Partnership for Advancing Technologies in Housing: Microcellular Polymers Processing for Lightweight and Energy Efficient Advanced Panel Systems

PATH：用于轻质和节能的先进面板系统的微孔聚合物加工该奖项支持PATH的一个研究项目，该项目旨在探索用于承重应用的厚片微孔聚合物的制造，例如用于房屋建筑的先进面板系统。微孔塑料是指具有大量非常小的气泡的闭孔热塑性泡沫塑料。通常，泡孔直径约为10微米，每立方厘米(Cm3)泡沫有108个或更多泡孔。微孔聚合物为房屋建筑应用提供了许多独特的优势。例如，微孔结构可以降低密度，从而减轻面板的重量。更轻的面板更具成本效益，并在房屋建造过程中提高安全性。此外，降低材料密度导致只使用真正需要的资源来保护自然资源。此外，微孔结构可以降低导热系数，从而提高面板系统的能效。基本的固态微孔工艺是两个阶段的间歇工艺。在第一阶段中，聚合物被放置在带有高压和不反应气体的压力容器中。此步骤通常在室温下进行。随着时间的推移，气体扩散到聚合物中，并在整个聚合物样品中达到均匀的浓度。当样品从压力容器中取出并置于大气压下时，就会产生一种“过饱和”样品，由于溶解到聚合物中的过量气体，这种样品在热力学上是不稳定的。在第二阶段，样品被加热到所谓的发泡温度。这一步骤通常在有温度控制的加热浴中进行。溶解气体降低了聚合物的玻璃化转变温度，发泡温度只需高于气体-聚合物体系的玻璃化转变温度，就可以使气泡形核和长大。由于聚合物仍处于固态，因此产生的泡沫被称为“固态泡沫”，以区别于在挤出机中从聚合物熔体中产生的传统泡沫。这项受资助的研究将探索使用多种聚合物生产厚质微孔样品的可行性，包括当今建筑材料中使用的一种常见塑料聚氯乙烯；被认为比聚氯乙烯具有成本竞争力的聚合物PET；以及一些最近推出的高强度聚合物，如PEEK和PEI。将探索一些气体作为物理发泡剂。这些气体包括二氧化碳和氮气。这项研究将通过增加承载应用的新维度来推进新兴微孔聚合物技术的最新发展。它还将为本科生和研究生提供一个在发现和科学理解的环境中学习和成长的绝佳机会。

PATH: Microcellular Polymers Processing for Lightweight and Energy Efficient Advanced Panel SystemsAbstractThis award supports a PATH research project to explore the manufacture of thick sheets of microcellular polymers for load-bearing applications such as advanced panel systems for house construction. Microcellular Plastics refer to closed-cell thermoplastic foams with a very large number of very small bubbles. Typically, the cells are of order of 10 micrometers in diameter, and there are 108 or more cells per cubic centimeter (cm3) of the foam. The microcellular polymers offer a number of unique advantages for house construction applications. For example, the microcellular structure can reduce the density, leading to a reduction in the weight of the panels. Lighter panels are more cost effective and promote safety during house construction. In addition, reducing material density leads to conservation of natural resources by only using what is truly needed. Further, the microcellular structure can reduce the thermal conductivity and thus improve the energy efficiency of the panel systems. The basic solid-state microcellular process is a two-stage batch process. In the first stage, the polymer is placed in a pressure vessel with a high-pressure and non-reacting gas. This step is usually conducted at room temperature. Over time, the gas diffuses into the polymer, and attains a uniform concentration throughout the polymer specimen. When the specimen is removed from the pressure vessel and brought to the atmospheric pressure, a "supersaturated" specimen that is thermodynamically unstable due to the excessive gas dissolved into the polymer is produced. In the second stage, the specimen is heated to what is termed the foaming temperature. This step is typically carried out in a heated bath with temperature control. The dissolved gas lowers the glass transition temperature of the polymer and the foaming temperature needs only to be above the glass transition temperature of the gas-polymer system in order for the bubbles to nucleate and grow. Since the polymer is still in a solid state, the foams thus produced are called "solid-state foams" to distinguish them from the conventional foams that are produced in an extruder from a polymer melt. The funded research will explore the feasibility of producing thick microcellular specimens using a number of polymers, including PVC, a common plastic used in building materials today; PET, a polymer considered cost-competitive with PVC; and some of the more recently introduced high-strength polymers such as PEEK and PEI. A number of gases will be explored as a physical blowing agent. These gases include carbon dioxide and nitrogen. The research will advance the state-of-the-art of the emerging microcellular polymers technology by adding the new dimension of load-bearing applications. It will also provide an excellent opportunity for both undergraduate and graduate students to learn and grow in an environment of discovery and scientific understanding.