Use of a Lewis Acid Surfactant Combined Catalyst in Cationic Polymerization in Miniemulsion:  Apparent and Hidden Initiators

Abstract

A Lewis acid surfactant combined catalyst (LASC) was tentatively used in a cationic polymerization in miniemulsion of p-methoxystyrene (pMOS). In a first part, the initiating potential of trisdodecyl sulfate ytterbium (Yb(DS)3, 0.25H2O) was evidenced in the solution polymerization of pMOS initiated by the corresponding chlorinated adduct pMOS-HCl. Miniemulsion polymerizations of pMOS performed using the same initiating system gave rise to oligomers, but experimental conditions chosen could not evidence the expected LASC-mediated cationic polymerization process. Further studies showed that LASC is located at the interface and acts only as a surfactant together with SDS. The polymerization occurred due to the hydrolysis of pMOS-HCl. The resulting acidification of the water phase leads to the transformation of SDS into its sulfuric acid form acting as an inisurf according to an interfacial cationic polymerization process. Latex particles of pMOS incorporating narrowly distributed low molar mass chains were obtained.

Controlled cationic polymerization of cyclopentadiene with B(C6F5)3 as a coinitiator in the presence of water

“…In the late 1990s, Sawamoto's team,12 followed by Ganachaud et al13 and D'Agosto et al,14 showed that rare earth triflates, dodecylbenzenesulfonic acid alone or with Yb(OTf) 3 induced cationic polymerization of p ‐alkoxystyrenes in aqueous suspension. However, these catalytic systems applied only for the polymerization of p ‐alkoxystyrenes and, therefore, were of little interest for industry.…”

A Catalyst Platform for Unique Cationic (Co)Polymerization in Aqueous Emulsion

“…DAgosto et al [17] followed Kobayashis work to prepare LASC from ytterbium salts and the simple commercial surfactant sodium dodecyl sulfate.T he obtained complexes were,however,soluble neither in water nor in the monomer, and thus did not catalyze polymerization. Theu se of ytterbium complexed with bulky electrosteric anionic surfactants generated water-dispersible LASC.…”

Transapical repair of mitral valve paravalvular leakage using 3‐D transesophageal guidance

“…The number–average molecular weights of the synthesized polymers almost do not change with monomer conversion and slightly decrease while increasing the concentration of initiator (see Table 2). This indicates that the polymerization of CPD with 1/ B(C 6 F 5 ) 3 initiating system proceeds at the interface and that M n is controlled by interfacial polarity similarly to styrene23 or p ‐methoxystyrene13, 14 polymerization. The molecular weight distributions of the obtained polymers are typically somewhat higher than two as anticipated for irreversible transfer/termination reactions with water 13.…”