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Title: Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. V. Comparison with other surface treatments. [Gamma radiation]

Journal Article · · J. Appl. Polym. Sci.; (United States)

Helium gas plasma treatment of low-density polyethylene (LDPE) yields much lower peel strength than oxidative treatment using chromic acid and oxygen gas plasma. The practical adhesion, the bondability retention, and the bond durability of oxidatively treated LDPE sheets, bonded with epoxy adhesives, have been compared with those of partially hydrolyzed LDPE-methyl acrylate surface grafts. The oxidized surfaces easily lose the bondability by light rubbing with tissue paper, solvent extraction, heat aging, and artificial weathering, whereas the grafted surfaces retain the bondability. The bondability loss is due to removal of the oxidized layer, and the bondability retention is due to retention of the surface homopolymer layer. Conventional antioxidants stabilize the grafted but not the oxidized surfaces against thermal oxidative degradation. The grafted LDPE joints have much higher bond durability in humid environments than those of the oxidized LDPE joints. The dry and wet peel strengths of oxidized LDPE joints are greatly improved by application of primers consisting of a base epoxy resin and organic solvents. An adhesion mechanism involving penetration of epoxy adhesives into the oxidized layers and subsequent reinforcement of the layers by curing of the penetrated epoxy is proposed. 5 figures, 5 tables.

Research Organization:
Nippon Telegraph and Telephone Public Corp., Tokai, Japan
OSTI ID:
5486637
Journal Information:
J. Appl. Polym. Sci.; (United States), Vol. 25:1
Country of Publication:
United States
Language:
English