Efficient microwave welding of polypropylene using graphite coating as primers

Abstract Graphite coating was created on PP interface for an efficient microwave welding process. The graphite powder (GP) can significantly absorb microwave energy and transform into a large amount of heat upon the electromagnetic absorbent, leading to a sharp increase in temperature that can rapidly melt the interface of PP substrates and form a new structure where the GP was covered. The welding area of PP/GC samples obtained by microwave irradiation exhibited uniform surface appearance and high electric conductivity. Meanwhile, the PP/GC/PP samples showed high interfacial strengths, which were influenced by the duration of microwave welding, the size and content of GP in solder. And the bonding stress under optimal condition was about 2.17 MPa, which demonstrated great potential in plastic bonding and material processing.