基于红外光谱法的SBS改性沥青共混机理

Cross blend mechanism of SBS modified asphalt based on infrared spectra

采用高速剪切工艺在实验室制备了SBS物理和化学改性沥青,基于红外光谱法对SBS改性沥青中沥青的杂原子化合物及SBS中特征官能团进行分析,通过比较基质沥青、SBS、SBS物理改性沥青及SBS化学改性沥青的四种红外光谱图,揭示了SBS改性沥青的共混机理.结果表明SBS物理改性沥青的红外光谱图为基质沥青与SBS红外光谱图的简单叠加,说明SBS与基质沥青只是简单的物理共混共容.而SBS化学改性沥青的红外光谱图却有略微变化,说明由于SBS与基质沥青在强剪切力作用下的溶混炼以及稳定剂的添加,其中少量的SBS发生断裂,产生大分子自由基,从而与基质沥青发生化学反应,SBS之间发生交联反应而SBS与基质沥青之间发生了接枝反应.利用红外光谱法还可以测定SBS改性沥青中SBS的含量,从而评价SBS改性沥青的技术性能.

High-speed shearing technique was utilized to provide the SBS physical and chemical modified asphalt in the laboratory. Based on the infrared spectra, the heterocyclic compound and the diagnostic functional group of the asphalt are analyzed and the cross blend mechanism of SBS modified asphalt is revealed by comparing the spectrogram of matrix asphalt, SBS, SBS physical and chemical modified asphah. It was found that the spectrogram of SBS physical modified asphalt is the simple superposition of the SBS spectrogram and asphalt spectrogram. There is only physical mixing without any chemical reaction between SBS and matrix asphah. However, the spectrogram of SBS chemical modified asphalt does not just show that the chemical reaction occurs between SBS and matrix asphalt due to the appearance of macromolecule free radical in the SBS under the action of shearing force and stabilizer. It also can be caused by the graft reaction between SBS and matrix asphalt after the joint reaction by SBS itself. The content of SBS in SBS modified asphalt can be determined by infared spectra to evaluate the pavement performance of SBS modified asphalt.