| Octavinyl-POSS(POSS1)and the incompletely condensed silsesquioxane[(cyclo-C5H9)7Si7O9(OH)3,T7]were prepared in good yield by Feher's method..The reaction between T7,allyl-trichlorosilane and excess triethylamine in dry THF gave the corner-capped product, Allyl-cyclopentylPOSS(POSS2)。PVK-POSS nanocomposites were prepared by the free radical copolymerization。XRD and SEM studies indicate that POSS were completely molecularly dispersed in PVK below the 5 wt%of POSS content,while some POSS-rich nanoparticals were present when content of POSS was beyond 5%.GPC results showed that molecular weight of the PVK/POSS were increased with addition of POSS1 and POSS2.The PVK/POSS nanocomposites also displayed much higher glass transition temperatures(Tg) in comparison with neat PVK..As the POSS nanoparticles were introduced into the matrix,the absorption bands of PVK red shift to longer wave lengths in UV-vis measurement,the luminescent intensity of PVK nanocomposites was enhanced due to the good energy transfers between POSS nanoparticles and PVK.With the increasing of POSS content,the luminescent intensity was higher than neat PVK,and color purity was improved effectively.Four carbazole derivatives and two fluorene derivatives were prepared by nucleophilic substitution reaction。The primary products were separated for purification,and their microstructures are characterized through 1HNMR FTIR and UV spectrum..Successful preparation of six derivatives lays good basis for further research. |
