GOALI: Advanced Thiol-Ene Photopolymerizations

摘要：作者：Christopher Bowman和John Woods机构：科罗拉多大学提案号：0626023标题：目标ali：先进的巯基烯光聚合项目摘要光聚合是一种快速扩展的材料生产工艺，在一个数十亿美元的行业中，年增长率超过20%，被广泛应用于各个领域。工业越来越多地转向光聚合，因为这些反应提供了聚合物涂层的极快，无溶剂固化。这种反应比热反应更节能，而且在空间和时间上控制聚合物形成的能力使得环境固化和光刻技术得以发展。由于它们的优点，这些系统被广泛应用于从生物医学植入物到印刷应用、光刻工艺到高科技涂料等行业。尽管光聚合具有广泛的适用性，但传统的（甲基）丙烯酸酯基自由基光聚合工艺受到一系列缺点的限制，包括氧抑制、残留、未反应单体的存在、固化缓慢以及聚合引起的收缩和收缩应力的发展。这些限制都有可能通过巯基型光聚合反应得到解决。巯基烯光聚合代表了光聚合机理的一个根本转变，其中反应通过交替的传播和链转移反应进行。这种行为导致了网络的逐步生长进化，该网络具有显著的优势，涉及延迟凝胶化，有限的可提取物，克服氧抑制，减少收缩和收缩应力。由于缺乏了解和缺乏适当的、商业上可用的材料，硫烯聚合本身受到限制。该项目是科罗拉多大学和汉高公司合作开发的硫醇烯光聚合。研究将集中于硫醇基和烯基单体的合成和分析，这将改善高模量、高玻璃化转变温度材料的形成。除了合成新的高功能单体外，第二个目标涉及到多组分硫醇烯光聚合的发展。由于巯基烯的阶梯生长特性，其聚合过程中明显的延迟凝胶化导致了低应力涂层和薄膜；然而，在多组分聚合中，凝胶化的进一步延迟会导致收缩应力的增强降低。总的来说，这些发展将为一系列需要高玻璃化转变温度和/或低收缩应力材料的应用提供一种可行的基于光聚合的替代方案。这些目标都将与汉高的科学家和工程师合作完成，他们将评估合成方法的商业可行性，新形成材料的特性以及这些系统在各种商业应用中的潜力。广泛的影响这里开发的技术有潜力扩大光聚合物在各种工艺中的应用范围，如纳米压印步骤和闪光光刻，牙科修复剂，粘合剂和高科技涂层都将从这些发展中显著受益。此外，这个项目将直接影响学生，包括研究生和一系列本科生。

ABSTRACTPI: Christopher Bowman and John Woods Institution: University of ColoradoProposal Number: 0626023Title: GOALI: Advanced Thiol-Ene PhotopolymerizationsProject SummaryPhotopolymerization is a rapidly expanding processes for materials production, with more than 20% annual growth in a multibillion dollar industry that is utilized in a broad range of fields. Industry has increasingly turned to photopolymerizations because these reactions provide for extremely rapid, solvent-free curing of polymer coatings. The reactions are more energy efficient than their thermal counterparts and the ability to control polymer formation spatially and temporally has enabled facile ambient curing and photolithographic technologies to be developed. Because of their advantages, these systems are being utilized or explored in industries that range broadly from biomedical implants to printing applications to photolithographic processes to high technology coatings. Despite the broad applicability of photopolymerizations, the traditional (meth)acrylate-based free radical photopolymerization process is limited by an array of drawbacks that include oxygen inhibition, the presence of residual, unreacted monomer, slow curing, and polymerization induced shrinkage and shrinkage stress development. These limitations are all potentially solved by the utilization of thiol-ene-type photopolymerization reactions.The thiol-ene photopolymerization represents a fundamental shift in the mechanism ofphotopolymerizations in which the reaction proceeds via alternating propagation and chain transfer reactions. This behavior leads to a step growth evolution of the network that is radically mediated with significant advantages related to delayed gelation, limited extractables, overcoming oxygen inhibition, and reduced shrinkage and shrinkage stress. The thiol-ene polymerization itself has been limited by a lack of understanding and a lack of appropriate, commercially available materials. This project is a collaboration between the University of Colorado and Henkel Corporation for the development of thiol-ene photopolymerizations.The research will focus on synthesis and analysis of thiol and ene-based monomers, which will improve the formation of high modulus, high glass transition temperature materials. In addition to synthesizing new, highly functional monomers, a second goal relates to the development of multicomponent thiol-ene photopolymerizations. The delayed gelation apparent in thiol-ene polymerizations because of their step growth characteristic leads to low stress coatings and films; however, further delays in gelation that lead to enhanced reductions in the shrinkage stress will be achieved in multicomponent polymerizations. These developments, in total, will have impact by providing a viable photopolymerization-based alternative to a range of applications that require high glass transition temperature and/or low shrinkage stress materials. Each of these objectives will be accomplished in collaboration with scientists and engineers at Henkel who will evaluate the commercial feasibility of the synthetic approaches, the properties of the newly formed materials, and the potential for these systems in various commercial applications.Broad ImpactThe technologies developed here have the potential for expanding the range of photopolymer applications in processes as varied as nanoimprint step and flash lithography, dental restoratives, adhesives and high technology coatings will all benefit significantly from these developments. Also, this project will directly impact students including graduate and a range of undergraduate students.