Epoxy-Acrylate Hybrid Resin Systems: Photopolymerizations Outside the (Controlled Atmosphere) Box

JessopIntelligence优点：由自由基活性中心驱动的传播机制受到氧抑制的困扰。阳离子聚合方案会受到水分影响和固化速度较慢的影响。为了解决这些机制的局限性，杂化树脂系统被设计为使用阳离子和自由基机制的组合进行光聚合。(使用光而不是热引发聚合的优点包括显著节省能源成本、加工空间和时间；无溶剂系统；以及加强对引发物种生产的控制。)这些混合体系对氧气和水分的敏感性较低，并具有固化速度加快和成膜性能改善等优点。到目前为止，大多数研究都集中在这些体系的开发上；因此，有必要进行深入的研究，以创建基本的知识基础，使这些体系的影响和用途得到优化。本研究将研究基于同时包含环氧化物部分和丙烯酸酯部分的配方的杂化树脂体系，环氧化物部分经历阳离子开环光聚合，丙烯酸酯部分经历自由基光聚合。这项研究的目的是更好地了解实验变量如何影响这些体系(包括杂化单体和多单体体系)的大气敏感性，这反过来将促进杂化单体或体系在实际配方中的最佳加入。这一目标将通过以下方式实现：-确定改变杂化单体/体系中氧扩散影响区域的最具影响的因素。-表征杂化单体/体系中光引发剂体系之间的相互作用及其对动力学和物理性能的影响。-澄清水对杂化聚合物的动力学和物理性能的影响。-评估通过加入杂化单体/体系对丙烯酸酯和环氧化物配方的改进。将使用拉曼光谱和近红外光谱以及拉曼共聚焦显微镜来获得转化率、聚合速率和组成。将使用动态机械分析和表面硬度测试来将聚合物组成与物理性能相关联。这些动力学和物理信息的比较将有助于这些聚合物的反应设计，并将解决两个光聚合体系之间相互作用的重要问题。研究结果将有助于针对特定的最终用途定制树脂配方，特别是在薄膜、涂料和粘合剂中。广泛影响：这项研究可能会通过降低与抗氧抑制相关的成本、促进更快的反应、减少产品质量对湿度条件的依赖、提供更好的表面性能的聚合物，以及使薄膜能够在环境条件下生产，来影响光聚合行业。这一特征还将为生物医学、电信和航空航天工程领域的新应用提供增长机会。该项目还将对各级学生的教育体验产生直接影响。工程和科学专业的学生将从包含这些研究成果的聚合物科学系列课程中受益。几名本科生和高中教师和/或学生将被邀请参与这项研究的部分内容。该项目将引领爱荷华州通过暑期培训计划和学年课程向中学生和教师介绍工程概念。

0853411JessopIntellectual Merit: Propagation mechanisms that are driven by free-radical active centers are plagued by oxygen inhibition. Cationic polymerization schemes suffer from moisture effects and slower cure rates. To address the limitations of these mechanisms, hybrid resin systems have been designed to photopolymerize using a combination of cationic and free-radical mechanisms. (The advantages of using light to initiate polymerization rather than heat include significant savings in energy costs, processing space, and time; solvent-free systems; and increased control over the production of initiating species.) These hybrid systems exhibit lower sensitivity to oxygen and moisture and offer advantages such as increased cure speed and improved film-forming properties. To date, most studies have focused on the development of these systems; thus, there is a need for in-depth studies in order to create a fundamental base of knowledge that allows the impact and utility of these systems to be optimized.This research will investigate hybrid resin systems based on formulations that contain both an epoxide moiety, which undergoes cationic ring-opening photopolymerization, and an acrylate moiety, which undergoes free-radical photopolymerization. The goal of this research is to acquire a better understanding of how experimental variables affect the atmospheric sensitivity of these systems (both hybrid monomers and multi-monomer systems), which in turn will facilitate the optimal incorporation of hybrid monomers or systems in practical formulations. This goal will be accomplished by:- Determining the most influential factors in altering the oxygen-diffusion-affected region in hybrid monomers/systems.- Characterizing the interplay between photoinitiator systems in hybrid monomers/systems and their effects on kinetics and physical properties.- Clarifying the effect of water on the kinetics and physical properties of hybrid polymers.- Evaluating improvements made in acrylate and epoxide formulations by the incorporation of hybrid monomers/systems.Conversion, rate of polymerization, and composition will be obtained using Raman and near-infrared spectroscopies and Raman confocal microscopy. Dynamic mechanical analysis and surface hardness testing will be used to correlate polymer composition with physical properties. Comparisons of this kinetic and physical information will aid in reaction design for these polymers and will address important issues on the interactions between the two photopolymerization systems. Results will provide insight for tailoring resin formulations to specific end-use applications, especially in films, coatings, and adhesives.Broader Impacts: This research could impact the photopolymerization industries by decreasing costs associated with combating oxygen inhibition, facilitating faster reactions, decreasing the dependence of product quality upon humidity conditions, providing polymers with better surface properties, and enabling the production of thin films at ambient conditions. This characterization will also provide opportunities for growth of new applications in the fields of biomedicine, telecommunications, and aerospace engineering. The project will also have a direct impact on the educational experience of students at various levels. Students in engineering and science will benefit from a polymer science course series that will incorporate these research results. Several undergraduate students and high-school teachers and/or students will be invited to participate in portions of this research. Project Lead the Way Iowa will introduce secondary students and teachers to engineering concepts through a summer training program and academic-year classes.