Collaborative Research: Wetting Phenomena in Particle-Filled Polymers: Multifunctional Composites with Easy Processability

合作研究：颗粒填充聚合物中的润湿现象：易于加工的多功能复合材料

• 批准号: 1434674
• 负责人: Brian Young
• 金额: $ 6.88万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434674&HistoricalAwards=false
• 关键词: Collaborative; Research; Wetting; Phenomena; Particle

Fibers are often mixed into plastics to make them stiffer, stronger, or better electrical conductors. Yet such fiber-containing plastic composites are difficult to manufacture by standard molding or other processing. Furthermore, fibers often suffer damage during manufacturing. This project is to create a bridging system that converts particle fillers into a network of reformable fibers i.e. fibers that are capable of reassembling after breaking. Composites with such network can retain the initial design properties (such as high strength and toughness or high conductivity) without suffering property loss during processing. The Principle Investigators will conduct scientific outreach at pre-college level, especially at the Pittsburgh SciTech High School and two K-8 schools with high minority enrollment, to encourage students to pursue education in STEM disciplines.The specific hypothesis of this research is that composites containing a fiber-like labile filler can be realized by dispersing solid particles into a polymer matrix, and bridging them together by menisci of a wetting fluid. Since the menisci continuously break and reform during flow, the composites will have excellent processability. The properties of the resulting polymer composites may be tailored by suitable choice of filler, and this project will test fillers that realize composites with high stiffness, or high toughness, or high electrical conductivity. The hypothesis will be tested experimentally using polystyrene as the matrix plastic, and silica or metal particles as the particulate filler. Various thermoplastic materials will be used as the wetting phase that forms menisci between particles. Polystyrene, particles, and the wetting phase will be blended by a melt extrusion process optimized to realize meniscus-bridging of particles. Characterization includes tensile and impact testing, electrical conductivity measurements, and morphological studies by scanning electron microscopy. The intellectual significance of this project is to demonstrate that meniscus-bridging can be exploited to achieve materials with the processability of ordinary particle filled polymers, with the mechanical properties of fiber reinforced composites, or the electrical conductivity approaching metals. Furthermore, this project will advance the fundamental knowledge of capillary interactions in filled polymers.

纤维通常被掺入塑料中，以使其更坚硬、更坚固或更好地导电。然而，这种含纤维的塑料复合材料很难通过标准模塑或其他工艺制造。此外，纤维在制造过程中经常受到损害。该项目将创建一种桥接系统，将颗粒填充物转化为可变形纤维网络，即能够在断裂后重新组装的纤维。具有这种网络的复合材料可以保持最初的设计性能(如高强度和高韧性或高导电性)，而不会在加工过程中遭受性能损失。主要研究人员将在大学前的水平上进行科学推广，特别是在匹兹堡理工高中和两所少数民族入学率较高的K-8学校，以鼓励学生进行STEM学科的教育。本研究的具体假设是，含有纤维状不稳定填料的复合材料可以通过将固体颗粒分散到聚合物基质中，并通过润湿液体的半月板将它们连接在一起来实现。由于半月板在流动过程中不断断裂和重新生成，复合材料将具有良好的加工性能。通过选择合适的填料，可以定制聚合物复合材料的性能，本项目将测试实现高刚性、高韧性或高导电性的复合材料的填料。这一假设将以聚苯乙烯作为基质塑料，以二氧化硅或金属颗粒作为颗粒填充物进行实验验证。各种热塑性材料将被用来作为颗粒之间形成弯月面的润湿相。聚苯乙烯、粒子和润湿相将通过熔融挤出工艺进行共混，以实现粒子的弯月面桥联。表征包括拉伸和冲击测试、电导率测量和扫描电子显微镜的形态研究。该项目的智能意义在于证明可以利用弯月面架桥来获得具有普通颗粒填充聚合物的可加工性、具有纤维增强复合材料的机械性能或接近金属的导电性的材料。此外，该项目将促进填充聚合物中毛细管相互作用的基础知识。