Enhancement of mechanical properties of buckypapers/polyethylene composites by microwave irradiation

Buckypapers (BPs) were generally laid up interleaved with polyethylene (PE) films to form BPs/PE composites after hot press. However, the mechanical properties of BPs/PE composites as-prepared were not good enough owing to poor impregnation and weak interfacial interactions between the matrix and carbon nanotube (CNT). In this paper, controlled microwave radiation treatment was applied on the BPs/PE composites. It is found that the microwave irradiation can effectively improve the tensile strength and stiffness of BPs/PE composites. Specifically, the tensile strength of BPs/PE composites increases from 20.9 MPa upto 34.1 MPa, 2.8 times that of pure PE, while the modulus increases from 880 MPa to 1778 MPa, 3.0 times that of pure PE. In addition, the structures (including fractured morphology, the interfacial composition between CNT and PE, structure of CNT and PE matrix, and crystallization) of BPs/PE nanocomposites with and without microwave irradiation were observed by SEM, FTIR, Raman, X-ray, and DSC, and then a mechanism of microwave irradiation to enhance the mechanical properties of BPs/PE composites was also proposed.