cyltrichlorosilane prior to spinning facilitated the removal of the webs from the glass. After washing with ethanol and drying at room temperature and atmospheric pressure for 24 h, the webs were impregnated with resin by dipping them into diluted resin and they were allowed to dry and cure for at least 60 h. The reference films were obtained by curing the diluted resin between two Teflon sheets for 60 h.
Young's moduli, fracture stresses, and fracture strains of the composite and reference films were measured on a Zwick Z020 tensile testing machine. The initial distance between the clamps was set to 6.5 mm and the tests were performed at a strain rate of 7.5 mm/min. Specimens ca. 5 cm long and 8 mm wide were cut from the films. Film thicknesses were ca. 100 mm for the composites and ca. 200 mm for the reference film. The thickness of the reference film obtained by curing the diluted resin without covering was ca. 2 mm.
In most cases the specimens could not be fully stretched prior to the measurement thus the moduli and fracture strains were determined manually. The error in the distance between the clamps was at time zero usually on the order of 1ยฑ2 %.