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Aqueous Cationic Polymerization of p ‐Methoxystyrene Using Hydrophilic Phenylphosphonic Acids

2004; Taylor & Francis; Volume: 41; Issue: 3 Linguagem: Inglês

10.1081/ma-120028205

1520-5738

Robson F. Storey, Adam D. Scheuer,

Advanced Polymer Synthesis and Characterization

Abstract Abstract The use of phosphonic acids [(HO)2P(O)R, R = Ph or Ph‐o,m,p‐NO2] in conjunction with a water‐tolerant Lewis acid, ytterbium trifluoromethanesulfonate [Yb(OTf)3], induces the cationic polymerization of p‐methoxystyrene (pMOS). The polymerization is performed by addition of pMOS to a suspension of either nitrophenylphosphonic acid (NO2PPA) or phenylphosphonic acid (PPA) in an aqueous solution of Yb(OTf)3 at 23°C. Higher [NO2PPA]0 yielded higher initial polymerization rates, but had no effect on ultimate monomer conversion. Compared to PPA, NO2PPA yielded higher polymerization rates and higher ultimate conversions; however, PPA resulted in more controlled molecular weights and lower molecular weight distribution (MWD). The number‐average molecular weights of the polymers increased with conversion while MWD decreased. The polymerization rate was affected by the presence of polar or non‐polar solvents. Increasing the polymerization temperature dramatically increased the polymerization rate. Keywords: Aqueous cationic polymerizationYtterbium triflatePhenylphosphonic acidsWater‐tolerant Lewis acid Acknowledgment The research upon which this material is based was funded by both Hercules, Inc. and Eastman Chemical Company.