采用衰减全反射红外光谱检测改性沥青的SBS掺量及其老化降解程度

Characterizing SBS content and degradation rate of modified asphalt using ATR-FTIR

采用透射法和衰减全反射法(ATR)分别对不同SBS掺量(质量分数为0,3.0%,4.5%,6.0%和7.5%)和不同老化状态的改性沥青样品进行检测,并使用荧光显微研究改性沥青微观相态变化对光谱检测结果的影响。针对改性沥青的老化行为研究,提出适用于ATR法的改性沥青老化评价指标IB/S。研究结果表明:ATR法作为一种表面化学分析手段,其穿透深度(约1μm)远比透射法的小(约30μm),因此,改性沥青不均匀的微观相态可能干扰ATR检测,且SBS掺量越高,干扰越明显。在研究SBS改性沥青时,ATR法与透射法的检测结果不完全等同。当待测样品的SBS掺量较高时,建议采用透射法。IB/S指数并不以SBS浓度为基准,同时适用于透射法与ATR法,且可以评价未知SBS掺量改性沥青的老化程度。

The polymer modified asphalts(PMA)with varying polymer contents(0,3.0%,4.5%,6.0%and 7.5%)were examined by using transmission-FTIR and ATR-FTIR.Different aging conditions were considered.Also,fluorescence microscopy was conducted to directly identify the morphology change of PMA.A novel infrared index,namely IB/S was proposed to quantify the polymer degradation within PMA.The results show that the varying morphology of PMA associated with the extremely small scanning depth of ATR(1μm)accounts for the variability.IB/S is not designed based on the polymer concentration change during aging and is suitable for both transmission-FTIR and ATR-FTIR.