STRUCTURE AND MORPHOLOGY OF HIGHLY ORIENTED RADIATION CROSS-LINKED POLYETHYLENE FIBERS

Gel fraction, crystal size, melting temperatures and dynamic mechanical properties in tension have been measured for electron-beam irradiated high modulus polyethylene fibres. The fibres were irradiated either in nitrogen or acetylene gas, and post-treated by soaking in one of these atmospheres at 293 and 353 K. Wide angle X-ray measurements indicate that the crystal size remains unaltered by the irradiation. The results from d.s.c. and dynamic mechanical alpha-relaxation behaviour indicate that the presence of acetylene, either during or post-irradiation, increases the ratio between crosslinking and chain scission reactions.