TY - JOUR
T1 - Initiation of Vinyl Ether Polymerization by Trimethylsilyl Triflate, Dimethyl Sulfide, and Adventitious Water
AU - Cho, Chang Gi
AU - Feit, Ben Ami
AU - Webster, Owen W.
PY - 1992/4/1
Y1 - 1992/4/1
N2 - In an effort to use trimethylsilyl trifluoromethanesulfonate (TMSOTf) as an initiator for the living polymerization of isobutyl vinyl ether (IBVE) in the presence of dimethyl sulfide the Mn versus conversion plot showed a linear relationship for a given solvent. The slope, however, deviated from the calculated one based on an initiator efficiency of 1; i.e., the molecular weights were higher than expected. The addition of water or alcohol increased the initiator efficiency. This result indicated that triflic acid formed by hydrolysis of the TMSOTf was the true initiator. Indeed, in the presence of 2,6-di-tert-butyl-4-methylpyridine (DTBMP), a proton trap, no polymerization was observed up to 0 °C. Living polymerization occurred, however, with DTBMP in the system when an aldehyde or ketone was added. In these examples, a trimethylsiloxy group was shown to be covalently bound to the polymer by proton NMR. The number-average molecular weight, calculated by assuming there is one trimethylsilyl group per chain, agreed well with that obtained by GPC.
AB - In an effort to use trimethylsilyl trifluoromethanesulfonate (TMSOTf) as an initiator for the living polymerization of isobutyl vinyl ether (IBVE) in the presence of dimethyl sulfide the Mn versus conversion plot showed a linear relationship for a given solvent. The slope, however, deviated from the calculated one based on an initiator efficiency of 1; i.e., the molecular weights were higher than expected. The addition of water or alcohol increased the initiator efficiency. This result indicated that triflic acid formed by hydrolysis of the TMSOTf was the true initiator. Indeed, in the presence of 2,6-di-tert-butyl-4-methylpyridine (DTBMP), a proton trap, no polymerization was observed up to 0 °C. Living polymerization occurred, however, with DTBMP in the system when an aldehyde or ketone was added. In these examples, a trimethylsiloxy group was shown to be covalently bound to the polymer by proton NMR. The number-average molecular weight, calculated by assuming there is one trimethylsilyl group per chain, agreed well with that obtained by GPC.
UR - http://www.scopus.com/inward/record.url?scp=0026853231&partnerID=8YFLogxK
U2 - 10.1021/ma00034a004
DO - 10.1021/ma00034a004
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:0026853231
SN - 0024-9297
VL - 25
SP - 2081
EP - 2085
JO - Macromolecules
JF - Macromolecules
IS - 8
ER -