Ambient-Temperature RAFT Polymerization of Styrene and Its Functional Derivatives under Mild Long-Wave UV−vis Radiation

Abstract

Well-defined polystyrene and its functional derivatives, poly(vinylbenzyl chloride) (PVBC), poly-(N,N-diethyl vinylbenzylamine) (PDEVBA), and poly(vinylbenzyl alcohol) (PVBA) were synthesized via (S)-1-dodecyl-(S′)-(R,R′-dimethyl-R′′-acetic acid) trithiocarbonate-mediated ambient-temperature reversible additionfragmentation chain transfer radical (RAFT) polymerization of the corresponding styrenic-based monomers under mild long-waVe radiation, using a (2,4,6-trimethylbenzoyl) diphenylphosphine oxide photoinitiator. The effect of chloromethyl, hydroxymethyl, and tert-amino functionalities on reactivity and controlled behavior of ambienttemperature RAFT polymerization of styrenic-based monomers under mild conditions was studied in this paper. The results indicated that the photolysis of trithiocarbonate groups and the irreversible termination reactions of their intermediate radicals were significantly suppressed for the duration of the RAFT polymerization under mild long-wave radiation, thus keeping the characteristic living behavior. Kinetic studies confirmed the well-controlled behavior of these RAFT polymerizations. Moreover, the chloromethyl, tert-amino, or hydroxymethyl functionalities significantly improved reactivity of styrenic-based monomers, thus remarkably accelerating the process of ambienttemperature RAFT polymerization. Although RAFT polymerization of DEVBA and VBC monomers proceeded at a comparable rate, the initialization period in RAFT polymerization of DEVBA monomer was clearly longer than that of the VBC monomer. VBA was the most reactive monomer among these styrenic-based monomers. Ambient-temperature RAFT polymerization of VBA under mild long-wave radiation was well controlled up to 31% monomer conversion in 1.5 h. The living behavior of these ambient-temperature RAFT polymerizations facilitated the direct synthesis of well-defined all-styrenic-based block copolymers under mild conditions.

Living Radical Polymerization by the RAFT Process - A Second Update

“…MMA [296] St [296] 128* [283] S S C 12 H 25 S CO 2 H AA [91] CA [297] tBA [298] MA [299] (BMA) [300] (BMA) [300] CMA [301] MMA [122,283] (MMA) [122] BAM [302] DEAM [302,303] DMAM [302,303] EMAM [302,303] NIPAM [302][303][304][305][306] PAM [302,306] MVK [307] PVK [307] 297 [308] tBS [276] CMS [309] HMS [309] St [91,300,309] (St) [300] 4VP [310] Ip [311] 320 [312] 325 [100] 327 [309] 331 [313] 332 [313] NVP [103] 331-b-St [313] tBA-b-Ip [298] tBA-b-St [298] tBA-b-IP-b-St …”

“…[270,275,285,309,413,436] RAFT polymerization of St derivatives can be carried out at near ambient temperature (30 • C) with 115 as RAFT agent using 365 nm irradiation and (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide as photoinitiator. [309] The same photoinitiator with 420 nm irradiation was used in ambient temperature RAFT polymerization of the UV sensitive cinnamate derivative 298 [436] and for polymerization of BA and MA under solar irradiation (>400 nm) at 20 • C. [270] The use of ionizing radiation to initiate RAFT polymerization has been reviewed.…”

“…[270,275,285,309,413,436] RAFT polymerization of St derivatives can be carried out at near ambient temperature (30 • C) with 115 as RAFT agent using 365 nm irradiation and (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide as photoinitiator. [309] The same photoinitiator with 420 nm irradiation was used in ambient temperature RAFT polymerization of the UV sensitive cinnamate derivative 298 [436] and for polymerization of BA and MA under solar irradiation (>400 nm) at 20 • C. [270] The use of ionizing radiation to initiate RAFT polymerization has been reviewed. [33,437] Other studies on gammainitiated RAFT polymerization include the polymerization of MA and BA, [252] polymerization of NIPAM [269] and AA [269,354] in aqueous media, BA miniemulsion polymerization, [253] St/MAH/NVP terpolymerization, [288,289] MA polymerization with dithiocarbamate RAFT agents [405] and the grafting of styrenic monomers to cellulose [167,438] and t-butyl acrylate onto ethylene propylene rubber.…”

“…Styrene derivatives subjected to RAFT polymerization 348 [100,199] O 349 [138] O N N N 350 [158,309] N VBTAC 351 [159] Cl Ϫ Nϩ 352 [459] HN O 353 [321] O F F F F 354 [313] O F F F F 355 [313] [244] VBTPC 359 [34] Cl Ϫ P ϩ 360 [244] 361 [250] O N O 362 [207] O O O 363 [134] O O O Fe 364 [102] N 365 [102] N Table 23. Vinyl derivatives subjected to RAFT polymerization 366 [380] N 367 [380] N 368 [380] N 369 [390] N O O G. Moad, E. Rizzardo, and S. H. Thang [111,135] 370 [135,146] 375 [136] 376 [195] 377 [150] 378 [410] O O (H 3 C) 3 Si 372 [338,346,347] 373 [201] 374 [459] O [466] NAS 380 [160,299,317,345,347] 381 [178] 382 [222] [149,…”

Enantioselective Enzymatic Modification of Chiral Block Copolymers

“…[ 27 ] All block copolymers were obtained by RAFT polymerization using DDMAT as the chain transfer agent (CTA) together with AIBN as the radical initiator. [ 29 ] In a fi rst set of experiments, poly(styrene) macroinitiators ( M n = 3100 g mol − 1 , dispersity D = 1.1) were chain extended with 1R and 1S , respectively (Scheme 1 A). Confi rmation of the block copolymer formation was obtained from the shift of the SEC to higher mole cular weights upon chain extension ( Figure S1, Supporting Information).…”