Natural fiber hybridization has been peaking across industries as it offers a promising approach for developing sustainable and eco-friendly alternatives. In this study, hybrid coconut coir and tiger grass fiber composites of weight ratio 1:1 were fabricated by encapsulating their strands into epoxy resin and hardener matrices. The hardness and flexural performance of the hybrid fiber composite were characterized based on ASTM standards D2240 Adapted and D790 Adapted and compared with composites reinforced with the individual fibers. Among the three fiber composites, the hybrid composite exhibited the highest flexural modulus (2.41 GPa), representing a 35.3% improvement over pure coir composites and an 11.6% increase relative to pure tiger grass composites. This improved flexural stiffness of the hybrid composite is attributed to the mechanical compatibility of coir and tiger grass, resulting in effective stress transfer upon hybridization. In contrast, shore durometer hardness results showed no significant differences among the composites, with the hybrid composite recording an average hardness reading of 71. These results support that the hybridization effectively mitigates the mechanical limitations of the individual fibers offering broader potential for sustainable industrial and structural applications.

Natural materials used in broom-making like tiger grass fibers and midribs of coconut leaves have potential use in composites as alternative reinforcements due to their biodegradability and availability at lower prices while offering some possible enhancements on mechanical properties. In this paper, tiger grass fibers and coconut leaf midribs from locally made brooms were reinforced in epoxy resin in a unidirectional orientation. No chemical treatment was applied to the reinforcing materials. A hybrid fiber reinforced composite was also prepared using a manual casting process. The mechanical characterization performed are flexural and durometer hardness tests. Results revealed that all sample types of composites obtained lower mean flexural strength and hardness than the unreinforced sample. This could be linked to the absence of surface treatment that possibly led to a weaker adhesion between the fibers and the epoxy matrix. Moreover, all composites obtained almost similar flexural strength of about 74 MPa which might be primarily influenced by the epoxy strength since the load applied is in perpendicular direction with the unidirectional reinforcements. Nevertheless, an improvement of about 22 % was obtained in terms of the flexural modulus of the composite with coconut leaf midrib.

Natural fibers are considered as alternative reinforcements in composites due to their accessibility, affordability, renewability and potential positive effects on some properties. Sources of these fibers include bast, leaf, seed and grass. In this paper, untreated tiger grass fiber, which is typically used as material in soft brooms, has been reinforced in epoxy resin with varying loading of 0 %, 5 %, 10 %, 15 % and 20 % by mass of matrix. For the composite manufacturing, the samples were prepared with the use of silicone molds and were subjected to tensile and water absorption tests. Based from the results, the tiger grass fiber reinforcement has provided significant improvements on tensile strength. The sample with 20 % fiber content achieved the maximum strength of 42 MPa which correspond to about 91 % enhancement as compared to the plain sample. This could be associated with the stress transfer between the unidirectional fibers and the epoxy matrix. As for water absorption, all composites only attained minimal mean values that ranges from 0.035 % to 0.063 %. This could be linked to the water-resistant characteristic of the matrix that protected the reinforcing fibers from being exposed directly to water.

The incorporation of natural fillers like eggshells in polymers has gain attention due to their potential capability to enhance some properties while providing possible cost savings. In this paper, quail eggshells were used as bio-based filler in silicone rubber and their effects on the mechanical properties were investigated. For the composite manufacturing, samples containing 4.8 wt.% (5 phr), 9.1 wt.% (10 phr) and 13 wt.% (15 phr) of crushed quail eggshells were manually prepared. The mechanical characterization tests considered are compression, tensile and hardness. Based from the results, the sample with 4.8 wt.% filler achieved the highest compressive strength of 2.79 MPa and hardness of 53.3 which correspond to improvements of about 11 % and 6 % as compared to the plain rubber, respectively. These enhancements can be associated with the good dispersion of the filler at lower loading. However, higher filler contents resulted to a decrease in mechanical properties which could be linked to the possible agglomeration of crushed eggshells and weak filler to matrix interaction caused by lack of surface treatment. Nevertheless, the improvements attained by adding quail eggshells at lower percentage in rubber can still make it an alternative filler to consider.

Eggshells, which are mainly composed of calcium carbonate, have been considered as alternative filler in polymer composites to reduce cost and improve some of the material properties. One of the biofillers that has not yet widely studied for its potential use in rubber is quail eggshell. For this research study, the effects of quail eggshell filler on the abrasion resistance and thermal degradation of room temperature vulcanizing (RTV) silicone rubber were investigated. Samples with 0, 5, 10 and 15 wt. % quail eggshell filler were prepared through manual mixing and open molding process. Abrasion resistance test was performed based on ASTM D4060 while thermogravimetric-differential thermal analysis was utilized to examine thermal degradation. Results revealed that the abrasion resistance of silicone rubber increases as the eggshell filler content rises from 0 to 15 wt. %. The silicone rubber with 15 wt. % filler achieved the best abrasion resistance with a mass loss of about 44.7 % less than the sample without filler. For the thermal analysis, the sample with 15 wt. % eggshell filler achieved a higher peak degradation temperature of about 605.61 oC as compared to the plain sample (511.25 oC) but the latter appears to resist thermal degradation better at high temperatures.