Abstract
The influence of the antioxidants in polyethylene films on electron-beam-induced graft polymerization was studied. Four kinds of polyethylene film, namely, ultra-high molecular weight polyethylene（UHMWPE）, high-density polyethylene（HDPE）, low-density polyethylene（LDPE）, and LDPE-containing HDPE, were adopted. The antioxidants in these polyethylene films were extracted to enable their identification and quantification. The UHMWPE was found to contain one antioxidant: Irgafos168. Meanwhile, the HDPE and LDPE contained three antioxidants: BHT, Irgafos168, and Irganox1076. The LDPE-containing HDPE contained four antioxidants: BHT, Irgafos168, Irganox1076, and SUMILIZER GP. A monomer solution for graft polymerization to which these antioxidants were added was used for graft polymerization. When phenolic antioxidants such as BHT, Irganox1076, and SUMILIZER GP were added to the monomer solution for graft polymerization, the degree of grafting decreased as the amount of antioxidant increased. The behavior of antioxidants in polyethylene film before and after the electron beam irradiation was studied. Furthermore, the radical-scavenging activities of antioxidant degradants in LDPE-containing HDPE, irradiated with an electron beam, were studied. The amounts of BHT, Irgafos168, Irganox1076, and SUMILIZER GP in LDPE-containing HDPE were found to decrease as the electron beam irradiation dose was increased. When the electron beam irradiation dose was more than 100 kGy, the concentrations of BHT and Irganox1076 decreased to less than 10 ％. For an electron beam irradiation dose of more than 60 kGy, the concentrations of Irgafos168 and SUMILIZER GP decreased to less than 1 ％. A monomer solution for graft polymerization containing the antioxidant degradants in LDPE-containing HDPE, irradiated with an electron beam, was used to graft polymerization. As a result, the radical-scavenging activity of the antioxidant degradants disappeared.
