Novel E glass composites with polybenzoxazine and in situ generating reactive multi branched titanate for low temperature cure and high thermal resistance applications

Abstract

A new class of E glass fabric reinforced polybenzoxazine titanate composites (EBTA) were made with bisphenol F benzoxazine (BZ) and in situ generating reactive multi branched n-butoxy triethanol amine titanate (TEA) chelate in various ratios. The incorporation of TEA into a polybenzoxazine matrix could cause uniform dispersion within the polymer matrix and ring opening of oxazine at lower temperature, which result in an increase of the cross link density, stiffness and hindered network structures responsible for enhancing the thermal and water resistance. The hypothetical chemical reaction between BZ and TEA was understood by studying the reaction between model compounds such as phenol, tetra isobutyl titanate and triethanol amine. FTIR and DSC studies were utilized to optimize the curing studies and the final cure temperature was established for EBTA composites. The DMA analysis carried out on EBTA composites showed improved stiffness, crosslink density and service temperatures (T_g) with uniform phase distribution when compared to the E glass fabric reinforced polybenzoxazine composite. The thermal stability and char yield with TGA analysis, interfacial adhesion with SEM and hydrolytic stability for the EBTA composites using up to 23% of TEA were found to be improved when compared to the polybenzoxazine composite. The flame retardancy of EBTA composites were found to be retained for the V1 class of polybenzoxazine composite. The EBTA composites showed low maximum cure temperature, improved service temperature, cross link density, stiffness, water absorption resistance, thermal stability and char yield when compared to the E glass fabric polybenzoxazine composite.