Design, Characterization, and Evaluation of Elastomeric Materials

弹性体材料的设计、表征和评估

• 批准号: 9422223
• 负责人: James Mark
• 金额: $ 62.75万
• 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: 1995
• 资助国家: 美国
• 起止时间: 1995-01-15 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9422223&HistoricalAwards=false
• 关键词: Design; Characterization; Evaluation; Elastomeric; Materials

9422223 Mark End linking of functionally-terminated polymer chains will be used to obtain elastomers of known and controlled structures. Some will contain dangling-chain irregularities, and others unimodal and multimodal distributions of network chain-lengths. Included will be trimodal networks and unusually broad pseudo-unimodal networks obtained by combining separately-prepared batches of polysiloxanes of widely varying molecular weights. Additional elastomers will be produced under conditions giviing structures that are unusual in other respects, for example by cross linking in solution or in a state of strain. Experiments will be performed for identifying strain-induced crystallization, in elongation, biaxial extension, shear, and torsion. Simulations will also be carried out to characterize the crystallization occurring in some new polysiloxane chains of unusually high stereoregularity. Elastomeric gels will also be studied, including some involved in processing techniques giving liquid-crystalline polymers of enhanced orientation. Gelation kinetics will be studied, as will diffusion coefficients of solvents into and out of swollen networks. Novel reinforcing fillers will be prepared by the hydrolysis, photolysis, or thermolysis of organometallic materials such as silicates, titanates, zirconates, aluminates, 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. The resulting filler-reinforced elastomers will be characterized primarily by mechanical property measurements, electron microsocpy, and by X-ray and neutron scattering. Simulations will also be carried to elucidate reinforcing mechanisms in filler-reinforced elastomers in general. Finally, experiments will be carried out to exploit the ability of elastomeric domains to improve the impact resistance of polymer-ceramic hybrid composites in which the cer amic is the continuous phase. %%% The primary significance of these projects is the achievement of a better molecular understanding of rubberlike elasticity and the ways in which fillers reinforce elastomers. The results should provide importance guidance for producing elastomeric materials and elastomeric- modified ceramics having unusaully attractive mechanical properties.

官能封端的聚合物链的Mark End连接将用于获得已知和受控结构的弹性体。 有些将包含悬挂链的不规则性，和其他单峰和多峰分布的网络链的长度。 包括三峰网络和通过组合单独制备的分子量变化很大的聚硅氧烷批次获得的异常宽的假单峰网络。 另外的弹性体将在产生在其他方面不寻常的结构的条件下生产，例如通过在溶液中或在应变状态下交联。 将进行实验，以确定应变诱导结晶，在伸长率，双轴拉伸，剪切和扭转。 模拟也将进行表征的结晶发生在一些新的聚硅氧烷链异常高的立构规整性。 还将研究弹性体凝胶，包括一些涉及加工技术，使液晶聚合物的增强取向。 将研究甘精胰岛素动力学，以及溶剂进出溶胀网络的扩散系数。 新型增强填料将通过有机金属材料如硅酸盐、钛酸盐、锆酸盐、铝酸盐和简单金属盐如氯化铁的水解、光解或热解来制备。 特别重要的是确定最大化增强的颗粒尺寸，并表征颗粒形状的影响。 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、X射线和中子散射。 还将进行模拟，以阐明一般的填料增强弹性体的增强机制。 最后，将进行实验，以利用弹性域的能力，以提高聚合物-陶瓷混杂复合材料的耐冲击性，其中陶瓷是连续相。 这些项目的主要意义是实现更好的分子理解橡胶类弹性和填料增强弹性体的方式。 研究结果对生产具有特殊力学性能的弹性体材料和弹性体改性陶瓷具有重要的指导意义。