IMPROVED ADHESIVE PROPERTIES OF HIGH-MODULUS POLYETHYLENE STRUCTURES .2. CORONA GRAFTING OF ACRYLIC-ACID

High-modulus polyethylene (PE) tapes were grafted with acrylic acid us ing a two-step procedure. The tapes were first subjected to He/AT coro na discharge, immediately followed by exposure of the corona-treated t apes to acrylic-acid-saturated He gas. Evidence for the grafting was p rovided by X-ray photoelectron spectroscopy, which showed the surface of the treated tapes to consist of 64% acrylic acid and 36% PE. The gr afting of acrylic acid is confined to the outermost surface layers, as indicated by reflection infra-red spectroscopy. Pull-out tests showed that the corona grafting of acrylic acid improves adhesion to epoxy r esins by a factor of eight. Moreover, the increased adhesion is not ac hieved at the expense of a decrease in mechanical properties of the hi gh-modulus PE tapes.