Synthesis and characterization of novel epoxy resins-filled microcapsules with organic/inorganic hybrid shell for the self-healing of high performance resins

Novel microcapsules (MCs) with organic/inorganic hybrid shell were successfully fabricated using epoxy resin as core material and nano boron nitride (BN) and mesoporous silica (SBA-15) as inorganic shell materials in aqueous solution containing a water-compatible epoxy resin curing agent. The morphologies, thermal properties and Young's moduli of MCs were investigated. The results indicated that epoxy resins were encapsulated by BN/SBA-15/epoxy polymer hybrid layer, the resulting MCs were spherical in shape and the introduction of inorganic particles made MCs had rough surface morphology. The mean modulus value of MCs was from 2.8 to 3.1GPa. The initial decomposition temperature (T-di) of MCs at 5wt% weight loss was from 309 to 312 degrees C. MCs showed excellent thermal stability below 260 degrees C. The structures and properties of MCs could be tailored by controlling the weight ratio of inorganic particle. When the weight ratio of BN to SBA-15 was 0.15:0.10, MCs had the highest T-di and modulus. The resulting MCs were applied to high performance 4,4-bismaleimidodiphenylmethane/O,O-diallylbisphenol A (BMI/DBA) system to design high performance BMI/DBA/MC systems. Appropriate content of MCs could improve the fracture toughness and maintain the glass transition temperature (T-g) of BMI/DBA system. The core materials released from fractured MCs could bond the fracture surfaces of the BMI/DBA matrix through the polymerization of epoxy resins. When the healing temperature schedule of 100 degrees C/2h+150 degrees C/1h was applied, 15wt% MCs recovered 98% of the virgin fracture toughness of BMI/DBA. Copyright (c) 2016 John Wiley & Sons, Ltd.