Evaluation of Processing Effects on Polystyrene/Clay Nanocomposites Using an Excimer Laser

Polystyrene (PS)-Organically modified montmorillonite (OMMT) nanocomposites processed by injection molding were investigated for the effects of different OMMT concentration and melt-blending conditions using a KrF excimer laser operating at 248 nm wavelength. Results indicate that PS-OMMT nanocomposites show improved resistance to excimer laser irradiation, as revealed by reduced mass loss due to laser ablation at their surfaces, when the OMMT concentration is below 2 wt%. Further increases in OMMT wt%, above the 2 wt% value, resulted in increased mass loss due to laser ablation, when compared with ablation of the neat PS material. Our experimental results also revealed that the dispersion (exfoliation) state of OMMT plays an important role in excimer laser ablation behavior of PS-OMMT nanocomposites. This result indicates the possibility for using the excimer laser as an evaluation tool in assessing the degree of exfoliation in clay reinforced polymer nanocomposites, including the assessment of spatial distribution of clay particles in injection molded nanocomposite articles, as illustrated in this work.