【作者】 郝焕英；

【导师】 赫晓东；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2007， 硕士

【摘要】 聚合物基复合材料在使用过程中不可避免地会产生局部损伤和微裂纹,导致材料机械力学等性能下降,因此对微裂纹的及时修复是非常重要的,从而引出了一种新的材料—自修复材料。自修复材料的研制成功可以大大延长材料的使用寿命,特别是在那些人们很难进行现场修复的,如航空器、桥梁等复合材料应用领域,其应用潜力巨大。对复合材料进行自修复的方式之一是采用微胶囊技术。基于微胶囊技术的自修复材料是指将内包有修复液的微胶囊和催化剂分散于聚合物中,当产生裂纹时,伸展裂纹将导致微胶囊的破裂,其中的修复液被释放并由于毛细管作用流入裂缝中;当修复液与埋在聚合物中的催化剂相遇时,聚合反应被触发,将裂缝两面粘合,从而达到修复效果。本文采用原位聚合法,以尿素、甲醛为囊壁原料,以双环戊二烯(DCPD)为囊芯,合成脲醛树脂包覆DCPD微胶囊。为保证微胶囊的使用性,本文对微胶囊合成过程中乳化剂的选择及用量和原料配比进行了深入研究,确定了优化的合成工艺;通过光学-摄影显微镜(OM)观察并测量微胶囊粒径的大小及分布;采用扫描电子显微镜(SEM)观察微胶囊的表面形貌,测量微胶囊的壁厚;利用红外光谱(FTIR)分析判定微胶囊壁材是否形成;通过热失重(TGA)、差示扫描量热法(DSC)实验分析了微胶囊产品的热性能;另外还研究了微胶囊产品的缓释性能。研究结果表明,采用原位聚合法成功合成了以DCPD为囊芯的脲醛树脂微胶囊。优化的微胶囊合成工艺为:囊壁与囊芯的质量比为0.5:1,终点pH=2.5~3.0,乳化剂使用0.5g/L的DBS水溶液,搅拌速率为500r/min,控温60℃反应2~3h。在微胶囊合成过程中,原料配比、终点pH值、乳化剂种类与用量等对微胶囊产品的性能有很大的影响,且对微胶囊的合成状态有直接影响。更多还原

【Abstract】 It was inescapable that microcracks and partial damage often happened within the structure when polymer composite were used, which resulted in the mechanical performance of material descend. So it was very important to repair the microcracks in time. One new material called self-healing material was developed. The self-healing material could increase the reliability and service life of polymers. Especially in such applications as aircrafts and bridges where the damaged material was very hard to heal, the self-healing material had a great potential.One method for composites repair was to apply the technology of microcapsulates. The self-healing polymer material with microcapsulated healing agent was a structural polymeric material with the ability to heal cracks autonomically. The healing was accomplished by incorporating a microcapsulated healing agent and a catalytic chemical trigger within an epoxy. An approaching crack ruptured the embedded microcapsules, releasing the healing agent into the crack plane through capillary action. Polymerization of the healing agent was triggered by contact with the embedded catalyst, bonding the crack faces.The microcapsule with urea and formaldehyde as the raw shell material, and dieyclopentadiene (DCPD) as the core material was synthesized by in-situ polymerization in an oil-in-water emulsion. The optimum conditions of surfactant and mass ratio of the shell material to the core material in microencapsulation was studied in detail to ensure the microcapsules possess excellent maneuverability. The diameter of microcapsules were measured and the distribution of diameter was calculated by using optic microscope (OM). The surface morphological was examined and the wall thickness was measured by scanning electron microscopy (SEM). It was proved the wall materials have been formed by Fourier-transform infrared spectrometer (FTIR). The thermal properties were studied by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) experiments. And the osmosis of microcapsules was investigated. The results showed that the poly(urea-formaldehyde) microcapsules containing DCPD had been successfully synthesized. The optimum conditions are as follows: mass ratio of the shell material to the core material, 0.5:1; final pH value, 2.5~3.0; surfactant, sodium dodecylbenzene sulfonate (DBS), 0.5g/L; agitation rate, 500r/min, reaction temperature, 60℃, reaction time, 2~3h. The processing parameters, such as mass ratio of the shell material to the core material, final pH value, agitation rate, and surfactant, greatly influence the properties of microcapsules during in-situ polymerization. And the state of microencapsulation is dramatically dependent on mass ratio of the shell material to the core material, final pH value and surfactant.更多还原