Syntheses, Structures, Properties, and Applications of Some Novel Elastomers

一些新型弹性体的合成、结构、性能和应用

• 批准号: 0075198
• 负责人: James Mark
• 金额: $ 40.5万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0075198&HistoricalAwards=false
• 关键词: Syntheses; Structures; Properties; Applications; Some

The basic goal of this program 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 using more selective reactions designed to give networks of better known structure. Such tailor-made networks will be prepared by end linking functionally-terminated polymer chains, an approach that can also be used to synthesize unusual networks with multimodal network chain-length distributions. These results should give a much better molecular understanding of rubberlike elasticity, and provide guidance in the design of materials of unusually attractive mechanical properties. Experiments on these materials that are of particular interest will be stress-strain measurements for identifying maximum extensibilities and toughness. 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 maximized reinforcement, and characterizing the effects of 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 the thread elastomeric chains through reinforcing zeolites, and to prepare fillers that can be manipulated by a magnetic field. The resulting filler-reinforced elastomers will be characterized primarily by mechanical property measurements, electron microscopy, and by X-ray and neutron scattering. Two newer approaches which already show considerable promise are pulse-propagation measurements and Brillouin spectroscopy.This project is focused on learning how the structures of elastomeric materials can be controlled in order to maximize their mechanical properties. The most important structural features are the chemical natures of the elastomers and how they are linked into networks, and the most important properties are their strengths, extensibilities, and toughness. The approaches taken are primarily experimental, but will be guided by parallel computer simulations and analytical theory.

该程序的基本目标是获得结构-性能关系，可用于优化弹性体材料的性能。 例如，应力-应变结果的各种弹性体材料的伸长率，双轴拉伸，剪切和扭转将解释使用两个分析理论的基础上纠缠约束网络连接，和计算机模拟。 弹性体将包括通过工业中使用的一些相对不受控制的技术交联的商业上重要的聚合物，但也包括使用设计为提供更好已知结构的网络的更选择性反应制备的一些弹性体。 这种定制的网络将通过末端连接功能终止的聚合物链来制备，这种方法也可以用于合成具有多峰网络链长分布的不寻常网络。 这些结果应该给一个更好的分子理解橡胶样的弹性，并提供指导，在设计材料的异常有吸引力的机械性能。 对这些材料的实验是特别感兴趣的，将是确定最大延伸率和韧性的应力-应变测量。 新型增强填料如二氧化硅将通过前体如有机硅酸盐和简单金属盐如氯化铁的水解原位产生。 特别重要的是确定使增强最大化的粒度，表征使增强最大化的粒度的效果，以及表征颗粒形状和非球形颗粒取向的效果。 新型材料将通过用一种类型的陶瓷涂覆另一种类型的颗粒来制备。 还可以将弹性体链穿过增强沸石，并制备可以通过磁场操纵的填料。 所得填料增强弹性体的特征主要在于机械性能测量，电子显微镜，并通过X射线和中子散射。 两种新的方法已经显示出相当大的前景是脉冲传播测量和布里渊光谱。该项目的重点是学习如何控制弹性体材料的结构，以最大限度地提高其机械性能。 最重要的结构特征是弹性体的化学性质以及它们如何连接成网络，最重要的性能是它们的强度、延伸率和韧性。 所采取的方法主要是实验性的，但将由并行计算机模拟和分析理论指导。