Rheological and mechanical properties of poly(lactic) acid/cellulose and LDPE/cellulose composites

Abstract

In our work we studied composites of poly(lactic) acid (PLA) and low density polyethylene filled with cellulose fibres. The studied composite materials were manufactured with a twin-screw extruder. The extruded compound was processed in to samples using compression moulding. The content of cellulose in polymer/cellulose composites was varied. Effect of low amounts of cellulose on the rheological and tensile properties was studied. Tensile tests showed that the incorporation of cellulose into PLA matrix lead to stiffer but slightly more brittle and weaker materials, since Young's modulus increases and tensile strength and elongation at break slightly decrease. Mechanical results are in agreement with rheological behaviour: the composites exhibit the improvement in the storage and loss moduli of composites compared with that of matrix polymers. The composite dynamic viscosity increases with cellulose content in the same manner as loss and storage moduli. The processing and material properties of PLA/cellulose composites were compared to the more commonly used low-density-polyethylene/cellulose composites.