NER: Creation of Polymeric Nanofoams Based on Retrograde Vitrification

该奖项支持一个研究项目，旨在探索新的工艺策略，以开发具有纳米范围内的孔尺寸的闭孔聚合物泡沫。在聚合物材料中创造纳米级细胞的想法令人兴奋，而且在很大程度上尚未探索。由于独特的结构，纳米泡沫材料有望具有优于现有材料的上级性能，例如更高的强度重量比。此外，纳米泡沫将提供新的功能材料，可以针对所需的性质，例如导热率，介电常数，声学和阻尼系数进行定制。纳米泡沫具有用于目前使用泡沫聚合物的任何应用的潜力，具有进一步节省材料和提高性能的益处。这些新材料将在建筑、包装、汽车、微电子和家用产品中得到广泛的应用。本研究将探索使用固态发泡方法从PMMA-CO2体系中产生纳米泡沫。利用玻璃化现象增加气体的扩散性和溶解性。传统的固态发泡技术和应力诱导气泡成核方法将被探索，以开发纳米发泡工艺。 将设计和安装一个低温高压容器。将测量气体溶解度和扩散率。本研究将对新型奈米发泡材料的形态、机械性能、介电性能等进行表征。

This award supports a research project aimed at exploring novel process strategies to develop closed-cell polymer foams that have cell sizes in the range of nanometers. The idea of creating nano-scaled cells in polymeric materials is exciting and largely unexplored. Due to the unique structures, nanofoams are expected to have many properties that are superior to those of existing materials, such as a much higher strength-to-weight ratio. In addition, nanofoams would provide novel functional materials that could be tailored for the needed properties, for example, thermal conductivity, dielectric constant, acoustic and damping coefficients. Nanofoams have the potential to be used for any applications where foamed polymers are currently used, with the benefit of further material savings and improved performance. These novel materials will find a wide range of applications in construction, packaging, motor vehicle, microelectronics, and household products.This research will explore the creation of nanofoams from the PMMA-CO2 system using a solid-state foaming method. The retrograde vitrification phenomenon will be employed to increase the gas diffusivity and solubility. Both conventional solid-state foaming techniques and the stress induced bubble nucleation method will be explored to develop the nanofoaming process. A low temperature and high pressure vessel will be designed and instrumented. Gas solubility and diffusivity will be measured. Properties of the new nanofoam materials, such as the morphology, mechanical properties, and dielectric properties, will be characterized in this research.