Novel Biobased Drag Reducers, Flocculants, and Viscosifiers
Ram Prakash Singh Materials Science Centre Indian Institute of Technology, Kharagpur Kharagpur – 721 302, India
The polysaccharides are obtained from natural and microbial sources. They are cheap and biodegradable. However, their molecular weight and architecture differ from source to source. In authors’ laboratory, an elaborate research has been conducted by purifying and chemically modifying the various industrial polysaccharides It has been found that on purification the shear viscosity of their aqueous solutions increases due to removal of low molecular impurities. Further when they are grafted with polyacrylamide chains, the shear viscosity of their aqueous solutions increases and the drag reduction and flocculation characteristics are drastically enhanced. On hydrolysis of the grafted chains, due to their mutual repulsion, the molecular chains are further extended resulting in increment of the dimensions, there is a tremendous enhancement in drag reduction and flocculation characteristics besides several order increase in viscosity. The synergistic effects in flocculation are due to easy approachability of dangling polyacrylamide branches on rigid polysaccharide backbone. Based on this concept it has been observed that grafted amylopectin and glycogen exhibit the maximum flocculation attributes which are further enhanced on hydrolysis. The shear and extensional viscosity measurements of their aqueous solutions indicate high increase in both kind of viscosities on grafting and hydrolysis. They also reflect the molecular changes, rigid–flexible-rigid chain on grafting and hydrolysis respectively. The details of all the above features would be reported in the presentation.
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