Homogeneous Dispersion of Cellulose Nanofibers in Waterborne Acrylic Coatings with Improved Properties and Unreduced Transparency

Abstract

Cellulose nanocrystal has been widely used as a reinforcement filler in waterborne coatings, but the application of cellulose nanofiber (CNF) as a filler is difficult because of inhomogeneous dispersion. Herein, a facile and effective strategy to improve the dispersion of CNFs in the polymer matrix by mixing with γ-aminopropyltriethoxysilane (APS) is presented. The APS dosages 0.08−0.48 wt % to 0.3 wt % CNFs were investigated, and the dosage 0.16% was found to achieve a superior stability of CNFs in the aqueous solution. The APS(0.16%)-modified CNFs were then incorporated and demonstrated distributing uniformly in the waterborne acrylic coating. The as-prepared coatings retain high light transmittance around 90%, and display improved mechanical properties. The composite coatings show a maximum 500% improvement in Young's modulus, two-level improvement in hardness, and 35% reduction in abrasion loss as compared with those of neat coating. These results reveal that APS modification induces the homogeneous dispersion of CNFs in aqueous solution, and turns the CNF into an ideal reinforced filler for waterborne coatings.

Recent Advances in Nanocellulose Composites with Polymers: A Guide for Choosing Partners and How to Incorporate Them

“…The improved compatibility between modified CNF and PLA was reflected in the improved mechanical properties of the nanocomposite. APS-modified CNF was also used for the reinforcement of waterborne acrylic resin/polyester blend coating [ 239 ].…”

Chemically modified cellulose nanofibril as an additive for two‐component polyurethane coatings

“…In another study, the silylated CNF with 5, 10, 15, and 20 wt % contents improved the Young's modulus of the acrylate/polyurethane coatings . However, the flexibility of the coatings decreased with the addition of the silylated CNF …”

Industrial Application of Nanocelluloses in Papermaking: A Review of Challenges, Technical Solutions, and Market Perspectives

“…Another important parameter is NC dispersion. Some researchers have studied the effect of the NC mixing with the pulps on the mechanical paper properties [89] or the use of dispersant agents to improve the NC dispersion in a polymeric matrix [87,137,140,142]. However, there is no methodology to quantify the dispersion of the NC hydrogels in a water suspension before its application yet, although it may have a big influence on NC.…”