Evaluation of the Mechanical Properties of Natural Rubber/Baobab (Adansonia Digitata) Fibre Nanocomposite Using Response Surface Methodology: A Pedagogical Approach

Response surface methodologies are useful in achieving optimum processing conditions in materials development. This study highlights a pedagogical approach where conceptual methods useful in project-based learning can be sustained in the development of composite materials. In the study, the central composite design (CCD) in response surface methodology (RSM) was used to investigate the effect of processing pressure, temperature, pressing time, and reinforcement loading on the mechanical properties of natural rubber/baobab fibre nanocomposite. In addition, the processing parameters were optimised to obtain the optimum mechanical properties of the natural rubber/baobab fibre nanocomposite. The scientific aspects were taught to postgraduate students eager to learn simulation methods using the novel CACPLA (Communicate, Active, Collaborate, Problem-based solving, Learning and Assess) pedagogy. Amongst the investigated variables, compression pressure has the least impact on the composite’s Young’s modulus and hardness, whereas pressing temperature and the reinforcement loading showed a significant impact of 38.3% and 34.4%, respectively. Based on the analysis of variance (ANOVA), pressing temperature and reinforcement loading have a significant effect on the hardness property of the natural rubber (NR)/baobab fibre nanocomposite compared to processing pressure and pressing time. This is because high temperature degrades the vulcanizates and reduces the mechanical performance of the composites giving room to low resistance to indentation. An increase in baobab fibre particle loading increases the crosslink density and stiffens the nanocomposites. Since the selection of suitable parameters is important in obtaining the optimum desired properties from composites, optimisation of the investigated parameters for the composite was carried out. The optimum mechanical properties for the rubber/baobab fibre nanocomposite were obtained at a compression pressure of 1.50 MPa, pressing temperature of 130 °C, pressing time of 13 min, and reinforcement loading of 20.00 phr (part per hundred of rubber) with desirability of one (1). Validation of the optimal solution shows 97.57% correlation for Young’s modulus and 98.55% for hardness property . From the word cloud analysis, the words “matrix”, “chemistry”, “properties”, “polymer”, “composite”, and “interaction” were mentioned frequently implying that the teaching of the RSM simulation method emphasized more on the chemistry of