氢氧化镁等无机颗粒在有机聚合物中无机-有机表面能/极性适配性研究

Highly efficient utilization of natural resources has become a national strategy. Based on the fact that our domestic reserve of magnesium resources ranked top one in the world,this project focused on the matching problem of magnesium hydrate inorganic particles in organic polymer matix.Magnesium hydroxide,including brucite and those converted from hydromagnesite and/or magnesive, displays the marvelously potential future in the field of polymer fillers. However, the hydrophilicity, surface polarity and high loading level lead to the decrease of mechanical properties of polymer composites.This project proposed a novel strategy to control and adjust the mechanical properties of polymer composites based on the adaptation of surface free engergy theory. In detail, regularities on controlling the surface free energy and surface polarity of magnesium hydroxide particles and the dependent relationes between their surface free energy and dispersity in polymers would be systematically investigated. The bonding strength between the particles and adaptive molecules would also be examined. Furthermore, the relationship between molecular structure for proper surface free energy and mechanical properties of polymer composites would be detailedly analyzed. The mechanism on improvement of mechanical properties of polymer composites based on the adaptation and surface polarity could be also revealed in this proposal. This study would provide some experimental fundamentals for developing the interface interaction theory between inorganic and organic molecules and also brings the theoretical guideline for the value improvement of magnesium resources.

资源高效利用研究已成为国家战略。我国镁资源储量占世界第一，氢氧化镁等无机颗粒来源广泛，特性突出，在有机聚合物填料等方面显示出潜在发展空间。但因为这类无机颗粒的亲水疏油性、表面极性和较大添加量，导致添加后复合物力学性能显著下降等问题。本项目基于表面能等理论，在实验基础上提出用表面能适配性调控无机颗粒在有机聚合物中分散性，用表面极性适配及适配（改性）分子结构调控颗粒与聚合物结合强度，进而调控复合聚合物力学性能的思路。研究氢氧化镁颗粒表面能及表面极性调控规律、颗粒表面能和表面极性对其在聚合物中分散性及相互亲和性影响关系、颗粒表面与适配分子结合稳固性控制规律、无机-有机表面能/极性适配性及适配分子结构对复合聚合物力学性能调控关系等；揭示表面能、表面极性及适配分子结构等诸因素对复合聚合物力学性能提升机理。本研究为发展相界面上无机分子与有机分子相互作用理论提供实验依据；为提升镁资源价值提供理论指导。

氢氧化镁作为一种重要的阻燃材料在领域有着广泛应用。然而氢氧化镁具有较强极性，与有机基质表面极性差异极大，造成其在高分子基体中分散不均且结合力较弱，从而导致氢氧化镁的团聚和脱落，严重影响其应用性能。为了得到性能优异的氢氧化镁材料，通常要对其进行表面改性，但改性剂种类繁多，选取合适的改性剂工作量大，且没有合适的理论指导。本项目以水镁石为研究对象，通过对其进行表面改性来改变其表面能，将其作为添加剂应用到高聚物中，探索了改性剂结构与表面能的匹配关系以及表面能对水镁石-高聚物复合材料的力学性能的影响规律。结果表明，有机改性分子能明显改变水镁石的表面能，且表面能的变化与分子结构存在一定的构效关系：随着有机分子中烷基链碳数增加，水镁石的表面能先降低后趋于稳定，而复合材料的力学性能则表现出了升高后趋于稳定。作为对比研究，还对氢氧化铝颗粒进行了表面改性，得到了高性能的氢氧化铝-聚合物复合材料。此外，基于纳米工程技术将二氧化硅和硼酸锌等无机物原位包覆于水镁石颗粒表面，复合材料呈现出良好的力学性能和阻燃性能。本项目提出的表面能和表面极性适配理论为无机颗粒的表面改性提供了一定的理论基础。