氧气气氛中紫胶树脂的热分解动力学试验
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摘要
采用热分解动力学研究方法,在氧气气氛中同时监测紫胶树脂由室温至高温条件范围内的热质量(TG)和差示扫描量热(DSC)曲线,应用相应软件绘制微分热质量(DTG)曲线,测定紫胶树脂有氧热分解过程的特征参数变化;根据TG、DTG曲线,采用4种不同数学方法(Kissinger法、Starink法、FWO法、FRL法)计算紫胶树脂在氧气气氛中的热分解活化能,对计算结果进行了线性相关性检验;应用Malek法计算并推断紫胶树脂在氧气气氛中的热分解数学模型。结果表明:紫胶树脂在氧气气氛中的热分解反应为两步反应,且热分解反应过程中,体系的放热量高于吸热量;由于紫胶树脂具有聚合物特性,其热分解反应最大分解速率温度随升温速率的增大而增大。由于热分解反应体系的反应复杂性,4种数学方法中仅有Kissinger法、Starink法的计算结果具有密切的线性相关性,计算的热分解反应活化能分别为287.192、287.294 k J/mol; FWO法、FRL法的计算结果不具有密切的线性相关性,FRL法的线性相关性较差,但仍可依据FWO法的计算结果并结合TG、DTG、DSC曲线形状进行热分解机理的推断分析。应用Malek法对热分解反应进行了最概然机理函数的计算,紫胶树脂在氧气气氛中的热分解反应最接近于J-M-A方程,依据此方程的反应机理为随机成核和随后生长。依据DSC曲线,紫胶树脂在10、15、20、25℃/min升温速率时,黏流转变的起始、终止及峰值温度平均值,分别为46.6、146.5、80.1℃;计算了紫胶树脂在相应升温速率时的黏流转变焓变和熵变,平均值分别为199.4 J/g、0.56 J/(g·K)。
By using the thermal decomposition kinetics,TG and DSC curves of lac resin from room temperature to high temperature were simultaneously monitored in oxygen atmosphere. DTG curves were plotted with corresponding software. The characteristic parameters of lac resin during aerobic thermal decomposition were determined. According to TG and DTG curves,the thermal decomposition activation energy of lac resin in oxygen atmosphere was calculated by four different mathematical methods( Kissinger,Starink,FWO,and FRL method),and the linear correlation test was carried out for the calculated results. Malek method was used to calculate and infer the thermal decomposition mathematical model of lac resin in oxygen atmosphere. The results show that the thermal decomposition reaction of lac resin in oxygen atmosphere is a two-step reaction,and the exothermic quantity of the system is higher than that of absorbed heat in the process of thermal decomposition.Because lac resin has polymer properties,the maximum decomposition rate temperature increases with the increase of heating rate. Because of the complexity of the thermal decomposition reaction system,only Kissinger and Starink methods have close linear correlation in the four mathematical methods,and the activation energies of thermal decomposition reaction are287.192 and 287.294 kJ/mol,respectively. The results of FWO method and FRL method do not have close linear correlation,and FRL method is worse. However,the thermal decomposition mechanism can be inferred and analyzed according to the calculation results of FWO method and the shapes of TG,DTG and DSC curves. Malek method was used to calculate the most probable mechanism function of thermal decomposition reaction. The thermal decomposition reaction of lac resin in oxygen atmosphere was the closest to J-M-A equation. According to the reaction mechanism of this equation,random nucleation and subsequent growth were obtained. According to the curves of DSC,the average values of the beginning,ending and peak temperature of the viscous flow change of lac resin at the heating rates of 10,15,20,25 ℃/min are 46.6 ℃,146.5 ℃,and 80.1 ℃,respectively. The enthalpy and entropy changes of viscous flow transition at corresponding heating rate are calculated with the average values of 199.4 J/g and 0.56 J/( g·K),respectively.
