Influence of resin composition on quasi-static indentation, thermal stability, and thermal transport in jute–mesquite gum plaster of paris composites

This study investigates jute fiber–reinforced mesquite gum–plaster of paris (POP) composites with emphasis on quasi-static indentation (QSI), ultrasonic nondestructive evaluation, and thermal behavior. Five composite formulations (G100 to G50P50) were fabricated using a hand lay-up technique by varying the mesquite gum–POP ratio. QSI testing revealed that the G60P40 composite exhibited the highest indentation resistance (750 ± 12.7 N) and energy absorption (1247 ± 43 N.mm), indicating superior damage tolerance. Ultrasonic C-scan analysis confirmed reduced internal damage and improved structural integrity for G60P40 compared to gum-rich formulations, consistent with the force–displacement response. Thermogravimetric and differential thermal analyses showed multistage degradation behavior governed primarily by organic decomposition (≈260–370 °C) and gypsum dehydration in POP-containing composites, with increased residual mass reflecting higher inorganic content rather than delayed degradation onset. Thermal transport measurements indicated moderate thermal conductivity (≈0.23–0.43 W/m·K) and decreasing specific heat capacity with increasing POP content, consistent with the replacement of organic gum by inorganic calcium sulfate. Overall, the G60P40 formulation provides an optimal balance between indentation resistance, damage tolerance, and stable thermal response, highlighting the potential of these eco-friendly composites for non-load-bearing construction panels, interior applications, and sustainable building materials.