【作者】 蔡伟炜；

【导师】 杨辉；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2014， 博士

【摘要】 建筑物围护结构的隔热是降低建筑能耗、提高建筑物居住和使用功能的重要途径之一,其关键是隔热材料及体系。在各种建筑隔热材料及体系中,隔热涂料以其隔热性能好、经济性高、施工方便以及对热应力不敏感等特点而受到广泛关注,特别是反射型隔热涂料既可有效降低围护结构表面的温度,从源头上减少热流的传入,又在一定程度上改善城市热岛效应,降低光化学烟雾的生成几率。反射型隔热涂料的功能主要来自功能性隔热填料,但目前反射型隔热涂料用功能性隔热填料种类较少,功能较为单一。因此,亟需开发新的应用于反射型隔热涂料的功能性隔热填料。本文在综合论述了隔热涂料研究现状的基础上,针对隔热涂料用填料存在的问题,开展了新型反射型隔热填料及辐射型隔热填料的制备机理及应用技术研究,重点研究了核壳结构中空二氧化钛微球、多孔二氧化钛微球、二氧化钛/乙基纤维素复合多孔微球等基于多孔结构的反射型隔热填料以及纳米片状氧化锌、氧化锌纳米片球状团簇、氧化锌纳米棒/云母复合粉体等氧化锌(ZnO)基辐射型隔热填料的制备机理,并通过制备反射型隔热涂料,分析了反射型填料与辐射型填料对涂层隔热效果的影响,从而为新型功能性隔热填料的开发及应用奠定理论基础。主要研究结果如下：(一)开展了核壳结构中空二氧化钛微球及多孔二氧化钛微球的制备研究,系统研究原料组分以及制备工艺对多孔微球形貌及内部结构的影响,实现了核壳结构中空二氧化钛微球以及具有大孔结构的多孔二氧化钛徼球的可控制备.采用乳液法结合溶胶凝胶法,在螯合剂乙酰乙酸乙酯与前驱体钛酸四正丁酯摩尔比为1：1,钛酸四正丁酯与油相溶剂正辛醇体积比为1：2条件下,制备出具有良好球状形貌的二氧化钛凝胶微球；以制备的二氧化钛凝胶微球为原料,采用快速升温法制备出具有核壳结构的中空二氧化钛微球；在二氧化钛凝胶微球的制备体系中,引入相分离剂聚乙烯吡咯烷酮(PVP),借助相分离机理制备具有多孔结构的二氧化钛微球；随着PVP用量的增加,所得微球的内部孔径逐渐变大,当PVP用量增至1.903g时,微球平均大孔孔径为～1.3μm。(二)开展了二氧化钛/乙基纤维素复合多孔微球的制备研究,实现了二氧化钛/乙基纤维素复合多孔微球的可控制备。采用乳液法制备了乙基纤维素多孔微球,当油相溶液中乙基纤维素/乙酸乙酯质量比分别为0.4/10、0.8/10和1.2/10时,制得的微球具有较好的球状结构,其平均粒径分别为2.6、15.7和23.1μm,通孔孔隙率为72%、74%和68%；在乙基纤维素多孔微球制备体系中,添加纳米二氧化钛粒子后,所得二氧化钛/乙基纤维素复合粒子形貌均为球状结构,纳米二氧化钛粒子并未对其形貌产生显著影响；添加纳米二氧化钛对所得微球内部孔结构有一定的影响,纳米二氧化钛与乙基纤维素质量比分别为0.1/0.8、0.2/0.8和0.4/0/8时,所得复合多孔微球的通孔孔隙率分别为56%、54%和51%。(三)开展了高红外辐射率纳米氧化锌的制备研究,实现了纳米片状氧化锌以及氧化锌纳米片球状团簇的可控制备,对比分析了纳米片状氧化锌及氧化锌纳米片球状团簇红外辐射性能的差异。以二水合乙酸锌为原料,NaOH为矿化剂,采用水热法制备出分散性较好的纳米片状氧化锌粉体,其大小约在400nm,厚度在20～50nm之间；在纳米片状氧化锌的制备体系中,添加乳酸、柠檬酸以及聚丙烯酸钠等多官能度改性剂,促使纳米片状氧化锌粒子通过自组装形成氧化锌纳米片球状团簇；所得纳米片状氧化锌粒子与氧化锌纳米片球状团簇在8-14岫光谱区域内的红外辐射率分别为0.90以及0.88。(四)开展了氧化锌纳米棒/云母复合粉体的制备研究,实现了云母表面负载氧化锌纳米棒沉积密度的调节,阐明了纳米粒子团簇结构的形成对粉体红外辐射性的影响。采用液相沉积法制备了氧化锌/云母复合粉体,研究了云母表面晶种化以及氧化锌纳米棒在云母表面的沉积过程,ZnO在经过表面晶种化的云母颗粒表面以(002)面取向生长成棒状,其直径约为150nm,长度约为550nm；通过改变ZnO胶体粒子浓度可调节云母表面晶种化密度,从而控制云母表面氧化锌纳米棒的沉积密度；随着云母表面氧化锌沉积密度的增加,所得复合粉体的红外辐射率逐渐增加,最高达到0.863,而氧化锌纳米棒构成的球状粒子,其红外辐射率为0.851。(五)应用二氧化钛/乙基纤维素复合多孔微球为反射型填料,氧化锌纳米片球状团簇为辐射型填料制备反射型隔热涂料,研究了反射型填料与辐射型填料的隔热协同作用。以二氧化钛/乙基纤维素复合多孔微球为反射型填料制备反射型隔热涂料,并考察了二氧化钛/乙基纤维素复合多孔微球添加量对涂层隔热性能的影响,当二氧化钛/乙基纤维素复合多孔微球添加量为5.0wt.%时,所得涂层具有较好的隔热性能,覆有涂层的样板经半小时红外灯照射之后,其温度仅为67.7℃,而涂覆未添加多孔微球涂层的样板温度达到85.6℃；在此基础上,进一步考察了氧化锌纳米片球状团簇添加量对涂层隔热性能的影响,发现添加氧化锌纳米片球状团簇进一步改善了涂层的隔热性能,当氧化锌纳米片球状团簇添加量为1.0wt.%时,所得涂层的隔热性能最好,覆有涂层的样板经半小时红外灯照射之后,其温度进一步下降至63.9℃,表明反射型填料与辐射型填料具有一定的协同隔热作用。更多还原

【Abstract】 Insulation building envelopes are widely applied for their advantages on saving building energy consumption and improving the function of the buildings. And the insulation materials are vital to improve the insulation performance of building envelope. Amoung diverse insulation materials, insulation coatings are widely used because of their good insulation performance, economic reasons, applying convenience and their advantages on insensitivity to thermal stress. In addition, the application of solar heat reflecting insulation coatings can reduce the surface temperature of building envelope, save cooling energy, ameliorate urban heat island effect and reduce the smog probability. Generally, functional