Gas/Supercritical Fluid Injected Micro-/Nano-Layer Coextrusion Foam Processes

在汽车、航空航天、生物医学、食品和电子包装行业中，大多数新的先进聚合物产品含有两种或两种以上的聚合物和功能性添加剂，从而从每个组件中获得所需的性能。共挤压工艺在一步工艺中同时挤压多种材料，形成独特应用的多层结构。通过在加工过程中向塑料中引入气体或超临界流体（SCF），可以从任何塑料中制备泡沫。目前的泡沫工艺无法生产出具有超低密度、均匀纳米尺寸和/或梯度尺寸分布的高性能泡沫。我们提出了一种新的微/纳米层（MNL）共挤泡沫工艺技术，以创造两种工艺（即MNL共挤和发泡）之间的协同效应。随着对气体/SCF浓度相关的微观结构和细胞结构演变的深入了解，该技术将能够制造出具有定制性能的高性能复合泡沫。

Most new advanced polymeric products in the automotive, aerospace, biomedical, and food and electronics packaging industries contain two or more polymers and functional additives resulting in desired properties contributed from each component. The coextrusion process extrudes multiple materials simultaneously in a one-step process to form a multilayer structure for unique applications. Foams can be prepared from any plastic by introducing a gas or supercritical fluid (SCF) within the plastic during processing. Current foam processes are unable to produce high-performance foams with ultra low-density, uniform nano-sized cells and/or gradient cell size distributions. We propose a new micro-/nano-layer (MNL) coextrusion foam process technology to create the synergistic effects between two processes (i.e., MNL coextrusion and foaming). With in-depth understanding of gas/SCF concentration-dependent microstructure and cell structure evolutions, this technology will enable manufacturing of high-performance composite foams with tailored properties. This Discovery program focuses on developing and applying the MNL coextrusion foam platform, the first for Canada, to provide fundamental understanding of the manufacture of multiphase nano-structured composite foam materials with tailored properties. Aim 1 will provide the first data set quantifying crystal nucleation, growth, and lamellae orientation under a high-pressure gas/SCF in nano-layered structures, where such data are simply not available. Aim 2 will employ the MNL coextrusion foam platform with a direct gas/SCF injection capability to produce well-controlled low-density, nano-cellular composite foams, which is not currently available. Aim 3 will address gas/SCF sorption and desorption behaviours under both static and dynamic conditions. The dynamic data (i.e., under shear and extensional stresses) are more relevant to real foam processes and are lacking, thus showing a critical need to measure these properties accurately under more process-relevant conditions to understand microstructure and cell morphology evolutions with respect to gas concentration. Collectively, these three aims will enable manufacturing of well-engineered high-performance composite foam materials. The technological impact of this proposed program on the existing state of knowledge within the polymer and composites engineering and processing community is expected to be significant. In particular, the results will benefit Canadian companies manufacturing value-added plastic materials. Moreover, this interdisciplinary program, which encompasses manufacturing, polymer chemistry, polymer physics and materials science, will provide participating highly qualified personnel (HQP) with unparalleled training experience, helping them to acquire scientific knowledge, practical experience and soft skills, and to establish a professional network that will advance their careers in many disciplines.