Fatigue and tensile behaviors of fiber-reinforced thermosetting composites embedded with nanoparticles

The development of studying nanocomposites has grown up rapidly in the last decade. The objective of the current research is to study the influence of incorporating cellulose nanocrystals on the mechanical properties of polyester resins, as well as to develop continuous filament e-glass fiber-reinforced polyester nanocomposites, which combine traditional composites with the added advantages of nanocomposites. Cellulose nanocrystals were uniformly dispersed into the polyester resin by an ultrasonic processor. The incorporation and dispersion of cellulose nanocrystals were a state-of-the-art method aimed at overcoming poor dispersion problems at low weight fractions of nanoparticles. Three weight percentages of cellulose nanocrystals were prepared, which were 2%, 4% and 6%. Fatigue and tensile specimens were manufactured by resin transfer molding process. Cellulose nanocrystals were fully characterized by using X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy and zeta-sizer analysis. The optimum incorporation percentage of cellulose nanocrystals was used to prepare glass fiber-reinforced polyester specimens containing cellulose nanocrystals. Tensile and fatigue behaviors of glass fiber-reinforced polyester composites were evaluated by means of universal testing machine and rotating bending fatigue machine. A series of testing specimens for each property was examined in accordance with the corresponding ASTM and JIS standards. The experimental results showed that the addition of 4% cellulose nanocrystals to polyester matrix lead to the optimum tensile and fatigue properties. Mechanical properties were improved through the enhanced material design and proper selection of compatible nanoparticles, and adding cellulose nanocrystals in a weight fraction that does not affect the mechanical properties of glass fiber-reinforced polyester nanocomposites negatively. The presented design of material and geometry have shown promising results for wide range of applications, particularly in biomedical industry, energy and electronics.