PREPARATION AND CHARACTERIZATION OF POLYSTYRENE/LAYERED DOUBLE METAL HYDROXIDE NANOCOMPOSITES

Polystyrene/layered double hydroxide (PS/LDH) nanocomposites were prepared by in situ suspension polymerization of styrene in the presence of LDH intercalated with 4,4'-azobis(4-cyanovaleric acid) (ACP) groups and ACP/4-vinylbenzene sulfonate ( VBS) composite groups, respectively. The morphological structure, thermal degradation behavior and rheological properties of PS/LDH nanocomposites were characterized by transmission electron microscopy (TEM) X-ray diffraction (XRD), tbermogravimetric analysis (TGA) and capillary rheometry. It was found that ACP groups could successfully intercalate into the gallery of LDH individually or combined with VBS groups through the ion-exchange reaction. It was evidenced by the XRD and TEM results that PS/LDH nanocomposites with higher exfoliation degree of LDH could be prepared by using of LDH intercalated with ACP/VBS composite groups. LDH nano-layers were dispersed in PS matrix after the melt-processing. This was caused by the improved intercalation polymerization due to the initiation of intercalated ACP initiator. The TGA data evidenced that the thermal degradation temperatures of PS/LDH nanocomposites increased as the weight fraction of LDH increased, i.e, the thermal degradation temperatures corresponding to 10% weight loss were improved 25.4 degrees C, 34.4 degrees C, 47.4 degrees C and 52.9 degrees C when 1% , 3%, 5% and 7% LDH was incorporated into PS, respectively. It was also found that the melt flow rate of PS/LDH nanocomposites decreased as the weight fraction of LDH increased.