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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
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Discovery of Cellulose Nanocrystals as Pot-life Stabilizers for Epoxy Coatings

Scanning electron image of cellulose nanocrystals coordinated to the surface of an epoxy particle. Natalie Girouard, Georgia Institute of Technology
Scanning electron image of cellulose nanocrystals coordinated to the surface of an epoxy particle. Natalie Girouard, Georgia Institute of Technology
Snapshot: Waterborne epoxy coatings are high-value, sought-after environmentally friendly products in the coating industry mostly due to their ease of use, performance and low maintenance. Waterborne epoxy coatings are part of a $56 to 64 billion industry. Addition of cellulose nanocrystals to such coatings improves their mechanical and thermal properties, and significantly increases the long-term shelf life and sustainability.
Summary:

Researchers at the Georgia Institute of Technology and the Forest Service's Forest Products Laboratory in Madison, Wisc., have explored and refined the novel stabilizing capability of celluslose nanocrystals (CNCs) that result in a controlled delay in the onset of curing reactions in waterborne epoxy formulations, thus facilitating a stable one-part epoxy coating with a much longer shelf life. When the epoxy emulsion and CNCs are combined and stirred for some time, before the addition of the amine curing agent, the CNCs arrange themselves around the epoxy drops, enhancing the stability of the emulsion and promoting a homogeneous distribution the CNCs. This removes the need for anti-gelation agents, such as sulfuric acid, which are commonly used. When compared to a single-step mixing process, dispersion of the composite produced by the two-step mixing process is more homogeneous. This improved emulsion stability and homogeneity reduces the potential for heterogeneous film morphology to develop upon application, resulting in more consistent product performance, ease of use by the end user, and increased productivity for the manufacturer. A further benefit of the presence of CNCs is enhanced stiffness of the resulting epoxy below the glass temperature at which these formulations are commonly used. At 5 percent CNC loading the storage modulus is approximately 50 percent greater in the composite produced by the two-step mixing process than that of the composite produced by the one-step mixing method.
Princpal Investigator(s):
 Schueneman, Gregory


Research Location:
  • Georgia Institute of Technology


External Partners:
  • J. Carson Meredith
  • Meisha L. Shofner
  • Natalie Girouard

Fiscal Year: 2015
Highlight ID: 614
 
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