Investigations of structural, chemical and physical properties of natural lac and its reinforced composites

Abstract

Natural lac resin is secreted by the small parasitic insect Kerria Lacca on various host trees in India. It has been conventionally used as filling, protective, adhesive, binder and insulating material. Cultivated by tribal people for various applications, the earliest popularly known reference to its use is found in the Mahabharata epic. Because of the imminent danger of environmental degradation, mankind is now veering towards a refreshing global awareness of the need to use, natural products because of their organic, non-toxic and biodegradable nature. This way, the present study is focused to understand the physical, structural and chemical properties of these natural lac and its applied form chapadi (a mixture of lac and sand), which has been used, for more than 500 years, as an adhesive and filling material by traditional Swordsmiths in Rajasthan (India). In addition, new lac-based composites reinforced with carbon nanotubes and carbon fibres have been synthesised and studied for their structural and physical properties. Surface morphology and elemental composition of as synthesized samples have been carried out by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). FTIR spectra have been recorded in order to identify the organic functional group. Samples of CNTs and carbon fibre reinforced with pure lac have been found to be better adhesives. The study aims to understand the nature of these reinforced composites as a new material that can be used for various applications in future.