Effect of Hygrothermal Aging on Strength Performance of Cork Powder Reinforced Adhesive Joints

Abstract

Adhesives play a crucial role across various industries and applications due to their ability to bond materials together. They are used in numerous ways, ranging from everyday household applications to industrial and specialized fields. Strength is most critical factor to analyze before using the adhesive. Various techniques have already been developed and many are being developed to predict and improve the strength of adhesive. Addition of cork powder to the structural adhesive could improve the strength of adhesive joints through mechanical interlocking between the cork cells and the molecules of adhesive. However, even after the nanofiller reinforcement, the strength of adhesive is significantly affected by environmental parameters like temperature and humidity. The present study investigated the effect of hygrothermal aging on the strength characteristics of lap joints made using cork powder reinforced adhesive. Lap joints were experimentally investigated under two different humidity levels 80% and 100% RH. The cork powder was added in concentration of 0.25wt.%, 0.5wt.%, 0.75wt.% and 1wt.%. to study the reinforcing effects. The lap joints were made using aluminum as adherend and it was observed that strength properties of lap joints were not significantly affected in lap joints under different humidity levels. The only impact was on 0.25% cork powder concentration samples where strength decreased sharply for conditioned samples. In case of elongation 0.25% and 1% cork powder reinforced samples had minimum values. When each sample is compared at different conditioning levels it was observed that conditioning improved elongation values of 0.5%, 0.75% & 1% samples. The failure modes were mostly cohesive with 1% samples exhibiting adhesive failure and neat samples were failed in mixed mode.