Plant proteins as binders in cellulosic paper composites

Plant proteins are used – for the first time – in this work as bulk binders for cellulosic fibers in paper composites. Soy bean protein and wheat gluten were denatured by two methods, namely by: urea + NaOH and by urea + NaOH + acrylamide. Addition of increased amounts of the denatured proteins resulted in a significant increase in all paper strength properties. Soy protein led, in addition, to a remarkable enhancement in opacity. The use of proteins increased kaolin retention in the paper composites, while keeping the paper strength higher than the blank protein-free paper.The results show that plant proteins are favorable than synthetic adhesives; because they are biodegradable and do not cause troubles in paper recycling i.e. they are environmentally friendly.