SBS改性AH-70沥青乳化前后性能及微观结构研究

采用先改性后乳化的工艺制备苯乙烯-丁二烯嵌段共聚物(SBS)改性乳化沥青,将其蒸发残留物和改性沥青的性能进行对比,并利用荧光显微镜(FM)、傅里叶红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)及差示扫描量热(DSC)等分析手段,评价改性沥青乳化前后的微观结构及热稳定性变化。结果表明:改性沥青乳化后的软化点5、℃延度及弹性恢复率均减小,离析试验软化点差变大,性质衰减后仍较基质沥青有大幅度提高,符合I-D级规范要求;改性沥青为两相分散均匀的三维网状结构,乳化后沥青和SBS分子之间的交联结构并未发生明显变化,只是有少量SBS大颗粒析出、沥青发生轻微老化,热稳定性稍微变差。

Study on performance and microstructure of SBS modified asphalt AH-70 before and after emulsification

The styrene-butadiene block copolymer(SBS) modified asphalt emulsion was prepared by a modification-emulsification process.The performance of emulsion residue and modified asphalt was analyzed.The microstructure and thermal stability of SBS modified asphalt before and after emulsification were evaluated by means of fluorescence microscope,FT-IR,1H-NMR and DSC.The results show that compared with modified asphalt,softening point,5 ℃ ductility and elastic recovery of emulsion residue decrease and the difference of top and bottom softening point on separation test becomes large.However,those properties were still improved compared with base asphalt and conformed to I-D standard.SBS modified asphalt exhibits uniform three-dimensional network structure.After emulsification,the cross-linked structure between asphalt and SBS molecules remains unchanged,with a small amount of large SBS particles separating from modified asphalt,minimally aging of asphalt and slight reduction on the thermal stability of modified asphalt.