Towards the development of highly transparent, flexible and water-resistant bio-based nanopapers: tailoring physico-mechanical properties

The present works aims at developing cellulose-based nanopapers from TEMPO-oxidized cellulose nanofibers with tailored properties by means of the incorporation of cheap, widely available and easy-to-use additives. For this, nanopapers were produced by means of a papermaking-like route with a modified paper sheet former. Bleached kraft eucalyptus and pine pulps (BKEP and BKPP, respectively) were selected for comparison purposes and they were submitted to three different oxidation degrees. Those nanopapers prepared from BKPP at 10mmol/g exhibited the most well-balanced performance in terms of mechanical, optical and morphological properties and were selected for the study with glycerol and AKD. It was found that as the amount of glycerol was increased, mechanical properties were decreased due to a plasticizing effect, with no influence on water contact angle (WCA) and transmittance. However, when AKD was used, and especially when combined with glycerol, mechanical properties and WCA were significantly improved, mainly due to the esterification reaction. Overall, the present work shows different ways to tailor the mechanical, optical, surface and morphological properties of nanopapers, obtaining significant improvements on several properties with the combination of other additives, which can be easily found in cellulose-based industries. [GRAPHICS] .