The natural fibres obtained from various sources may be economically utilized to replace the synthetic fibres in fibre-reinforced composite materials. This study initiates by performing a novel vacuum pressurization impregnation (VPI) treatment of ripe areca husk fibres (AHF), followed by their mechano-chemical extraction. Further, the physical, thermal and morphological features are compared with the untreated ones with techniques like x-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The extraction parameters are optimized using response surface methodology (RSM) and particle swarm optimization (PSO) to minimize the hemicellulose content, which influences moisture absorption and fibre performance. The results show that VPI-treated AHF exhibits lower cellulose crystallinity, enhanced thermal stability and reduced porosity as compared to untreated fibres. The RSM develops a quadratic model with a precision of 41.6830 and detects any potential outliers, whilst PSO predicts optimal conditions of 7.2017% NaOH concentration, 1466.3 RPM stirrer speed and 8.805 h of stirring time, achieving an optimal response value of 0.319 g hemicellulose with an error of 0.62%. The study concludes that PSO is more efficacious than RSM in optimizing the extraction process for minimizing hemicellulose. Overall, the VPI-treated AHF shows great potential as a sustainable reinforcement in composite materials, offering improved mechanical and thermal properties through optimized extraction techniques.