The present study shows some important effects of chemical treatment on the structure and morphology of coir fibre. The objective of the present study is to optimise overall properties of coir fibre so as to use coir fibre as a reinforcing agent in thermoplastic and thermosetting polymers. In the present study, coir fibre is treated with ferric nitrate salt. A thermal treatment has been done at temperature of 1000°C by using annealing method. X-ray diffraction of the treated coir fibre reveals the crystalline nature of the fibre. Change in morphology has been found in coir fibre when subjected to scanning electron microscopy. Finally, the Fourier transform and infrared spectrographs show the presence of traces of iron oxide:fibre in the prepared composite.
Natural fiber reinforced polymer composites have to face many challenges in order to be commonly used as engineering materials [
Natural fibres are mainly required (next to cloth making) in the manufacture of composites. It is not only eco- friendly but also cost effective and durable. When compared to synthetic fillers such as glass, aramid, talc, and silica, natural fibres have a low density in many cases in comparison to synthetic fibres. Further, they do not leave any byproduct at the time of fabrication of composites because they are biodegradable in nature. In addition, these fibres can be processed at low temperature and therefore play a crucial role in energy investments for the production of composites [
The use of natural fibres as a reinforcing agent in polymer composites has been the centre of attraction among researchers during last so many years. The natural fibres are at a low density, and chemical treatments have been done, easy availability, renewable and biodegradable in nature. Though their use as a reinforcing agent is not much in vogue (because of their hydrophilic nature), their tendency to amass at the time of processing and their poor resistance to moisture [
In the present study, the main objective was to find effect of chemical treatment of coir fibre and see changes on the structure and morphology of fibre. It is clear from the obtained results that the chemically treated coir fibre is a reinforcing agent in polymer science and it is worth using as engineering materials in modern technology.
The fibre used for experimental study was taken from the temples of Bhopal.
The fibre used for experimental study was kept inside water for 24 hours and then washed so as to remove impurities like dust etc. After drying it, the chemical treatment was given.
Ferric nitrate (monohydrate, extra pure, Fe(NO3)3∙9H2O) and ammonium chloride (NH4Cl) was taken in the ratio 10:4 in 500 ml of distilled water. The mixture was stirred till a homogenous solution was obtained. In this mixture 10 g of processed coir fiber was added and then 1:1 solution of NH4OH (liquid ammonia) was added to it and left the solution for one hour. Again the mixture thus obtained was dried and then annealed in muffle furnace at 1000˚C and kept it at that temperature for 15 min.
The reaction may take place in this way
When ferric nitrate reacts with ammonium chloride and ammonium hydroxide along with coir fiber at 1000˚C ferric oxide is formed which is confirmed through XRD analysis and other byproducts like 6NH4NO3 ammonium nitrate and HOCl (hypoclorous acid) decomposed at such high temperature and only ferric oxide is left.
The material formed was found to have the structure that of like sand crystals with holes in physical appearance. The sample appeared in powder form and it is rusty in color.
The scanning electron microscope (SEM) images have been taken out from Japan made, JSM 6390A (JEOL Japan) at dissimilar magnification of the above prepared samples. Before SEM examine the prepared samples were layered with gold in a vacuum coating unit. The cross section areas ranging of samples were approximately 1 cm to 5 microns in width and the magnification ranging of SEM was the order of 20× to approximately 30,000×, with spatial resolution of 50 to 100 nm.
The XRD measurements were carried out using Bruker D8, X-ray diffractometer. The X-rays were produced using a sealed tube and the wavelength of X-ray was 0.154 nm, and also operated at 40 kV and 100 mA with radiation source (CuK-alpha). The angle (2q) was scanned in the range of 5 to 80 at speed of 1.2 min−1.
The X-rays were detected by using a fast counting detector based on silicon strip technology (Bruker Lynx Eye detector). From the X-ray diffraction study it is clear that treated fibre composites are crystalline in nature and shows the peaks of Fe2O3 [
The XRD pattern of the received composite is shown in
The XRD measurement of present samples has been shown in
The FTIR analysis of treated fibre has been depicted in
From the FTIR analysis (
Further, the FTIR study shows that when the coir fibre is treated by ferric nitrate salts there is a shift in the absorption from 3446 cm−1 to 3397 cm−1 which suggests that there is removal of impurities like lignin, cellulose and hemi-cellulose in the fibre [
From above study it is clear that there is a trace of coir fibre in the sample in which there is an improvement in the removal of impurities in the fibre. However the peak at 556 cm−1 proposes the presence of γ-Fe2O3 in the sample. As a result, it can be concluded that there is successful synthesis of iron oxide (γ-Fe2O3) fibre by annealing.
Finally, we were concluded the following discussions from the present experiment work:
A change in the morphology and structure has been found after the treatment of coir fibre which is confirmed by SEM technique.
The XRD analysis shows that treated coir fibre composites are crystalline in nature and shows the traces of γ-Fe2O3:fibre.
Finally, the FTIR study also shows that when the coir fibre is treated by ferric nitrate salts there is a shift in the valley from 3446 cm−1 to 3397 cm−1 which suggests that there is removal of impurities like lignin, cellulose and hem-cellulose in the fibre.
This study deals with the preparation of coir fibre composites with some new modification methods. Finally based upon the present study, one can draw the following conclusions:
It is clear that chemical treatment of coir fibre is an effective method to modify the properties of fibre. Change in the morphology of coir fibre has been seen through SEM analysis. An XRD study reveals the crystal structure of the samples. The FTIR study confirms the reduction of impurities from the fibre.
The authors are thankful to UGC-DAE Consortium, Indore for providing research facilities. The authors are also highly grateful to Vice Presidency for Graduate/Studies and Scientific Research at University of Tabuk, and Ministry of Higher Education, Kingdom of Saudi Arabia for the kind financial assistance.