【作者】 周莹；

【导师】 詹晓力； 陈丰秋；

【作者基本信息】 浙江大学 ， 应用化学， 2004， 硕士

【摘要】 纳米蒙脱土在聚合物中的剥离分散性是制备高性能蒙脱土／聚合物纳米复合材料的关键。现有的研究多集中于纳米复合材料的制备方法和性能改善，不能很好地解释蒙脱土在聚合物中剥离分散的机理以及复合材料形态与性能的关系。本文选择相容性好的蒙脱土／环氧树脂复合体系作为研究对象，对该体系的插层剥离过程及其影响因素、蒙脱土的分散形态与性能的关系、固化动力学行为等进行了深入的研究。 通过XRD测试研究有机蒙脱土／环氧树脂复合体系的插层行为及剥离机理。结果表明，蒙脱土／环氧树脂的插层及剥离分散主要取决于蒙脱土中有机处理剂的性质，有机处理剂活性大有利于复合体系的插层与剥离，同时受到固化剂种类及用量、混合插层条件和固化条件等影响。 分析认为有机蒙脱土在环氧树脂中剥离的实现需同时满足热力学条件和动力学条件。其中热力学条件很容易满足，通过计算，环氧树脂的固化反应热大于蒙脱土片层剥离所需的推动力，由此推断蒙脱土片层剥离的驱动力为环氧树脂在片层之间发生固化反应的聚合热。从动力学角度来看，蒙脱土层间环氧树脂的固化反应与层外环氧树脂的固化反应是一对竞争反应，层间环氧树脂相对于层外环氧树脂的固化速度较快对有机蒙脱土的剥离至关重要，能促进层间环氧树脂固化反应的因素将有利于有机蒙脱土的剥离分散。 制备了填充型、插层型和剥离型三种蒙脱土／环氧树脂复合材料，并对其结构和性能进行表征。结果表明，蒙脱土在环氧树脂中的分散性直接影响复合材料的性能。有机蒙脱土在环氧树脂中剥离起到了增强增韧的作用，并显著提高了耐热性能。在剥离型有机蒙脱土／环氧树脂纳米复合材料中，当有机蒙脱土含量为2wt％时，复合材料力学性能最好。 采用DSC研究E—51环氧树脂与N，N′-双(2—羟乙基)甲基十二烷基铵蒙脱土(DK2)在2-乙基-4-甲基咪唑(M-Q固化剂)作用下的固化反应动力学。推导出该复合体系的固化工艺参数，发现加入DK2使复合体系的固化温度下降。同时采用Kissinger方程与Crane方程计算发现加入DK2使复合体系的活化能降低。初步建立了DK2／EP／M-Q复合体系固化反应的酸催化机理模型，推导出固浙江大学硕士学位论文周莹摘要，，.一一、一一一~、，da__。、，、二~、，___一，*，*、一_、_，_~~，、，二.、忧汉皿迷毕力程刀，万.=八1。妙一a)“。遇过寺温p5U头叛粒让J嵌误型，迸一步 “t验证了层间环氧树脂聚合反应促进蒙脱土片层剥离分散的推断。 在以上对蒙脱土剥离分散、复合材料的性能、复合体系固化反应动力学的研究基础上，本文提出一种既适用于纳米级层状硅酸盐又适用于纳米颗粒的分散思路:微区相化学反应解聚纳米团聚体，用以解释纳米粒子在聚合物基体中分散的一般性规律。更多还原

【Abstract】 Dispersedness of montmorillonite(MMT) in polymer is the key to preparation of the high-powered MMT / polymer nanocomposite. However, most of the researches just focus on the preparation of nanocomposites and the improvement of the performance, much more comprehensive and further work need to be done. In our work, MMT / epoxy(EP) nanocomposites made by intercalation was chosen to study the intercalation process ,exfoliation mechanism, dispersedness of MMT and its properties and the curing reaction kinetics, etc.First, intercalation and exfoliation behaviors of organ clays in epoxy resin has been investigated by XRD. It was found that the intercalation and exfoliation ability of organ clays was basically determined by the intercalation reagent used, also determined by the properties of curing reagent and conditions of blending and curing.The exfoliation mechanism was discussed. The results revealed that if the montmorillonite was exfoliated, both the thermodynamics condition and the dynamics condition were all fulfilled. As the heat of epoxy curing reaction calculated exceeded exfoliation impetus of montmorillonite, the driving force of montmorillonite exfoliation is the polymerization energy released by the curing reaction. In addition, the dynamics condition was needed for the exfoliation. The exfoliation of montmorillonite was laid on the competition of the curing of the intra-gallery resin with the curing of the extra-gallery resin. If the intra-gallery epoxy cured faster, it will drive the clay to exfoliate before the extra-gallery epoxy resin reaches its gel point. Otherwise the extra-gallery epoxy resin will gel firstly and block the further exfoliation of the clay. So the factors facilitating the curing of the intra-gallery epoxy would enhance the exfoliation of organ clays.Secondly, three montmorillonite / epoxy composites were prepared as filled composite, intercalated composite and exfoliated composite. The mechanism properties results indicated that the exfoliation of organ clay in epoxy resin was essential for enhancing properties of nanocomposites. It was indicated that intensity and toughness was increased by the exfoliation of organ clays in epoxy resin, and the heat-resistant property was also increased significantly. When the content of the organ clay was 2 wt %, the properties of exfoliated composite reached the optimum.Lastly, the curing reaction kinetics of E-51 and DK2 cured by 2-ethyl-4-methyl imidazole (M-Q) was investigated by DSC. The curing technical parameters werederived; it was found that the curing temperature of composite was descended by DK2. Synchronously the. activation energy of DK2 / EP / M-Q calculated by Kissinger equation and Crane equation was lower than the activation energy of EP / M-Q. Acid catalysis mechanism model of DK2 to epoxy curing was elementarily set up, thevelocity equation of this curing reaction was obtained: . Thedtmechanism model was validated by isothermal DSC experiments , the activation energy calculated was decreased by the content of DK2 increased , Ea of pure epoxy/ M-Q was 79.92 kJ/mol , and Ea of 15 % DK2 / EP / M-Q was 51.95 kJ/mol ,above judgment was testified .On the basis of the above researches on the exfoliation and dispersedness of MMT, properties and the curing reaction kinetics, an approach that using chemical reaction in the tiny intra-gallery to dis-coalesce the nano-reunite was proposed to explain the immanence driving force of the exfoliation of MMT both in nano-layered silicates and in nanoparticles .更多还原