Dispersing and stabilizing cellulose nanoparticles in acrylic resin dispersions with unreduced transparency and changed rheological property
This paper evaluates the potential of using 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanoparticles (T-CNPs) as additives to tune the rheology of water-based acrylic resin (AR) coatings for flexible packaging applications. Three T-CNPs of T-CNF, T-MCC, and T-CNC were prepared from three starting cellulosic materials: cellulose nanofibers (CNF), microcrystalline cellulose (MCC), and cellulose nanocrystals (CNC), respectively. Their sizes ranged from 20 nm to 20 μm in diameter, and 234 nm to over 500 nm in length. The oxidation imparted carboxyl groups on the surfaces of nanoparticles ranging from 1.99 to 2.79 mmol/g and increased the zeta-potentials of the nanoparticles, clearly improving the dispersibility and stability of the CNPs in AR. The AR/T-CNP dispersion showed unreduced transparency. The morphologies of the T-CNPs affected the rheological properties of the AR/T-CNP dispersions. The larger aspect ratio of T-CNF and T-MCC resulted in the high viscosity and solid-like viscoelastic behavior of the AR/nanoparticle dispersions at a concentration of 0.78 wt%. The CNC and T-CNC with a smaller particle size and aspect ratio had less effect on the viscosity and rheological behavior of the resulting dispersions compared with the others—even at a high content of 1.30 wt%. Due to a lower aspect ratio but a relatively large particle size, the AR/T-MCC dispersions exhibited elastic gel-like rheological properties at a low content.
KeywordsCellulose nanoparticles TEMPO-oxidation Acrylic resin Aspect ratio Transparency Rheological property
This study was supported by the Northwest Advanced Renewables Alliance project sponsored by the National Institute of Food and Agriculture (Grant No. 2011-68005-30416), the National Science Foundation Industry & University Cooperative Research Center for Bioplastics and Biocomposites, and China Scholarship Council.
- Bousfield D, Richmond F, Bilodeau M (2013) The properties of paper coating layers that contain cellulose nanofibrils. In: TAPPI international conference on nanotechnology for renewable materials, Stockholm, SwedenGoogle Scholar
- Hunter RJ (1981) Zeta potential in colloids science. Academic Press, New York. https://doi.org/10.1016/b978-0-12-361961-7.50007-9 Google Scholar
- Kargarzadeh H, Ahmad I, Abdullah I, Dufresne A, Zainudin SY, Sheltami RM (2012) Effects of hydrolysis conditions on the morphology, crystallinity, and thermal stability of cellulose nanocrystals extracted from kenaf bast fibers. Cellulose 19:855–866. https://doi.org/10.1007/s10570-012-9684-6 CrossRefGoogle Scholar
- Lin L, Shuai Z, Jin Z, Zhen XZ, Hu H, Xin Z et al (2013) Tempo-mediated oxidation of microcrystalline cellulose: influence of temperature and oxidation procedure on yields of water-soluble products and crystal structures of water-insoluble residues. Fibers Polym 14:352–357. https://doi.org/10.1007/s12221-013-0352-8 CrossRefGoogle Scholar
- Ruiz M, Cavaille J, Dufresne A, Graillat C, Geŕard J (2001) New waterborne epoxy coatings based on cellulose nanofillers. Macromol Symp 169:211–222. https://doi.org/10.1002/1521-3900(200105)169:1<211::AID-MASY211>3.0.CO;2-H
- Veigel S, Grüll G, Pinkl S, Obersriebnig M, Müller U, Gindl-Altmutter W (2014) Improving the mechanical resistance of waterborne wood coatings by adding cellulose nanofibres. React Funct Polym 85:214–220. https://doi.org/10.1016/j.reactfunctpolym.2014.07.020 CrossRefGoogle Scholar
- Wang L (2013) Dynamic and steady rheological properties of printing pastes and the influence on printing performances. Doctoral dissertation, Donghua University, ChinaGoogle Scholar
- Yu HY, Qin ZY, Liu L, Yang XG, Zhou Y, Yao JM (2013) Comparison of the reinforcing effects for cellulose nanocrystals obtained by sulfuric and hydrochloric acid hydrolysis on the mechanical and thermal properties of bacterial polyester. Compos Sci Technol 87:22–28. https://doi.org/10.1016/j.compscitech.2013.07.024 CrossRefGoogle Scholar