Preparation And Performance Of Graphene/PBO Copolymer Films

Poly(p-phenylene-2,6-benzobisoxazole)(PBO) films is one of high-perform-ance organic polymer films, which is characterized by low density, superior mechanicalproperties, excellent thermal and thermo-oxidative stability and good flame retardance.It has great potential to apply in various frontier fields, such as aeronautics astronauticsand weaponry et al. Although, PBO films have excellent performances, but in order tofurther improve the mechanical properties of PBO films, upgrading existinghigh-performance film variety, there is an urgent need modifying it. In this paper, inorder to improve the mechanical properties and heat retardant levels of PBO film, wedesign two graphene derivatives, which are graphene oxide(GO) and graphenenitride(GO-NH2). We use GO and GO-NH2as reinforcing filler, using―one-pot‖preparegraphene/PBO copolymer films.In this paper, we use Hummers method prepare GO. Using a novel―one-pot‖and asimple―off HCl‖polymerization prepares GO/PBO copolymer films. In this process,the carboxyl(-COOH) on the GO surface can react with4,6-diaminoresorcinoldihydrochloride(DAR), so we can acquire DAR modified GO(GO-DAR). GO-DAR hasbetter compatibility and reactivity in PBO matrix. It can covalent connect with PBOsuccessfully. On this basis, by changing the amount of GO, using―hot pressing‖preparethree kinds of GO/PBO copolymer films with differents levels of GO.Similarly, in order to further improve the dispersion of GO in PBO matrix, enhancechemical reactivity of functional group on the surface of graphene. We useethylenediamine modified graphene secondly. Specific reaction process as follows: GOas raw material, Dicyclohexylcarbodiimide (DCC) as dehydrating agent,4-dimethylaminopyridine(DMAP) as catalytic agent, Ethylenediamine as reagentprepare GO-NH2. On this basis, using–NH2on the GO-NH2react with p-phthalic acid.using new and unique "one-pot" in-situ polymerization process prepare three kinds ofGO-NH2/PBO copolymer films with differents levels of GO-NH2.In this paper, we analyse the chemical structure, crystal structure, morphology andfunctional group amouts of GO and GO-NH2, they can be identified monolayer. Tofurther explore the reaction mechanism of―one pot‖preparation, we annalyse thechemical structure of GO-DAR and GO-NH2-PTA carefully. The results showed that:GO and GO-NH2can respectively react with the two monomers of PBO efficiently. Inaddition, we also carefully analyse chemical structure, crystallization behavior ofGO/PBO and GO-NH2/PBO copolymer films, and compare the Section morphology,mechanical properties and thermal properties of the two copolymer films of differentGO and GO-NH2dosages. The experiment research results show: GO and GO-NH2both can be covalently grafted to PBO molecular chain. With the increase of GO and GO-NH2, the mechanical properties, heat resistance of two kind of copolymer filmsimprove remarkably, and GO-NH2has better modified outcome.