高掺量橡胶化生物沥青的相分离机理研究

Phase Separation Mechanism of High-content Rubber Modified Bio-asphalt

在基质沥青的基础上引入生物油制备生物沥青,然后再加入高掺量橡胶使生物沥青橡胶化,采用动态剪切流变仪分析高掺量橡胶化生物沥青的流变学特性,借助红外光谱分析高掺量橡胶化生物沥青在相分离过程中的官能团变化,同时利用荧光显微镜、凝胶色谱和分子动力学分析相分离过程中的相态结构,揭示其相分离机理。通过研究发现生物沥青中胶粉的最佳掺量为35%。结果表明:胶粉掺量会显著改变高掺量橡胶化生物沥青的流变学特性,而生物油则可显著降低高掺量橡胶沥青的相分离参数,缓解高掺量橡胶沥青微观形貌中胶粉颗粒的团聚,提升体系的相容性,增加胶粉在沥青中的溶解度;当胶粉掺量为40%和45%时,高掺量橡胶化生物沥青体系呈凝胶态,分子结构表现出紧密链接和空间互联的网络状,分子分散程度极低,极易出现相分离现象,并产生聚沉。

On the basis of base asphalt, bio-oil is introduced to prepare bio-asphalt, and then high-content rubber is added to rubberize the bio-asphalt. The rheological properties of the high-content rubber modified bio-asphalt(HCRMBA) are analyzed by dynamic shear rheometer. The functional group changes of HCRMBA are analyzed during the phase separation process, and the phase structure during the phase separation process is analyzed by fluorescence microscopy, gel chromatography and molecular dynamics, and the phase separation mechanism is revealed. After study, it is found that the optimum amount of rubber powder in bio-asphalt is 35%. The results show that the content of waste rubber powder can significantly change the rheological properties of HCRMBA, while the bio-oil can significantly reduce the phase separation parameters of HCRMBA, alleviate the agglomeration of rubber powder powders in the micro-morphology of HCRMBA,improve the compatibility of the system,and increase the solubility of rubber powder in asphalt.HCRMBA presents a gel state when the content of rubber powder is 40% and45%,and its molecular structure shows a network of close links and spatial interconnection.The degree of molecular dispersion of HCRMBA is very low,and the phase separation phenomenon,polymerization and precipitation are easy to occur.