Towards a mechanism for surface hydrophobization of paper

Paper in proceeding, 2017

Surface hydrophobization of paper, also referred to as surface sizing, is often needed for printing and packaging purposes. Typically, hydrophobic nanoparticles in combination with starch are applied on the paper surface. In this study two types of hydrophobic nanoparticle suspensions, one cationic and one anionic, were investigated in order to gain deeper knowledge about the mechanism behind surface sizing. A study was performed where the interactions between the particles and anionic starch were investigated and this study revealed that on addition of starch the cationic particles formed aggregates while the anionic particles were unaffected. This aggregation behaviour was found to be beneficial for the surface sizing performance. The impact of salt was also investigated and it was found that by increasing the ionic strength with NaCl or with Na 2 SO 4 larger agglomerates were formed. The surface hydrophobization efficiency of such aggregates was found to be lower, however.