Radical polymerization of methyl methacrylate in the presence of phosphorus compounds

Polymerization of methyl methacrylate in the presence of P-H acids, such as bis(pirocatechol)hydrospirophosphorane and bis(2,3-butanediol)hydrospiroph osphorane as well as ethylene-bis[thio(1,3,2-phosphothiolane)], was studied . It was shown that phosphorus compounds are involved in the redox initiati on of polymerization, although the activity of phosphorus-containing redox initiating systems is appreciably lower, as compared to nitrogen- and sulfu r-containing compounds. It was demonstrated that the peculiarities of perox ide-initiated polymerization in the presence of ethylene-bis[thio(1,3,2-pho sphothiolane)] are accounted for by the structure of its molecule, in which a phosphorus atom is shielded by three sulfur atoms attached to this phosp horus. The behavior of initiating systems based on this compound is determi ned for the most part by the presence of sulfur atoms rather than by phosph orus ones.