MECHANICAL PROPERTIES AND MORPHOLOGY OF ACID MODIFIED CARBON NANOTUBE/DGEBA-BRIDGED POLYSILSESQUIOXANE COMPOSITES

摘要

Diglycidyl ether of bisphenol A (DGEBA)-bridged polyorganosiloxanes precursors have been prepared successfully by reacting diglycidyl ether of bisphenol A epoxy resin with (3-aminopropyl)triethoxysilane. Acid-modified and unmodified multiwall carbon nanotubes (MWCNTs) were dispersed in the diglycidyl ether of bisphenol A-bridged polyorganosiloxane precursors to prepare the carbon nanotube/diglycidyl ether of bisphenol A-bridged polysilsesquioxane (CNT/DGEBA-PSSQ) nanocomposites. SEM microphotographs demonstrate that acid-modified CNT exhibits better dispersion than unmodified CNT in DGBEA-PSSQ. The mechanical properties of nanocomposites depend strongly on the affinity between CNT and the polymer matrix. Adding multiwall carbon nanotubes markedly enhances the mechanical properties of nanocomposites. The mechanical properties of acid-modified CNT/DGBEA-PSSQ nanocomposites, except for tensile strength, are more favorable than those of unmodified CNT. Tensile strength depends on the length of the CNT. Acid modification reduced the length of CNT. Raman spectra also verified that acid modification destroyed the structure of CNT.