Wednesday 7 November 2012

Practical Polysaccharides: Some Less Known Stories of Cellulose, Starch and Chitin

This paper by Jacek K. Dutkiewicz of Buckeye Technologies Inc was given at this years Insight Conference organised by MTS in Norfolk Virginia.  We thought it was good enough to appear here in several instalments so here's the first part. (The nonwovens from thermoplastic starch look particularly interesting.)

Polysaccharides are everywhere and all around us. They are in plants, animals, LCD screens, tires, medicines, cosmetics, paints, nonwovens, and binders. We use them as food, tools, furniture, paper, home, cloth … and so on and on.
Cellulose is the most abundant natural polymer followed by chitin. Starch belongs to the group of most common polycarbohydrates and its importance is mainly due to the fact that it is digestible by humans and stores energy. 

Combined together, polysaccharides represent the largest group of polymers harvested and produced in the world [1]. It is because they are renewable and extremely useful in countless areas of applications whose number is steadily growing. Cellulose, chitin and starch are liked by scientists and researchers due to their chemical and physical properties and by product developers due to their availability and affordability depending on the grade and on specific target applications. Starch is the cheapest of all three, cellulose is much more expensive and chitin, especially its preferred derivative chitosan, in order of magnitude is more costly than starch.

What can these natural polymers offer as raw materials? Fig. 1 illustrates
some useful chemical and physical features which allow for converting the polysaccharides into infinite number of useful products.

So many studies have been conducted with polycarbohydrates for centuries that some of them, even relatively recent may not be well known or remembered although they can offer valuable information for product developers. TRIZ (Russian acronym for TIPS – theory of inventive problem solving) is an innovation method developed in the 1950’s in the Soviet Union. Since it was imported to the Western world a few decades ago it has become an effective tool for product developers. For example, TRIZ suggests that many technical problems which need to be solved today already have their solutions – we just need to find these solutions. They may not be immediately visible because they can exist outside of the scope of our expertise or may have been forgotten because the timing of their disclosure was not right. It is almost as with some discoveries made by scientists or with masterpieces created by artists whose greatness remained unrecognized in their times. The examples of less known solutions and concepts that will be shown here may not necessarily qualify as big breakthroughs but, depending on the need, they may still have enough value to add to the existing technical knowledge base.
(Go to Part 2)

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