Ari Ämmälä

Amino-modified cellulose nanocrystals with adjustable hydrophobicity from combined regioselective oxidation and reductive amination.

The controlled revision of surface properties to alter the hydrophobic features of nanocellulose is a potential technique to obtain materials for many novel applications and to replace oil-based materials acting as amphiphilic polyelectrolytes, among others. In this study, linear amines with increasing chain length were used to adjust the hydrophobicity of amphiphilic cellulose nanocrystals (CNCs). Methyl-, ethyl-, n-propyl-, n-butyl-, n-pentylamine, and n-hexylamine were introduced into a cellulose backbone using combined periodate oxidation and reductive amination in an aqueous environment. A high-pressure homogenizer was used to liberate a highly transparent (over 85% at visible light range) nanocrystal dispersion containing CNCs with a length of 73-131 nm and a width of 5-6 nm. All of the CNCs had similar charge density but the hydrophobicity, indicated by the contact angle measurement from the films, increased gradually from 64° to 109° as a function of amine chain length. Thus, this study demonstrated the fabrication of uniform, amphiphilic nanosized polyelectrolytes with modifiable hydrophobicity.

Bioeconomy potential - focus on Northern Finland

The paper contributes towards improving the understanding over the potential of bioeconomy by focusing on a regional context. The study is realised by applying a combination of PESTEL analysis, resource analysis and analysing true and potential cases with high bioeconomy relevance and potential for substantial commercial volume. Hence, this article combines approaches of strategy development and analyses cases in bioeconomy context with a specific regional perspective. The results provide an overview on the potential of bioeconomy, particularly that of Northern Finland, but also the entire country. The article brings forward sustainability considerations aside from demonstrating the complexity inherent to the topic. Opportunities and potential are demonstrated by presenting case examples. The findings can benefit both the academia and those involved in planning and implementing relevant actions towards bioeconomy - both in general and in the selected setting.