## 3 Results and Discussion
### Mechanical Properties  
The tensile strength can be defined as the maximum stress that a material can bear before breaking when it is allowed to be stretched or pulled against the applied load [48]. The tensile strength of the composites in this research were determined and the results are shown in Figure 5. As can be seen from the figure, EQ-35 exhibited the highest tensile strength. In comparison to the pure epoxy composite (97.66 MPa), the addition of a quartzfiber fraction into the composite tended to increase the tensile strength. EQ-20 showed a tensile strength of 166.3 MPa, EQ-25 showed a tensile strength of 170.35 MPa, EQ-30 showed a tensile strength of 194.26 MPa, and EQ-35 showed a value of 226.15 MPa.  
The results show that the tensile strength improved significantly by adding a small quantity of reinforcing fibers. This increase was mainly due to the presence of quartz fibers. Other contributing factors include fair adhesion of the fiber-resin matrix, crosslinking of the epoxy resin, and applied pressure during composite manufacturing. Due to inclusion of quartz fibers, the composite structure exhibits heterogeneity, which enables it to absorb more stress and exhibits less deformation compared to pure epoxy resin. The fractured specimen is shown in Figure 6; the deformation started from the surface and then a huge amount of energy was absorbed at the fiber-resin interfaces. The tensile load was distributed across the epoxy resin, then at interface and subsequently transferred to the quartz fibers, resulting in overall higher tensile strength.  
From these results, we found that tensile strength was enhanced upon increasing the fiber fraction, and EQ-35 (0.35) had the highest tensile strength (226.15 MPa). This was a result of the effective wetting of quartz fibers by the epoxy resin and the improved interfacial bonding resulting from the greater contact area between the fibers and resin. These all contributed to increasing the tensile strength.  
The stress-strain curves obtained during the bend strength test are shown in Figure 7. The bending strength of the pure epoxy composite was 155.3 MPa, that of the quartz fiber/epoxy composite EQ-20 was 209.66 MPa, EQ-25 was 240.63 MPa, EQ-30 was 322.99 MPa,  
Figure 5: Tensile strength of quartz fiber/epoxy composites.  
Figure 6: Fractured specimen (35% quartz fibers). (**a**) Tensile test; (**b**) bending strength test.  
and EQ-35 was 330.69 MPa. Bending strength was found to increase with the increase in quartz fibers due to their better interfacial adhesion with the epoxy resin. The highest value of bending strength was observed for EQ-35 which was 53.03% higher than that of the pure epoxy composite. Embedding quartz fibers enhanced the bending property twofold and the addition of fibers raised the strength in a linear trend. The bending load was distributed among the resin, at the interface, and on reinforcing fibers. The quartz fiber/epoxy composites' ability to resist and bear bending load was increased. The highest value of bending strength of EQ-35 was 330.69 MPa, which was slightly higher than that of EQ-0.30 (322.99 MPa). The woven quartz fiber fabric evenly absorbed the stresses hence resulted in a higher bending strength. The fractured specimen presented brittle nature of both the quartz fibers and cured epoxy resin as shown by Figure 6. Upon curing epoxies exhibit toughness; nevertheless, the inclusion of quartz fibers imparts a geometric structure and form thereby augmenting their toughness. The increased values of tensile strength and bending strength are indicative of the durable composite structure.