热处理温度对SiO_(2)微纳纤维形貌及隔热性能的影响

Effect of Heat⁃treatment Temperature on Morphology and Thermal Insulation Properties of SiO_(2) Micro⁃Nano Fibers

为探究煅烧温度与纤维膜隔热性能之间的关系,以正硅酸乙酯(TEOS)和聚乙烯吡络烷酮(PVP)为主要原料,采用静电纺丝技术结合后续热处理制备了SiO_(2)微纳纤维膜。利用热重⁃差热联用热分析仪、X射线衍射仪、傅里叶变换红外光谱仪、扫描电子显微镜和导热系数仪研究了SiO_(2)/PVP杂化纤维膜的热分解过程以及热处理温度对其产物物相组成、微观形貌和隔热性能的影响。结果表明:杂化纤维膜经600℃及以上温度热处理后,产物均为无定形态SiO_(2);随着热处理温度的升高,无定形态SiO_(2)有向晶态转化的趋势,且纤维的平均直径呈先减小后增大的规律。产物的热导率与纤维直径呈正相关,当热处理温度为800℃时,SiO_(2)微纳纤维的平均直径最小,热导率最低(0.0325 W/(m·K)),其隔热性能优于600℃、1000℃热处理温度下的样品,也优于传统石英纤维隔热毡。本工作为SiO_(2)纤维膜隔热性能的优化提供了一定的实验基础。

To explore the relationship between the calcination temperature and the thermal insulation performance of the fiber membrane,this study used tetraethyl orthosilicate(TEOS)and polyvinylpyrrolidone(PVP)as raw materials to prepare SiO_(2) micro⁃nano fiber membranes through electrospinning in combination with a follow⁃up heat treatment.Thermogravimetric and differential thermal analysis,X⁃ray diffractometer,Fourier infrared spectrometer,scanning electron microscope and thermal conductivity meter were applied to study the thermal decomposition process of SiO_(2)/PVP hybrid fiber membranes and the influences of calcination temperature on the products􀆳phase composition,micromorphology and thermal insulation performance.The results showed that the products were all amorphous SiO_(2) after they were calcinated at 600℃ or above.As heat treatment temperature rose,amorphous SiO_(2) showed a tendency to transform into crystalline state,and the average fiber diameter decreased before increasing.The products' thermal conductivity was positively related to fiber diameter.When the heat treatment temperature was 800℃,SiO_(2) micro⁃nano fibers had the smallest average diameter and the lowest thermal conductivity(0.0325 W/(m·K)),the thermal insulation performance of which is better than that of the sample at heat treatment temperatures of 600℃ and 1000℃ and traditional quartz fiber insulation felt.This experiment provides a substantial experimental basis for optimizing the thermal insulation performance of SiO_(2) fiber membrane.