导　　师： 杨卓如

学科专业： 081701

授予学位： 博士

作　　者： ;

机构地区： 华南理工大学

摘　　要： 预涂金属卷材由于其多变的色彩,轻便,易加工及优越的机械性能,越来越多的被应用到建筑、汽车、家电面板等领域。随着城市发展对节能的要求越来越高,金属卷材对隔热的需求也日益显著。将相变材料应用于建材行业可以减缓能源的供求之间在时间和速度上的不匹配程度,有效降低建筑能耗。随着高分子合成技术的发展,合适微胶囊壁材的获得以及生产工艺的简单化,使相变材料储存主要以微胶囊形式出现。本文采用微胶囊化技术,以三聚氰胺-甲醛树脂/(MF/)为壳层,包覆石蜡,制备相变材料微胶囊,采用微胶囊形成过程的在线分析和分子模拟等方法研究微胶囊成囊机理,指导微胶囊的设计和制备;然后在微胶囊表面接枝金红石型纳米二氧化钛粒子进行改性,来提高微胶囊对太阳光的反射率;最后将改性微胶囊与表面处理的六钛酸钾晶须等隔热功能颜填料配伍,进行了隔热卷材涂料的应用研究。 通过原位聚合法制备MF树脂为壳层、石蜡为核的相变微胶囊,探讨了乳化剂种类、预聚体滴加速度、核壳比及乳化剂苯乙烯马来酸酐共聚物/(SMAH/)分子量大小对相变微胶囊表面形貌、粒径分布和热性能的影响,得到制备MF-石蜡相变微胶囊的最优条件。FTIR、SEM、DSC表征结果表明优化的工艺条件为:采用SMA1000PH为乳化剂,乳化剂用量为石蜡用量的1.5wt/%,微胶囊制备过程中预聚体滴加速度为0.35mL//min,核壳比为3:1。在最佳条件下制得的相变微胶囊粒径大部分在8~10μm左右,芯材含量为71/%,相变潜热为126.71J//g。 借助计算机模拟考察了SMAH在正二十一烷/(石蜡/)//水体系乳化效果及SMAH分子在正二十一烷//水界面排布方式,研究了不同分子量SMAH对微胶囊形成过程的影响,提出了使用不同分子量SMAH时微胶囊的成囊模型。DPD方法模拟结果表明,体系加入SMAH后,正二十一烷液滴的粒径变小。SMAH分子量增加,液滴中正二十一烷的密度增加,SMAH的增溶效果增强。基于分子动力学模拟结果提出了微胶囊的成囊模型,认为微胶囊壳层的形成分为三个阶段,即MF树脂预聚体小粒子在溶液中的聚集阶段、MF树脂预聚体大粒子在SMAH表面沉积阶段、预聚体大粒子缩聚成壳阶段。使用SMAH的分子量不同,微胶囊壳层形成过程不同,其最终壳层形貌也不同。低分子量的SMAH更有利于微胶囊粗糙表面的形成,而采用高分子量的SMAH制备出的微胶囊表面光滑、平整。 采用表面化学反应法,以相变微胶囊做为母粒子,以纳米金红石型二氧化钛为子粒子成功制备了表面接枝纳米二氧化钛微胶囊微球。探讨了纳米二氧化钛处理工艺、接枝工艺、二氧化钛用量对复合粒子表面形貌和热性能的影响,得到二氧化钛表明接枝改性优化的工艺条件为:预聚体滴加完毕后紧接滴加纳米二氧化钛分散液,其用量为微胶囊质量的10/%。 以相变微胶囊及表面接枝纳米二氧化钛微胶囊复合粒子为功能原料,饱和聚酯树脂为成膜物质,表面改性六钛酸钾晶须为填料,高反射率黑色颜料为颜料,配制单层隔热卷材涂料,并对隔热卷材涂料的性能进行了研究。结果表明:微胶囊的用量、六钛酸钾的用量、涂层设计方式等因素对涂膜的机械性能、隔热性能等有显著影响。提出了单涂层最优配方为:以饱和聚酯树脂为基料,加入薛特30C940颜料、1.5wt/%六钛酸钾晶须、3wt/%表面接枝纳米二氧化钛微胶囊,得到单涂层的热反射率为93.9/%,太阳光发射比为87/%,且涂膜的机械性能和耐溶剂性达到卷材涂料使用要求。 Due to a wide range of colours, easy cut to required lengths, bent, profiled or deep drawn, without damaging the organic coating, the prepainted coil has numerous applications in various industries, such as in the construction industry, the automotive and transport industries, etc. The need for intelligent solar heat management solutions like thermal insulating coatings is increased with more requirement of energy-saving, especially in coil coatings. Along with the development of polymer technology, microcapsulation of phase change materials /(microPCMs/) with a higher reflectivity to sunlight provides a means to solve the super-cool problem and interfacial combine with circumstance materials. There are many advantages of microencapsulated PCMs, such as increasing heat transfer area, reducing PCMs reactivity towards the outside environment and controlling the changes in the storage material volume as phase change occurs. The objective of this study is to synthesize microcapsules containing paraffin with melamine-formaldehyde /(MF/) shell by in situ polymerization, and graft nanosized TiO/_2/(rutile type/) to the surface of microPCMs for a higher reflectivity to sunlight, and then energy-saving coil coatings were prepared using TiO/_2-grafted microPCMs and surface modified potassium titanate whisker/(PTW/). The encapsulating mechanism of microPCMs was studied by focused beam reflectance measurement /(FBRM/) and molecular simulation. MicroPCMs with paraffin core and MF resin shell were prepared using in situ polymerization. The effect of emulsifier style, prepolymer’s feed rate, core//shell ratio and molecular weight of the