Some Modern Aspects of Elastomer Science and Technology

该研究提出的一个实际目标是获得可用于优化弹性体材料性能的结构-性能关系。例如，各种弹性体材料在伸长率、双轴延伸、剪切和扭转方面的应力-应变结果将使用基于缠结约束网络结的分析理论和计算机模拟来解释。弹性体将包括商业上重要的聚合物，通过工业中使用的一些相对不受控制的技术进行交联，但也包括一些制备具有不寻常的双峰链长分布的弹性体，通过末端连接功能终止的聚合物链来提高最终性能。附加弹性体将在具有一些特殊优势的结构条件下产生，例如在溶液中或在应变状态下通过交联。在这些材料上进行的特别有趣的实验将是应力应变测量，以确定最大的延展性和韧性。弹性凝胶将用于生产具有增强取向和改善机械性能的可生物降解薄膜。第二个主要主题涉及弹性体的应变诱导结晶，伸长率，但也包括几个重要的变形，其结果几乎完全缺乏。一些分析理论和计算机模拟将在并行研究中进行。新型增强填料如二氧化硅将通过水解前驱体如有机硅酸盐和简单金属盐如氯化铁在原位生成。特别重要的是确定最大限度增强的颗粒大小，并描述颗粒形状和非球形颗粒方向的影响。新型材料将通过用另一种类型的陶瓷涂覆一种类型的颗粒来制备。还可以通过增强沸石来编织弹性链。所得到的填充增强弹性体将主要通过机械性能测量、电子显微镜、x射线和中子散射以及脉冲传播测量来表征。模拟也将进行阐明在一般填充弹性体的增强机制。最后，将进行实验，以利用弹性畴提高陶瓷为连续相的聚合物-陶瓷杂化复合材料的抗冲击性。这里特别感兴趣的是通过在一个相中使用网络结构的连通性来“挫败”不同双组分系统中通常类型的相分离来控制色散水平。提案中描述了更广泛的影响，包括开发一个弹性体和橡胶样弹性模块，用于在“移动实验室”中部署，为辛辛那提的K-12学生提供科学和工程演示和实验。三个“温尼贝戈”大小的大型移动教室正在配备，每个教室都将配备必要的设备，让学生有机会进行比通常在典型的K-12场所可能进行的更高级的实验。

One practical goal of the research proposed is to obtain structure-property relationships that can be used to optimize the properties of elastomeric materials. For example, stress-strain results on a variety of elastomeric materials in elongation, biaxial extension, shear, and torsion will be interpreted using both analytical theories based on entanglement-constrained network junctions, and computer simulations. Elastomers will include both commercially important polymers cross linked by some of the relatively uncontrolled techniques used in the industry, but also some elastomers prepared to have unusual bimodal chain-length distributions that improve ultimate properties by end linking functionally-terminated polymer chains. Additional elastomers will be produced under conditions giving structures that have some unusual advantages, for example by cross linking in solution or in a state of strain. Experiments on these materials that are of particular interest will be stress-strain measurements for identifying maximum extensibilities and toughness. Elastomeric gels will be used to produce biodegradable films of enhanced orientation and improved mechanical properties. The second major topic involves strain-induced crystallization in elastomers, in elongation, but also in several important deformations in which results are almost entirely lacking. Some analytical theory and computer simulations will be carried out in parallel investigations. Novel reinforcing fillers such as silica will be generated in-situ by hydrolyses of precursors such as organosilicates, and simple metal salts such as ferric chloride. Of particular importance will be identifying the particle size that maximizes reinforcement, and characterizing the effects of particle shape and the orientations of non-spherical particles. Novel materials will be prepared by coating particles of one type with a ceramic of another type. It will also be possible to thread elastomeric chains through reinforcing zeolites. The resulting filler-reinforced elastomers will be characterized primarily by mechanical property measurements, electron microscopy, X-ray and neutron scattering, and pulse-propagation measurements. Simulations will also be carried out to elucidate reinforcing mechanisms in filled elastomers in general. As a final topic, experiments will be carried out to exploit the ability of elastomeric domains to improve the impact resistances of polymer-ceramic hybrid composites in which the ceramic is the continuous phase. Of particular interest here is control of the level of dispersion by using the connectivity of networks structures in one of the phases to "frustrate" the usual types of phase separation in disparate two-component systems.Broader impacts, described within the proposal, include developing a module on elastomers and rubberlike elasticity for deployment in a "Mobile Laboratory" to bring science and engineering demonstrations and experiments to K-12 students in Cincinnati. Three large "Winnebago" sized mobile classrooms are being outfitted, and each will be stocked with the equipment necessary to allow students the opportunity to carry out more advanced experiments than usually possible in typical K-12 venues.