Synthesis And Characterization Of Poly(p-phenylenebenzobisoxazole)s With Linear And Two-Dimensional Crosslinked Structure

Poly(p-phenylenebenzobisoxazole)(PBO) is a new generation of polymer fibric material designed and synthesized by the modem theories and methods of organic synthesis and polymerization.The fibers which are spun by the method of dry-jet and wet-spinning have lots of outstanding performances such as high tensile strength,modulus,excellent thermal resistance and flame retardant properties and are widely used in some high-technique fields. In this paper,we designed the synthesis route which contained the steps of acetylization, oximation,Beckmann Rearrangement and deoxidization to obtain 4,6-diaminoresorcinol dichloride(DAR·2HCI) with high purity.Then the DAR·2HC1 was neutralized with the trimethylamine aqueous to produce 4,6-diaminoresorcinol(DAR).DAR was polymerized with trimesic acid(TMA) to obtain the crosslinked PBO resin at a high temperature.The Infra-red spectra,NMR spectra,XRD spectra and DSC methods were used to prove the chemical structure of monomers and PBO polymers.The results will be of significance to extend the synthesis method and application field of PBO.