Applications of Polymerization-induced Phase Separation of Restorative Materials

描述（由申请人提供）：1999年，美国的患者接受了85，788，400例复合治疗，并且数量还在继续增加。牙科复合材料修复代表了最普遍的生物材料暴露，旨在恢复替代组织的形式和功能。因此，这些广泛使用的材料的进一步改进将对医疗保健产生相当大的影响。虽然目前的材料通常是好的，但牙科复合材料仍然存在限制其实用性和性能的缺陷。这些问题包括：相对低的转化率导致可浸出的单体，其沿着吸水，提供机械性能随时间的下降;缺乏韧性;和最显著的是，引起应力的过度聚合收缩。与聚合相关的收缩和应力意味着不能可靠地实现完整的修复边缘。所有这些问题使安装复杂化，并限制了它们的使用寿命。在这个项目中，我们通过聚合物材料的固有多功能性来解决这些问题，这些多功能性允许控制异质结构的形成。聚合诱导的相分离将用于产生具有高转化率、改善的韧性并且特别地具有最小应力发展的纳米至微米尺度的非均相聚合物材料，这是由于该方法特有的后期收缩恢复。该研究计划提供了（i）形成非均相聚合物的全甲基丙烯酸酯树脂组合物，（ii）通过应用于具有不同反应性官能团的单体的混合物的同时的自由基和阳离子光聚合方法获得的非均相互穿聚合物网络的受控形成，和（iii）引入用于增强填料的新型表面处理，其在基于相分离树脂的复合材料中提供互补的额外定制界面。所提出的程序将清楚地描绘出有效的控制参数，可以用来操纵聚合诱导相分离过程，以生产低收缩和低应力的聚合物材料，相对于传统的均质材料具有改善的强度，耐久性和韧性。这些得到的复合制剂将适合作为下一代改进的牙科清洁剂。这项研究将推进对复杂聚合物系统的基本理解，同时提供修复材料的短期和中期临床益处。

DESCRIPTION (provided by applicant): In 1999, patients in the USA received 85,788,400 composite restorations and the numbers continue to rise. Dental composite restorations represent the most prevalent exposure to biomaterials designed to restore form and function of replaced tissues. As such, further improvements in these widely used materials will have a considerable health care impact. While current materials are generally good, dental composites still suffer from deficiencies that limit their utility and performance. These problems include: relatively low conversion leading to leachable monomer, which along with water uptake, provide a decline in mechanical properties over time; lack of toughness; and most significantly, excessive polymerization shrinkage that causes stress. Shrinkage and stress associated with polymerization mean that intact restored margins can not be achieved reliably. All these problems complicate the placement of restorations and limit their service life. In this project, we address these issues through the inherent versatility of polymeric materials that allows controlled formation of heterogeneous structures. Polymerization-induced phase separation will be used to create nano- to micro-scale heterogeneous polymeric materials with high conversion, improved toughness and notably, with minimal stress development due to a late-stage shrinkage recovery unique to this approach. The research plan provides for development of (i) all-methacrylate resin compositions that form heterogeneous polymers, (ii) controlled formation of heterogeneous interpenetrating polymer networks obtained by simultaneous free radical and cationic photopolymerization processes applied to mixtures of monomers with different reactive functional groups and (iii) introduction of novel surface treatments for reinforcing fillers that provide a complementary additional tailored interface in composite materials based on the phase-separating resins. The proposed program will clearly delineate the effective control parameters that can be used to manipulate the polymerization-induced phase separation process to produce low shrinkage and low stress polymeric materials with improved strength, durability and toughness relative to conventional homogeneous materials. These resulting composite formulations will be suitable as next generation, improved dental restoratives. This research will advance fundamental understanding of complex polymeric systems while providing short- and medium-term clinical benefits with restorative materials.