Surface modification by continuous graft copolymerization. I. Photoinitiated graft copolymerization onto polyethylene tape film surface

A process has been developed for continuous photoinitiated graft copolymerization of acrylamide (AM) and acrylic acid (AA) onto the surface of high‐density polyethylene (HDPE) tape film, presoaked in a solution containing monomer and initiator under nitrogen atmosphere. As photoinitiator we have used benzophenone, which is efficient for photografting of polyolefins with acrylic monomers. The presoaking procedure of the tape film is very important for efficient photografting within short irradiation times. In ESCA spectra of the grafted tape film the relative intensity of the nitrogen over carbon peaks of film grafted with acrylamide is about 5–10% after 6 s irradiation time. The relative intensity of oxygen over carbon peaks in ESCA spectra of film grafted with acrylic acid is about 10–20% after 8 s irradiation time. The effects of varying the monomer concentration in presoaking solution and the different irradiation conditions on the grafting yield have been investigated. This technique has the advantages of being a continuous process with short irradiation times without requirements of vacuum conditions and appears to be promising for practical applications.