The growing demand for polymeric materials makes them significant in both industry and the environment, and the task of making them sustainable is becoming increasingly challenging. Cellulose presents an opportunity to minimize the effect of non-degradable materials. Cellulose nanofiber (CNF) is part of a class of cellulose fibers with superior performance due to its high strength and stiffness combined with low weight and biodegradability. This work aimed to produce composites using Low Density Polyethylene (LDPE) as matrix and CNF from Pinus sp. (Pinus) and Eucalyptus sp. (Eucalyptus) as reinforcement. The CNF were obtained by mechanical defibrillation of the cellulose, subsequently the water was removed by centrifugation to then produce a master with CNF and LDPE using a thermokinetic homogenizer. The master was milled and blended with LDPE to obtain booster concentrations of 1, 2 and 3 percent by weight (wt. %). To characterize the composite, tensile and flexural tests, thermal and rheological analysis were performed. As a result, an increase of between 3 and 4% in the crystallinity of the composite was evidenced with the addition of Pinus CNF and a reduction of 2 to 3% in the crystallinity index with the addition of Eucalyptus CNF. Thermal stability increased for all compositions. For mechanical properties, increasing the CNF content increased the stiffness and tensile strength. In general, it was found that the process is an effective alternative to produce composites of LDPE with cellulose nanofibers.
