In order to solve the problems of low energy utilization rate and poor structural stability of photothermal conversion materials,a tightly arranged upper layer of nanotube array was constructed on the basis of graphene film by means of micro imprinting technology.Meanwhile,a porous aerogel base was formed by fixed-point dropping and multiple foaming.Thus,a graphene-based photothermal conversion material with integrated structure of light absorbing upper layer and heat insulating base was prepared.The results indicated that the light trap constructed from graphene hollow nanotubes could not only significantly increase the number of light reflections,but also reduce the light reflectivity.The length of the nanotubes was directly proportional to the light absorption ability of the material,which could increase the absorbance to over 98％under the imprinting conditions of 85kN and 8h.Besides,the combination of porous insulation base could effectively improve the photothermal conversion behavior and water evaporation effect of the material,and achieve 87％photothermal conversion efficiency and 1.3kg/(m2•h)water evaporation rate at the base thickness of 6mm.
Rigid polyurethane foams (RPUFs) were prepared using biomass soybean oil-based polyol and ammonium polyphosphate (APP) as raw materials. The effects of APP on the thermal stability and combustion performance of soybean oil-based polyol-modified RPUFs were investigated by thermogravimetric analysis, pyrolysis kinetic analysis, limiting oxygen index (LOI) test, cone calorimetry (CONE), scanning electron microscopy (SEM), and smoke density (Ds). The results showed that the modified RPUF with 20 wt% APP (RPUF-S3-20) had the lowest mass loss, the highest integrated programmed decomposition temperature and the highest activation energy. In addition, RPUF-S3-20 had the lowest Ds (30.9), the highest light transmittance (61.4 %), the lowest heat release rate (602.7 kW/m(2), 506.8 MJ/m(2), and 847.3 kW/m(2)) and the total heat release (18.3 MJ/m(2), 21.4 MJ/m(2), and 31.4 MJ/m(2)), which showed that RPUF-S3-20 had good thermal stability and flame retardant performance. The current results can provide an effective reference for the preparation of environmentally friendly RPUF by bio-based modification.
通过以双酚A型环氧树脂(E-51)为树脂基体,双酚A型酚醛环氧树脂为改性剂,4,4-二氨基二苯砜(DDS)为固化剂,研制出了一种耐高温环氧胶粘剂.结果表明:酚醛环氧树脂的加入能够大幅度地提高环氧胶粘剂的耐温性能.动态热机械分析结果显示,酚醛环氧树脂的加入,使环氧树脂体系的玻璃化转变温度(Tg)从216.46℃提高到了 234.03℃;在氮气氛围下,其失重5％的温度从387.03℃提高到了 395.779℃;在空气氛围下,其失重5％的温度从373.95℃提高到了 381.271℃.同时,酚醛环氧树脂改性环氧胶粘剂的150℃剪切强度比常规环氧树脂体系提高了 35.9％,175℃剪切强度提高了 10.06MPa.预期在民用航空等领域可得到广泛的应用.
采用共混挤出的加工方法,以聚偏氟乙烯(PVDF)为基材,通过添加相容性好的聚甲基丙烯酸甲酯(PMMA)和耐温性较高的聚酰胺6(PA6),制备出耐温性较高和制备成本较低的PVDF/PMMA/PA6热熔胶.通过热变形维卡软化点试验机、热重分析仪、微机控制电子万能试验机以及扫描电子显微镜分析了 PA6含量对PVDF/PMMA/PA6热熔胶微观结构、粘接性能以及热稳定性的影响.结果表明:PA6质量分数为15％时,热熔胶粘接性能最优,经过150℃热处理之后粘接强度仍能保持40.76N/15mm,满足150℃条件下剥离强度保持40N/15mm的要求;PA6质量分数为15％时,热熔胶的维卡软化温度为156℃,初始分解温度为350℃,383℃时最大分解速率为—27.2％/min.
多孔地质聚合物由于制备工艺简单、耐高温、力学性能优异、隔热性能极佳等优势被广泛应用于诸多行业,近十年来已成为最具研究前景的无机多孔材料之一.为了进一步提高、优化多孔地质聚合物的性能或赋予其新的功能,人们对多孔地质聚合物复合材料的开发和应用付出了巨大的努力.综述了目前多孔地质聚合物复合材料制备方法(包埋轻质/多孔填料、直接发泡、增材制造等)领域的最新进展,并从吸附性能、热稳定性能、机械性能三方面介绍了多孔地质聚合物复合材料的相关应用,旨在促进开发新型地质聚合物复合材料的制备路线,并扩大其在相关领域的应用.