By using the thermal decomposition kinetics,TG and DSC curves of lac resin from room temperature to high temperature were simultaneously monitored in oxygen atmosphere. DTG curves were plotted with corresponding software. The characteristic parameters of lac resin during aerobic thermal decomposition were determined. According to TG and DTG curves,the thermal decomposition activation energy of lac resin in oxygen atmosphere was calculated by four different mathematical methods( Kissinger,Starink,FWO,and FRL method),and the linear correlation test was carried out for the calculated results. Malek method was used to calculate and infer the thermal decomposition mathematical model of lac resin in oxygen atmosphere. The results show that the thermal decomposition reaction of lac resin in oxygen atmosphere is a two-step reaction,and the exothermic quantity of the system is higher than that of absorbed heat in the process of thermal decomposition.Because lac resin has polymer properties,the maximum decomposition rate temperature increases with the increase of heating rate. Because of the complexity of the thermal decomposition reaction system,only Kissinger and Starink methods have close linear correlation in the four mathematical methods,and the activation energies of thermal decomposition reaction are287.192 and 287.294 kJ/mol,respectively. The results of FWO method and FRL method do not have close linear correlation,and FRL method is worse. However,the thermal decomposition mechanism can be inferred and analyzed according to the calculation results of FWO method and the shapes of TG,DTG and DSC curves. Malek method was used to calculate the most probable mechanism function of thermal decomposition reaction. The thermal decomposition reaction of lac resin in oxygen atmosphere was the closest to J-M-A equation. According to the reaction mechanism of this equation,random nucleation and subsequent growth were obtained. According to the curves of DSC,the average values of the beginning,ending and peak temperature of the viscous flow change of lac resin at the heating rates of 10,15,20,25 ℃/min are 46.6 ℃,146.5 ℃,and 80.1 ℃,respectively. The enthalpy and entropy changes of viscous flow transition at corresponding heating rate are calculated with the average values of 199.4 J/g and 0.56 J/( g·K),respectively.
引文
[1]陈晓鸣,陈又清,张弘,等.紫胶虫培育与紫胶加工[M].北京:中国林业出版社,2008.
[2]吴统芳.溶剂对紫胶清漆及漆膜性能的影响[J].涂料工业,1990(4):10-14.
[3] FARAG Y,LEOPOLD C S. Development of shellac-coated sustained release pellet formulations[J]. European Journal of Pharmaceutical Sciences,2011,42(4):400-405.
[4] LIMMATVAPIRAT S,LIMMATVAPIRAT C,PUTTIPIPATKHACHORN S,et al. Enhanced enteric properties and stability of shellac films through composite salts formation[J]. European Journal of Pharmaceutics and Biopharmaceutics,2007,67(3):690-698.
[5] LIMMATAVAPIRAT S,NUNTHANID J,PUTTIPIPATKHACHORN S,et al. Effect of alkali treatment on properties of native shellac and stability of hydrolyzed shellac[J]. Pharmaceutical Development and Technology,2005,10(1):41-46.
[6] GHOSHAL S,KHAN M A,KHAN R A,et al. Study on the thermo-mechanical and biodegradable properties of shellac films grafted with acrylic monomers by gamma radiation[J]. Journal of Polymers and the Environment,2010,18(3):216-223.
[7] LUANGTANA-ANAN M,NUNTHANID J,LIMMATVAPIRAT S.Effect of molecular weight and concentration of polyethylene glycol on physicochemical properties and stability of shellac film[J].Journal of Agricultural and Food Chemistry,2010,58(24):12934-12940.
[8]于海洋,王昉,刘其春,等.新型丝素蛋白膜的结构和热分解动力学机理[J].物理化学学报,2017,33(2):344-355.
[9] SLOVK V,UK P. Pitch pyrolysis kinetics from single TG curve[J]. Journal of Analytical and Applied Pyrolysis,2004,72(2):249-252.
[10]胡荣祖,高胜利,赵凤起,等.热分解动力学[M].北京:科学出版社,2008.
[11]王明峰,蒋恩臣,周岭.玉米秸秆热解动力学分析[J].农业工程学报,2009,25(2):204-207.
[12]董国华,冀浩博,张弘,等.紫胶树脂的热分解过程及动力学研究[J].昆明冶金高等专科学校学报,2017,33(5):63-69.
[13]王韶旭,赵哲,谭志诚,等.丙硫异烟胺的热稳定性及其热分解动力学[J].物理化学学报,2007,23(9):1459-1462.
[14]应宗荣.高分子材料成形工艺学[M].北京:高等教育出版社,2010:116-126.
[15]张予东,李宾杰,徐翔民,等. ZnSn(OH)6的热分解动力学[J].物理化学学报,2007,23(7):1095-1098.
[16]钱人元.高分子凝聚态的几个基本物理问题[J].中国科学院院刊,2000(3):174-177.
[17]李云雁,胡传荣.试验设计与数据处理[M].2版.北京:化学工业出版社,2011.
