疏水改性ZSM-5吸附剂吸附CO2研究

传统方法采用5A沸石分子筛控制航天器舱内CO2浓度,因沸石与水蒸气的亲和力较大,在高湿度条件下将导致CO2吸附的失效。通过ZSM-5分子筛与无机硅粘结剂、助剂和水混合成面团状后挤压成形、干燥、焙烧,制备了一种分子筛吸附剂,经水蒸气/酸洗,疏水改性处理后,通过低温N2吸脱附、H2O/CO2吸附等温线、XRD等手段进行表征和评价。结果表明,所制备的疏水分子筛吸附剂比表面积达296m2/g,CO2的吸附性能略有提高,且疏水性优良,在90%相对湿度下吸水率只有约1%。     

免维护铅酸蓄电池滤气片制造工艺研究

免维护铅酸蓄电池用滤气片的组成，烧结工艺及疏水处理工艺对孔隙率、透气率、疏水性及耐酸性有很大影响。以Ａｌ２Ｏ３和ＳｉＯ２为主要成份的滤气片在１１００～１６００℃烧结后，经聚四氟乙烯疏水处理后用于免维护电池，能有效地阻止水份的损耗。     

基于疏水功能表面的飞机防覆冰机理研究进展

如何规避飞机结冰产生的飞行安全隐患一直是航空领域的重要问题。近年来,疏水材料表面被动防覆冰概念被提出并快速发展起来。首先介绍了在液滴冲击阶段防止表面结冰的机理及方法,系统综述了包括减少水滴与表面接触时间以及减少冰核形成时间的研究方案。又进一步介绍了液滴结冰后的防覆冰机理,综述了通过优化疏水表面性能及微纳结构形貌减小冰黏附力的研究进展。最后对疏水表面防覆冰的发展趋势进行了展望。     

SiO2气凝胶制备及疏水改性研究

采用六甲基二硅氮烷(HMDZ)和六甲基二硅氧烷(HMDSO)为表面改性剂,对正硅酸乙酯(TEOS)经溶胶-凝胶过程制备的凝胶进行表面改性,大幅度简化了洗涤过程,常压干燥制备了疏水SiO2气凝胶,并研究了表面改性剂对SiO2气凝胶结构和性能的影响.结果表明,所制备的疏水SiO2气凝胶有良好的疏水性能,吸附水量低于3%,与水的接触角大于130°;疏水SiO2气凝胶的密度、比表面积和孔隙率分别为150～225 kg/m3、750～900 m2/g和88%～93%,其颗粒尺寸为1～100 nm.     

疏水涂层的制备及性能

涂层的疏水效果不仅取决于涂料自身表面自由能的大小,还与其表面粗糙度有密切的关系.通过向涂料中添加疏水助剂降低表面能,控制喷涂工艺提高涂层表面粗糙度,制备了巯水涂层.研究了疏水剂的种类、用量以及表面粗糙度对涂层疏水性能的影响.结果表明:当疏水剂的用量为5wt％,表面略微粗糙时,接触角达到139.,具有良好的疏水效果.     

Effect of boron doping on waterproof and dielectric properties of polyborosiloxane coating on SiO2f/SiO2 composites

A hydrophobic coating of the silica fiber reinforced silica composites (SiO_2f/SiO₂) was synthesized by sol-gel method using methyltriethoxy-silane (MTES) and boric acid (B(OH)₃) as raw materials. The relationship among boron doping, chemical structure of precursors and durability of hydrophobic coatings was discussed. The Si-O-B and methyl groups were successfully introduced in the gel precursors according to the FT-IR and XPS results. The resins were filled in the internal and surface holes of the SiO_2f/SiO₂ composites partially or completely, which is beneficial to reduce the physical adsorption of the moisture. In addition, hydroxyl groups of the SiO_2f/SiO₂ composites reacted with the resins and hydrophobic methyl groups were introduced, leading to the reduction of the chemical adsorption of water. Also, the boron doping was beneficial to enhancing the physical cross-linking between the coating and the SiO_2f/SiO₂ composites, and improved the adhesion of the coating to the substrate. The results show that the optimal hydrophobic coating with contact angle 130.33°, moisture absorption 0.33% and adhesion level 1 is obtained when the molar ratio of MTES to B(OH)₃ is 10:4. The real permittivity of M10B4 is constant in the range of 2.32–2.51 and the dielectric tangent loss is constant in the range of 5.5 × 10⁻⁴–8.7 × 10⁻³. The hydrophobic coating has excellent dielectric properties.