Optimizing acrylonitrile grafting onto delignified rice straw via response surface methodology towards its flame retardancy and durability intensification

Abstract

The current research emphasizes on grafting of acrylonitrile onto pretreated rice straw for making low cost roofing material. The technique was improved by means of optimization for analyzing the impact of some parameters such as polymer dose, time and temperature of grafting. The optimization process applied in this research work was response surface methodology (RSM). The process was optimized through quadratic model of regression using ANOVA study (analysis of variance). 3-dimensional (3D) surface plots of the response and 2-dimensional (2D) contour analyses were adopted for further investigation of the collective synergies amidst the functional variables and to find out the optimal values for the percentage of grafting. The maximum grafting percentage was found at a grafting time of 97.59 min, grafting temperature of 77.52 oC and monomer concentration of 16.82 cubic centimeters (cc). At this condition, the highest percentage of polymer grafting from predictions according to the employed model was 60.07% which showed desirability equal to 1. The validation of these predictions was performed experimentally, with the observed result being 59.97% which is nearly equal to the theoretical values predicted by the model. Therefore, the model was able to deliver an optimized condition appropriate for polymer grafting onto rice straw for intensifying its durability.