GOALI: Advanced Thiol-Ene Photopolymerizations

摘要：Christopher Bowman和John Woods研究所：科罗拉多大学提案编号：0626023标题：GOALI：高级硫醇-烯光聚合项目概述光聚合是一种快速发展的材料生产工艺，在一个数十亿美元的行业中，每年增长超过20%，用于广泛的领域。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其快速的、无溶剂的固化。 这些反应比它们的热反应更节能，并且在空间和时间上控制聚合物形成的能力使得能够开发出容易的环境固化和固化技术。 由于它们的优点，这些系统正在广泛地用于从生物医学植入到印刷应用到印刷工艺到高科技涂层的行业中。 尽管光聚合具有广泛的适用性，但传统的基于（甲基）丙烯酸酯的自由基光聚合方法受到一系列缺点的限制，这些缺点包括氧抑制、残留的未反应单体的存在、缓慢固化以及聚合诱导的收缩和收缩应力发展。 硫醇-烯型光聚合反应是光聚合反应机理的一个根本转变，它通过交替的链转移反应和链增长反应进行。 这种行为导致网络的逐步生长演变，其具有与延迟凝胶化、有限的可提取物、克服氧抑制以及降低的收缩和收缩应力相关的显著优点。 硫醇-烯聚合本身受到缺乏理解和缺乏适当的市售材料的限制。该项目是科罗拉多大学和汉高公司合作开发的硫醇-烯光聚合技术，研究重点是硫醇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，高功能的单体，第二个目标涉及多组分硫醇-烯光聚合的发展。 在硫醇-烯聚合中明显的延迟凝胶化，因为它们的逐步生长特性导致低应力涂层和膜;然而，在多组分聚合中将实现导致收缩应力增强降低的凝胶化的进一步延迟。 总的来说，这些发展将通过为需要高玻璃化转变温度和/或低收缩应力材料的一系列应用提供可行的基于光聚合的替代方案而产生影响。这些目标都将通过与汉高的科学家和工程师合作来实现，他们将评估合成方法的商业可行性、新形成材料的性能以及这些系统在各种商业应用中的潜力。广泛影响这里开发的技术有可能扩大光聚合物在纳米压印步骤和闪光光刻等各种工艺中的应用范围，牙科清洁剂、粘合剂和高技术涂料都将从这些发展中显著受益。此外，该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.