Study of a composite from reactive blending of methylol urea resin with natural rubber

Abstract

This study was designed to study some physical properties of a composite derivable from reactive
blending of methylol urea resin (MUR) with natural rubber (NR). Formaldehyde emission, decreased
with increase in NR concentration in the blend. Elongation at break and viscosity recorded an initial
increase but gradually decreased with increase in NR concentration. The melting point however showed
an opposite behavior. The incorporation of NR significantly lowered both the refractive index and the
density of this composite. The highest viscosity was recorded at 50:50% blend ratio. Formaldehyde
emission level, moisture uptake and elongation at break recorded for this composite are within
acceptable levels required in the coating industry. Also water resistant and flexibility compared
favorably with those of conventional paint binders. The low refractive index may be favorable for low
gloss coating at low pigmentation levels of coating systems.