Nauclea latifolia herb root waste reinforced epoxy polymer composite: The study of effects, modelling, certainty and sensitivity analysis

The requirement for cleaner and healthy environment is a drive for waste recycling programs. In this study, suitable reinforcement for composite production was extracted from Nauclea latifolia herb root waste (NLHRW) through alkalization. Proximate composition and crystallinity of NLHRW and alkalized NLHRW (ANLHRW) were determined using gravimetric method and X-ray diffractometer (XRD). The individual and interaction effect of production factors (size, weight fraction, and mould compression force) on composite characteristics (flexural strength (FS), modulus (FM), and water absorption (WA)) of ANLHRW reinforced epoxy polymer composite was investigated, modeled and optimized using response surface methodology (RSM). The thermal stability and failure mechanism of the optimally developed ANLHRW reinforced composite were investigated using thermogravic analyzer (TGA) and Scanning Electron Microscope (SEM). The sensitivities of the composite properties to production factors were investigated using Monte Carlo simulation (MCS). Results showed that alkali treatment improved the cellulose content and crystallinity of the fiber. Fiber size and weight fraction increased the FS and FM while mould compression force reduced the WA of the composite. The determined optimum composite production condition was 322.62 μm fiber size, 24.06 wt% fiber weight fraction and 98.10 N mould compression force to give a composite’s FS of 16.9905 MPa, FM of 1046.36 MPa and WA of 3.71057 %. The percentage validation error was 0.70, 0.56 and 0.80 % for FS, FM and WA respectively. The composite produced with the validated optimum condition showed a decrease in thermal resistance than cured unreinforced epoxy plastic and had varied failure mechanisms such as fiber pull out and fiber breakage. The composite properties were dominantly sensitive to fiber weight fraction. The composite produced can be applied in dry low-load bearing applications such as automobile interiors or wet no-load bearing application such as desert cooler pad.