Fabrication and characterisation of polyester/hexagonal boron nitride/sisal fibre hybrid composites for microelectronic applications

Abstract

ABSTRACT The main focus of the work is on developing a new class of hybrid composite with polyester as the continuous phase and micro-sized hexagonal boron nitride (hBN) and short sisal fibre as the discontinuous phases. The effect of loading of discontinuous phases on the different properties of the composites is analysed experimentally. The incorporation of either of the discontinuous phases unwillingly increases the void content and water absorption rate. With hBN content, the density increases, whereas, with sisal fibre content density decreases. The hybrid combination of fillers successfully improves the glass transition temperature (Tg) and coefficient of thermal expansion (CTE) of the polymeric resin. The maximum Tg reported is 106.2°C and the minimum CTE reported is 51.7 × 10−6/oC for the polyester reinforced with 40 wt. % hBN and 5 wt. % sisal fibre. The incorporation of hBN upsurges the thermal conductivity but also increases the dielectric properties. The dielectric properties gainfully reduce with the addition of sisal fibre. Dielectric properties also decrease with an increase in the working frequency. The incorporation of sisal fibre slightly reduces the thermal conductivity of the composites. The mechanical properties like tensile strength and flexural strength of the hybrid composite increase when the combination of hybrid fillers is judicially selected, whereas, the compressive strength and hardness of the composite increase with filler/fibre loading with maximum 131.4 MPa and 80.0 Shore D number, respectively. Due to the improved overall properties, the composite material under investigation can find its potential application in various microelectronic applications.