Composite Of Benzoxazine, Epoxy And MWNT

Multiwalled carbon nanotubes(MWNTs) is composed of concentric cylinder which is formed by curled graphite layer. It has exceeding mechanics performance, high chemical and heat resistance, excellent electric conduction and photoelectricity property. Polybenzoxazine is a novel thermal set resin. It not only has the excellent properties of conventional phenol resin, but also has good dimension stability, good toughness, stable dielectric constant and very low moisture absorption.In this paper, two methods are used to modify MWNT. Three different structure benzoxazine was synthesized by melt method and solution method.The MWNT after one modifying method was mixed with two different structure benzoxazine(allylamic benzoxazine and diamine benzoxazine) and epoxy separately. Two Composites of Benzoxazine, Epoxy and MWNT was prepared. In this method, use HNO₃ to treat MWNT to add hydroxyl and carboxyl and then modify MWNT with TDI to add isocyanate group.The mixed system and composite of benzoxazing, Epoxy and MWNT arecharacterized by IR, DSC, DMA, SEM and TG. The surface modification ofMWNT decreased the curing temperature of the system and improved the adhesion between MWNT, benzoxazine and epoxy. The step-curing of this system was researched. Dynamic mechanical analyses and Thermal gravity analyses indicated the storage modulus and heat resistance was improved. The dispersed MWNT inside composite was observed by SEM.