Some Modern Aspects of Elastomer Science and Technology

这项研究的一个实际目标是获得可用于优化弹性材料性能的结构-性能关系。例如，各种弹性材料在拉伸、双向拉伸、剪切和扭转方面的应力-应变结果将使用基于纠缠约束网络连接的分析理论和计算机模拟来解释。弹性体将既包括通过行业中使用的一些相对不受控制的技术进行交联的具有商业重要性的聚合物，也包括一些准备具有不寻常的双峰链长分布的弹性体，这些分布通过末端连接官能化端基聚合物链来改善最终性能。在具有某些特殊优点的结构的条件下，例如通过在溶液中或在应变状态下进行交联会产生额外的弹性体。对这些材料特别感兴趣的实验将是确定最大延伸率和韧性的应力-应变测量。弹性凝胶将用于生产具有更强取向和更好机械性能的生物可降解薄膜。第二个主要话题涉及弹性体中的应变诱导结晶，伸长，但也有几个重要的变形，其中几乎完全缺乏结果。一些分析理论和计算机模拟将在并行研究中进行。新型的增强填充剂，如二氧化硅，将通过有机硅酸盐等前体和简单金属盐(如三氯化铁)的水解原位生成。尤其重要的是确定最大化增强的颗粒大小，并表征颗粒形状和非球形颗粒取向的影响。通过将一种类型的颗粒与另一种类型的陶瓷包覆来制备新型材料。还可以通过增强沸石来穿线弹性体链条。最终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。还将进行模拟，以阐明填充弹性体中的增强机制。作为最后一个主题，将进行实验，以开发弹性域的能力，以提高聚合物-陶瓷混杂复合材料的冲击性能，其中陶瓷是连续相。这里特别令人感兴趣的是，通过使用其中一个阶段中网络结构的连通性来控制分散程度，以“挫败”不同两组分系统中常见的相分离类型。提案中描述的广泛影响包括开发一个关于弹性体和橡胶状弹性的模块，用于部署在“移动实验室”中，为辛辛那提的K-12学生带来科学和工程演示和实验。正在配备三个大型的“Winnebago”大小的移动教室，每个教室都将配备必要的设备，使学生有机会进行比典型的K-12场馆通常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.