and 0.03%，initiator between 0.12%and 0.16% and the initial monomer concentration between 20% and 30%，a resin with the best property wasprepared. The water absorbency of the best resin is 1 680 mL/g. The order of the ions effecting the resin' s wa-ter absorbencyis K*