posted on 2017-06-27, 00:00authored byYoungman Yoo, Jeffrey P. Youngblood
The main aim of this study is to
verify whether cellulose nanocrystal
(CNCs)-reinforced tung oil (TO) composites are effective for wood
finishes and offer enhanced mechanical and weathering performance
owing to the high strength, stiffness, and barrier properties of CNCs.
To achieve even dispersion of CNC particles in a polymeric coating
film, surface hydrophobization of the CNCs was carried out by grafting
poly(lactic acid) oligomers and oleic acid. These new TO coating formulations
contain 0 (controlled sample) to 10 wt % of hydrophobized cellulose
nanocrystals (hCNCs). The coating performance (degree
of wrinkle, leveling, and instantaneous filling) of the hCNC–TO finishes as well as their coating properties (topography,
optical properties, mechanical properties, and gas permeability) were
investigated in this study. The influence of the hCNC content in the tung oil composite coatings was examined using
scratch/impact resistance tests and oxygen transmission rate (OTR)
measurements. An increase in the hCNC content led
to an increase in scratch/impact resistance as well as a slight decrease
in the color-b change, gloss, surface roughness, and OTR value of
their film coatings. The hCNC–TO composites
for wood coatings presented here showed enhanced performance for utilization
in wood-working processes in terms of desired mechanical properties
(scratch and impact resistance), weathering performance (color stability),
and easy production without any deterioration in surface gloss and
roughness after the addition of hCNC to a TO matrix.
The hCNC enhanced coating system is a promising candidate
for substantial protection of wood surfaces in demanding settings.