Isolation of high value nanofibers from lignocellulosic feedstocks is a costly and resource intensive process. This stems from the complex structure of the raw material which contains hierarchical crystalline cellulose within hydrophobic lignin layers. This inherent structure makes inquiries regarding suitability of a certain lignocellulose for nanofibrillation difficult. Further nuances are present due to the common usage of both mechanical and chemical processing, often using pre-delignified wood as starting material.

In this study we look at how the isolation of nanofibers is a↵ected by inherent wood properties by nanofibrillating wood from trees that has been physically stimulated to produce biomass with higher cellulose/lignin ratio and a different cell wall structure. Cryocrushed samples have been processed with i) mechanical, ii) chemical and iii) mechanical-chemical treatments, where (one-pot) direct TEMPO-catalyzed oxidation with different severity and high-pressure homogenization serve as controlled chemical and mechanical factors, respectively.

The nanofibers have been characterized in suspension according to traditional procedures regarding degree of fibrillation, and then made into dense nanopapers for mechanical characterization. The material behavior is discussed in relation to the structure of the initial biomass and corresponding fibrillation efficiency. The results are presented in terms of both mechanical disintegration and chemical (carboxylation) derivatization.