Impact of Starch Addition on Properties of Urea Formaldehyde/Starch Copolymer Blends for Application as a Binder in the Coating Industry

Urea formaldehyde resin was reactively blended with various concentrations (10-70%) of cassava
starch in order to formulate a paint binder for emulsion paint formulation. Some physical properties
and formaldehyde emission of the blended resin were investigated. Viscosity initially decreased
before a gradual increase was noted with increase in starch concentration. Refractive index and
elongation at break increased initially but gradually decreased with cassava starch content in the
blend. Gel time, density, melting point, moisture uptake and formaldehyde emission decreased with
increase in starch inclusion. The interaction between the two different polymers shows that 50%
starch was the optimal loading inclusion. This new system has advantages of low brittleness, low
formaldehyde emission and water reduction characteristics. Therefore, the polymer blend can be
recommended as binder for coating industry. This results present cassava starch modified methylol
urea as a resin with relatively very low moisture uptake and formaldehyde emission against the
traditional hard and brittle resin. The increase in elongation at break and reduction in density is also a
positive value to the coating industry. Therefore, this work has shown that biodegradable starch films
could be used to produce copolymer composite binder for the coating industry especially in the
formulation of emulsion paints.