Effect of short glass fiber/filler particle proportion on flexural and diametral tensile strength of a novel fiber-reinforced composite

Abstract Purpose To evaluate the effect of glass fiber/filler particles proportion on flexural strength and diametral tensile strength of an experimental fiber-reinforced composite. Methods Four experimental groups ( N =10) were created using an experimental short fiber-reinforced composite, having as a factor under study the glass fiber (F) and filler particle (P) proportion: F22.5/P55 with 22.5wt% of fiber and 55wt% of filler particles; F25/P52.5 with 25wt% of fiber and 52.5wt% of filler particles; F27.5/P50 with 27.5wt% of fiber and 50wt% of filler particles; F30/P47.5 with 30wt% of fiber and 47.5wt% of filler particles. The experimental composite was made up by a methacrylate-based resin (50% Bis-GMA and 50% TEGDMA). Specimens were prepared for Flexural Strength (FS) (25mm×2mm×2mm) and for Diametral Tensile Strength (DTS) (3×6 O mm) and tested at 0.5mm/min in a universal testing machine. Results The results (in MPa) showed significance (different superscript letters mean statistical significant difference) for FS ( p p B ; F25/P52.5: 245.77±26.80 AB ; F27.5/P50: 246.88±32.28 AB ; F30/P47.5: 259.91±26.01 A . DTS results: F22.5/P55: 21.82±4.42 B ; F25/P52.5: 22.00±7.40 B ; F27.5/P50: 18.63±4.41 B ; F30/P47.5: 31.05±2.97 A . In SEM analysis, areas without fiber reinforcement demonstrated to be more prone to the presence of bubbles and crack development. The group F30/P47.5 showed areas with a great quantity of fibers without empty spaces for crack propagation. Conclusion Increasing fiber content results in higher flexural and diametral tensile strength of an experimental composite reinforced with glass fibers.