SYNTHESIS AND POLYMERIZATION OF A BULKY STYRENIC MONOMER AS AN IN-CHAIN KNOT FOR POLYROTAXANES

p-[Tris(p-t-butylphenyl)methyl]phenoxymethylstyrene (10) was prepared as a mixture of meta and pala isomers via Williamson ether synthesis from vinylbenzyl chloride. Monomer 10 polymerizes smoothly under free-radical conditions. Under anionic polymerization conditions, nucleophilic attack at the benzylic position displaces the substituted phenoxide ion; by using an excess of n-butyllithium, however, a polymer of complex structure, high molecular weight and polydispersity of 2.2 was formed. On the basis of its steric bulk and polymerizability, new monomer 10 is therefore a useful in-chain 'knot' or 'stopper' for polyrotaxane synthesis using free-radical techniques, but not via anionic methods.