Vapour Permeability Index of Silver Nanoparticle -Modified Termite Mould Clay

Abstract

One of the challenges of food security is attributed to high postharvest storage losses of grains. These losses can be minimized by using Termite Mound Clay (TMC) which has long been established as an adequate material for silo construction. This study therefore, focused on the use of silver nanoparticles (AgNPs) to modify clay microstructure and consequently inhibit water vapour permeability. The TMC-AgNPs composite films were prepared using a solution casting method based on the grey-Taguchi experimental design and optimization. Experiments were designed at three different levels using an orthogonal array with TMC (4, 8, and 12 g), AgNP (10, 15, and 25 ml), Glycerol (1.6, 2.2, and 2.8 ml), and Distilled water (150, 250, and 350 ml) as input parameters. Samples were casted on an already fabricated leveled film mold and allowed to dry at room temperature (23 ± 2°C) for 2 days. The samples were tested for Compressive Strength (CS), Water Vapour Transmission Rate (WVTR), and Water Vapour Permeability (WVP) using gravimetric techniques following ASTM E90–80. The thickness, CS, WVTR, and WVP have ranges of 2.38–2.70 mm, 9.35–14.80 MPa, 33.86-105.91 g/h.m, and 2.52–7.73 g.mm/h.m2kPa, respectively. The optimization study showed that the thickness increased from 2.43 to 2.70, WVTR decreased from 29.59 to 29.32 (g/h.m2) compressive strength increased from 12.10 to 12.37 MPa while water vapour permeability reduced from 2.52 to 2.25 g.mm.h.m2 kPa. The developed AgNP-Modified TMC l had minimal water vapour permeability and higher compressive strength making it suitable for silo construction.