Mechanical, Thermal, Morphological, and Fibre Characteristics During Injection Moulding of Green Composites

The current work demonstrates the mechanical, thermal, and morphological characteristics of green composites processed by injection moulding. Bamboo fibre (BF) was chemically treated with 2% sodium hydroxide (NaOH) for 4 h to develop eco-friendly bamboo fibre-reinforced polylactic acid (BF/PLA) composites. Initially, the effect of fabrication parameters namely fibre length (2, 3, 4, 5, and 6 mm) and fibre loading (10, 20, and 30 wt%) on the tensile and flexural properties of the BF/PLA composite was investigated. Then the effect of the injection parameters namely injection pressure (70, 90, and 110 bars), injection speed (40, 50, and 60 mm/s), and injection temperature (165, 175, and 185 degrees C) on the mechanical properties was investigated by evaluating the tensile, flexural, compression, and shear properties of the developed BF/PLA composite. The significance of the fabrication and injection parameters was statistically analyzed using the grey relation analysis (GRA) technique. The thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG) were also performed to investigate the thermal performance of the developed composites. Furthermore, the morphology of the mechanically failed specimens was studied using a Field-Emission Scanning Electron Microscope (FE-SEM). The fibre dispersion, fibre orientation, and fibre length retention were also investigated to assess the characteristics of fibre during injection moulding of the developed composites. The optimum injection parameters to achieve better mechanical properties were found as A2-B3-C1 (injection pressure: 90 bars, injection speed: 60 mm/s, and injection temperature: 165 degrees C). The thermal stability of pure PLA was found better than the BF (20%)/PLA composite. The original fibre length retention in the Rank 1 composite was 59.3%.