Abstract
Cellulose nanocrystal (CNC) composite coatings may impart many benefits in packaging, electronic, optical, etc. applications, however, large-scale cellulose coating production is a major engineering challenge. A versatile roll-to-roll reverse gravure process for the manufacture of cellulose nanocrystal-poly(vinyl alcohol) (CNC–PVA) coatings on a flexible polymer substrate was investigated in the present work. CNC content was varied from 0 to 100% to determine the effect of CNC concentration on coating anisotropy. Coatings were characterized by polarized light microscopy, UV–Vis spectrophotometry, cross-hatch adhesion testing and optical profilometry. This method produced uniform, highly transparent coatings with surface roughness less than 100 nm for all CNC–PVA weight ratios examined. The isotropic-anisotropic coating transformation was observed above 50% CNC, with a maximum anisotropy at 70% CNC along the shear direction. Anisotropic CNC–PVA coatings exhibited increased water vapor barrier performance due to the increased CNC packing and density.
Original language | English |
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Pages (from-to) | 6547-6560 |
Number of pages | 14 |
Journal | Cellulose |
Volume | 25 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1 Nov 2018 |
Keywords
- Anisotropy
- Cellulose nanocrystals
- Poly(vinyl alcohol)
- Roll-to-roll
- Transparency