Polymerizability bicyclic monomers

Polymerizability of bicyclic monomers is generally higher than the polymerizability of disubstituted cyclic monomers. This is because closure of an additional ring usually increases the angular strain moreover, conformational strain may also be increased due to the forced unfavourable conformation in the monomer molecule. In 1,4-epoxycyclohexane (7-oxabicyclo 2,2,l heptane) the 6-membered ring has to adopt the boatlike conformation while in the chain segment a more stable chair conformation may be attained (cf. Sect. 2.6.1) ... 

The condensation polymers (105) have been prepared (80JOC5325) by ring-opening polymerization of bicyclic lactam (101), the urethanes (102) and (103) and urea (104 Scheme 28). The polymerizability of these monomers, compared with the inertness of isomers (106)... 

Therefore, we hope to discuss the polymerization mechanism and polymerizability of bicyclic compounds containing oxygen atoms and their relation to the monomer and polymer structures. Finally, some biomedical application of polymers will be mentioned. 

Many kinds of bicyclic ethers, acetals, and orthoesters have been cationically polymerized. Almost all bicyclic compounds have shown polymerizability. A few monomers give dimer or higher oligomers instead of polymers. The results are listed in Table 1. The polymerizability for unsubstituted bicyclic compounds is summarized in Table 2. 

Most of the SPS-t-B polymer was suspended in benzene and was subjected to the oxidation reaction by oxygen in the presence of free radical polymerizable monomers, that is, MMA and n-butyl methacrylate (BMA). As illustrated in Scheme 19.2, the SPS-t-B was selectively oxidized and transformed to a stable polymeric radical for the polymerization of MMA and BMA. The resulting reaction mixture was carefully fractionated by Soxhlet extraction using boiling THF to remove any PMMA or poly(butyl methacrylate) (PBMA) homopolymers. In most cases, only a very small amount (about 10%) of homopolymer was present, which may have been initiated by the radical in a bicyclic ring... 

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