Composite laminates are prepared based on new agro waste of 4% alkali-treated and untreated Lagenaria siceraria fiber (LSF)-reinforced epoxy resin using four different fiber lengths of 3, 5, 7, and 9 mm with five different fiber contents of 15, 20, 25, 30, and 35 wt% by compression mold technique. The composite laminates were cut according to ASTM standard dimensions to test its mechanical properties like tensile, flexural, compression, and impact strength. The mechanical properties are enhanced for increase in the fiber length upto 7 mm and 30 wt% of untreated and treated fiber; however, further increase (such as fiber content and fiber length) in parameters causes decrease in mechanical properties for both treated and untreated LSF-reinforced composites. Scanning electron microscopy (SEM) of fractured composite laminates studies was carried out to analyze the fiber–matrix interaction. The composite reinforced with 7 mm fiber length and 30 wt% of alkali-treated fiber composites exhibits better mechanical properties compared to other combination.

This study mainly focuses on the possibility of using Coccinia Indica (CI) fiber as reinforcement in structural polymer composite materials because of its lightweight and eco-friendly nature. Fibers were extracted from the dried stems by combing process using metal teeth brush. The thermo-physico-mechanical properties, chemical compositions, and morphological structures of CI fiber were analyzed in detail. A higher percentage of cellulose content in CI fiber and the lesser amount of skimpy lignin, hemicellulose, ash, and wax content were confirmed through chemical analysis. The functional groups with their corresponding peaks were depicted through FTIR analysis. XRD studies divulge that the CI fiber contains crystallinity index (CrI) of 53.03% and crystallite size (L) of 5.81 nm. SEM revealed that the fiber possesses cylindrical morphology with multi-cellular structure. The presence of parenchyma and chlorenchyma tissues in the cell wall of CI fiber was also confirmed, which helps for better adhesion and mechanical properties to the composite. TGA study reveals that the major degradation of CI fiber occurs at a temperature range of 204.16°C to 376.3°C. The tensile strength of cellulose-based CI fiber is comparable with the other conventional fibers and it is well enough for its usage as reinforcing material in composite manufacturing.