Studies on development of adhesive material from post-consumer (waste) expanded polystyrene: a two-edged sword approach

Abstract

In the present study, low-cost adhesive materials are prepared by valorizing a post-consumer (waste) expanded polystyrene (EPS). The adhesives are prepared by dissolving the waste EPS in six different solvents namely n-butyl acetate (n-BA), tetrahydrofuran (THF), methyl ethyl ketone (MEK), m-xylene, carbon tetrachloride (CTC) and gasoline, and the corresponding additives are designated as AD-B, AD-T, AD-M, AD-X, AD-C, and AD-G, respectively. Various physico-chemical properties such as solubility, moisture content, viscosity, adhesive (shear) strength, shear modulus, etc. of the adhesives are characterized in detail. Among the chosen solvents, the solvent MEK offered maximum solubility of the EPS. Paper and wood-based substrates were used to quantify the adhesive strength of the in-house developed adhesives. The study revealed that the in-house prepared adhesives are appropriate to stick paper and wood-based substrates. The adhesive strength of the adhesives is also compared with commercial adhesives namely fevistick and fevicol. The order of shear strength of the studied adhesives for wood as a substrate is AD-X < AD-B < AD-T < AD-M < fevicol. The obtained value of shear strength of AD-X, AD-B, AD-T, AD-M, and fevicol is 1081, 1372, 3791, 4407, and 4722 kPa, respectively. The investigation shows that the shear strength of AD-M is comparable (around 7 % lower) with the shear strength of the commercial fevicol. The in-house developed adhesives show more elastic in nature compared to the fevicol adhesive. The study further revealed that the in-house developed adhesives are also suitable to bind clay and ceramic-based substrates. From the investigation, it can be concluded that the EPS derived additives can be used as a suitable substitute for commercial adhesives to bind various materials.