论文总字数：18438字

摘 要

二氧化硅气凝胶是一种具有发达孔道结构的新型轻质纳米多孔材料，具有高孔隙率、低密度、比表面积大、导热系数小、导电系数等特点。在催化、吸附、隔热等材料领域有广阔应用前景。但是未经过表面修饰的SiO₂ 气凝胶具有多孔性的结构，且表面连有亲水基团-OH,会导致SiO₂ 气凝胶易于吸附水分。吸收的水分再蒸发过程会导致硅凝胶结构的崩塌。限制了二氧化硅气凝胶的应用。本文以正硅酸四乙酯为（TEOS）为硅源，分别用甲基硅酸钠以硅源、催化剂、气凝胶后改性等方式加入，找出最优改性方式，并对所得疏水型毡子进行性能研究。首先，分别以一步碱凝胶-溶胶法和酸碱两步凝胶-溶胶法制备法SiO₂气凝胶。其次，甲基硅酸钠为改性剂以不同加入方式用酸碱两步凝胶-溶胶法制备SiO₂气凝胶。最后，在上述实验的基础，研究不同改性浓度、改性时间制备出的SiO₂气凝胶毡子性能。发现随着改性浓度的增加，改性后疏水角度变大，浓度增至一定值后，疏水效果不变；控制改性浓度，改性时间越长疏水改性效果越好，当改性时间达到一定值时再增加改性时间，疏水改性效果不变。

关键词:耐高温 疏水改性 SiO₂气凝胶 疏水角

Study on preparation and performance of high temperature

resistance of hydrophobic modified SiO₂ aerogel materials

Abstract

Silica aerogel is one kind has developed a new type of porous lightweight nano porous materials, with high porosity, low density, large specific surface area, small coefficient of thermal conductivity, conduction coefficient, etc .In the field of catalysis, adsorption, thermal insulation materials such as have broad application prospects .But not after surface modification of SiO₂ aerogel has porous structure, and the surface has a hydrophilic group - OH, causes a SiO₂ aerogel is easy to be adsorbed water. Absorption of moisture and evaporation process can lead to the collapse of the silicon gel structure. These limit the application of hydrophilic silica aerogel. Based on four ethyl orthosilicate (TEOS) as silica source, respectively with methyl sodium silicate as silicon source, catalyst, aerogel after modification methods such as add, find out the optimal modification methods, and research of the hydrophobic type felt performance .First ,alkaline gel - sol respectively by step method and acid-base two-step gel - sol prepared SiO₂ aerogel .Second, methyl sodium silicate as the modified agent with different ways to join with acid-base two-step gel - sol prepared SiO₂ aerogel .Finally, on the basis of the above experiment, the different modified modification time, concentration of SiO₂ aerogel felt performance is prepared. Found that with the increase of modified concentration, hydrophobic modified Angle greaten, concentration increased to a certain value, the hydrophobic effect; The longer the modification time, concentration control of modified hydrophobic modification effect, the better, when the modification time reaches a certain value increase, the modification time hydrophobic modification effect remains the same.

Key Words: High temperature resistant; Hydrophobic modification; SiO₂ aerogel ; hydrophobic Angle

目录

摘 要 I

第一章 文献综述 1

1.1 引言 1

1.2疏水SiO2气凝胶热学方面的应用 1

1.3 隔热材料 2

1.3.1 隔热材料的概述 2

1.4 疏水SiO2气凝胶的研究现状 3

1.5 研究目的和内容 4

1.5.1 研究目的 4

1.5.2 研究内容 4

第二章 耐高温疏水改性SiO2气凝胶材料的制备及性能研究 6

2.1 实验原料与仪器 6

2.1.1实验原料 6

2.1.2 实验仪器 6

2.2 实验方法 7

2.2.1 醇凝胶的制备 7

2.2.2醇凝胶的疏水改性 9

2.2.3 醇凝胶与玻璃纤维复合及改性 10

2.2.4 改性剂浓度对改性效果的影响 10

2.2.5改性时间对改性效果的影响 11

2.3 实验结果分析测试 11

第三章 实验数据与分析 13

3.1一步法和两步法制备复合材料实验结果分析 13

3.2改性方式实验结果分析 13

3.3改性剂浓度对疏水效果以及表观密度的实验结果分析 13

3.4改性时间对疏水效果以及表观密度的实验结果分析 15

3.5红外谱图分析 17

第四章 结论与展望 20

4.1 结论 20

4.2 展望 21

参考文献 22

致 谢 24

第一章 文献综述

1.1 引言

随着现代经济发展，能源的需求越来越大，但是可用能源越来越少，价格越来越高，这些因素都制约了经济的发展。为了缓解能源危机，越来越多的人开始重视节能减排。二氧化硅气凝胶因为其轻质、保温、隔热的性能在航天化工、冶金、节能建筑等领域越来越受到大家的重视与研究。

请支付后下载全文，论文总字数：18438字