Assessment on the effects of the operational conditions on the manufacture of PLA-based composites using an integrated compounding–injection moulding machine

Cellulose fibres were employed as reinforcement agent for biodegradable composites using polylactic acid (PLA) as a polymer matrix. PLA can be obtained from renewable resources, and it is attracting much interest owing to its favourable physico-mechanical properties and biodegradability. Prior to composite compounding, two commercial PLA from different suppliers were characterized for apparent density, flow index, crystallinity, thermal properties, melt flow rheology and intrinsic viscosity for comparison. In experiments performed with an integrated compounding–injection moulding machine (ICIM), the effects of the processing conditions on the mechanical properties of composites (tensile strength, stiffness and strain at break) were analyzed using a Taguchi experimental design. Other properties of the composites, such as surface morphology and fibre length distribution, were also considered. ICIM technology provided composites with better mechanical properties and lower fibre degradation than the conventional sequential extrusion and injection moulding (SEIM) technology.