DEVELOPMENT AND CHARACTERIZATION OF BAOBAB POD FIBRE NANOCELLULOSE REINFORCED LOW DENSITY POLYETHYLENE POLYMER COMPOSITES

Abstract

This study focused on the use of Baobab pod fibres as a potential reinforcement material for polymer nanocomposites. The physical, chemical and mechanical properties of the fibres were investigated in order to fully comprehend its behaviour. Box-Behnken module of response surface methodology (RSM) available in “Design Expert® Version V10” was used to establish design matrix, optimize treatment conditions and analyze experimental data. The optimization of chemical treatment of fibre predicts solution for NaOH concentration at 6.963, soaking time of 359.9. Fibres were chemically treated in order to remove lignin, pectin and other impurities and also to improve the adhesive tendency with the reinforcement material. Acid hydrolysis was then used to produce cellulose nanocrystals (CNC) from the treated fibres. An increase in the cellulose content of 17.9 % was recorded after NaOH treatment and a further increase of 25.3 % was recorded after acid hydrolysis. The effect of NaOH treatment and acid hydrolysis on surface morphology, crystallinity, and thermal properties of fibres were investigated using Fourier Transform Infrared (FTIR), Scanning electron microscopy/Energy dispersive X-ray spectroscopy (SEM/EDS), X-ray Diffraction (XRD) and Thermogravimetric analysis (TGA/DTA). The fibre reinforced composites were produced using compression moulding at a temperature of 150 0C for 30 min and a formulation of nanocellulose (CNC) to low density polyethylene (LDPE) ratios of 10-90 wt%, 20-80 wt%, 30-70 wt% and 40-60 wt% were used respectively. The mechanical properties of the fibre and that of the composites produced were then investigated. Single fibre length was obtained to be 50.42 mm; density was 0.65 g/cm3 , tensile strength of 40.15 MPa, water absorption of 9.40 % and cellulose content of 53.2%. The composite with 10-90 wt% CNC/LDPE ratios was found to have a good water absorption property of 0.212 % and the best mechanical properties with tensile property of 75.72 MPa, Impact strength of 4.46 J/mm2 , flexural strength of 17.24 MPa and hardness of 26.7 HV. Based on the results obtained, it shows that Nanocellulose hydrolyzed from Baobab pod fibres has excellent properties for use as polymer reinforcement