以水性聚氨酯体系制备聚氨酯/蒙脱土纳米混杂材料

【作者】 韩朝晖；

【导师】 余鼎声；

【作者基本信息】 北京化工大学 ， 材料学， 2000， 硕士

【摘要】 聚合物基复合材料把无机物的高模量、尺寸稳定性以及光、电等特性与高分子材料的韧性、易加工性、电绝缘性巧妙地结合起来。在许多方面都表现出优异的性能。为进一步增加复合材料中各组分之间的相互作用，希望将一个或多个组分以纳米尺寸均匀分散在另一组分的基体中，得到了混杂材料。其性能比相应的常规复合材料有了较大的改善，甚至表现出全新的性质。 聚氨酯是一种发展迅速的多功能高分子合成材料，但迄今国内尚无关于制备聚氨酯／蒙脱土混杂复合材料的研究。国外虽然有介于大分子插入和小分子原位聚合插入来制备聚氨酯／蒙脱土混杂复合材料的研究，但该方法反应过程中由于大量使用溶剂，容易对环境造成污染，而且回收溶剂成本也较高。本文则采用水性聚氨酯乳液以水为分散介质，具有对环境无污染、不燃、成本低等特点，结合本实验室多年来从事原位聚合法、溶液大分子插入法、熔融大分子插入法制备聚合物／蒙脱土混杂材料研究的基础上，采用乳液共混-共凝的方法来提出一种制备聚氨酯／蒙脱土混杂复合材料的新技术。 为制备混杂材料，本文首先通过自乳化聚合制备了阴离子型水性聚氯酯基础乳液，着重研究了以二羟甲基丙酸为离子源合成阴离子型的水性聚氨酯乳液的制备过程，详细讨论制备过程中各种影响因素，包括多元醇种类及分子量、NCO／OH投料比、亲水基团含量、固含量及低分子二元醇类扩链剂等对水性聚氨酯乳液性能的影响。在此基础上，选择适宜制备混杂材料的基础乳液体系，利用蒙脱土层间阳离子的水化作用，使蒙脱土的晶层结构在水中发生分离，蒙脱土的水分散体与聚氨酯基础乳液均匀混合，蒙脱土的晶层和聚氨酯乳液的乳胶粒相互穿插，利用带有碱性侧基的聚氨酯乳液，在用酸絮凝时使聚氨酯带上正电侧基，带正电聚合物能够与带负电的蒙脱土晶层产生强烈的静电作用，共絮凝制备了聚氨酯／蒙脱土混杂复合材料。本文采用XRD、TEM、DSC、FT-IR等多种实验手段对混杂材料的制备、相态结构、热性质和材料的力学性能进行了表征和测试。结果表明，蒙脱土晶层均匀分散于聚氨酯基体中，达到了纳米级分散，能够起到良好的补强作用。更多还原

【Abstract】 Polymer based composites combined the good process property, electrical insulation and toughness of polymer with the properties of inorganic materials, such as high module, good dimension stability. To increase the interfacial action among the components in the components, the dispersion dimension which would be nanometer level or molecule level was desired, so the hybrids would be prepared. The properties of hybrids were improved greatly for the fine dispersion structure and strong interfacial interaction, while they owned some new special properties.Polyurethane is a multifunctional synthesis material. But there are still no reports about the research on polyurethane/ montmorllonite hybrids using aqueous polyurethane emulsion. The aqueous polyurethane emulsion uses water as solvent, so this polyurethane is superior not only in strength, tactile sensitivity to the wearer, but also in oil-resistance, flexibility, feeling and a relative low cost to the conventional polyurethane. By intercalating hydrophilic group COOH, the self-emulsifying polyurethane was prepared. The preparation process is well discussed and many effects such as hydrophilic group content, solid content and different chain-extenders on polyurethane emulsions are well studied.So based on the aqueous polyurethane emulsion we prepared and those polymer/ montmorllonite hybrids which were prepared through in situ polymerization, solution intercalation and melting intercalation, a new method named "latex blending and coagulating" was firstly put forward. Montmorllonite could be dispersed uniformly in water for the hydration of the action between the layers. The layers could be separated from each other to form a colloid and the layer would penetrate with the latex particle. The aqueous polyurethane emulsion was prepared and selected by means of molecule design. When the latex blended with the montmorllonite -water dispersion, a suspension could be formed. It could be coagulated by the diluted hydrochloric acid, and then the hybrids were prepared,which had strong interfacial action between the polymer and the clay layers by the ion bond. A new hybrid Polyurethane/ montmorllonite was prepared and characterized with XRD, TEM, DSC and FT-IR. The preparation process, morphology and their thermal and mechanical properties were studied. The results indicate that the montmorllonite could be used as a good reinforcing agent for polyurethane when layer was dispersed in nanometer level, and the hybrids’ mechanical properties were improved.更多还原