超临界二氧化碳/乙醇共发泡法制备聚醚酰亚胺泡沫制品

Preparation of Poly(ether-imide)Foam Parts by Supercritical Carbon Dioxide/Ethanol Co-foaming Method

本工作采用一步泄压釜压发泡技术研究了聚醚酰亚胺(PEI)的超临界二氧化碳(scCO_(2))发泡行为,系统研究了饱和压力、发泡温度和泄压速率对PEI泡孔结构的影响,进一步引入共发泡剂和成核剂来分别改善PEI的发泡性能和优化泡孔结构。通过釜压发泡熔接技术,在受限金属模具空腔中同时完成PEI珠粒的发泡与熔接,制备了发泡倍率及泡孔结构可调的PEI泡沫制品。结果表明,以scCO_(2)作发泡剂,发泡条件较为苛刻且所得PEI泡沫具有微孔结构,但整体发泡倍率小于3倍;加入共发泡剂如四氢呋喃(THF)和乙醇(EtOH)等可明显改善PEI的发泡性能、提升发泡倍率,引入碳纳米管(CNTs)作成核剂可显著优化泡孔结构、提高材料成核数量和泡孔密度;通过釜压发泡熔接制备的PEI及PEI/CNTs泡沫制品珠粒熔接质量良好,力学性能优良,PEI泡沫制品的拉伸强度和压缩强度分别为5.7 MPa和5.6 MPa。

In this paper,the foaming behaviors of poly(ether-imide)(PEI)in supercritical carbon dioxide(scCO_(2))were studied by depressurization batch foaming method.The effects of saturation pressure,foaming temperature and depressurization rate on PEI foam structure were systematically studied.Co-blowing agents and nucleating agent were further introduced to enhance the foaming ability and optimize the foam structures.PEI beads were foamed and fused simultaneously in the confined stainless mould to obtain PEI foamed parts with adjustable expansion ratio and cellular structure.The results indicated that the expansion ratio of PEI by using scCO_(2) as foaming agent were less than 3 fold,due to the harsh foaming conditions;the introduction of co-blowing agents such as tetrahydrofuran(THF)and ethanol(EtOH)was very helpful to improve the foaming ability and increase the expansion ratio,the nucleation number and cell density could be further enhanced by using carbon nanotubes(CNTs)as nucleating agent.The PEI and PEI/CNTs foam parts obtained from co-foaming method featured fine inter-bead bonding qualities and exhibited excellent mechanical performance,the tensile strength and compression strength of the PEI foam were 5.7 MPa and 5.6 MPa,respectively.