Haloform plasma modification of polyolefin surfaces

Polyolefin surfaces (polyethylene and polypropylene) were exposed to haloform (CHX3) plasmas for introduction of monosort halogen groups. Bromoform and chloroform plasmas produced selectively C–Br (100 Br/100 C) and C–Cl (200 Cl/100 C) groups in high yields. The bromoform plasma showed 1–3 and the chloroform plasma 2–7 post-plasma introduced O-functionalities per 100 C. The polyolefin C–Br groups were grafted wet-chemically or by exposure to the vapour of amines, diols and glycols. Thus, spacer molecules could be covalently bonded to maximal 15 spacer molecules per 100 C for the smallest grafted molecules and 1.2 molecules/100 C for larger molecules as octaaminophenylene-POSS. After metal evaporation the end groups of these polymer-bonded spacer molecules formed also covalent bonds to the metal. Thus, flexible, hydrophobic and barrier elements were introduced into the polymer–metal interfaces for high-impact, high-durable and water-resistant metal–polymer composites as measured by means of peel strengths.