Chemistry Reference
In-Depth Information
CHAPTER 12
Utilization of Green Materials
for Coating Applications
SHAILESH N. SHAH,*
a
SHARATHKUMAR K. MENDON
b
AND
SHELBY F. THAMES
b
a
Bio-Energy Research Group, Chemistry Department, Faculty of Science,
The Maharaja Sayajirao University of Baroda, Vadodara 390002, India;
b
School of Polymers and High Performance Materials, 118 College Drive
#5217, Hattiesburg, MS 39406, USA
*Email: shilshilp@hotmail.com
12.1 Introduction
A coating is a covering applied to the surface of an object (substrate) for the
purpose of decoration (e.g., gloss, appearance, color) and/or protection (e.g.,
corrosion resistance, wear resistance, scratch resistance). The coating
process involves the application of a thin film of functional material to any
of a variety of substrates such as metal, concrete, masonry, wood, paper,
fabric, leather or plastic.
Natural materials preceded petrochemicals by millennia in coating ap-
plications. The earliest cave paintings employed charcoal, iron oxides and/or
chalk as pigments, and animal fats, blood, egg whites and yolks as binders.
1
Pitches and balsams comprised the protective coatings of ancient Egyptian
ships.
2
Sap obtained from the Rhus vernicifera (varnish tree) was used as a
vehicle in Japanese lacquers as early as 400 A.D.
3
Shellac (a resin secreted by
the female lac bug, Laccifer lacca) finishes were one of the dominant wood
finishes in the early 19
th
Century. Historically, resins such as copal, dammar,
sandarac and rosin were key film-formers in varnishes. Milk-based paints
