Starch Biocomposite Reinforced With Chemically Modified Hibiscus esculentus Biofibers

The global proliferation of non-biodegradable plastics in landfills and marine ecosystem represents a critical environmental crisis. To mitigate this, present study explores the development of sustainable, starch based bio composites. Starch biocomposites was fabricated using corn starch matrix cross-linked with urea-formaldehyde and reinforced with chemically modified Hibiscus esculentus biofibers. The mechanical and structural properties of cross-linked starch matrix and resulting biocomposite were comprehensively evaluated by universal testing machine, Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, and X ray diffraction. Mechanical testing revealed that while the cross-linked starch matrix achieved tensile, compressive and flexural strengths of 11.26, 21.93, and 35.51 MPa, respectively. However, the incorporation of 15 wt% modified fibers in matrix significantly enhanced these properties to 17.2, 37.64, and 67.5 MPa. Thermal analysis indicated a substantial increase in stability; the final degradation temperature rose from 525°C (neat corn starch) to 671°C for the fiber reinforced biocomposites. Furthermore, the biocomposite demonstrated superior resistance to water and acid–base environments compare to starch matrix alone. In flammability tests of biocomposites, magnesium hydroxide fillers outperformed zinc borate in providing flame-retardant properties. These findings highlight the potential of starch fiber sustainable biocomposites as high performance, biodegradable alternatives to synthetic plastics, supporting the transition toward a circular economy.