聚脲甲醛-生物油微胶囊的研制及性能探究

为研究微胶囊对沥青路面微裂纹的愈合效果,首先利用聚脲甲醛(作为微胶囊壁)和生物油(作为微胶囊心)采用原位聚合法制备微胶囊,采用扫描/透射电子显微镜(SEM/TEM)和热重分析(TGA)探究微胶囊的外观形貌和热稳定性；然后将微胶囊用于制备微胶囊/苯乙烯-丁二烯-苯乙烯(Microcapsule/SBS)复合改性沥青,通过动态剪切流变仪(DSR)和离析试验探究微胶囊的掺加对复合改性沥青路面性能的影响；最后通过延度愈合率试验验证微胶囊的愈合效果,并结合宏微观试验分析其愈合机理。结果表明：微胶囊呈现类球状,且表面较为粗糙,增大了与沥青的接触面积。微胶囊的热稳定性较好,其囊壁可承受沥青混合料生产过程中的高温环境。随着微胶囊的添加,复合改性沥青的低温塑性和耐热性均有所改善。此外,复合改性沥青的储能模量和损失模量也有所提升,即微胶囊的添加提升了SBS改性沥青的黏弹性能,这可能是由于添加的微胶囊与SBS和基质沥青具有很好的相容性,且微胶囊均匀分散在沥青内部并嵌入SBS呈现的网状结构中,这也在离析试验和荧光显微试验中得以证实。当微胶囊的掺量为0.4%时,复合改性沥青的愈合率达到最高。

Fabrication and mechanism of the action of polyurea formaldehyde-bio-oil microcapsules

To investigate the healing effect of microcapsules on microcracks in asphalt pavements, microcapsules were first prepared by in-situ polymerization from polyurea formaldehyde (as microcapsule wall) and bio-oil (as microcapsule heart), the appearance morphology and thermal stability of the microcapsules were investigated by scanning/transmission electron microscopy (SEM/TEM) and thermo gravimetric analysis (TGA). The microcapsules were then used to prepare microcapsule-styrene-butadiene-styrene (Microcapsule/SBS) composite modified asphalt, and the effect of microcapsules on the performance of the composite modified asphalt pavement was investigated by dynamic shear rheometry (DSR) and segregation tests. Finally, the healing effect of microcapsules was verified by ductility healing rate test and the healing mechanism was analyzed by a combination of macro and micro tests. The results showed that the microcapsules showed sphere-like shape and rougher surface, which increased the contact area with asphalt. In addition, the microcapsules have better thermal stability and their microcapsules wall can withstand the high temperature environment during the asphalt mixture production. With the addition of microcapsules, low temperature plasticity and heat resistance of the composite modified asphalt were increased. In addition, the storage modulus and loss modulus of the composite modified asphalt were also improved, i.e., the incorporation of microcapsules enhanced the viscoelastic properties of SBS modified asphalt, which can be attributed to the good compatibility of the added microcapsules with SBS and base asphalt. The uniform dispersion of the microcapsules within the asphalt and embedded in the reticular structure presented by the SBS was confirmed in the segregation tests and the fluorescence microscopy test. The highest healing rate of the composite modified asphalt was achieved when the content of microcapsules was 0.4%.