Modified POSS Polymers for Stone Conservation

这项科学研究的智力价值在于开发了用于结石固结的聚合物的实用合成，这种聚合物具有与天然石材相似的“纳米到宏观”长度尺度。通过利用纳米尺度(POSS，1 nm-10 nm)和宏观尺度(聚合物)，在保存和固结系统中，可以实现长度尺度和性质与天然石材的延续，从而增强石材。POSS硅烷醇显示出与大量化合物配位的能力；然而，人们对它们与天然石材表面的相互作用知之甚少。对于POSS硅烷醇，我们寻求对POSS-硅醇/石材界面相互作用的基本了解--这一理解可能导致高性能石材固化剂的设计--特别是对于最先进的溶胶凝胶剂失效的碳酸钙石材。使用POSS-硅醇/硫醇-X体系(其中X代表AN、(甲基)丙烯酸酯、乙烯基醚等)开发了一种新的结石固结方法。它可以作为液体单体树脂应用于石材(提高渗透深度)，并通过正面光聚合(FPP)进行固化。通过这种方法，PI试图开发POSS/硫醇-X材料的结构-性能关系，以便关键参数，即玻璃化转变温度、模数、热膨胀系数和折射率可以与特定的石材类型相匹配。POSS-硅醇对界面粘结的作用以及POSS/硫醇-X树脂对表面能、水蒸气传输和孔隙率的作用是基本重要的，并将被阐明。非技术摘要处理石材变质是一个复杂的过程，必须考虑石材的成分和结构、聚合处理的性质、石材与处理的相互作用以及石材处理对非均质基质的长期影响。这项工作的目的是开发一种基于POSS-硅醇聚合物系统的先进的石材保护方法，旨在改善石材的固结和防水性能。这项研究的社会影响将从发展对聚合物与石材表面相互作用的基本了解到最终实现新材料技术来保护美国的文化遗产。该项目的跨学科性质将为聚合物科学研究生和本科生提供一个独特的机会，让他们体验与1)纳米材料(混合塑料)行业领先者和2)美国国家公园管理局内唯一的保存研究和技术中心(国家保存与培训技术中心，NCPTT)的直接互动和合作。一项重要的外展和传播计划涉及针对文化遗产项目保护的K-12亲身聚合物科学活动，以及开发网络研讨会/播客，以提高对保护科学家面临的重大挑战的认识，并传播这项研究的成果。

TECHNICAL ABSTRACTThe intellectual merit of this SCIART research is in developing practical syntheses of polymers for stone consolidation that possess "nano-to-macro" length scales similar to that of natural stone. By utilizing both nano (POSS, 1nm-10nm) and macroscopic length (polymer) scales in a conservation and consolidation system, a continuation of length scale and properties with those in natural stone can be achieved thus strengthening the stone. POSS silanols show the ability to coordinate a large number of chemical compounds; however their interaction with natural stone surfaces is poorly understood. For POSS silanols, we seek a fundamental understanding of the POSS-silanol/stone interfacial interactions -- an understanding that may lead to the design of high performance stone consolidants -- particularly for calcium carbonate stones where state-of-the-art sol-gels fail. A novel approach to stone consolidation is developed using POSS-silanol/thiol-X systems (where X represents an -ene, (meth)acrylates, vinyl ethers, etc.) which can be applied to stone as liquid monomer resins (improving depth of penetration) and cured via frontal photopolymerization (FPP). From this approach, the PIs seek to develop structure-property relationships of the POSS/thiol-X materials such that critical parameters, i.e. the glass transition temperature, modulus, CTE, and index of refraction can be matched to a particular stone type. The role of POSS-silanol on interfacial adhesion and POSS/thiol-X resins on surface energy, water vapor transport, and porosity are of fundamental importance and will be elucidated.NON-TECHNICAL ABSTRACT Treatment of stone deterioration is a complex process that must take into consideration the stone composition and structure, the nature of the polymeric treatment, the interaction between stone and treatment, and the long term effects on the heterogeneous matrix created by the treatment on stone. It is the aim of this work to develop an advanced stone conservation approach based on POSS-silanol polymer systems designed to improve stone consolidation and water repellency.The societal implications of the research will range from the development of fundamental understanding of polymer interactions with stone surfaces to the ultimate realization of new materials technology for the conservation of America's cultural heritage. The interdisciplinary nature of this project will provide a unique opportunity for graduate and undergraduate polymer science students to experience direct interaction and collaboration with 1) an industrial leader in nanomaterials (Hybrid Plastics) and 2) the only preservation research and technology center (National Center for Preservation and Training Technology, NCPTT) within the U.S. National Park Service. A significant outreach and dissemination plan involves K-12 hands-on polymer science activities directed at conservation of cultural heritage items and the development of webinar/podcast to broaden awareness of the grand challenges facing conservation scientists and disseminate the results of this research.