Cellulose nanofibrils: Challenges and possibilities as a paper additive or coating material - A review

Today, there is widespread scientific and commercial interest in cellulose nanofibrils (CNF). The exploration of new manufacturing methods and pre-treatments has enabled a less energy intensive production of CNF. In this review the use of CNF in paper making applications as a paper additive or coating material have been summarized and discussed. CNF can be added directly into the pulp furnish, and by using a relatively low amount of CNF together with suitable retention aids potential problems related to dewatering can be avoided. This type of CNF addition enables either decreased basis weight or increased filler content with maintained paper strength. CNF can also be applied in coating formulations. Increased surface smoothness and enhanced barrier properties are key benefits obtained by CNF containing coatings, but challenges exist such as the high water content of CNF coatings and the low moisture resistance of CNF barriers. Further research is still needed but, at least in some papermaking applications, CNF is not far from implementations on a commercial scale.