基于物理机械互锁结构的有机/无机牙科复合树脂制备及其结构性能研究

Dental resin composites are critical hard tissue substitutes to restore dental caries. However, the restoration fracture is the main cause for failure due to the insufficient mechanical properties of dental composites. Building of the micromechanical interlocking between porous fillers and organic matrix is the best way to resolve this problem, from a point of view of the interfacial bonding. In this project, spherical porous fillers with controllable morphology and structure and “porous and nonporous” multimodal fillers are prepared based on the self-assembly in microemulsions and the close-packed structures. The effect of the microemulsion phase behavior on the morphology and structure of porous fillers will be studied. Dental composites can be then fabricated under complex external fields and photo-polymerization, with the free radical polymerizable monomers as the organic matrix. During the forming process and the polymerization of dental composites, the revolution process of micromechanical interlocking and the distribution of multimodal fillers under complex external fields will be investigated in detail. The analysis of filler packing structures from theory to practice will be conducted. The rheology behavior, the interfacial bonding, and the mechanical properties of dental composites will also be studied. Finally, the relationship of structure and properties of dental composites will be obtained. This project will offer theoretical basis and technical support for the development of dental composites with high performance.

牙科复合树脂是龋病治疗的重要材料。针对复合树脂力学性能不足而造成修复体断裂的问题，本项目拟从有机与无机相界面出发，利用多孔填料与有机基体间形成的物理机械互锁结构，可以提高复合树脂界面性能的特点，结合微乳液自组装和等球体最紧密堆积理论，制备具有可控形貌和孔结构的球形多孔填料，用其构建“多孔+无孔”多级填料，探索微乳液相行为对多孔填料形态结构的影响规律并进行结构表征；进一步，以可自由基聚合的单体为有机基体，通过复杂外场和光致交联制备复合树脂，跟踪复合树脂成形及聚合过程，揭示物理机械互锁结构及多级填料分布状态在复杂外场下的演变规律；对比复合树脂中多级填料的理论堆积结构与实际堆积结果的差异；研究复合树脂流变行为、界面性能及力学性能，阐明微观结构与宏观性能的构效关系。通过本研究的实施，为研发适宜于龋病治疗的高性能复合树脂材料奠定理论基础和提供技术支持。

牙科复合树脂是龋病治疗的重要材料。针对复合树脂力学性能不足而造成修复体断裂的问题，本项目从基体与填料界面角度出发，利用多孔球形填料与有机基体间形成的物理机械互锁结构提高复合树脂界面性能。首先，通过改变微乳液体系中硅源、模板剂的结构及用量，精确调控球形多孔SiO2 (dendritic porous silica，DPS) 的粒径 (75-1000 nm) 和孔结构 (平均孔径：7.0-24.6 nm)；DPS粒子的可控合成遵循成核-生长机制。其次，基于等球体最紧密堆积结构，理论计算了填充于初级填料四面体空隙、八面体空隙中二级球型粒子的最大尺寸，成功构筑了多级填料体系。结果表明，二级填料的加入可有效改善复合树脂的力学强度，其中当两种二级粒子共同使用时对复合树脂具有最佳的增强效果，其弯曲强度、弯曲模量和压缩强度分别为192.3 ± 26.5 MPa、16.2 ± 3.5 GPa和402.8 ± 47.4 MPa，相较于DPS-pen单填料充填树脂分别提高了46.7、107.7和14.3%。最后，以甲基丙烯酸酯基类单体为有机基体，通过剪切应力等外场和光致交联制备复合树脂，研究了物理机械互锁结构的变化规律、树脂-填料的界面相互作用以及微观结构与宏观性能的构效关系。结果表明，在外力场作用下，树脂基体更易被引入到DPS填料的孔结构中，进而在光固化聚合过程中，填料与树脂之间形成类似“十字绣”结构的微观机械嵌合作用，提高界面结合力。因此，该类树脂可以承受更多的应力，并阻止裂纹的延伸和扩展，提高树脂的力学性能。上述研究工作为龋病治疗用高性能复合树脂的研发提供了理论基础和技术支持。