壳聚糖衍生物处理碳纳米管改性聚丙烯腈基碳纤维

自制了邻苯二甲酰化壳聚糖、萘甲酰化壳聚糖、羧甲基化壳聚糖等3种壳聚糖衍生物对多壁碳纳米管(MWNTs)进行表面处理,发现邻苯二甲酰化壳聚糖(PhthCS)能有效提高MWNTs在极性6～10范围溶剂中的分散性及稳定性,并考察了PhthCS的分子量及浓度对MWNTs的分散性及稳定性的影响;通过微观形貌和元素分析,发现MWNTs部分表面包覆了一层厚度约为5～10 nm的包覆膜.经凝胶纺丝工艺制备了PhthCS-MWNTs/聚丙烯腈复合原丝,经预氧化、炭化制备了复合碳纤维,SEM结果表明PhthCS-MWNTs在复合原丝和复合碳纤维中分散均匀,良好取向;PhthCS-MWNTs对复合原丝和复合碳纤维的力学性能具有明显的改善作用,当PhthCS-MWNTs含量为0.5%时,复合碳纤维的拉伸强度提高了19.8%;增加PhthCS-MWNTs用量对复合碳纤维的拉伸模量具有显著提高,当PhthCS-MWNTs含量为3%时,复合碳纤维的杨氏模量从6.24 GPa提高到了13.86 GPa,增大了122%

Study on Polymerization Kinetics of Methylene Diphenyl Diisocyanate

The polymerization processes of methylene diphenyl diisocyanate (MDI) had been studied in flow atmosphere of high purity N(2) using TG-DSC-DTG techniques. The kinetic parameters of the polymerization process were calculated through the Flynn-Wall-Ozawa method and the polymerization raechanism of MDI was also studied with the Satava-Sestak and Coats-Redfern methods. The results indicated that: the process calculated could be attributed to the mechanism of random nucleation and subsequently growth, with the mechanism function being G(alpha)=-In(1-alpha)(1/2). The activation energy and pre-exponential factor were E=58.42 kJ/mol and A=5006 min(-1), the kinetic equation may be expressed as: -In(1-alpha)(1/2)=5006 Xexp(-58.42X1000)/8.314XT)t

二苯甲烷二异氰酸酯mdi聚合反应动力学研究

The polymerization processes of methylene diphenyl diisocyanate (MDI) had been studied in flow atmosphere of high purity N(2) using TG-DSC-DTG techniques. The kinetic parameters of the polymerization process were calculated through the Flynn-Wall-Ozawa method and the polymerization raechanism of MDI was also studied with the Satava-Sestak and Coats-Redfern methods. The results indicated that: the process calculated could be attributed to the mechanism of random nucleation and subsequently growth, with the mechanism function being G(alpha)=-In(1-alpha)(1/2). The activation energy and pre-exponential factor were E=58.42 kJ/mol and A=5006 min(-1), the kinetic equation may be expressed as: -In(1-alpha)(1/2)=5006 Xexp(-58.42X1000)/8.314XT)t

二苯甲烷二异氰酸酯mdi聚合反应动力学研究

The polymerization processes of methylene diphenyl diisocyanate (MDI) had been studied in flow atmosphere of high purity N(2) using TG-DSC-DTG techniques. The kinetic parameters of the polymerization process were calculated through the Flynn-Wall-Ozawa method and the polymerization raechanism of MDI was also studied with the Satava-Sestak and Coats-Redfern methods. The results indicated that: the process calculated could be attributed to the mechanism of random nucleation and subsequently growth, with the mechanism function being G(alpha)=-In(1-alpha)(1/2). The activation energy and pre-exponential factor were E=58.42 kJ/mol and A=5006 min(-1), the kinetic equation may be expressed as: -In(1-alpha)(1/2)=5006 Xexp(-58.42X1000)/8.314XT)t

铅化合物催化二氨基二苯甲烷与碳酸二甲酯反应机理的红外光谱研究

研究了Pb（OAc）2.3H2O催化二氨基二苯甲烷（MDA）与碳酸二甲酯（DMC）反应合成二苯甲烷二氨基甲酸甲酯（MDC）的稳定性和成分变化,发现乙酸铅在反应过程中会形成含氨基配体的碱式碳酸铅,该化合物对MDC的合成仍具有较高活性.采用红外光谱结合原位控温液体池技术研究了其催化机理,结果表明,铅催化剂的配体对其催化活性起重要作用,双齿配位方式向单体配位方式的转变是催化剂起作用的关键步骤;并在此基础上提出了铅催化剂催化MDA与DMC反应的机理

