Influence of Particle Size and Hot-Pressing Parameters on Mechanical Properties of Bamboo-Based Composite Materials

A novel series of biocomposites was prepared through the utilisation of hot-pressing and blending methods, utilising bamboo particles of varying sizes and a zein solution. The influence of particle size and the parameters of hot pressing on the mechanical properties of the composites was investigated through the application of an alkali solution to pre-treat the bamboo particles and the employment of ultra-high pressure to pre-handle the zein solution. Four response surface models were established to optimise the processing parameters based on mechanical testing experiments and quadratic regression analysis. The influencing factors were moisture content, press temperature, and press time, and the responses were modulus of rupture (MOR), modulus of elasticity (MOE), tensile strength (TS) and 2 h thickness swelling rate (2h-TSR). The findings indicated that the TS of composites reached a maximum value of 17.5 MPa with a bamboo particle size of 40 mesh; the MOR and MOE of composites reached a maximum value of 28.72 MPa and 2669.75 MPa when the bamboo particle size was 60 mesh; regarding the 2h-TSR of composites the lowest value of 5.8% was obtained for 80-mesh bamboo particle size. The optimum moulding process parameters were obtained with moisture content ranging from 14% to 16%, press temperature ranging from 170 °C to 175 °C, and press time ranging from 12 min to 15 min, respectively.