RESUMEN
Unsized single-end rovings are oxygen plasma pretreated and organosilicon plasma coated using plasma nanotechnology to optimize the interphase in glass-fiber-reinforced polyester composites and to determine the achievable range of their shear strength for potential applications. This surface modification of the fibers allows us to vary the shear strength of the composite in the range of 23.1 to 45.2 MPa at reduced financial costs of the process, while the commercial sizing corresponds to 39.2 MPa. The shear strength variability is controlled by the adhesion of the interlayer (plasma nanocoating) due to the variable density of chemical bonds at the interlayer/glass interface. The optimized technological conditions can be used for continuous surface modification of rovings in commercial online fiber-processing systems.
RESUMEN
The growing demand for polymer composites and their widespread use is inevitably accompanied by the need to know their degradation behavior over a sufficiently long period of time. This study focuses on commercial glass fiber rovings, which were stored in the indoor environment for up to 11 years. Fibers with different storage times, from fresh up to the oldest, were used to produce unidirectional fiber-reinforced polyester composites that were characterized to determine their shear and flexural properties dependent on fiber storage time. A significant decrease in shear strength was observed throughout the aging of the fibers, down to a decrease of 33% for the oldest fibers. An important finding, however, was that the significant decrease in shear strength was only partially reflected in the flexural strength, which corresponded to a decrease of 18% for the oldest fibers at consistent flexural modulus.