反应耦合法制备苯氨基甲酸甲酯产物分离过程的模拟

对碳酸二甲酯(DMC)和二苯基脲反应耦合法合成苯氨基甲酸甲酯(MPC)的产物进行分离研究;测定了MPC的热重数据以及MPC-DMC物系的汽液平衡数据;在考虑了各组分分离特性的基础上,确定了单塔减压侧线采出工艺;采用AspenPlus过程模拟软件对分离工艺进行了模拟计算。优化的操作条件为:理论塔板数为12块,进料位置为第8块塔板,侧线采出位置为第4块塔板,塔顶采出量为535.3kg/h,侧线采出量为16.0kg/h,塔釜绝对压力为98.94kPa,回流比为0.12。在此条件下,分离得到的塔顶产品中xDMC=99.6%,DMC的收率大于99.0%;塔釜产品中xMPC=98.7%,MPC的收率大于99.0%

铅化合物催化二氨基二苯甲烷与碳酸二甲酯反应机理的红外光谱研究

研究了Pb（OAc）2.3H2O催化二氨基二苯甲烷（MDA）与碳酸二甲酯（DMC）反应合成二苯甲烷二氨基甲酸甲酯（MDC）的稳定性和成分变化,发现乙酸铅在反应过程中会形成含氨基配体的碱式碳酸铅,该化合物对MDC的合成仍具有较高活性.采用红外光谱结合原位控温液体池技术研究了其催化机理,结果表明,铅催化剂的配体对其催化活性起重要作用,双齿配位方式向单体配位方式的转变是催化剂起作用的关键步骤;并在此基础上提出了铅催化剂催化MDA与DMC反应的机理

乙醇衍生新方法对异氰酸酯类产品的定性、定量分析研究

针对非光气氨基甲酸甲酯热解法制备4,4′-二苯甲烷二异氰酸酯(MDI)反应过程中异氰酸酯类产物无法定性、定量分析的技术难题,选用乙醇为衍生剂,利用高效液相色谱对中间产物4-(4′-苯氨基甲酸甲酯)苯甲烷异氰酸酯(MMI)及产物MDI的乙醇衍生物进行分析,成功建立了异氰酸酯类产物简单、快速、精确的高效液相色谱分析方法———乙醇衍生法。通过对产物进行熔点测定、元素分析、核磁共振氢谱、质谱等分析测试,证实分离所得样品即为高纯度的MMI及MDI乙醇衍生物。液相色谱条件为:流动相甲醇-水(体积比60∶40),流速1.2 mL/min,柱温30℃,紫外检测波长245 nm。在一定的质量浓度范围内,MMI及MDI乙醇衍生物纯品的线性相关系数均大于0.999 9,相对标准偏差均小于1.0%

二苯甲烷二氨基甲酸甲酯热分解制备二苯甲烷二异氰酸酯的表观动力学研究

研究了在癸二酸二（2-乙基己基）酯溶剂中二苯甲烷二氨基甲酸甲酯（MDC）热分解产生二苯甲烷二异氰酸酯（MDI）的反应机理,建立了二苯甲烷二氨基甲酸甲酯的分解反应动力学模型.通过实验测定,对不同温度下体系中各物质的浓度数据进行线性拟合得到反应速率方程.结果表明,MDC的热分解分为2个步骤,均为一级反应.两步反应的活化能分别为138.82和167.78 kJ/mol;指前因子分别为1.51×10^12和5.33×10^14min-1

铅化合物催化二氨基二苯甲烷与碳酸二甲酯反应机理的红外光谱研究

研究了Pb（OAc）2.3H2O催化二氨基二苯甲烷（MDA）与碳酸二甲酯（DMC）反应合成二苯甲烷二氨基甲酸甲酯（MDC）的稳定性和成分变化,发现乙酸铅在反应过程中会形成含氨基配体的碱式碳酸铅,该化合物对MDC的合成仍具有较高活性.采用红外光谱结合原位控温液体池技术研究了其催化机理,结果表明,铅催化剂的配体对其催化活性起重要作用,双齿配位方式向单体配位方式的转变是催化剂起作用的关键步骤;并在此基础上提出了铅催化剂催化MDA与DMC反应的机理