Authors: Jingjing Lin Xiaodong Wang
Publish Date: 2008/07/01
Volume: 43, Issue: 13, Pages: 4455-4465
Abstract
A series of ocresol novolac epoxy oCNERbased composites containing various amount of SBA15 SBA16 and MSUX type mesoporous silicas were prepared and their performances were evaluated Morphological investigation by SEM reveals that the mesoporous silicas achieve a good dispersion in the oCNER matrix due to an effective surface modification The dielectric constants of all the composites were measured in the frequency range of 50–1000 kHz The investigation suggested that the dielectric constant could be reduced from 40 of the pure thermosetting oCNER to 371 373 and 373 by incorporating 5 wt SBA15 SBA16 and MSUX respectively The reduction is attributed to incorporation of air voids stored within the mesoporous silicas the air volume existing in the gaps on interfaces between the mesoporous silica and the matrix and the free volume created by introducing largesized domains The composites present stable dielectric constants across the wide frequency range An improvement of thermal stability of the oCNER is achieved by incorporation of the mesoporous silica materials while the enhanced interfacial interaction between the surfacemodified mesoporous silica and the oCNER matrix has also led to an improvement of toughness
Keywords: