|MadSci Network: Chemistry|
Interlinked ring-shaped (cyclic) molecules have actually been synthesized and characterized. They are called catenanes. According to Wikipedia http://en.wikipedia.org/wiki/Catenane up to seven rings have been connected.
Since the size of the rings is limited, as far as well-characterized moleceules are concerned, these molecules are not really polymers in the practical sense. They might be called oligomers. The larger the rings, the more difficult it becomes to prepare, isolate, let alone connect molecules of uniform structure, since we have no "molecular tweezers" to accomplish the feat, contrary to the dreams of some nanoscientists.
In order to create a useful material, at least hundreds of rings would have to be joined, which can be considered well nigh impossible, given the low probability of orderly, sequential threading through the ring at the end of the chain. Now, even if we had such a chain material, say purely hydrocarbon-based (no polar groups), the chains themselves would be quite resistant to rupture, but they would glide against each other, just like any other hydrocarbon polymer of low molecular weight. You would expect a waxy type of material, with rather low melting point, hardly worth the trouble...
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