Extraction and characterization studies of carica papaya fiber reinforced epoxy polymer composites

Abstract

The need for eco-friendly green materials in engineering and domestic applications stimulated researchers to search for new natural fibers. Non-biodegradable materials are very detrimental to nature and so currently researchers are concentrating on natural fiber reinforced green composites. The requirement for natural fiber is increasing, which encourages the researchers to find new natural fibers and make them as reinforcement in the polymer matrix. The properties of the natural fibers are largely influenced by their origin, age, part of plants and different extraction methods. For effective surface roughness, natural fibers need chemical modification. After chemical modification, the physical, chemical and mechanical properties of natural fibers have improved when compared with raw fibers. The bark fibers identified from various plants (jute, hemp, kenaf, flax, okra and ramie) has enthralled the researchers with their easy accessibility and desirable properties. Taking all the above aspects into account, present research initiates the extraction and characterization studies of Carica papaya fibers (CPFs). Bark fibers identified from the Carica papaya (CP) plant which most probably have better qualities and not yet been studied despite their global presence. This study aims to identify the physicochemical properties of raw and chemically treated CPFs in comparison to other known natural fibers. The CPFs were extracted using traditional microbial degradation. Thermal behavior of the raw CPFs shows that cellulose started degrading at the temperature of 322.1°C. The value of density (943 kg/m3 ) of the raw CPFs may confirm the usage in light weight applications. The results obtained from Fourier transform infrared (FTIR) and X-ray diffraction (XRD) showed that the raw CPFs were rich in cellulose content (38.71wt. %) with a Crystallinity index (CI) of 56.34%. Alkali treatment of CPFs has been optimized at 5% (w/v) NaOH and 60 min soaking time. Chemical analysis revealed the reduction of hemicellulose and lignin in optimally treated CPFs. The FTIR spectra of both fibers had supported this evidence. Optimally treated CPFs have relatively higher tensile strength (548 ± 14.6 MPa) than the raw CPFs (530 ± 11.2 MPa) due to chemical modification. Atomic force microscopy (AFM) results show more prominent hills and valleys in the surface morphology of the optimally treated CPFs which confirmed the rough surface. newline