Improvement of gas barrier property of polyolefins by diamond-like carbon deposition and photografting polymerization



The gas barrier properties of isotactic polypropylene (iPP) and high-density polyethylene (HDPE) are both significantly improved by diamond-like carbon (DLC) deposition and photografting polymerization using acrylic acid (AA) monomers. In fact, the gas barrier properties can be highly improved just by DLC or by AA-photografting polymerization. The improvement observed by AA-photografting polymerization is more pronounced than that by DLC deposition in our general experimental condition. In more detail, the oxygen barrier property of DLC-deposited and AA-grafted iPP is considerably improved by ∼10 times when compared with that of neat iPP. As for HDPE, the oxygen barrier property is enhanced by nearly six times through DLC deposition and photografting polymerization. By observing the surfaces, 30 nm layer of DLC and 1.0 μm of AA-grafted layer are firmly constructed on the polyolefins, which should contribute to the enhancement of the oxygen barrier property. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013