[18]卢林刚,张晴,徐晓楠,等.一种无卤阻燃聚丙烯的热分解动力学[J].高分子材料科学与工程,2010,26(11):39-43.
[19]黄玲,王正洲,梁好均.无卤阻燃聚乙烯的热分解动力学研究[J].中国科学技术大学学报,2006,36(1):34-38,55.
[20]鲍士龙,陈网桦,陈利平,等.2,4-二硝基甲苯热解自催化特性鉴别及其热解动力学[J].物理化学学报,2013,29(3):479-485.
[21]陈炳和,许宁.化学反应过程与设备:反应器选择、设计和操作[M].3版.北京:化学工业出版社,2016:23-24.
[22]殷敬华,莫志深.现代高分子物理学:下册[M].北京:科学出版社,2001:99-100.
[2]吴统芳.溶剂对紫胶清漆及漆膜性能的影响[J].涂料工业,1990(4):10-14.
[3] FARAG Y,LEOPOLD C S. Development of shellac-coated sustained release pellet formulations[J]. European Journal of Pharmaceutical Sciences,2011,42(4):400-405.
[4] LIMMATVAPIRAT S,LIMMATVAPIRAT C,PUTTIPIPATKHACHORN S,et al. Enhanced enteric properties and stability of shellac films through composite salts formation[J]. European Journal of Pharmaceutics and Biopharmaceutics,2007,67(3):690-698.
[5] LIMMATAVAPIRAT S,NUNTHANID J,PUTTIPIPATKHACHORN S,et al. Effect of alkali treatment on properties of native shellac and stability of hydrolyzed shellac[J]. Pharmaceutical Development and Technology,2005,10(1):41-46.
[6] GHOSHAL S,KHAN M A,KHAN R A,et al. Study on the thermo-mechanical and biodegradable properties of shellac films grafted with acrylic monomers by gamma radiation[J]. Journal of Polymers and the Environment,2010,18(3):216-223.
[7] LUANGTANA-ANAN M,NUNTHANID J,LIMMATVAPIRAT S.Effect of molecular weight and concentration of polyethylene glycol on physicochemical properties and stability of shellac film[J].Journal of Agricultural and Food Chemistry,2010,58(24):12934-12940.
[8]于海洋,王昉,刘其春,等.新型丝素蛋白膜的结构和热分解动力学机理[J].物理化学学报,2017,33(2):344-355.
[9] SLOVK V,UK P. Pitch pyrolysis kinetics from single TG curve[J]. Journal of Analytical and Applied Pyrolysis,2004,72(2):249-252.
[10]胡荣祖,高胜利,赵凤起,等.热分解动力学[M].北京:科学出版社,2008.
[11]王明峰,蒋恩臣,周岭.玉米秸秆热解动力学分析[J].农业工程学报,2009,25(2):204-207.
[12]董国华,冀浩博,张弘,等.紫胶树脂的热分解过程及动力学研究[J].昆明冶金高等专科学校学报,2017,33(5):63-69.
[13]王韶旭,赵哲,谭志诚,等.丙硫异烟胺的热稳定性及其热分解动力学[J].物理化学学报,2007,23(9):1459-1462.
[14]应宗荣.高分子材料成形工艺学[M].北京:高等教育出版社,2010:116-126.
[15]张予东,李宾杰,徐翔民,等. ZnSn(OH)6的热分解动力学[J].物理化学学报,2007,23(7):1095-1098.
[16]钱人元.高分子凝聚态的几个基本物理问题[J].中国科学院院刊,2000(3):174-177.
[17]李云雁,胡传荣.试验设计与数据处理[M].2版.北京:化学工业出版社,2011.
[18]卢林刚,张晴,徐晓楠,等.一种无卤阻燃聚丙烯的热分解动力学[J].高分子材料科学与工程,2010,26(11):39-43.
[19]黄玲,王正洲,梁好均.无卤阻燃聚乙烯的热分解动力学研究[J].中国科学技术大学学报,2006,36(1):34-38,55.
[20]鲍士龙,陈网桦,陈利平,等.2,4-二硝基甲苯热解自催化特性鉴别及其热解动力学[J].物理化学学报,2013,29(3):479-485.
[21]陈炳和,许宁.化学反应过程与设备:反应器选择、设计和操作[M].3版.北京:化学工业出版社,2016:23-24.
[22]殷敬华,莫志深.现代高分子物理学:下册[M].北京:科学出版社,2001:99-100.