Controlled radical double ring-opening polymerization of 2-methylene-1,4,6-trioxaspiro[4,4]nonane

Controlled radical double ring-opening polymerization of 2-methylene-1,4,6- trioxaspiro[4,4]nonane (MTN) has been achieved with tert-butyl perbenzoate (TBPB) as initiator in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy free radical (TEMPO) at 125 degreesC. The molecular weight polydispersity of the polymers is obviously lower than that of polymers obtained by conven tional procedures. As the [TEMPO]/[TBPB] molar ratio increased, the polydis persity decreased and a polydisperty as low as 1.2 was obtained at high TEM PO concentration. With the conversion of the monomer increasing, the molecu lar weight of the polymers turned higher and a Linear relationship between the M-W, and the monomer conversion was observed. The monomer conversion, h owever, did not exceed 30%. (C) 2000 Society of Chemical industry.