Preparation and properties of wood plastic composite reinforced by ultralong cellulose nanofibers

Wood plastic composites (WPCs) were reinforced by ultralong cellulose nanofibers (CNF), which were extracted from poplar flour. To solve the aggregate problem of CNF in nonpolar high density polyethylene (HDPE), a new method, which was corresponding to preblending the mixture of wood flour and HDPE powder in the CNF suspension with continuously stirring at 80°C for 2 h was used before the extrusion process. The capillary rheological tests showed CNF could increase the apparent viscosity of WPCs obviously. From the SEM images, abundant CNF were distributed on the fracture surface of WPCs uniformly and compactly like “spider web.” Compared with WPC without CNF, the bending strength, bending modulus, and impact strength of WPCs with 20 wt% CNF increased by 93.01, 153.64, and 116.55%, respectively. The thermal expansion coefficient of WPCs with 20 wt% CNF decreased by 61.30%. The storage modulus of WPCs was greatly improved with the addition of CNF. POLYM. COMPOS., 37:1206–1215, 2016. © 2014 Society of Plastics Engineers