ZnSn(OH)6的熱分解動(dòng)力學(xué)

物理化學(xué)學(xué)報( Wuli huarue xuebao)JulyActa Phys.-Chim.Sin.,2007,23(7):1095-10981095[Notewww.whxb.pku.edu.cnZnSn(OH)6的熱分解動(dòng)力學(xué)張予東李賓杰2徐翔民2李德亮1(河南大學(xué)化學(xué)化工學(xué)院河南開(kāi)封475001;2河南大學(xué)特種功能材料重點(diǎn)實(shí)驗室,河南開(kāi)封475001)摘要:用 TG/DTG聯(lián)用技術(shù),在25、50、100、150200K·min2不同線(xiàn)性升溫條件下,研究了 ZnSn(OH)的熱分解過(guò)程結果表明,在氮氣氣氛下, ZnSn(OH)在298873K范圍內發(fā)生了一步分解其失重率與理論計算值相符應用非等溫多重掃描速率法對熱分解過(guò)程進(jìn)行了動(dòng)力學(xué)分析,ZnSn(OH)在氮氣中分解的活化能E=12877k.mol-,指前因子lgA)=10.61,機理函數為 Mample單行法則關(guān)鍵詞: TG/DTG;熱分解;機理;動(dòng)力學(xué)中圖分類(lèi)號:O642;0643;06116Thermal Decomposition Kinetics of ZnSn(oH)6ZHANG Yu-Dong LI Bin-Jie XU Xiang- Min" LI De-Liang(College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475001, Henan Province, P. R. China;Laboratory for Special Functional Materials, Henan University, Kaifeng 475001, Henan Province, P. R. ChinaAbatract: The thermal decomposition processes of Zn Sn(OH) were studied using TG/DTG at various heating ratesof 2.5, 5.0, 10.0, 15.0, 20.0 K. min. The results showed that the decomposition proceeded through one step innitrogen atmosphere at the temperature range from 298 to 873 K. a good agreement was found between the mass lossof the thermal decomposition of Zn Sn(OH) and the theoretical mass loss. The thermal decomposition kinetics wasinvestigated employing non- isothermal multiple scanning method. The activation energy for the decompositionreaction of ZnSn(OH) was determined to be E=128. 77 kJ.- in nitrogen atmosphere and the pre-exponential factorof its kinetics equations was calculated to be lg(A/s-)10.61. The mechanism function was obtained to be mampleKey Words: TG/DTG; Thermal detion: Mechanism: Kinetics阻燃劑正隨著(zhù)高分子材料的廣泛應用而迅速發(fā)法研究了材料的熱穩定性.Xu和 Donald等用熱展羥基錫酸鋅由于具有無(wú)毒、阻燃和抑煙的特性,分析法考察了羥基錫酸鋅添加到軟質(zhì)聚氯乙烯越來(lái)越受到人們的關(guān)注,有可能成為Sb2O2的替代(PVC)后材料的分解變化,研究了其對軟質(zhì)PVC的品之一闆.羥基錫酸鋅受熱分解生成錫酸鋅并脫水吸阻燃和抑煙作用.但到目前為止,關(guān)于羥基錫酸鋅的熱,在高溫下鋅與錫對脫鹵化反應具有催化作用,熱分解動(dòng)力學(xué)研究還未見(jiàn)報道本文利用非等溫多從而起到阻燃抑煙效果.所以,研究羥基錫酸鋅的分重掃描速率法研究了羥基錫酸鋅的熱分解動(dòng)力學(xué),解動(dòng)力學(xué)對于研究其分解阻燃機理十分重要.為進(jìn)一步研究該物質(zhì)的阻燃機理提供有益的信息熱分析技術(shù)已被廣泛應用于研究阻燃材料的熱穩定性、分解機理和熱分解動(dòng)力學(xué). Cusack等將1YH中國煤化工羥基錫酸鋅加入到系列溴代聚酯樹(shù)脂中,用熱分析CNMHG品)在瑞士MurReceived: December 27, 2006; Revised: March 20, 2007; Published on Web: May 10, 2007Correspondingauthor.Email:zyd71@henu.edu.cn;Tel+86378-2192河南大學(xué)自然科學(xué)基金重點(diǎn)項目(XKO6ZD003資助C Editorial office of Acta Physico-Chimica Sinica1096Acta Phys.