1250263-72-9Relevant articles and documents
Thermal transitions and reaction kinetics of polyhederal silsesquioxane containing phenylethynylphthalimides
Seurer, Bradley,Vij, Vandana,Haddad, Timothy,Mabry, Joseph M.,Lee, Andre
, p. 9337 - 9347 (2010)
Thermal transitions and reaction kinetics of polyhedral oligomeric silsesquioxane (POSS) with phenylethynylphthalimide (PEPI) moieties were investigated. Specifically, this study was designed to probe the influence of the POSS peripheries, types of spacer group in between the PEPI and the SiO 1.5 core, the architecture of the PEPI arrangement with respect to the SiO1.5 core, and the number of PEPI groups per cage on the thermal transitions and the cross-linking reaction of phenylethynyl. PEPI-POSS compounds with isobutyl peripheries exhibited lower melting temperatures as compared to those with phenyl periphery, consequently these isobutyl PEPI-POSS derivatives have a higher phenylethynyl reaction rate, although the onset of reaction temperature was not significantly affected. Changing the spacer group from propyl to phenyl causes an increase in the melting transition temperature along with a higher heat of fusion at melting; however, the more rigid phenyl spacer enables the PEPI-POSS to form a higher degree of crystallinity upon cooling. The more rigid phenyl spacer also initiates the polyene reactions at lower temperatures. For POSS with PEPI attached to either side of the cage, there are two isomers with respect to the SiO1.5 core. This mixture of two isomers inhibits the formation of crystallinity as compared with the "pendent" derivative where both PEPI groups come off from the same corner of POSS cage. Finally, it was found that these PEPI-POSS molecules have reaction kinetics and onset temperatures on par with organic hexafluorophenylethynyl oligoimides, which make these PEPI-POSS molecules excellent candidates as nanocomposite additives in high performance composite applications.
