Relation between the reactivities of vinyl monomers in ionic polymerizations and their ¹H NMR spectra

Abstract

Abstract1H NMR chemical shifts of the protons in the vinyl groups of monomers are correlated with their reactivities in anionic, coordinated anionic, and cationic polymerizations. The relative reactivities of styrenes in anionic addition reactions with living polystyrene increase linearly with the chemical shift of the proton trans to the substituent (δH1). Only the plot for 2,4,6‐trimethylstyrene deviates very much from the linear relation because of the large steric hindrance. The relative reactivities of methacrylates in anionic copolymerizations increase with increasing chemical shifts of protons attached to the β‐carbon of methacrylates. In cationic polymerizations of styrenes, the relative reactivities decrease with increasing δH1. The relative reactivities in coordinated anionic polymerizations with Ti‐containing Ziegler initiators show a typical feature of cationic polymerization, and those with V‐containing initiators show a typical feature of anionic polymerization, indicating the importance of the coordination process in the propagation reaction with Ti‐containing initiator systems. From the results, it can be concluded that the chemical shifts of the protons attached to the β‐carbon of vinyl monomers can be used as a practical measure of the reactivity of vinyl monomers in ionic polymerizations and also as a tool for understanding the mechanism of polymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2134–2147, 2002

RAFT Polymerization of Vinylthiophene Derivatives and Synthesis of Block Copolymers Having Cross-Linkable Segments

“…The comparison of chemical shifts of vinyl groups of the monomers evaluated by 1 H NMR spectroscopy (Figure ) supported the different reactivity of DB3VT, compared with those of 2VT and 3VT. The 1 H NMR chemical shifts of vinyl groups of monomers were reported to be correlated with the reactivities of monomers. , These results suggest that incorporation of the bromide groups at the 2,5-positions on the thiophene ring in DB3VT leads to the improvement of the reactivity of the vinyl group, in addition to the suppression of unfavorable side reactions occurred on the thiophene ring. On the basis of these preliminary results, we selected DB3VT for our further investigations toward the precise synthesis of poly(vinylthiophene) derivatives having low polydispersity and controlled molecular weights.…”

Neurotrophin‐eluting hydrogel coatings for neural stimulating electrodes

“…For the PEGPLA intermediary, notable peaks consisted of 1750 cm −1 = PLA, COO; 2870 = PEG, CH 2 ; 3445 = PEG, OH for FTIR and 1.55 = PLA, CH 3 ; 3.64 = PEG, CH 2 ; 4.92 = PLA, CH for NMR (Figure 1). For the final acryl‐PEGPLA product, peaks included 1730 = acryl, COO; 1750 = PLA, COO; 2870 = PEG, CH 2 ; 3445 = PEG, OH (absent) for FTIR and 1.55 = PLA, CH 3 ; 3.64 = PEG, CH 2 ; 4.92 = PLA, CH; 5.81, 6.12, 6.41 = acryl, CH, CH 2 50 for NMR (Figure 1).…”

RAFT Polymerization of Vinyl Sulfonate Esters for the Controlled Synthesis of Poly(lithium vinyl sulfonate) and Sulfonated Block Copolymers

“…The 1 H NMR chemical shifts of vinyl groups of monomers were reported to be correlated with the reactivities of monomers. , The comparison of chemical shifts of vinyl groups of the monomers evaluated by 1 H and 13 C NMR spectroscopy (Supporting Information, Figures S7 and S8) supported the different reactivities of primary alkyl vinyl sulfonate (NES and BES), compared with those of the other two vinyl sulfonate esters (IPES and PES). These results suggest that the different substituent groups on the sulfonate ester moiety have significant influence on the reactivity of the vinyl group in these monomers.…”