Controlled Dielectric Properties of Polymer Composites from Coating Multiwalled Carbon Nanotubes with Octa-acrylate Silsesquioxane through Diels-Alder Cycloaddition and Atom Transfer Radical Polymerization

Industrial & Engineering Chemistry Research (2014), 53(16), 6699-6707.

Zhang Wenjing, Zhou Zheng, Li Qifang, Chen Guang-Xin

Abstract: A synthetic strategy of coating multi-walled carbon nanotubes (MWCNTs) with crosslinkable octa-acrylate polyhedral oligomeric silsesquioxane (POSS) by combining Diels-Alder cycloaddns. with atom transfer radical polymn. in a controlled manner is reported. First, the furfuryl-2-bromoisobutyrate is synthesized by an esterification reaction from 2-bromoisobutyryl bromide and furfuryl alc. Then, the MWCNT-based initiators of atom transfer radical polymn. (ATRP) are synthesized through a Diels-Alder reaction between MWCNTs and furfuryl-2-bromoisobutyrate with controlled grafted content. The MWCNT initiators are used to initiate the ATRP reaction of the octa-acrylate POSS on the MWCNT surface. Finally, a core-shell structure with a MWCNT at the center is obtained, with the thickness of the POSS shell adjusted through different initiators from 5, 10, to 15 nm. The POSS-coated MWCNT is compounded with polyvinylidene fluoride to obtain a kind of composite which has both high dielec. permittivity and low dielec. loss.