摘要
研究不同的表面修饰剂对常压制备三氧化硅气凝胶疏水性、弹性以及热学性能的影响。采用溶胶-凝胶一步法,以正硅酸甲酯(TMOS)为硅源,乙醇(EtOH)为溶剂,氢氟酸(HF)为催化剂制备得到了氧化硅气凝胶,其典型的反应各组分配比为TMOS:EtOH:HF=1:3:0.05。选用甲基三甲氧基硅烷(MTMS),六甲基二硅氮烷(HMDZ)和三甲基氯硅烷(TMCS)3利修饰剂对二氧化硅湿凝胶进行表面改性,通过场发射扫描电镜、接触角观测仪、FT-IR红外光谱仪、动态力学性能分析仪和Hotdisk热分析仪分析得到了不同修饰剂得到的气凝胶的结构和性能。结果表明:TMCS修饰的气凝胶疏水角最大(149°).MTMS修饰的最小(136°)。不同修饰剂得到的气凝胶的力学性能和热学性能差别不大,都能保持很好,弹性模量可达到3.85 MPa,热导率低至0.029 W/(m·K)。
The effect of different surface modification agents on the hydrophobic,mechanical and thermal properties of ambient pressure dried silica aerogels was studied.Aerogels were synthesized by sol-gel method using Tetramethoxysilane(TMOS),ethanol(EtOH) and hydrogen fluoride(HF) as precursor,solvent and catalyst,respectively.The optimal volume ratio of TMOS:EtOH:HF is 1:3:0.05.Methyltrimethoxysilane(MTMS),hexamethyldisilazane(HMDZ) and trimethylchlorosilane(TMCS) were selected as surface modification agents,The characteristics of aerogels with different modifications were analyzed by Scan electron microscope,Contact angle meter,Fourier transform infrared spectroscopic,dynamic mechanical analyzer and hot disk thermal analyzer.The results show that aerogels modified with TMCS has the largest contact angle(149)followed by HMDZ agents,and the contact angle of aerogels modified with MTMS is the smallest(136).The mechanical and thermal properties of the three modified aerogels are good and show little differences.The elastic modulus of aerogels is about3.85 MPa at room temperature and the thermal conductivity is as low as 0.029 W/(m·K).
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2012年第S3期454-457,共4页
Rare Metal Materials and Engineering
基金
NSFC(50824001)
