摘要
以正硅酸乙酯(TEOS)为前驱体,无水乙醇和去离子水为溶剂,采用溶胶-凝胶法制备了SiO_(2)气凝胶,再以不同含量(0,1%,3%和5%(质量分数))短切碳纤维为增强材料,在胶凝完成后,经过表面改性,采用常压干燥工艺,制备了碳纤维增强SiO_(2)气凝胶复合材料。采用XRD、SEM、FT-IR和孔径测试等方法对制备所得复合材料的微观结构、形貌、孔径分布和导热性能进行了测试分析。结果表明,碳纤维增强SiO_(2)气凝胶复合材料为典型的非晶态结构,属于毛细凝聚特征的介孔材料,碳纤维的掺杂并没有改变SiO_(2)气凝胶的晶态结构;未掺杂碳纤维的SiO_(2)气凝胶的颗粒相互堆搭,掺入碳纤维的SiO_(2)气凝胶颗粒的孔隙明显减小,孔洞结构较为完整,碳纤维的掺入填充了大尺寸孔隙,有助于气凝胶孔径分布区间的收窄,当碳纤维的含量为3%(质量分数)时,颗粒分布最佳;随着碳纤维含量的增加,复合材料的导热系数呈现出先降低后升高的趋势,当碳纤维的含量为3%(质量分数)时,样品的导热系数最低为0.019 W/(m·K)。综合来看,当碳纤维的含量为3%(质量分数)时,复合材料的保温性能最佳,在建筑保温材料领域具有广阔的应用前景。
SiO_(2) aerogels were prepared by sol-gel process using tetraethyl orthosilicate(TEOS)as precursor,and ethanol and deionized water as solvent.Then,carbon fiber reinforced SiO_(2) aerogel composites were prepared by surface modification and normal pressure drying after gelation,and chopped carbon fibers with different contents(0,1 wt%,3 wt%and 5 wt%)were used as reinforcement.The microstructure,morphology,pore size distribution and thermal conductivity of the composites were tested and analyzed by XRD,SEM,FT-IR and pore size test.The results showed that the carbon fiber reinforced SiO_(2) aerogel composite was a typical amorphous structure.It was a mesoporous material with capillary condensation characteristics.The doping of carbon fibers didn’t change the crystalline structure of SiO_(2) aerogels.The SiO_(2) aerogel particles of the undoped carbon fibers stacked together.The pores of the SiO_(2) aerogel particles mixed with carbon fibers decreased significantly,and the pore structure was relatively complete.The incorporation of carbon fibers filled large pores,which helped to narrow the pore size distribution of aerogels.When the content of carbon fiber was 3 wt%,the particle distribution was the best.With the increase of carbon fiber content,the thermal conductivity of the composites decreased first and then increased.When the content of carbon fiber was 3 wt%,the lowest thermal conductivity of the sample was 0.019 W/(m·K).Overall,when the content of carbon fiber is 3 wt%,the thermal insulation performance of the composite is the best,and it has a broad application prospect in the field of building thermal insulation materials.
作者
冯满
FENG Man(School of Building Management, Chongqing Metropolitan College of Science and Technology,Chongqing 402167, China)
出处
《功能材料》
CAS
CSCD
北大核心
2022年第5期5213-5217,共5页
Journal of Functional Materials
基金
重庆市教委科学技术研究项目(KJQN201902505)。
关键词
碳纤维
SiO_(2)气凝胶
复合材料
保温性能
导热系数
carbon fiber
SiO_(2)aerogels
compound material
thermal insulation performance
thermal conductivity
