SYNTHESIS AND CHARACTERIZATION OF RARE EARTH DOPED PHOSPHORS FOR LIGHTING APPLICATIONS

Abstract

Polymer composites, particularly with nanofillers have attracted a lot of attention by the present day researchers. In rubber composites carbon black is a typical reinforcing material. However, due to environment issues and dark colour of the carbon black, several researchers focus on development of other reinforcements / fillers in rubber composites during the last few years. Recently, halloysite nanotubes (HNTs) have been used as a new type of filler for polymers, such as epoxy, polypropylene and polyvinyl alcohol, EPDM to improve the mechanical and thermal properties of the composites. HNTs are a kind of naturally occurring aluminosilicate (Al2 Si2O5(OH)4.2H2O), with hollow nanotubular structure. newlineThis research work deals with the preparation and properties of HNT reinforced natural rubber composites. Natural rubber (NR) nanocomposites have been prepared by incorporating various content (phr) of Halloysite Nanotubes (HNT), onto natural rubber using banbury mixer and two roll mill. Effect of addition of HNT content on rheological, mechanical, thermal and morphological properties of the NR-HNT nanocomposites was studied. Rheological properties include Mooney viscosity, mooney scorch, cure index. Mechanical properties studied are tensile strength, elongation at break and hardness. Thermal stability was checked by TGA for analyzing the effect of nanofiller loading to rubber matrix. Wear characteristics was also studied with the help of Din abrader. XRD, Optical microscopy, SEM and TEM analysis indicate good dispersion of the HNT filler into NR. The results obtained for various properties indicate that the NR-HNT nanocomposites have improved wear, mechanical, thermal and morphological properties. NR HNT composites, owing to the high reinforcing activity of the HNTs as compared to conventional silica or carbon black, use of this filler can be extended to the green tyre formulation where a large amount of silica and carbon black are being used to get a high performance and mileage of the tyre. newline