-Chim. Sin, 2007Vol 23Toledo TG/SDTA851型熱分析儀上進(jìn)行.動(dòng)態(tài)氮氣基本一致氣氛,流速為40mL·min-.樣品在測試前用瑪瑙研22非等溫分解動(dòng)力學(xué)缽小心研磨,以使試樣粒度降低并均勻,從而改善傳22.1求取活化能E熱;測量溫度范圍為298到873K;升溫速率分別為通過(guò)非等溫分解動(dòng)力學(xué)研究可揭示ZnSn(OH25、5.0、10.0、15.0、20.0K分解的反應機理,獲得其最概然機理函數以及相應的動(dòng)力學(xué)參數表1列出了在5種不同升溫速率(β)2結果與討論下, ZnSn(OH受熱分解時(shí)的DTG峰溫T用多重掃21熱行為、熱分解機理描速率法( multiple scanning method), Flynn-waZnSn(OH的典型TGDG曲線(xiàn)如圖所示(在氮 Ozawa(FWO)法2(1), Kissinger法(2)和 Starink氣中升溫速率為25K·min+,ZnSn(OH在463K時(shí)法叫(3)處理這些數據,獲得相應的活化能E和指前開(kāi)始分解,逐漸脫去羥基生成錫酸鋅和水,到873K因子A:時(shí)熱重曲線(xiàn)呈水平,表明此時(shí)產(chǎn)物已完全變成錫酸 Flynn-Wall-Ozawa法:鋅,失重率為1897%,與理論值1888%基本一致Ig B=lg(0.4567E其反應方程式如下:RG(α)-2315RTZnSn(OH→ EnSo+3HOKissinger法:DTG曲線(xiàn)上僅有一個(gè)峰,與TG曲線(xiàn)上失重的臺階對應,表明 ZnSn(OH的熱分解過(guò)程為一步分解.Starink法由ZnSn(OH在氮氣中的TG曲線(xiàn)圖2)可知,不同升溫速率下的TG曲線(xiàn)均相吻合,說(shuō)明其失重速率M是品=Ck式中,a為轉化率,R為普適氣體常數,G(a)為積分機理函數,C為常數由表2可知,用三種多重掃描速率法所獲得的8-2.5.min活化能E值非常接近,而且線(xiàn)性系數和標準偏差的m0數值都表明實(shí)驗數據代入的方程具有良好的線(xiàn)性表3列出了不同加熱速率下 ZnSn(OH)熱分解過(guò)程0004的基本數據0.005222判斷反應是否一步反應300400500600700800900用FWO方程(1)和 Friedman方程(4)根據等轉化率法求算活化能,得到不同a對應的E值(表4)圖1znSn(OH)6的TG/DTG曲線(xiàn)Friedman方程Fig 1 TG/DTG curves of ZnSn(oH)6表1不同加熱速率下ZnSn(OH)的DTG曲線(xiàn)的峰溫Table 1 Peak temperatures(T, )of DTG curves atB/(K")(from left to right)various heating rates(B)9525,50,10.0,15.0.20.0150TK47799485.66496.525029950731表2用多重掃描速率法獲得的熱分解動(dòng)力學(xué)參數Table 2 Kinetic parameters of thermal decompo-sition obtained using multiple scanning methods中國煤化工093002567CNMHG0.90900313112znSn(OH)在不同加熱速率下的TG曲線(xiàn)13230Fig 2 TG curves of ZnSn(OH) atF-W-0: Flynn-Wall-Ozawa equation; E: activation energdifferent heating ratesr linear coefficient: SD: standard deviationNo.7張予東等:ZnSn(OH)的熱分解動(dòng)力學(xué)1097表3不同加熱速率下 ZnSn(OH)k熱分解過(guò)程的基本數據Table 3 Basic data of thermal decomposition of ZnSn(OH) at various heating ratesConversion rate(a)k 10 dadT/K- T/K 10(da/dT)/K- T/K 10'(do/dT)/k- T/K 10/(da/dT/K-10(da/dT/k-46126267467932.47478.123.01187649094248467.123.77474.183.52184803.18490007494212.8846942423476623.99487.473.41495293.74499653018083492114.10497574.00502053.76475.2618273494504403.93484.565.08496.225018l50663478.755.35486.37498.234.284.305089351138482424490.165025250833514.17184.57492353.8105.03511075]7.703513.6650899515553.3l522973.48In[(m )=In(Af(a)]-k表4不同加熱速率下ZnSn(OH)的TG數據由式(1)和(4)所得的活化能由表4可見(jiàn),用FWO法求得的反應活化能 Table4 Activation energies(E) obtained by TG data(020≤a≤0.80)比用 Friedman法求得的略高,但of Zn Sn(OH) according to the Eqs. (1)and (4)atvarious heating rates二者隨著(zhù)α的增大變化平穩,分解反應的活化能變化不大,分解反應具有類(lèi)似的變化規律,這說(shuō)明 onversion rate() e w-o method friedman methodZnSn(OH6的分解反應很可能是一步反應同時(shí),由02013986121.13ZnSn(OH)的DTG曲線(xiàn)上僅有一個(gè)峰的變化也可以說(shuō)明這一點(diǎn)125.10035223最概然機理函數的判定微商法 Achar-Brindly-Sharp(ABS)方程嗎133.8512202Ef(a)drl18.77積分法 Coats-Redfern(CR)方程嗎130.221178l12839114.5511390123.18117,71將實(shí)驗數據a、T、ddT代入上述兩個(gè)方程,結合43117.06種常用的固體反應動(dòng)力學(xué)函數fa)和G(a),根據l31.50線(xiàn)性?xún)?yōu)劣和標準偏差大小,微商法與積分法結果的示取表2和表5中結果的平均值得ZnSn(OH分解的致性,發(fā)現No.6基本符合上述條件,如表5所“動(dòng)力學(xué)三因子 kinetic triplet分別是,E=128表5用CR(Eq(6)和ABS(Eq5)法計算所得ZnSn(OH6分解過(guò)程的動(dòng)力學(xué)參數Table 5 The kinetics parameters of thermal decomposition obtained by C-R(Eq- (6))and A- B-s(Eq- (5)methodsC-R methodA-B-S methodFunction No tIE(kJ·mol)099670.03513127860.98l1007951134.4512.1509983002521中國煤化工0.99690.03373yHECNMH1501093099510.04054119310.98980.060500.98400.07988Average E value 127.24l098Acta Phys.-Chim Sin, 2007VoL 23kJ·mol,lg(A/s+)=1061,反應的機理函數系 Lampl2005,21(7:752[岳林海金達萊,呂德義徐鑄德物理化學(xué)單行法則,為一級反應,反應的機理為隨機成核,隨學(xué)報,2005,21():752]后生長(cháng)機理反應的微分形式為,a)=1-a;積分形o;wnwH: 1ao, Y. H, xu2mom強,武偉式為,G(a)=-n(1-a)焦運紅,徐建中化工學(xué)報2006,57(5):12598 Jang, B N. wilkie, C. A. Thermochimica Acta, 2005, 426(1-2結論采用非等溫掃描速率法研究了ZnSn(OH的分 sack,; onk,; ,J.A., Reynolds, s.J.J. Fire解機理和分解動(dòng)力學(xué).在氮氣氣氛下,ZnSn(OH在Mater.,1989,141):2310 Donald, J F; Kelvin, K S.J. VinyL. Add. Tech, 1997, 3(1): 33298-873K范圍內為一步分解,對應的動(dòng)力學(xué)參數11H,Rz:.Sh,Q.z, Thermalanalysis kinetics. Beijing: Science為,E=12877 k.mol,lg(A/s-)=10.61,反應機理系Pres,2001[胡榮祖,史啟禎熱分析動(dòng)力學(xué)北京:科學(xué)出版隨機成核和隨后生長(cháng)其微分形式為,fa)=1-a;積社,2001分形式為,Ga)=-n(1-a)12 Ozawa, T.J. Thermal Analysis, 1970, 3: 303 Flynn, J. H; Wal, L.A. J. Polym. Sci. Part B: Polymer Letters,References14 Kissinger, H. E. Anal. Chem, 1957, 29(11): 1701 Petsom, A; Roengsumran, S Ariyaphattanakul, A Sangvanich,15 Starink, M. Thermochimica Acta, 1996, 288(1-2): 94P.J. Poly. Degrad. Stab, 2003, 80(1): 1716 Cong, C J; Luo, S. T Tao, Y. T. Zhang, K. L. Chem. J. Chin.2 Ewa, K w.J. MacromoL. 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