Uncommon Organic Polymers

Some organic polymers are rather unique and are not common in nature. An example is the polymer from the leaf cuticle of some plants such as Agave americana [1]. This cuticular material contains a macromolecular material that contains polysaccharides and a polymethylene moiety in the estimated ratio 60/40 by weight. Pyrolysis products of an isolated macromolecular fraction of the cuticular material has been proven to have the following structure  

Pyrolysis products show a significant level of long aliphatic chain methyl ketones. These are probably generated by the mechanism suggested in the structure of the polymer. Long chain fatty acids also have been obtained in the pyrolysis of cuticular macromolecular constituents of Agave americana. 

Pyrolysis also has been utilized for the determination of the structure of unique natural polymers in certain lacquers such as those produced by Rhus vernicifera and Rhus succedanea [2] and utilized as surface coating for wood, porcelain, etc. in Japan. The pyrolysis products of the two lacquer films at 400° C contain respectively laccol and urushiol, and each also contains alkenes, alkanes, alkenylphenols, and alkylphenols. From these results it was possible to assign the following structure for laccol polymer  

A similar structure (with 15 carbons on the aliphatic chain) was obtained for urushiol polymer. 

Different other bioorganic polymers were analyzed using pyrolytic techniques. As an example, sporopollenin, a polymer from the outer wall of pollen particles, was studied using Py-MS [3]. It was found that p-coumaric acid is abundant in the pyrolysate of pollen from several plants, and it was inferred that this molecule is a structural unit of the sporopollenin skeleton. 

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Polymers are huge—molecular weights of 1,000,000 are not uncommon. Building polymers requires reactive organic functional groups. 

The preparation of polymers in this early phase of synthetic organic chemistry seems not to have been uncommon. It must not be concluded from the above citations, however, that their polymeric nature usually was comprehended. In the vast majority of instances this was not the case. 

Specific methods have been established for quite a large number of compounds or analytic problems. Among these are amino acids, sugars in food, common organic adds in food, vitamins, and additives (e.g., antioxidants) in polymers. Column manufacturers may have an applications database from which they can recommend a column and a method. However, it is recommended to rely on literature methods only, if the methods are well established and have been proved out in many laboratories. EPA methods or pharmacopoeia methods fall into this category, but a single reference on a method for an uncommon analyte should be viewed with caution. It is not unconunon that such a method does not work or does not work well when duplicated. In such a case, we are actually better off to develop a new method ourselves. 

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