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

*9761580 Tan这个第一阶段小型企业创新研究第一阶段项目将使用一种新技术，使用一步操作来处理微孔泡沫，并且不使用或释放任何危险化学品/气体。所提出的发泡技术利用热力学不稳定原理，以氮气为发泡气体。该发泡剂将发泡未填充和填充的液晶和半结晶聚合物(LCPs&amp；PPS)，这些聚合物具有优异的强度和刚性重量比、良好的耐溶剂性、阻隔性和高温稳定性。吹塑过程将使碳/玻璃纤维沿着发泡基质的支柱对齐。已经证明，对于无定形聚合物，微孔泡沫塑料的性质与其固体泡沫相似。因此，低密度微孔LCP和PPS泡沫塑料的拉伸强度将在20到30ksi以上。这些微孔泡沫塑料的温度稳定性和机械性能将远远高于商业上可用的结构泡沫塑料，包括Rohacell和Divinycell。可以使用这些泡沫通过热压来制造夹层结构，从而降低制造和组装成本。传统的硬质闭孔泡沫塑料加工技术涉及多个步骤，并且所使用的发泡剂有毒。一些硬质泡沫在后处理步骤中会释放出有害气体。低密度微孔LCP&PPS泡沫塑料预计将有许多商业应用，包括用于高速飞机、航空航天、外层空间飞行器的夹层结构材料、火箭和推进部件的外壳和支撑结构。LCD和PPS的常规应用包括各种电子连接器、电子和视听设备。它们可以被建议的微孔LCP和PPS泡沫塑料取代，具有同等的性能，但重量轻得多。在地面应用中，由于重量轻得多，使用这些类型的微孔泡沫塑料制造的梯子和桥梁将具有极大的移动性。***

*** 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. ***