emulsifier styrene-maleic anhydride copolymer /(SMAH/) on the surface morphology, size distribution and thermal properties of microPCMs were studied with Scanning electron microscopy /(SEM/) method and differential scanning calorimetry /(DSC/). When the mass ratio of SMA1000PH emulsifier to paraffin is 1.5/%, the feed rate of prepolymer is 0.35mL//min and the mass ratio of paraffin to prepolymer is 3:1, the phase change latent heat and PCM content reach to the maximum value of 126.7 J//g and 71/%, respectively. Irregular spherical microPCMs with mean diameter of 8~10μm are obtained. The dissipative particle dynamics /(DPD/) simulation method was used to study the aggregation behavior of SMAH at interface of n-heneicosane//water and the molecular dynamics /(MD/) method was used to study the arrangement of SMAH molecule on the n-heneicosane//water interface. DPD simulation results show that accumulation behavior occurrs when the SMAH is added. With the increase of molecule weight of SMAH, the density of n-heneicosane in box increases and solubilization of SMAH is strengthened in the system. According to the results of MD simulation, a microencapsulation forming model is developed. The forming process of shell consists of three steps: /(1/)small prepolymer particles assembles to bigger ones; /(2/)big prepolymer particles areabsorbed by SMAH and aggregated in the surface of n-heneicosane drops; /(3/) prepolymer particles condensate and form a shell. The results show that surface morphology of microPCMs is affected greatly by the molecule weight of SMA. Low molecule weight SMAH is suitable for rough surface encapsulation, while high molecule weight results in a smooth surface. Nanocomposite microspheres were successfully prepared by grafting TiO/_2 particles to microPCMs via chemical reaction method. The effects of surface modification of nano TiO/_2 particles, dosage and adding time of TiO/_2 dispersion on the surface morphology and thermal storage properties of the mocrosphere ware investigated. The results indicate that the optimized method is immediate adding the TiO/_2 dispersion when all the prepolymer was added to the reaction system, and the optimal mass ratio of TiO/_2 to microPCMS is 10/%. Energy-saving coil coatings were prepared using saturated polyester as film former material, TiO/_2-grafted microPCMs and surface modified PTW as fuctional thermal storage material and thermal insulation material, high reflectivity black 30C940 as pigments. The thermal properties and mechanic behaviors of coil coatings were investigated. It was indicated that the usages of microPCMs, TiO/_2-grafted microPCMs and surface modified PTW have a great effect on the thermal properties of coatings. When the mass ratio of black pigments to white pigments is 5:95, the mass ratio of modified PTW to coatings and TiO/_2-grafted microPCMs to coatings is 1.5/% and 3/% respectivly, the heat reflectivity and the total solar reflectance reach to the maximum value of 93.9/% and 87/% respectively without reducing the mechanic behaviors of the coil coatings.

关 键 词： 节能 卷材涂料 相变材料 微胶囊 计算机模拟

分 类 号： [TQ630.7]

领　　域： [化学工程]