【作者】 张立；

【导师】 钟理；

【作者基本信息】 华南理工大学 ， 化学工艺， 2017， 硕士

【摘要】 TDI-TMP加成物被广泛应用在家具木器漆、防腐涂料和防水涂料等表面装涂,它赋予漆膜多种优异性能。TDI与TMP的反应过程动力学对聚合物结构、性能和游离单体含量起决定性作用。本文通过多种物理、化学方法和仪器表征的手段对反应体系进行了综合分析,系统的研究了反应的动力学和反应各组分含量的变化。研究主要包括以下几个方面:首先,探讨了反应温度、反应进行程度对预聚物的物理化学性能的影响,得出反应温度50℃,NCO转化率为55~60%时加阻聚剂,为反应的最佳条件,得到的产物分子量分布均匀,游离单体含量低。采用FT-IR、GPC、HRMS和1H-NMR等表征方法,分析了预聚物的化学结构。结果表明,温度对2,4位-NCO反应活性有选择性,低温有利于4位的-NCO优先反应,高温有利于2位的-NCO参与反应。其次,采用LCMS的方法对50℃、65℃和80℃反应中间体的含量进行追踪,并提出了TDI和TMP三步连串反应的基础反应模型。分析得出了不同温度下各步反应的反应速率常数。温度对反应中间体AB、AB2生成速率影响较小,其活化能分别为12.76kJ/mol、16.58 kJ/mol,反应终产物AB3对温度更敏感,活化能达到25.63 kJ/mol,反应总的表观活化能Ea=54.97 kJ/mol。此外,通过Matlab软件进行反应动力学拟合,所得中间体含量的理论计算值与实验结果相匹配,验证了动力学参数的准确性。最后,通过化学改性法,使用自制催化剂和长链醇,制备出低粘度、低游离TDI、高容忍度的TDI-TMP预聚物。研究表明,最佳催化剂用量为0.5 wt%,NCO转化率39.0%为最佳加入时机,合成原料配比m(TDI)/m(TMP)=4.0较为适宜,合成的TDI-TMP预聚物游离TDI=0.38、粘度=900 mPa·s;用正十二醇改性取得很好的效果,用量为3 wt%,此时二甲苯容忍度可达到3.5以上。更多还原

【Abstract】 TDI-TMP adducts is widely used in furniture wood finishing,anti-corrosion coating,waterproof coating and other surface coating,which offers films with a variety of excellent properties.The reaction process and kinetics of TDI and TMP play a crucial role in the structure,properties and content of free-TDI.In this paper,the reaction system is analyzed comprehensively by a variety of physical,chemical and instrumental methods.Moreover,the kinetics of the reaction and the changes in various reaction component concentrations are studied systematically.The study mainly includes the following aspects:Firstly,the effects of reaction temperature and reaction progress on the physical and chemical properties of the prepolymers are discussed.the reaction temperature of 50℃ and NCO conversion rate of 55-60 % are the optimal reaction conditions,under which the as-prepared product exhibits uniform molecular weight distribution and low free monomer content.The chemical structure of the prepolymers is analyzed by FITR,GPC,HRMS and 1H-NMR.The results show that temperature can significantly affect the reaction selectivity of 2’-and 4’-NCO in TDI.Low temperature favors the preferential reaction of 4’-NCO,while high temperature favors the reaction involving 2’-NCO.Secondly,the concentrations of reaction intermediates at the reaction temperatures of 50℃,65℃ and 80℃ are tracked by LCMS,and a basic reaction model of three-step consecutive reaction between TDI and TMP is proposed.The reaction rate constants at different temperatures for each reaction step are obtained.Temperature has small influence on the production rates of reaction intermediates AB and AB2,whose activation energy is 12.76 kJ/mol and 16.58 kJ/mol,respectively.The final product of reaction AB3 is more sensitive to temperature,with the activation energy reaching 25.63 kJ/mol.The overall apparent activation energy of reaction is obtained through calculation,which is Ea = 54.97 kJ/mol.In addition,the concentrations of various reaction intermediates obtained by Matlab kinetics fitting match with the experimental results,thus verifying the accuracy of the experimentally obtained kinetic parameters.Finally,TDI-TMP prepolymer with low viscosity,low F-TDI and high tolerance is prepared by chemical modification using self-made catalyst and long chain alcohols.It is experimentally found that the optimal catalyst dosage is 0.5 wt%,whose optimal addition time is when the NCO conversion rate reaches 39.0%.The ratio of raw material m(TDI)/m(TMP)= 4.0 is appropriate,at which the TDI-TMP prepolymers synthesized has a F-TDI = 0.38,and a viscosity = 900 mPa·s.Modification with 3wt% n-dodecanol yields excellent result,where the xylene tolerance can reach above 3.5.更多还原