Statistical modeling and optimization of the flexural strength, water absorption and density of a doum palm-Kankara clay filler hybrid composite

A hybrid doum palm leaves and Kankara clay particulate reinforced polyvinyl chloride (PVC) composite material was developed with light weight materials. Mixture design experiment using Design Expert 10.0 software was employed and the sample composites were produced using compression molding. Mathematical models of the flexural strength, water absorption and density were developed and statistically validated. Analysis of the statistical models showed that the flexural strength fitted best with the quartic model, water absorption fitted best with cubic model while the density suited with the linear model. All the models were found to be statistically significant in predicting the respective properties with p-values less than 5%. An optimized formulation with the objective of maximization of the flexural strength and minimization of the water absorption and density was determined at 11.69, 58.31 and 30% of doum palm leaves particulates (reinforcement), PVC (matrix) and Kankara clay (filler) respectively. The mathematical models can therefore be used to navigate and predict the flexural strength, water absorption and density within and outside the experimental design space (constraint region).