عنوان مقاله [English]
MgCl2/C2H5OH adducts with constant relative ratio of 1/3 were prepared and kept at 120oC for different lengths of times of 5, 10, 20, 30, 50, 90,120 and 220 h. Then the samples were quenched and analyzed by XRD and BET. No meaningful changes were observed in the specific surface area of the samples, while XRD spectra showed 3 peaks at 2θ<15o for samples kept at 120oC for 5 h. These 3 peaks were gradually replaced by a single peak for samples kept at120 oC for 120 h and beyond. Dealcoholation of the samples caused a dramatic change in specific surface area from 3.6 m2/g to 284.7 m2/g. Also XRD indicated that the peak at 2θ <15o totally vanished and it was replaced by a weak amorphous type of peak. Catalysts produced from these supports were used to polymerize ethylene. It was observed that with increasing the specific surface area of the supports and the time of polymerization, the activity of the catalysts was enhanced dramatically.