The natural cottony aspect of silk‐floss tree fruit fiber allied with its high‐cellulose content turned our attention for their application at the nanocellulose production since spares the prerefining and pulping processes that are obligatory for the size reduction of the main cellulosic fiber sources. This study presents preparation and characterization of cellulose nanofibers (CNFs) using mechanical defibrillation to explore their potential in the preparation of polymer composites using polyvinyl acetate (PVAc) emulsion. We characterized and subjected silk‐floss fruit fiber to four chemical treatments. Based on the degree of delignification, treatments with sodium chlorite (II) and their mixture with methanol and toluene (IV) were chosen for further studies. The resulting CNFs were characterized by Fourier‐transform infrared, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning and transmission electron microscopy. Composites were prepared using several amounts (0.50‐1.00 wt%) of CNFs and their tensile strengths were determined. Composites containing 1.00% CNFs (Treatment II) were found to exhibit lowest strength while those with 0.5% CNFs (Treatment IV) showed the highest strength with 351% and were 518% higher resistant than the PVAc matrix, respectively.