Molecular Weight and Functional End Group Control by RAFT Polymerization of a Bisubstituted Acrylamide Derivative

Abstract

Controlled radical polymerization of the bisubstituted acrylamide derivative N-acryloylmorpholine (NAM) has the potential to yield telechelic polymers, one end of which can subsequently be grafted to latex particles. Once grafted, the other chain end of the polymer can be used as an immobilization site for species with applications in molecular biology and biomedicine. The controlled polymerization of NAM using reversible addition−fragmentation chain transfer (RAFT) is performed using two new chain transfer agents SC(Z)−SR bearing the same functional propanoic acid group (R) and two different Z groups, benzyl (CTA 1) and phenyl (CTA 2). RAFT polymerization of NAM mediated by CTA 1 is very fast (>80% conversion in less than half an hour at 65 °C). The linear evolution of M̄ n and the low polydispersity indices (M̄ w/M̄ n < 1.2) are in accord with the expected characteristics of a living polymerization. CTA 2 leads to broader M̄ w/M̄ n's (<1.4). The resulting CTA-capped polymers were further used to yield an amphiphilic polyNAM-block-polystyrene. These α,ω-functionalized polyNAM chains were characterized by 1H NMR and MALDI-ToF mass spectrometry.

Reversible addition fragmentation chain transfer (RAFT) polymerization of styrene in fluid CO2

“…Experimental data (reaction time, t; monomer conversion, X; number-average molecular weight, M n ; peak molecular weight, However, for the lowest RAFT agent concentration a deviation from the theoretical values to lower molecular weights can be observed. Such deviations are occasionally observed in RAFT polymerizations and were generally attributed to SEC calibration errors [24,25]. The fact that we used a polystyrene standard calibration and that the effect is dependent on CDB concentration renders this explanation unlikely.…”

Synthesis and characterization of thermo-responsive particles of poly(hydroxybutirate-co-hydroxyvalerate)-b-poly(N-isopropylacrylamide)

“…2,2'-Azobisisobutyronitrile (AIBN) was purified by recrystallization in absolute ethanol. The RAFT agent (2-((2-Phenyl-1-thioxoethyl)thio)propanoic acid (PTET PA) was synthesized according to the methodology described in the literature [21]. N,N-dicyclohexyl carbodiimide -DCC (Aldrich, 99%) and 4-dimethyl aminopyridine -DMAP (Aldrich, 99%) were used as received.…”

"Smart" Multifunctional Polymers for Enhanced Oil Recovery

“…Employing these homopolymers as macro-chain transfer agents (macroCTAs) for subsequent copolymerizations facilitated the preparation of styrenic-styrenic 15 and acrylamidoacrylamido 19 block copolymers, respectively. While styrenic-acrylamido block copolymers have been prepared in organic media by various CRP techniques, 20,21 including RAFT, [22][23][24][25][26] to date there have been no examples of the block copolymerization of dissimilar monomer classes in water.…”