LDPE-based composites reinforced with surface modified cellulose fibres: 3D morphological and morphometrical analyses to understand the improved mechanical performance

In this study, we reported the use of X-ray microtomography (mu CT) as a new analytical tool to investigate better the dispersion of natural filler in the polymer matrix. The pre-treated sugarcane bagasse (SCB), richer in cellulose, was first functionalised by hexamethyldisiloxane (HMDS) and then added (10, 20 and 30 wt% filler) to low-density polyethylene (LDPE) by melt mixing. The microstructure organization of the cellulose in the composites was studied using 3D and 2D mu CT images, where it was possible to obtain an in-depth morphological and morphometric analysis. Thus, the synergistic effect of the filler on the mechanical properties of the polymer matrix as a function of surface chemistry was well clarified without the need of a large number of micrographs as is required to show the quality of dispersion using conventional imaging techniques. The characterisation method reported here is an easy, non-destructive and powerful way to characterise the cellulose fibres dispersion in LDPE-based composites and it can be applied to other fillers and polymer matrices.