Polymer break down

A 1,3-Cydopentadiene polymerizes slowly at room temperature to yield a polymer that has no double bonds except on the ends. On heating, the polymer breaks down to regenerate 1,3-cyclopenladiene. Propose a structure for the product. 

Polymers break down slowly or not at all, but the corresponding monomers can usually be degraded more readily. 

Drugs are sometimes enclosed in water-soluble polymers to control the rate of drug release. The polymer breaks down in the body overtime at a predictable rate and gradually releases the drug. 

HC6F4, on the basis of similar vibrational spectra, and also for (C6Fs)2TlCl, on the basis of isomorphism with the eorrespondihg bromide. In benzene solution the polymer breaks down to dimeric species. 

Many polymers break down in successive stages as the temperature is raised. For example, a side group elimination reaction will normally be followed at higher temperatures by fragmentation of the residual, modified polymer chain. The observed behaviour may then depend on whether the temperature is raised gradually or rapidly. 

Upon oxidative degradation, the complex lignin polymers break down into a suite of simple lignin-derived phenols which are indicative of their source. Of these, p-coumaric acid occurs only in non-woody angiosperm and gymnosperm tissues ( 7), and is therefore, of considerable interest as a potential carrier of a carbon isotope signal for C3/C4 ratios in the catchment vegetation. Both... 

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