Polymerization of Glycidyl Phenyl Ether with Benzyl Phenylphosphonates as Novel Thermally Latent Initiators

The cationic polymerization of glycidyl phenyl ether (GPE) was examined with novel phosphonic acid esters, O,O- di- p -methylbenzyl phenylphosphonate ( 1a ), O,O- dibenzyl phenylphosphonate ( 1b ), and O,O- di- p -nitrobenzyl phenylphosphonate ( 1c ), as initiators. GPE did not convert with 1a − c even at 210 °C in the absence of ZnCl 2 . In the presence of ZnCl 2 along with phosphonic acid esters 1a, 1b, and 1c, the polymerization of GPE did not proceed below 90, 130, and 170 °C, respectively, but it rapidly proceeded to afford polyGPE with M n of 2500−5000 above those temperatures. It was found that 1a, 1b, and 1c served as thermally latent initiators in the polymerization of GPE in the presence of ZnCl 2 . Electron-donating substituents on the benzyl group of the phosphonic acid esters increased the initiator activity. The initiation species was identified as a benzyl cation by 13 C-labeled experiments.