Evaluating the performance of gamma irradiated okra fiber reinforced polypropylene (PP) composites: comparative study with jute/PP

Abstract

In this study, two bast fibers such as okra and jute were selected to manufacture composites taking polypropylene (PP) as matrix material by means of compression molding technique with maintaining 40% fiber content on the total weight of the composites. Investigation was done on tensile properties such as tensile strength (TS), tensile modulus (TM), elongation at break (EB%), bending properties such as bending strength (BS), bending modulus (BM) and impact properties like impact strength (IS) and hardness (Shore-A) of the composites. From analyzed data, it was found that Okra/ PP composites showed very competitive mechanical properties to Jute/PP composites. Non-irradiated okra composite showed the value of TS, TM, BS, BM, IS and hardness to be 32.2 MPa, 602 MPa, 55.6 MPa, 3.6 GPa, 19.54 kJ/m 2 and 95 (Shore-A), respectively, whereas that value for non-irradiated jute composite was 35.5 MPa, 629 MPa, 71.5 MPa, 4.5 GPa, 21.48 kJ/m 2 and 96 (Shore-A), respectively. The composite samples were exposed to different intensities of gamma radiation (250-1000 krad) at a dose rate of 330 krad/h and changes in mechanical properties were examined. Both irradiated composites (500 krad) showed significant improvement of mechanical properties compared to that of the non-irradiated composites. Maximum TS, TM, BS, BM and IS value were found to be 41.9 MPa, 685 MPa, 72 MPa, 4.7 GPa and 22.6 kJ/m 2 , respectively for irradiated okra composite and 45.3 MPa, 717 MPa, 88 MPa, 6.7 GPa and 24.3 kJ/m 2 , respectively for irradiated jute composite. Fourier transform infrared spectroscopy was used to identify the surface groups of the composites. Water absorption, degradation behavior of the composites under soil and heat medium were also performed. Degradation tests revealed that okra composite retained its original mechanical properties higher than that of jute composite. The morphology of the composites was inspected by scanning electron microscope.

Development and Characterization of Bio-Composites from the Plant Wastes of Water Hyacinth and Sugarcane Bagasse: Effect of Water Repellent and Gamma Radiation

“…The improvement in TS is due to modification or rearrangement of the polymeric structure of the composites at lower gamma radiation doses. In detail, gamma radiation is known as strong ionizing radiation, which can penetrate the polymeric structure of composites and create different types of reactive sites such as free radicals, ions and peroxides [ 33 , 34 , 35 ]. Therefore, these reactive species can cross-link each other and create a longer polymeric chain with larger molecules.…”

“…Gamma radiation is a powerful radiation which can reorganize the polymer structure and create a more crystallized structure of the material. Gamma radiation has been successfully applied in several studies to increase the mechanical properties of NFPCs [ 32 , 33 , 34 , 35 ]. In the current study, five different doses of gamma radiation, e.g., 100–500 krd were applied to the composites.…”

Effect of glass fiber loading and reprocessing cycles on the mechanical, thermal, and morphological properties of isotactic polypropylene composites

“…Composite materials' properties are determined by the reinforcing fiber properties making them find broad applications in various sectors due to their distinctive blending of mechanical and physical properties. [15][16][17] The composites strengthened with man-made fibers, carbon and glass fibers, for example, are presently dominating natural fiber-reinforced composites because of their moisture and corrosion resistance, stability, and improved strength. [18][19][20][21] However, some of these fibers interrupt the homogeneity of the resin matrix due to poor interaction with the resin, which negatively affects the mechanical properties.…”

Biologically degummed and chemically treated okra bast fibers-reinforced Poly(vinyl alcohol) composites

“…Due to bearing high cellulose content, high tensile strength, stiffness, and aspect ratio; okra bast fiber has been used to make a composite with a variety of polymers viz. polypropylene [13], epoxy [14], light density polythylene (LDPE) [15], etc. The composites of PVA and okra fiber may also have the prospective to produce materials with excellent mechanical properties and promising performance.…”