Tack and bonding strength of carbohydrate-based adhesives from different botanical sources

Modified and unmodified starch extracted from root crops, cereals and a legume have been assessed as bases for adhesives for paper–paper, paper–cardboard, paper–metal and paper–glass substrates. Adhesives based on unmodified starch from all the crops investigated produced low or high tack for paper–paper and paper–cardboard depending on the intensity of mechanical action/heat applied in the formulation process. None of the starches produced good tack for paper–metal and paper–glass. Adhesives based on starch from yam, cassava, potatoes and corn modified by acid moisturing and roasting produced high tack and bonding strength for paper–paper and paper–glass. The effect of modification on these properties is attributable to the decrease in molecular size of the glycosidic chain of starch.