Empirical Analysis of the Effect of Nano-Silica Reinforcement on the Gas Barrier Properties of Polyethylene Films for Agricultural Packaging in North West Nigeria

Agricultural product packaging films in North West Nigeria must provide effective barriers against oxygen and moisture transmission to extend shelf life of stored grains, dried legumes, and processed foods in climatic conditions characterised by high temperature and humidity variability. This study empirically analyses the effect of nano-silica particles on the gas barrier properties of linear low-density polyethylene blown films, assessing the potential to improve packaging performance for agricultural storage applications in Kano and Sokoto states. Nano-silica particles were functionalised with silane coupling agents to improve polymer matrix compatibility. Films containing 1, 3, 5, and 7 percent nano-silica by weight were produced by blown film extrusion at a commercial facility in Kano State. Oxygen transmission rate and water vapour transmission rate were measured using ISO 15105-2 and ISO 15106-1 procedures. Tensile properties, haze, and optical clarity were characterised as functional quality indicators. Transmission electron microscopy examined nano-silica dispersion uniformity, and the tortuous path model was applied to interpret barrier property improvements. Results demonstrate that 5 percent nano-silica loading achieved 42 percent reduction in oxygen transmission rate and 38 percent reduction in water vapour transmission rate relative to unfilled polyethylene film. Particle agglomeration at 7 percent loading diminished barrier improvement, consistent with tortuous path model predictions. Tensile properties were marginally affected, with strength retention exceeding 93 percent. Haze increased progressively with nano-silica content, limiting optical quality for applications requiring high transparency. The study recommends 3 to 5 percent nano-silica as the optimal loading for barrier-enhanced agricultural packaging films in North West Nigeria. Keywords: nano-silica, polyethylene film, gas barrier, agricultural packaging, blown film