Raman imaging as a tool for assessing the degree of mixing and the interface between polyethylene and cellulose nanocrystals

© Published under licence by IOP Publishing Ltd. The incorporation of spray-dried cellulose nanocrystals (CNCs) into thermoplastics raises the question about the degree of the mixing, given that typically the former are hydrophilic and the latter hydrophobic. Raman imaging has been used as a non-destructive method for the spatial quantification of the mixing process of CNCs in HDPE. A series of polyethylene based composites was prepared by melt compounding using cellulose nanocrystals (CNCs) as a nano-filler. The cross sectional areas of nanocomposite filaments were investigated using confocal Raman microscopy. The degree of mixing between CNCs and HDPE is quantified using this method. It is shown that CNCs have a strong tendency to agglomerate. However, a certain degree of mixing between CNCs and HDPE is observed from Raman images and chemical images obtained by spectroscopy.