pigments are vital to fulfill the high reflecting performance of solar heat reflecting insulation coatings. However, the widely use of solar heat reflecting insulation coatings has not forced substantial emergency of functional pigments and the effective functional pigments for the solar reflecting insulation coatins are still needed. Thus, the development of new functional pigments for the solar heat reflecting insulation coatings is still a promising field.In this dissertation, we studied the preparation and application of reflecting and emissive pigments for solar reflecting insulation coatings based on the research status of the solar reflecting coatings. Core-shell structured hollow titania microspheres, porous titania microspheres and titania/ethyl cellulose (EC) composite porous microspheres were prepared as reflecting pigments, in which the synergistic effect between titania and microvoids can be realized to improve the light-scattering power of reflecting pigments; zinc oxide (ZnO) nanosheets, ZnO nanosheets based spherical aggregates and ZnO nanorod/mica composite powders were prepared as emissive pigments, in which the relative high emissivity of nanosized ZnO particles and the good dispersibility of nano ZnO based aggregates were both taken in consideration. Thus, a solution for preparation of functional pigments was suggested in the dissertation. The main results are as follows:Core-shell structured hollow titania microspheres and macroporous titania microspheres were prepared and the effects of composition and process route on the final structure were studied systematically:(1) Titania gel microspheres were first prepared by sol-gel process in O/W emulsions with1:1of ethyl acetoacetate (EAA)/tetra-n-butyl titanate (TBT) molar ratio and1:2of TBT/1-octanol volume ratio.(2) The core-shell structured hollow microspheres were prepared by heating the obtained titania gel microspheres at constant heating rate.(3) The macroporous titania microspheres were prepared by using polyvinylpyrrolidone (PVP) as the pore inducer in manufacturing process of titiana microspheres; the macropores inside the porous microspheres were induced by phase separation initiated by PVP; the inner pore size increased with increasing the additive PVP from0.190g to1.903g and the corresponding inner pore sizes of the microspheres obtained with different additive PVP increased from～500nm to～1.3μm.Titania/ethyl cellulose (EC) composite porous microspheres were prepared.(1) EC composite porous microspheres were prepared in O/W emulsion by solvent diffusion with0.4/10,0.8/10and1.2/10of EC/ethyl acetate (EA) mass ratio, and the average particles sizes were2.6,15.7and23.1μm, respectively; the interconnected porosity were72%,74%and68%, respectively.