Subhash Nimanpure; S. A. R. Hashmi; Rajnish Kumar; Archana Nigrawal; H.N. Bhargaw; Ajay Naik
Abstract
Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly ...
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Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly distributed in polymer matrix. These composites were characterized in term of electrical, mechanical and thermal properties to investigate the stability for high strength electrical insulation materials. Excellent mechanical properties were observed. Tensile, flexural and impact strength of composites at 40 wt. % fibril loading improved by 151.34, 197.43 and 360.07 % as compared to unsaturated polyester resin. A few micro-mechanical models were compared with the experimental values. Nielson-Chen Model predicted the experimental data most accurately. The electrical properties of surface modified sisal fibril composites improved significantly in higher frequency. DSC analysis showed that the decomposition temperature of composite was higher, around 22°C than that of the polyester resin. Thermal degradation reduced and was observed in the range of 83-87% of fibril composites as compared to 97% of resin. Fibril composites are highly sensitive to electrical frequency and exhibit excellent electrical insulation property at 20 kHz. Alkali treated fibril based composites resulted an environment friendly thermally stable, high strength insulation material. Copyright © 2018 VBRI Press.
Rajnish Kumar; S. A. R. Hashmi; Subhash Nimanpure; Ajay Naik
Abstract
Randomly distributed kenaf fibre with varying length (5-50mm) and weight fractions (25-40%) were used to reinforce epoxy resin to prepare environment friendly composites. Effect of fibre length with constant fibre loading on dynamic mechanical properties was studied and its effect on storage modulus, ...
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Randomly distributed kenaf fibre with varying length (5-50mm) and weight fractions (25-40%) were used to reinforce epoxy resin to prepare environment friendly composites. Effect of fibre length with constant fibre loading on dynamic mechanical properties was studied and its effect on storage modulus, loss modulus and damping factor were investigated. Kenaf fibres were also subjected to alkali treatment to improve interaction with the epoxy resin. The mechanical properties of composites improved with the length and loading of fibres. Tensile strength, flexural strength and impact strength of composites at 40 wt% of fibre reinforcement improved by 46, 51 and 97% as compared to the composites containing 25 wt% of kenaf fibre. It was also observed that fibre folds developed during mixing became significant factor which limited the improvement in mechanical strength of kenaf epoxy composites. A few important predictive models namely rule of mixture, Haplin-Tsai, Nielson Chen and Manera models were compared with the experimental values obtained in this present study. Manera model predicted the experimental data most accurately. Alkali treatment improved the interface and its outcome reflected in the improved modulus that increased 21.76% in samples having 10mm length of kenaf fibre. Copyright © 2017 VBRI Press.