【作者】 谢小琴；

【导师】 梁国正；

【作者基本信息】 苏州大学 ， 材料学， 2009， 硕士

【摘要】 高性能泡沫材料是一类理想的轻质结构材料,在航天航空等对质轻要求严格的领域扮演越来越重要的角色。随着社会的进步,作为高性能泡沫材料应具有耐高温、高强度、阻燃等的性能特点,而现有泡沫材料自身缺点均难以满足要求。因此,新型高性能泡沫材料的研制成为材料研究领域的热点和重点。双马来酰亚胺树脂是耐热树脂的新型品种,而目前针对双马来酰亚胺树脂基泡沫材料的研究鲜见文献报道,因此本文以烯丙基双酚A改性双马来酰亚胺(BDM/BA)树脂为基体,首次展开了高性能双马来酰亚胺树脂基阻燃泡沫材料的研究。本文首先进行了双马来酰亚胺树脂泡沫材料的制备工艺的研究。探讨了BDM/BA预聚工艺对泡沫材料的泡孔形态结构的影响,考察了发泡剂的分解速率、预聚体的凝胶时间以及发泡温度与时间对泡沫材料密度和形态结构的影响,确定了BDM/BA泡沫材料的制备工艺为预聚时间为60min,发泡温度为160°C,发泡时间为35min。研究了发泡剂的含量对泡沫材料的形态结构、热性能、介电性能及其机械性能的影响。研究结果表明,泡沫材料具备良好的耐热性和力学性能,且泡沫材料的形态结构与介电性能随着发泡剂含量的变化而变化。当发泡剂含量为9%时,泡沫材料的泡孔结构及分布最均匀、泡沫密度最低、孔隙率最高,且其介电常数与损耗值均最小。首次采用多壁碳纳米管(MWNTs)和粘土(clay)制备了双马来酰亚胺阻燃泡沫材料。研究结果表明,泡沫材料中添加碳纳米管,在增强材料的同时也改善了阻燃性能。首先,当BDM/BA泡沫材料中添加1%MWNTs时,材料的热释放速率峰值和总热释放值均能降到最低,而压缩强度达最大,且MWNTs的加入不影响泡沫材料的点燃时间;而随着MWNTs的逐渐增加,泡沫材料的质量损失速率显著下降。当泡沫材料中同时添加等量的MWNTs与clay时,这两种填料能发挥协效作用,热释放速率峰值、总热释放值及质量损失速率值比单独添加MWNTs或clay的相应值低,而且能形成有整体外形的炭层。更多还原

【Abstract】 High performance foams are ideal lightweight structural materials, which play more and more inportant role in fields required light-weight such as aerospace and aviation. High performance foams should have outstanding thermal resistance, high strength and outstanding flame retardance, however, present foams do not completely meet those requirements. Therefore, developing a new kind of high performance foams has been a hot and important subject in the field of material science and technology.Bismaleimide resin is one kind of heat-resistant thermosetting resin, but few investigations are related on developing high performance foams based on bismaleimide resin. In this thesis, high performance foams based on diallyl bisphenol A modified bismaleimide (BDM/BA) were developed in the first time, and the structure-properties relationship of BDM/BA foams were intensively studied.The preparation technology of BDM/BA foams was firstly investigated. In detail, the effects of prepolymerization condition of BDM/BA foams on morphology and structure of resultant foams, such as the decomposition rate of blowing agent (AC135), gelation time of prepolymer as well as blowing temperature and time, have been discussed. Judging from the results, the optimum prepolymerization condition is 140°C for 60 min, and the foaming condition is 160°C for 35 min.The effects of the content of blowing agent on the morphology, thermal behaviors, dielectric properties and mechanical properties were also investigated. Results show that the resultant foams have outstanding thermal stability and mechanical properties, while the morphology and dielectric properties of BDM/BA foams are depended on the content of blowing agent. The BDM/BA foam with 9wt% AC135 has uniform cell distribution, low density, high porosity as well as low dielectric constant and loss.Flame-retardant BDM/BA foams were prepared by using carbon nanotubes (MWNTs) and clay as combined flame-retardants for the first time. Results show the incorporation of MWNTs into BDM/BA foam can not only increase the mechanical strength, but also improve the flame-retardancy of the foam. The foam with 1%MWNTs has the minimum peak release rate and total heat release value, and the maximum compressive strength. In addition, the incorporation of MWNTs into BDM/BA foam does not affect the ignition time; with the increase of MWNTs content in foams, the mass loss rate declines significantly. When both MWNTs and clay are added into foams, they not only show obvious synergism effect to reduce the peak heat release rate, the total heat release value and the mass loss rate, but also lead to form a whole carbon layer.更多还原