Preparation and characteristics of poly(benzoxazine-urethane)/graphene oxide composites: Toughness, mechanical and thermal properties

ABSTRACT

Poly(benzoxazine-urethane)/graphene oxide [poly(Bz-PU)/GO] composites were successfully prepared by blending benzoxazine (Bz) with graphene oxide (GO) and isocyanato (NCO)-terminated polyurethane prepolymer (PU), followed by thermally activated polymerization of the blends. The network was formed via the mutual reaction and intermolecular interaction among the hydroxyl of GO, NCO groups of PU and phenolic hydroxyl of Bz. The toughness shown from SEM images and tensile properties of polybenzoxazine (PBz) plastic composites can effectively be improved by alloying with PU and GO. The onset curing temperature and exothermic peak maximums of the polymerization obtained from differential scanning calorimetry decreased resulted from the GO addition. The thermogravimetric analysis showed that the incorporation of 0.5 wt% of GO slightly improved the thermal stability of poly(Bz-PU)/GO composites. Additionally, the storage modulus improved and the glass transition temperature (Tg) increased gradually as the increasing GO content not beyond a certain amount. Finally, the exothermic peaks of the polymerization were shifted to lower temperature, and the thermal stability increased for the ternary composites as the number average molecular weights (Mn) of polyol decreased.

KEYWORDS:

• polybenzoxazine
• Polyurethane prepolymer
• Graphene oxide
• Poly(benzoxazine-urethane)/graphene oxide
• Composites

Funding

This work was financially supported by the National Natural Science Foundation of China (Grant No. 51273054) and the Natural Science Foundation of Anhui Province's Higher Education of China (No. KJ2015A205).