Statistical Response Surface Modeling of Tensile Strength and Moisture Diffusion in Hygrothermally Aged Jute Fiber Composites

The jute fiber-reinforced polymer composites were subjected to hot-pressing at temperatures of 60 °C, 80 °C, and 100 °C, followed by hygrothermal treatment for durations ranging from 0 to 64 hr. The statistical response surface modeling of tensile strength ( UTS ) and gain in weight, ΔW (%), was done using Minitab Statistical Software 22.4.0. The independent variables considered for UTS were hot-pressing temperature ( θ ) and treatment time ( t ). However, for the ΔW (%), it was the hot-pressing temperature ( θ ) and the square root of treatment time ( ẗ ). The maximum UTS was observed at the severity factor corresponding to moderate hot-pressing temperature and the smallest treatment time. However, the maximum ΔW (%) was observed at the lowest hot-pressing temperature and the largest square root of treatment time. The statistical modeling of UTS indicates that the effect was in the order of θ*θ > t > t*t > θ > θ*t . The contour lines indicated a significant interaction between independent variables. Moreover, the slope of the surface plot indicated that the treatment time was a more critical factor near the optimum, while the hot-pressing temperature had some tolerance. Furthermore, the statistical modeling of ΔW (%) indicates that the effect was in the order of ẗ > ẗ*ẗ > θ*θ > θ > ẗ* θ . The small curvature of contour lines indicated a non-significant interaction between independent variables. The hygrothermal conditions which provided the maximum UTS enable the matrix cracking, while the conditions for maximum ΔW (%) showed voids and swelling.