High‐strength and antistatic PET / CNTs bead foams prepared by scCO 2 foaming and microwave sintering

This paper reported the high strength and antistatic polyethylene terephthalate (PET) bead foam with a typical segregated structure prepared by supercritical carbon dioxide (scCO2) foaming and microwave selective sintering. Firstly, carbon nanotubes (CNTs) were coated on the surface of PET pellets, and then the composite foam with segregated structure was prepared via scCO2 foaming in a confined mold. The interfaces among PET foamed beads were further sintered by utilizing the selective heating behaviors of microwave, which greatly enhanced the interfacial strength and thus the overall mechanical strength of bead foam. The final composite foam showed an electrical conductivity of 0.004 S/m with an extremely low CNTs loading of 0.138 vol%, and its mechanical strength reached as high as 10.44 MPa, far superior to the composite without microwave treatment. Thus, the problem in the welding of PET bead foams and antistatic properties could be solved. The effect of the foaming conditions on the structure and properties of PET foam were systematically investigated, providing a novel method for the preparation of high strength and antistatic engineering plastics composite foam.