Accurate Structural Control and Block Formation in the Living Polymerization of 1,3-Dienes by Nitroxide-Mediated Procedures

Abstract

The living free radical polymerization of 1,3-dienes, such as isoprene and 1,3-butadiene, has been shown to be a facile process in the presence of alkoxyamine initiators based on a 2,2,5-trimethyl-4-phenyl-3-azahexane-3-oxy, 2, skeleton. These α-hydrido nitroxide derivatives were able to control the homopolymerization to high conversion and molecular weights from 1000 to 100 000 amu with polydispersities of 1.06−1.15 readily obtained. Block and random copolymers based on combinations of 1,3-dienes with a variety of functionalized vinyl monomers, such as styrene, acrylate, or methacrylate derivatives, could also be prepared with similar control. In comparison with 2,2,6,6-tetramethylpiperidinoxy (TEMPO), these new systems represent a dramatic improvement in the ability to control the polymerization of 1,3-dienes and further demonstrate the versatility of nitroxide-mediated living free radical procedures.

Well-Controlled Living Polymerization of Perylene-Labeled Polyisoprenes and Their Use in Single-Molecule Imaging

“…18 Their functional group tolerance makes alkoxyamines suitable candidates for the synthesis of polymers with predicted length. For studies of the dynamics and rheology of melts, the use of low entanglement molecular weight polymers is also desirable.…”

Recent advances in controlled/living radical polymerization in emulsion and dispersion

“…A class of persistent radical precursors is alkoxyamines, alkylated derivatives of nitroxides that generate nitroxides as mediators (deactivators) and alkyl radicals as initiating species upon their decomposition. [115][116][117][118][119][120] Although TEMPO is most efficient in polymerization of St at high temperature, other nitroxides and alkoxyamine derivatives allow for low temperature polymerization of St as well as (meth)acrylates.…”

Síntese de copolímeros em bloco de p-acetoxiestireno com isopreno através de polimerização "viva" via radical livre

“…nicas de polimerização "viva" radicalar, com o objetivo de sintetizar copolímeros em bloco com distribuição de massa molar estreita [3][4][5][6] . Os copolímeros em bloco são uma classe única de materiais poliméricos que sofrem separação de fase da ordem nanométrica e têm uma variedade de aplicações inclusive como dispersantes, compatibilizantes e modificadores de viscosidade.…”

“…Assim sendo, existem poucos artigos na literatura que relatam a polimerização controlada via radical "livre" de p-acetoxiestireno [9][10][11][12][13] . Hawker et al [4] estudaram a copolimerização randômica em massa de isopreno com p-acetoxiestireno na presença do inciador 2,2,5-trimetil-4-fenil-3-azahexano-3-óxi., sob atmosfera de argônio a 125 °C por 36 h. Os copolímeros de poli(p-acetoxiestireno-coisopreno) (PASt-co-PIP) foram caracterizados por GPC, IR e RMN. Eles sintetizaram copolímeros de PASt-co-PIP bem definidos para uma faixa de composição em peso de 75 a 25 % de isopreno com um bom controle da massa molar ( n M = 17.000 -20.500 g/mol) e da polidispersidade (PD = 1,1 -1,3).…”