The differential thermal analysis （DTA） curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O3 with Li2CO3 and MnO2, The reaction began at about 503K, and fin...The differential thermal analysis （DTA） curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O3 with Li2CO3 and MnO2, The reaction began at about 503K, and finished at about 873K. The apparent activation energy of Kissinger method was about 122.77kJ.mol^-1, the reaction orderwas 1.67, the frequency factor was 7.81×10^9, and therefore the dinetic epuation was dδ/dt=A·exp（- E/RT）·（1-δ）^n=7.81×10^9, exp（-122770/RT）·（l-δ）^1.67 . Coats-Redfem integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112. 13kJ· mol^-1 and 1.18 × 10^9, respectively, rather close to that of Kissinger method. X-ray diffraction （XRD） and scanning electron microscope （SEM） results shown that the synthesized LiMn2O3 possesses pure phase, regular shape and normal particle distribution.展开更多
以马来海松酸(MPA)、新戊二醇(NPG)、三羟甲基丙烷(TMP)、间苯二甲酸(IPA)、己二酸(AA)、间苯二甲酸-5-磺酸钠(5-SSIPA)为原料,采用先分步熔融后溶剂回流法制得水可分散型松香基聚酯多元醇(WDRPP)。探讨了反应时间、催化剂用量、n(—OH)...以马来海松酸(MPA)、新戊二醇(NPG)、三羟甲基丙烷(TMP)、间苯二甲酸(IPA)、己二酸(AA)、间苯二甲酸-5-磺酸钠(5-SSIPA)为原料,采用先分步熔融后溶剂回流法制得水可分散型松香基聚酯多元醇(WDRPP)。探讨了反应时间、催化剂用量、n(—OH)∶n(—COOH)和亲水单体用量对反应的影响,并利用傅里叶红外光谱(FT-IR)和^(13) C NMR对产物进行了表征。利用热重分析(TG)研究了WDRPP的耐热性,并采用Coats-Redfem法对WDRPP的热分解动力学试验数据进行拟合分析,得到动力学参数。结果表明,当反应时间为5.5 h(熔融反应3 h,溶剂回流2.5 h),催化剂用量为0.10%,n(—OH)∶n(—COOH)为1.4∶1,亲水单体用量为2.86%时,制备的WDRPP的热稳定性和WDRPP水分散体的稳定性最佳;WDRPP的最大失重速率温度(Tmax)为406.7℃、热解反应活化能为64.65 k J/mol,且热分解动力学曲线线性良好(R^2=0.997 3),表明WDRPP热分解过程符合一级反应动力学规律;FT-IR和^(13) C NMR的分析结果表明WDRPP制备成功。展开更多
文摘The differential thermal analysis （DTA） curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O3 with Li2CO3 and MnO2, The reaction began at about 503K, and finished at about 873K. The apparent activation energy of Kissinger method was about 122.77kJ.mol^-1, the reaction orderwas 1.67, the frequency factor was 7.81×10^9, and therefore the dinetic epuation was dδ/dt=A·exp（- E/RT）·（1-δ）^n=7.81×10^9, exp（-122770/RT）·（l-δ）^1.67 . Coats-Redfem integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112. 13kJ· mol^-1 and 1.18 × 10^9, respectively, rather close to that of Kissinger method. X-ray diffraction （XRD） and scanning electron microscope （SEM） results shown that the synthesized LiMn2O3 possesses pure phase, regular shape and normal particle distribution.
文摘以马来海松酸(MPA)、新戊二醇(NPG)、三羟甲基丙烷(TMP)、间苯二甲酸(IPA)、己二酸(AA)、间苯二甲酸-5-磺酸钠(5-SSIPA)为原料,采用先分步熔融后溶剂回流法制得水可分散型松香基聚酯多元醇(WDRPP)。探讨了反应时间、催化剂用量、n(—OH)∶n(—COOH)和亲水单体用量对反应的影响,并利用傅里叶红外光谱(FT-IR)和^(13) C NMR对产物进行了表征。利用热重分析(TG)研究了WDRPP的耐热性,并采用Coats-Redfem法对WDRPP的热分解动力学试验数据进行拟合分析,得到动力学参数。结果表明,当反应时间为5.5 h(熔融反应3 h,溶剂回流2.5 h),催化剂用量为0.10%,n(—OH)∶n(—COOH)为1.4∶1,亲水单体用量为2.86%时,制备的WDRPP的热稳定性和WDRPP水分散体的稳定性最佳;WDRPP的最大失重速率温度(Tmax)为406.7℃、热解反应活化能为64.65 k J/mol,且热分解动力学曲线线性良好(R^2=0.997 3),表明WDRPP热分解过程符合一级反应动力学规律;FT-IR和^(13) C NMR的分析结果表明WDRPP制备成功。
