In accordance with the present invention, at least two sheets of a thermoplastic polyalkene are bonded to one another to form a bonded product and at least one surface of a polyalkene is formed on at least a part of a synthetic nonhydrogenated, unvulcanized elastomeric product to form a bonded product by disposing the sheets of polyalkene or at least one sheet of polyalkene on the synthetic elastomeric product, as the case may be, in a mold, closing the mold and subjecting the assembly to microwave energy at a power level, for a time and while applying a pressure sufficient to bond the two polyalkene sheets or the polyalkene sheet to the synthetic elastomeric material, as the case may be.