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In this work, Abelmoschus manihot waste fibre was utilized to fabricate epoxy-based composite; raw, 15% alkali-treated and 130% grafted AMF composites were prepared with 10%, 20% and 30% loadings, and the mechanical properties were evaluated. It was observed that, at 30% loading, 130% grafted composite gave the highest tensile strength of 65.73 MPa and the flexural, impact strength, interlaminar shear strength and microhardness gave 130%, 7.06 J, 67.9 MPa and 64%, respectively. Chemical resistance was also found to be excellent for grafted AMF at 30% loading. Similarly, the DMA analysis indicated an increase in storage and loss modulus with grafted fibre composite and a decrease in Tan δ with 30% loadings. Dimensional stability was excellent with respect to grafted AMF composites. SEM analysis proved superior bonding with grafted AMF composites followed by alkali and raw composites. The vertical burning test took a long time to burn off for the grafted AMF composites at 30% loading. TGA proved to be excellent with higher loading in the case of grafted AMF composite. Void volume decreased with respect to fibre loading and with the help of surface modification using alkali treatment and grafting of the fibres. [ABSTRACT FROM AUTHOR]

This paper deals with the graft copolymerization of methyl methacrylate (MMA) on the backbone of Abelmoschus manihot fibres (AMF) successfully carried out under aqueous medium using Fenton's reagent [(ferrous ammonium sulphate (FAS) (8.0 × 10–3 M) and H2O2 (0.12 M)] as a redox initiator and N,N′-methylene bisacrylamide as a crosslinker to impart hydrophobic properties. Grafting was optimized under different conditions concerning time, temperature, monomer ratio, material to liquor ratio, initiator concentration. Maximum graft add-on% obtained was 130% at a temperature of 75 °C, 3:1 monomer to fibre ratio, time of 150 min, 1:75 fibre to liquor ratio and 20:20 (FAS: H2O2) initiator concentration. The grafted AMF fibres were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies. FT-IR spectroscopic data showed a peak at 1726 cm−1 of C=O (ester), and another peak at 1650 cm−1 of adsorbed water was absent in the grafted fibre. The grafted fibre showed excellent thermal stability with an overall weight loss of 51.8% and char residue of 48.2% as well as X-ray diffraction of MMA grafted AMF showed 23% crystallinity and crystallinity index of 0.19. These raw and grafted fibres also subjected to physico-chemical properties like moisture absorbance, swelling behaviour and chemical resistance studies showed that MMA grafted AMF exhibited hydrophobic properties. Therefore, due to this hydrophobic behaviour, the oil absorbency of MMA grafted AMF was studied towards four emulsions: crude oil saline, engine oil saline, diesel oil saline and used engine oil saline. In total, 130% grafted AMF fibre absorbed 30.07 g of crude oil, 12.20 g of diesel oil, 16.00 g of engine oil and 17.32 g of used engine oil. These results showed that the oil removal efficiency of the grafted AMF was intact by oil fraction type and can be applied for all kinds of oil fraction spillage. [ABSTRACT FROM AUTHOR]