NER: Process for Increasing the Exfoliation and Dispersion of Nano-particles into Polymeric Matrices Using Supercritical Carbon Dioxide

NER：使用超临界二氧化碳增加纳米粒子剥离和分散到聚合物基质中的过程

• 批准号: 0507995
• 负责人: Donald Baird
• 金额: $ 10万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0507995&HistoricalAwards=false
• 关键词: NER; Process; Increasing; Exfoliation; Dispersion

ABSTRACT - 0507995VA Polytechnic Institute & State University NER: Process for Increasing the Exfoliation and Dispersion of Nano-particles into Polymeric Matrices Using Supercritical Carbon Dioxide Background: All the promises and claims that the addition of nano-particles to polymer matrices will miraculously lead to exceptional mechanical, barrier, electrical, and thermal stability properties have not been completely fulfilled because the improvements in properties seem to plateau when reaching levels of about 4 wt%. Only for nylon 6 have levels of 7-wt% been reached before the properties plateau because of hydrogen bonding between the amide groups and the nano-clay particles. The plateau of properties is attributed to the inability to keep the nano-particles exfoliated as the concentration is increased. The three most common methods used to synthesize nano-clay composites, i.e. intercalation of a suitable monomer and subsequent in situ polymerization, intercalation of polymer from solution, and polymer melt intercalation, have not been successful in leading to loading levels greater than about 4 wt%. However, reaching nano-clay particle levels of the order of 10 wt% could lead to a modulus increase of the order of a factor of 5 or more rather than a factor of 1.5 to 2.0(at 4 wt %). Goal: The Goal of this research is to explore the possibility of using supercritical carbon dioxide (sc CO2 ) to increase the level of nano-clay particles which remain exfoliated at levels greater than 5 wt% and preferably as high as 10 wt%. Several previous studies provide evidence that sc CO2 can swell the layered silicates, which thereby may enhance the ease of polymer intercalation into the galleries of the clay. A continuous method is proposed for swelling nano-clays and exfoliating them with sc CO2 and then subsequently injecting the mixture into a molten polymer stream. Furthermore, it is expected that because sc CO2 is highly soluble in a number of polymers it will aid dispersion of the exfoliated clay particles and at same time lower the viscosity of the melt. Once mixing is complete sc CO2 can be extracted from the system leaving the particles dispersed within the thermoplastic. In addition to using microscopy and rheological techniques to identify the degree of exfoliation, mechanical properties of thermoplastic composites will be determined. Intellectual Merit: The concept of a novel, high risk, environmentally benign process for exfoliating and dispersing nano-particles into polymer melts will evolve from this work which should be applicable to a range of nano-particle systems beyond nano-clays and toother polymer matrices. Broader Impact: The approach proposed here is novel and should lead to the filing of a patent application. It has the potential to lead to a signficant increase in the level of nano-partilces and, hence, a significant increase in properties. The increase in properties will extend the range of use of nano-composites especially in the automotive industry and rapid prototyping. The project will initially be one-year duration and, hence, the education of students will have to be planned carefully. However, at least one undergraduate (from an underrepresented group) and a graduate student, who are part of our polymer program, will be exposed to the field of nano-composites and the use of environmentally benign methods for generating improved materials. Furthermore, as part of an interdisciplinary research team, they will learn the importance of a cooperative team effort in solving technical problems. Research Theme (Manufacturing Process): A novel environmentally clean manufacturing process is proposed for generating thermoplastic nano-composite materials with signficantly improved properties.

ABSTRACT - 0507995VA Polytechnic Institute & State University NER: Process for Increasing the Exfoliation and Dispersion of Nano-particles into Polymeric Matrices Using Supercritical Carbon Dioxide Background: All the promises and claims that the addition of nano-particles to polymer matrices will miraculously lead to exceptional mechanical, barrier, electrical, and thermal stability properties have not been completely fulfilled because the达到约4 wt％的水平时，物业的改善似乎稳定。 仅对于尼龙6，由于酰胺基和纳米粘土颗粒之间的氢键，在性质高原之前达到了7 wt％的水平。财产的高原归因于无法随着浓度的增加而保持纳米粒子的去除。 用于合成纳米粘合复合材料的三种最常见方法，即合适的单体和随后的原位聚合，溶液中聚合物的插入以及聚合物融化的插入量，并没有成功地导致载荷水平大于4 wt％。 但是，达到10 wt％的纳米粘土颗粒水平可能会导致模量增加5倍或以上，而不是1.5至2.0（4 wt％）。 目的：这项研究的目的是探索使用超临界二氧化碳（SC CO2）的可能性，以增加在大于5 wt％的水平，优选高达10 wt％的纳米 - 层颗粒水平。 先前的几项研究提供了证据表明SC CO2可以膨胀分层的硅酸盐，从而可以增强聚合物插入粘土画廊中的易于性。 提出了一种连续的方法，用于肿胀纳米盘并用SC CO2去角质，然后将混合物注入熔融聚合物流中。 此外，预计由于SC CO2高度溶于许多聚合物，因此它将有助于分散去角质的粘土颗粒，并同时降低熔体的粘度。一旦混合成为完整的SC CO2，就可以从系统中提取，使颗粒分散在热塑性塑料中。除了使用显微镜和流变技术鉴定去角质程度外，还将确定热塑性复合材料的机械性能。 智力优点：新颖，高风险，环境良性过程的概念将纳米粒子脱落和分散到聚合物融化中，这项工作将从这项工作中发展，该作品应适用于纳米粘膜以外的一系列纳米粒子系统，并适用于多聚合物矩阵。 更广泛的影响：这里提出的方法是新颖的，应该导致提交专利申请。 它有可能导致纳米副作用水平的显着增加，从而显着增加。 物业的增加将扩大纳米复合材料的使用范围，尤其是在汽车行业和快速原型制造中。 该项目最初将是一年的持续时间，因此，必须仔细计划对学生的教育。 但是，至少有一个本科（来自代表性不足的群体）和一名是我们聚合物计划的研究生，将暴露于纳米复合材料领域，并使用使用环境良性方法来产生改进的材料。 此外，作为跨学科研究团队的一部分，他们将学习合作团队在解决技术问题方面的重要性。 研究主题（制造过程）：提出了一种新颖的环境清洁制造过程，用于生成具有明显改进特性的热塑性纳米复合材料。