SBIR Phase I: Processing of Microcellular Foams from Unfilled and Filled Liquid Crystalline and Semicrystalline Polymers

*** 9761580 Tan这个第一阶段的小企业创新研究第一阶段的项目将使用一种新的技术来处理微孔泡沫，使用单步操作，不使用或释放任何危险化学品/气体。提出的泡沫技术利用热力学不稳定性原理，以氮气为泡沫气体。申请人将发泡未填充和填充的液晶和半晶体聚合物（lcp & PPS），这些聚合物具有优异的强度和刚度重量比，良好的耐溶剂性，阻隔性和高温稳定性。吹制过程将使碳/玻璃纤维沿着泡沫基体的支柱排列。对于非晶聚合物，微孔泡沫的性质与它们的固体对应物相似。因此，低密度微孔LCP和PPS泡沫将具有20至30 ksi以上的抗拉强度。这些微孔泡沫将有更高的温度稳定性和机械性能比那些市售结构泡沫，包括Rohacell和Divinycell。夹层结构可以用这些泡沫通过热压制成，从而降低制造和组装成本。传统的硬质闭孔泡沫的加工技术涉及多个步骤，而且所用的发泡剂是有毒的。一些硬质泡沫在后处理过程中会释放出有害气体。低密度微孔LCP & PPS泡沫有望有许多商业应用，包括高速飞机、航空航天、外太空飞行器、火箭和推进部件的外壳和支撑结构的夹层结构材料。lcp和PPS的传统应用包括各种电子连接器，电子和视听设备。它们可以被所提出的微孔LCP和PPS泡沫所取代，它们具有相同的性能，但重量要轻得多。在地面应用中，使用这类微孔泡沫制造的梯子和桥梁由于重量轻得多，移动起来非常方便。＊＊＊

*** 9761580 Tan This Phase I Small Business Innovation Research Phase I project will use a novel technique to process microcellular foams using a single-step operation and that does not use or release any hazardous chemicals/gases. The proposed foaming technique uses the principle of thermodynamic instability with nitrogen as the foaming gas. The proposer will foam both the unfilled and filled liquid crystalline and semicrystalline polymers (LCPs & PPS) which have excellent strength and stiffness to weight ratio, good solvent resistance, barrier properties, and high temperature stability. The blowing process will align the carbon/glass fibers along the struts of the foamed matrix. It has been demonstrated for amorphous polymers that the properties of microcellular foams are similar to their solid counterparts. Therefore, the low-density microcellular LCP and PPS foams will have tensile strength in the range of 20 to over 30 ksi. These microcellular foams will have much higher temperature stability and mechanical properties than those of the commercially available structural foams including Rohacell and Divinycell. Sandwich structures can be fabricated using these foams by heat pressing, thereby reduce manufacturing and assembling costs. Conventional processing techniques for rigid closed-celled) foams involve multiple steps and the blowing agent used is toxic. Some rigid foams give off hazardous gases during the post-processing steps. Low-density microcellular LCP & PPS foams are expected to have many commercial applications including sandwich structural materials for high speed aircraft, aerospace, outerspace vehicles, housing and support structures for rockets and propulsion components. Conventional applications of LCPs and PPS include various electronic connectors, electronic and audio-visual devices. They can be replaced by the proposed microcellular LCP and PPS foams with equivalent performance but much lighter in weight. On the ground applications, ladders an d bridges fabricated using these classes of microcellular foams would have extreme convenience of mobility because of much lighter weight. ***