Stereoselectively water resistant hybrid nanopapers prepared by cellulose nanofibers and water-based polyurethane

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University of Oulu

Abstract

Cellulose nanopapers, known for excellent mechanical properties, loses 90% of their stiffness in the wet conditions. In this study, we attempt to improve the wet mechanical properties of cellulose nanopaper by incorporating polyurethane by a novel and ecofriendly method. Water based PU was dispersed along with CNFs in water and hybrid nanopapers were prepared by draining water under vacuum followed by forced drying. These hybrid nanopapers have a gradient interpenetrating structure with PU concentrated towards one side and CNFs towards the other, which was confirmed by scanning electron microscopy, x-ray photoelectron spectroscopy and contact angle measurements. Because of this, the nanopapers are water resistant on one surface (PU rich side) and hydrophilic on the other (cellulose rich side), making them stereoselectively water resistant. When wetted with water on the PU side, the hybrid nanopaper with 10% PU is able to retain 65% modulus; on the other hand, the reference retains only 10% of the modulus. Similar results are seen in the tensile and the yield strength. Additionally, the hybrid nanopapers have higher elongation and improved thermal stability. The reported material is relevant to the applications such as flexible electronics and transparent displays.

Details

Original languageEnglish
Pages (from-to)286-293
Number of pages8
JournalCarbohydrate Polymers
Volume199
Publication statusPublished - 1 Nov 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • Cellulose nanopapers, Flexible composites, Gradient interpenetrating network, Hybrid materials, Polyurethane, Water resistance

ID: 29089922