Polymers Large molecules degradable

Pyrolysis involves the thermal decomposition, degradation, or cracking of a large molecule into smaller fragments. Pyrolysis GC is an excellent technique for identifying certain types of compounds which cannot be analyzed by derivatization, e.g., polymers. The pyrolysis temperamre is typically between 400°C and 1000°C. A number of analytical pyrolyzers have been introduced and are commercially available. The devices consist of platinum resistively heated and Curie point pyrolyzers. The carrier gas is directed through the system, and the platinum wire is heated to a certain temperature. The material decomposes, and the fragmentation products are analyzed. ... 

Early studies with many types of enzymes failed to find evidence for intermediate products between large polymers and the ultimate products of an enzymatic degradation. From these studies a concept developed of explosive reaction, in which a large molecule was thought to be adsorbed to an enzyme, and held until completely digested. Currently, there is no basis for such a hypothesis. In some cases it has been found that the affinity of smaller molecules for the enzyme is greater than that of the parent compound, so that accumulation of intermediates is minimized, but where adequate methods (as chromatography) are available, it can usually be shown that each bond split is caused by an independent reaction. ... 

In spite of the efficacy of exogenous interferon, the major search has been for Interferon inducers. Synthetic polymers have been effective inducers and some of the characteristics apparently necessary for activity are as follows a large molecule with a high density of free anionic groups, not readily degradable and not readily eliminated. Agents with these characteristics include polymers of maleic anhydrides, polyacrylates and carboxylates. Polyacrylic acid (PAA) and polymethacrylic acid (PMAA) have induced Interferon in tissue culture and protected mice infected with Mengo virus and vaccinia and vesicular stomatitis viruses,76. Salts of polyvinyl sulfate appear to have dual activity since they induce interferon activity in mice but not in tissue culture, and the antiviral activity exerted is not correlated with virus interferon sensitivity. ... 

Biological systems degrade large molecules by hydrolysis and oxidation. It is essential that there are hydrolyzable and/or oxidizable (less eflfective) functional groups along the polymer chain for biodegradability. 

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