Bionanocomposites produced from cassava starch and oil palm mesocarp cellulose nanowhiskers

•Cassava starch/OPMF-CNW films (1–10%) were utilized to produce films.•Mechanical shearing can produce stable CNW and reduce the chemical treatment.•Mechanical properties were improved with the increase of CNW up to 6wt%.•CNWs from OPMF are suitable as reinforcing fillers for biodegradable starch plastics.•The stiffening of starch/OPMF-CNWs is related to effective filler/matrix interaction. Cassava starch films reinforced with cellulose nanowhiskers from oil palm mesocarp fibers were produced by casting. Nanowhiskers were obtained by sulphuric acid hydrolysis followed by microfluidization and incorporated in starch films at various loadings (1–10wt%). Morphological and mechanical characterizations showed that the reinforcing effect of oil palm cellulose nanowhiskers was significant at loadings of up to 6wt%, which was determined to be the nanowhiskers percolation threshold. Above this content, formation of agglomerates became more significant, causing a decrease in mechanical properties of starch bionanocomposites. Below percolation threshold, such as 2wt%, elongation at break increased by 70%, showing an effective reinforcing effect. Dynamic mechanical analyses revealed filler/matrix interactions through hydrogen bonding in bionanocomposites.