Fibrillation by Design: Start with Why your cellulose is fibrillating.

Academic research and development of high-performance, bio-based material from cellulose fibrils is spurring and setting new landmarks [1]. The common approach of manufacturing these prototypes is: (1) the manufacturing cellulose (nano) fibrils by one or several comminution processes (for example homogenization, grinding, ultrasonication, extrusion) in combination with pre-treatment routines, followed by (2) documentation of the cellulose quality and (3) documentation of manufactured material quality. This fast-forward trial-and-test approach is efficient to attract attention to the field and advance the application possibilities. The neglected focus on the cellulose comminution mechanism becomes however a bottleneck when scaling production and hence jeopardizing the benefit for society that an industrial production of these high-performance bio-based materials promises. Producing Quality by Design [2] needs to understand process mechanistics. Simply; Start with Why your cellulose is fibrillating.

In this talk we will present our efforts to develop a mechanistic based understanding of the cellulose fibre fibrillation in hyper inertial flow conditions present in homogenizers and Microfluidizers®. We setup a laboratory twin, the Hyper Inertia Microfluidizer (HIMF), and recorded by high-speed imaging the in-situ fibre behavior during acceleration of fibres into the microchannel geometry. Together with ex-situ cellulose fibril suspension properties we developed a new understanding of the cellulose fibre comminution which we believe is a two-step process: (1) fragmentation by tension and buckling from acceleration into microchannels and (2) fibrillation of cellulose fragments from bending delamination in a turbulent flow.

[1] T. Li, Nature, 590, 2021, 47-56. [2] L. X. Yu, AAPS J., 16, 2014, 771-783.