Deformation micromechanics of a thermoplastic-thermoset interphase of epoxy composites reinforced with poliethylene fiber

The polyethylene fibre is one of the strongest man-made materials; its strength is based on its high crystalinity order. Nevertheless, due to the Polyethylene chemical nature, it shows a low reactivity, which limits its use for composite materials, especially with thermoset matrices like the Epoxy resin. The present work uses Raman Spectroscopy to monitor the loading and failure of a thermoplastic-thermoset interface. Pull-out specimens were prepared with Spectra 1000 Polyethylene fibre embedded in a epoxy resin block; the fibre extraction was performed in a stepwise fashion and with the aid of a micro-Raman, spectra were taken along the interface through out the whole process. The technique allowed to measure the interface strength and to monitor the propagation of the debonding front up to total failure. Some results correspond to specimens were the interface was improved by changing the surface chemistry of the thermoplastic fibre to make it more compatible to the thermoset matrix. © 2004 Kluwer Academic Publishers.