Reversible addition–fragmentation chain‐transfer graft polymerization of styrene: Solid phases for organic and peptide synthesis

Abstract

The γ‐initiated reversible addition–fragmentation chain‐transfer (RAFT)‐agent‐mediated free‐radical graft polymerization of styrene onto a polypropylene solid phase has been performed with cumyl phenyldithioacetate (CPDA). The initial CPDA concentrations range between 1 × 10−2 and 2 × 10−3 mol L−1 with dose rates of 0.18, 0.08, 0.07, 0.05, and 0.03 kGy h−1. The RAFT graft polymerization is compared with the conventional free‐radical graft polymerization of styrene onto polypropylene. Both processes show two distinct regimes of grafting: (1) the grafting layer regime, in which the surface is not yet totally covered with polymer chains, and (2) a regime in which a second polymer layer is formed. Here, we hypothesize that the surface is totally covered with polymer chains and that new polymer chains are started by polystyrene radicals from already grafted chains. The grafting ratio of the RAFT‐agent‐mediated process is controlled via the initial CPDA concentration. The molecular weight of the polystyrene from the solution (PSfree) shows a linear behavior with conversion and has a low polydispersity index. Furthermore, the loading of the grafted solid phase shows a linear relationship with the molecular weight of PSfree for both regimes. Regime 2 has a higher loading capacity per molecular weight than regime 1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4180–4192, 2002

In Situ Formation of Protein–Polymer Conjugates through Reversible Addition Fragmentation Chain Transfer Polymerization

“…[13][14][15] In a number of publications, the technique has proven to be useful for the preparation of polymer conjugated systems by in situ polymerization of monomers from the RAFT-agent-anchored substrates. [16][17][18][19][20][21] However, to our knowledge, the utility of the RAFT technique in the in situ preparation of polymerbiomacromolecule conjugates has not yet been reported. Herein, we demonstrate the first, RAFT-mediated in situ preparation of polymer-protein conjugates.…”

Basic Features and Techniques

“…In practice, the radiation doses required to achieve graft in the simultaneous method are lower than the other two methods. The reversible addition fragmentation transfer mechanism (discussed earlier) can also operate in the radiation initiated grafting technique [147,148] . In the ionic mode, two different types (cationic and anionic) mechanisms can operate.…”

Xanthate‐Mediated Controlled/Living Free‐Radical Polymerization under 60Co γ‐Ray Irradiation: Structure Effect of O‐Group

“…More recently Bai et al found that controlled/living free radical polymerizations of vinyl monomers can be performed under 60 Co g-ray irradiation in the presence of dibenzyl trithiocarbonate [11][12][13] and dithiobenzoic acid, [14] though the g-ray irradiated polymerization is generally very difficult to control. Subsequently, Quinn et al reported the living free radical polymerizations of styrene [15] and methyl methacrylate, [16] and the graft polymerization of styrene onto a polypropylene solid phase [17,18] under g-ray irradiation with cumyl phenyldithioacetate and cumyl dithiobenzoate. Pan and co-workers [19] successfully prepared cyclic poly(methyl acrylate) with controlled ring size and narrow-ring-size distribution by the g-ray irradiation polymerization of methyl acrylate at À30 8C in the presence of cyclic initiator.…”