Controlled radical (co)polymerization of (meth)acrylic esters via the reversible addition-fragmentation chain-transfer mechanism

Abstract

The homopolymerization of acrylic and fluoroacrylic esters mediated by benzyl dithiobenzoate and dibenzyl trithiocarbonate proceeds in the controlled mode via the reversible addition fragmentation chain transfer mechanism, while the controlled radical polymerization of methacrylic esters is not effected under these conditions. The molecular mass characteristics of the copolymers of acrylic and methacrylic esters may be satisfactorily controlled by benzyl dithiobenzoate-mediated copolymerization when the con tent of acrylic esters is no less than 50 mol %. If a reversible addition fragmentation chain transfer agent active with respect to only one of the monomers is used, compositionally homogeneous narrowly dispersed copolymers are formed via the azeotropic copolymerization of the monomers up to high conversions. The controlled copolymerization of N vinylpyrrolidone and fluoroacrylates allows the synthesis of alternating narrowly dispersed amphiphilic copolymers with properties different from those of alternating copolymers with a broad molecular mass distribution.

Porous, functional, poly(styrene-co-divinylbenzene) monoliths by RAFT polymerization

“…57,58 The availability of retained trithiocarbonate groups for further reaction was shown by graing of glycerol monomethacrylate with apparent success indicated by morphological changes in the monolith and altered separation of analytes post-graing. However, DBTC is known to be a poor RAFT agent for methacrylates, 29,31,59,60 which casts some doubt on the validity of mechanistic conclusions. Moreover, no characterization by spectroscopic or elemental analysis for detection of the trithiocarbonate groups was provided.…”

Reversible addition-fragmentation chain transfer (RAFT) (Co)polymerization of isobornyl acrylate

“…In experiments, BTB, which is an efficient RAFT agent in the homopolymerization of acrylates [17,18], was used; thus, there is good reason to believe that the polymerization of isobornyl acrylate in the presence of BTB will proceed via controlled/living mechanism. Figure 1 shows that the molecular weight distribution curves of PIBA samples obtained in the presence of 10 -2 -(5 × 10 -2 ) mol/L BTB shift to the high molecular weight region with monomer conversion.…”

Thermal and photo-RAFT polymerization of 2,2,2-trifluoroethyl α-fluoroacrylate

“…On the contrary, the RDRP of α-fluorinated acrylates has only been scarcely reported. [39][40][41][42][43][44][45] Boutevin's group 39,40 reported the ATRP of n-butyl -fluoroacrylate (FABu) using ethyl 2-bromoisobutyrate (EBiB) and CuX (X= Br or Cl)/ 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as the catalyst. The dispersity of the resulting polymer was as low as 1.14.…”

“…40 However, the measured molar masses were quite different from the theoretical values due to the inefficient chain transfer reaction of the CTA employed. To the best of our knowledge, the RDRP of α-fluorinated monomers bearing fluorinated pendent group (1,1,1,3,3,3-hexafluoroisopropyl αfluoroacrylate, FAHFiP) was only reported by Semchikov et al [42][43][44][45] using dibenzyl trithiocarbonate as chain transfer agent (CTA). After determining the reactivity ratios of FAHFiP and N-vinylpyrrolidone (NVP), these authors reported that an alternating copolymer was formed.…”