(2) Titania particles were added to fabricate titania/EC composite porous microspheres, while the added titania did not affect the spherical structure of obtained powders much; the addition of titania particles greatly affected the inner structure of the obtained microspheres; the interconnected porosity of the obtained microspheres with0.1/0.8,0.2/0.8and0.4/0/8of titania/EC mass ratio were56%,54%and51%which were much less than that of the microspheres obtained without titania particles.Zinc oxide (ZnO) nanoparticles with high emissivity and its aggregates were prepared and the effect of different state of aggregation on the resulting emissivity was studied by comparing the two particles.(1) ZnO nanosheets were prepared by hydrothermal process with zinc acetate dehydrate as precursor, NaOH as the mineralizer; the size of the obtained nanosheets was approximately400nm, while the thickness was in the range of20～50nm.(2) Multifunctional additives such as lactic acid, citric acid and sodium polyacrylate were used to fabricate ZnO nanosheets based spherical aggregates.(3) The emissivities of the ZnO nanosheets and nanosheets based spherical aggregates in8-14μm wavelength region were0.90and0.88, respectively.ZnO nanorod/mica composites particles were prepared to further illustrate the effect of different state of aggregation on the resulting emissivity.(1) ZnO nanorod/mica composites particles were prepared by chemical liquid deposition; the ZnO nanorods deposited on the mica plates had the preferential orientation of the c axis with150nm of diameter and550nm of length.(2) The density of ZnO nanorods on mica surface was controlled by different density of ZnO seed crystal on mica surface which was controlled by different colloid concentration; the density of ZnO nanorods on mica surface increased with increasing colloid concentration, and the emissivity of the obtained composite particles in8～14μm wavelength region were0.800,0.841,0.858and0.863, respectively; however, the ZnO nanorods based spherical particles attained0.851of emissivity in8-14μn wavelength region.The titania/EC composite porous microspheres as reflecting pigment and the ZnO nanosheets based spherical aggregates as emissive pigment were used to prepare a solar reflecting insulation coating to confirm the synergistic effect between the two pigments to enhance the insulation performance.(1) When the amount of the additive titania/EC composite porous microspheres was5.0wt.%, the obtained coatings attained the best heating insulation performance; the temperature of the sample plate after300minutes irradiation by infrared lamp was67.7℃, while the temperature of the sample plate coated with coatings without pigments was85.6℃(2) The effect of emissive ZnO nanosheets based spherical aggregates was also confirmed by adding the spherical aggregates particles to the coatings obtained with5.0wt.%titania/EC composite porous microspheres; it was demonstrated that the additive ZnO particles further improve the insulation performance of the solar reflecting insulation coating; the temperature of the sample plate after300minutes irradiation was63.9℃.更多还原