Determining the mechanical properties of microcrystalline cellulose (MCC)-Filled PET-PTT blend composites

Polymer composite materials consisting of poly(ethylene terephthalate) (PET)-poly(trimethylene terephthalate) (PTT) blends and microcrystalline cellulose (MCC) were prepared by injection molding. The composites were analyzed for tensile, flexural, and impact strength as well as density determinations. There was no statistical difference in terms of mechanical properties between the control PET-PTT blend and 2.5 wt% MCC-filled composites. Because of better compatibility as well as better stress-transfer properties, the tensile strength of the composites was larger (reaching values from 24.8-36.3 MPa with the addition of 20 wt% MCC). Elongation at break of the composites was greater (reaching values from 2.3-3.3% with the addition of 20 wt% MCC). The tensile modulus of MCC-filled composites systemically increased with increasing MCC loading (reaching values from 1.11-1.68 GPa with the addition of 30 wt% MCC). The flexural modulus of composites was higher than the control PET-PTT blend. The modulus also increased with increasing MCC loading (reaching values from 2.10-3.37 GPa with the addition of 30 wt% MCC). The Izod impact strength of the composites decreased as the MCC loading increased and this observation was in good agreement with commonly observed filled polymer systems.