Enhanced mechanical performance of epoxy/micro balloon/micro fibril cellulose composites

Lightweight and strong polymer composites are essential for improving the fuel efficiency of transportation. The syntactic foams composed of a polymer matrix and hollow microspheres are lightweight but often fragile. This study investigates a hybrid epoxy composite incorporating microballoons and microfibrillated cellulose (MFC), with 5 phr dioctyl phthalate (DOP) added to enhance its ductility and mechanical strength. The results indicate that DOP has improved the mechanical properties, with the composite containing 1 phr MFC that shows the highest flexural strength (51.09 MPa; 55.53 MPa cm³/g) and tensile strength (28.41 MPa; 30.88 MPa cm³/g). All the composites have exhibited a low density of approximately 0.92 g/cm³, remaining below 1 g/cm³. These findings highlight the significant role of DOP and MFC to improve the mechanical performance of lightweight syntactic foam composites, offering valuable insights into their application in various engineering fields.