FLUORESCENCE STUDIES ON MORPHOLOGICAL CHANGE OF ST/DVB CROSSLINKED GELS DURING CHLOROMETHYLATION  

作　　者：ZHANG Jixiang LI Hexian WANG Guochang WANG Lin WANG Ying HE Binglin 

机构地区：[1]State Key Laboratory of Functional Polymer Materials For Adsorption and Separation and Institute of Polymer Chemistry,Nankai University,Tianjin 300071,China

出　　处：《Chinese Journal of Reactive Polymers》2002年第2期185-191,共7页中国反应性高分子(英文版)

基　　金：National Natural Scientific Foundation of China (Project grant No.29574165; 29928003; 29874019); National Natural Scientific Foundation of Tianjin (Project grant No.013604011)

摘　　要：The morphological change of St/DVB crosslinked gels during chloromethylation wasstudied by fluorescence spectroscopy using St/DVB crosslinked and hypercrosslinked gels as controlsamples. It has been found that with increase of chlorine content, the excimer emission band (~325nm)approaches to vanish, while the intensity of multi-ring aggregate emission band (~420nm) quicklyreaches a maximum, and then decreases sharply accompanied by appearance ofa new broad bandcentred at ca 488nm which roughly coincides with the typical emission band of hypercrossllinkedSt/DVB gels. Mearwhile, the result of IR measurement suggests that methylene bridge between phenylrings forms and increases with chloromethylation process. These results are explained in terms ofaside reaction of post-crosslinking, which densifies the loosely crosslinked networks and undoes thedensely entangled microgel nuclei. As a result, the morphology of the crosslinked gels becom es morehomogeneous with chloromethylation.The morphological change of St/DVB crosslinked gels during chloromethylation was studied by fluorescence spectroscopy using St/DVB crosslinked and hypercrosslinked gels as control samples. It has been found that with increase of chlorine content, the excimer emission band (~325nm) approaches to vanish, while the intensity of multi-ring aggregate emission band (~420nm) quickly reaches a maximum, and then decreases sharply accompanied by appearance of a new broad band centred at ca 488nm which roughly coincides with the typical emission band of hypercrossllinked St/DVB gels. Mearwhile, the result of IR measurement suggests that methylene bridge between phenyl rings forms and increases with chloromethylation process. These results are explained in terms of a side reaction of post-crosslinking, which densifies the loosely crosslinked networks and undoes the densely entangled microgel nuclei. As a result, the morphology of the crosslinked gels becomes more homogeneous with chloromethylation.

关 键 词：Crosslinked Polystyrene CHLOROMETHYLATION Fluorescence Spectroscopy Hypercrosslinked Gels 

分 类 号：O632.13[理学—高分子化学] O631[理学—化学]