Bio‐waste particles embedded epoxy‐glass fiber based hybrids with coefficient of thermal expansion close to metals

Abstract In the present work, the coefficient of thermal expansion (CTE) of the rice husk ash (RHA) particles embedded epoxy‐glass fiber (EP/GF) hybrids was investigated. The EP/GF/RHA hybrids containing 0–10 wt.% RHA were fabricated and characterized. The density of the hybrids was found in the range of 1.61–1.68 g/cm 3 . The linear (i.e., in‐plane) CTEs of the EP/GF composites were significantly reduced to about 16.5–19.4 × 10 −6 /°C and 17.4–20.6 × 10 −6 /°C along the parallel and transverse directions of the fibers, respectively. Additionally, through thickness (i.e., out‐of‐plane) CTEs of the EP/GF/RHA hybrids were also reduced significantly after the addition of RHA particles. The CTE of the EP/GF composite decreased from 66.4 × 10 −6 /°C (without RHA) to 42.2 × 10 −6 /°C when it was reinforced with 10 wt.% RHA. The hybrids exhibited in‐plane CTEs ~16.5–19.4 × 10 −6 /°C, which are close to that of metals due to the good adhesion of the epoxy with the GF and RHA particles. These values are very close to the CTE values of solder and copper. This suggests that the developed hybrids could reduce the problem of warping and thermal stresses. In brief, the use of these hybrids will definitely increase the life of solder joints, electronic packaging substrates, and printed circuit boards. Highlights Rice husk ash was used as a filler in a glass fiber–epoxy matrix to reduce CTE. SEM revealed good adhesion between epoxy and reinforcements. The in‐plane CTE of 16.5–19.4 × 10 −6 /°C indicates excellent dimensional stability. Rice husk ash decreased the out‐of‐plane CTE of the hybrids significantly. Anisotropic CTEs make these hybrids useful for futuristic printed circuit boards.