采用点击化学的反应挤出过程研究

Click reaction becomes an effective method to precisely control the structure of the polymer chains owning to its fast reactions rate and high selectivity. Application of click reaction involves either reaction in solution with focus on precisely control of chain structure, or bulk production materials without solvent, focusing on performance and ignoring the structure control. Bulk reaction system is characterized with high viscosity, which limits polymer chain mobility and leads to deviation of the reaction rate significantly from intrinsic dynamics of the click reaction. Currently, there is a lack of systematic studies covering the control of polymer chains structure with click reaction in the absence of solvent conditions, manipulation of material's aggregation structure and thereby the macroscopic properties. Reactive extrusion integrates polymer reaction and processing together, and possesses the advantages such as solvent-free, environment-benign, and high efficiency for continuous commercial production. This project intends to combine the short residence time of reactive extrusion and fast reaction rate of click reaction with the purpose of developing an efficient process for production of polymeric materials with designed structure. First, intrinsic kinetics of thiol-expoy click reaction will be studied in dilute solution. Sequentially, the influence of click reaction on polymer chain structure, the effects of chain structure on chain mobility, and impact of mobility on reaction of the groups attached to the polymer chain will be investigated. Based on above studies, click reaction will be carried out in the reactive extrusion process. Combining with the researches on morphology evolution, the methods of controlling the chain structure and aggregation structure using the click reaction extrusion process will be revealed. Finally, the relationship between structure and properties of the products will be elucidated.

点击反应速度快、选择性高，是精确控制高分子链结构的有效方法。现有点击反应的应用或在溶液中进行以精确控制产物链结构；或以本体法生产材料、侧重性能、忽略结构控制。本体反应体系粘度高，高分子链段运动能力受限，点击反应进程偏离其本征动力学，使产物链结构的控制变得困难。目前，尚缺乏在无溶剂条件下构建设定结构高分子链、进而控制材料聚集态结构及宏观性能的系统研究。反应挤出集高分子反应及加工为一体，具有无溶剂、环保、易连续化规模生产的特点。本项目拟将反应挤出的短停留时间与点击反应的快反应速度相结合，开发一种高效过程制备具有定制结构的高分子材料。将首先在稀溶液中考察巯基与环氧官能团的点击反应本征动力学，进而研究本体过程中高分子链段运动能力及其链端官能团间点击反应过程的相互影响规律。并将点击反应用于反应挤出过程，结合相形态演变的研究，揭示该过程中产物链结构及聚集态结构的调控规律，并阐明其结构与性能的关系。

以二巯基乙酸乙二醇酯和苯基缩水甘油醚作为巯基和环氧模型化合物，采用纯碱性催化剂，得到不同实验条件下的反应动力学数据，并建立动力学模型，较好地预测巯基-环氧的本体反应动力学。对比各基元反应的速率常数，发现：巯基-环氧反应的控速步骤为巯基官能团与碱性催化剂反应生成巯基负离子的过程；仅在特定反应体系和反应温度下，才能简化成现有文献中所指的二级反应。.在双螺杆挤出机中利用巯基与环氧的点击反应，通过改变反应条件与原料结构和配比，制备了一系列不同结构的线性热塑性环氧树脂材料，发现利用巯基-环氧反应可以增大环氧树脂的分子量，并提高样品的耐热性能。通过巯基-环氧反应将柔性链引入环氧树脂体系进行扩链反应，还可有效地提高样品的冲击强度，使之接近交联环氧树脂的水平。.通过聚丙二醇（乙二醇）二缩水甘油醚与二巯基乙酸乙二醇酯的点击反应，制备了扩链柔性环氧树脂；再与酚醛环氧混合；并利用糠硫醇中巯基与环氧的点击反应，接入呋喃基团；加入4,4’-双马来酰亚胺基二苯甲烷，通过Diels-Alder点击反应制备不同结构的热可逆交联增韧环氧树脂材料，实现交联材料的重复加工。利用红外测试、溶胀溶解性能测试、DSC测试和流变测试证明交联增韧环氧树脂的热可逆性质。并表征了该产物的力学性能及热稳定性，探究了结构对材料性能的影响。改性后的增韧环氧树脂较酚醛环氧树脂交联体系，抗冲强度最高可提升151%。.结合线性聚双环戊二烯（LPDCPD）和金属配位交联制备了化学可逆的PDCPD基配位聚合物金属凝胶。首先，合成了完全可溶的LPDCPD；通过逆电子效应的Diels-Alder点击反应将具有与金属离子配位能力的3, 6-二吡啶基-1, 2, 4, 5-四嗪单元引入LPDCPD链中，制得大分子配体；最后通过大分子配体与金属离子进行配位反应制备了化学可逆的聚合物金属凝胶。考察了交联密度、金属离子种类、溶剂和聚合物浓度对金属凝胶性能的影响。最后，通过加入乙二胺作为竞争性配体，实现解交联反应。分离出的大分子配体可重新与金属离子配位，形成相应的金属凝胶。