Controlled grafting of cellulose esters using SET‐LRP process

Abstract

Here, we present the first example of application of single-electron transfer living radical polymerization (SET-LRP) process to a controlled grafting of cellulose esters, cellulose diacetate (CDA), and cellulose acetate butyrate (CAB). The cellulose ester macroinitiators with various functionality densities have been prepared by acylation of the backbones with 2-bromoisobutyryl (BrIB) and dichloroacetyl (DCA) groups, respectively. Methacrylate monomers were polymerized using DCA-functionalized macroinitiators in the presence of pentamethyldiethylene triamine as a ligand. At 30 C, the reaction is rather slow, reaching about 10% conversion after 3 to 6 h of polymerization, whereas the higher temperature (60 C) perceptibly speeds up the polymerization so that methyl methacrylate (MMA) conversion is $30% after 5 h. Graft copolymers with random-type and diblock-type grafts having amphiphilic character were also synthesized. For acrylate grafting (BuA and t-BuA), BrIB-functionalized macroinitiators are more convenient in a combination with a low concentration of Cu(0) and Me 6 TREN as a ligand and polymerization is detectably faster even at the lower temperature than that of MMA. Kinetic studies show ''living'' character of both the graftings. Important advantages of SET-LRP, compared with classic ATRP, are (i) higher polymerization rate, (ii) lower extent of recombination of the growing grafts and (iii) negligible coloration of the products with catalytic residua, so that the prepared polymers do not require additional careful purification.

In vitro evaluation of avidin antibody pretargeting using 211At‐labeled and biotinylated poly‐L‐lysine as effector molecule

“…3), indicating that the polymerization proceeded under controlled/“living” conditions. This agrees with the results reported by Vlcek et al,30 who found that the grafting of (meth)acrylate monomers onto cellulose esters via SET‐LRP could be realized in a well‐controlled manner. Very recently, Nguyen et al found that 2‐bromoisobutyric acid could give improved control over molecular weight evolution in the SET‐LRP of methyl acrylate than its counterpart of 2‐bromopropionate 31.…”

Well‐defined succinylated chitosan‐O‐poly(oligo(ethylene glycol)methacrylate) for pH‐reversible shielding of cationic nanocarriers

“…3), indicating that the polymerization proceeded under controlled/''living'' conditions. This agrees with the results reported by Vlcek et al, 30 who found that the grafting of (meth)acrylate monomers onto cellulose esters via SET-LRP could be realized in a well-controlled manner. Very recently, Nguyen et al found that 2-bromoisobutyric acid could give improved control over molecular weight evolution in the SET-LRP of methyl acrylate than its counterpart of 2-bromopropionate.…”

Cellulose‐based graft copolymers with controlled architecture prepared in a homogeneous phase

“…Radical polymerization is by far the most used method for grafting of cellulose, and numerous examples can be found in the literature. These use either traditional redox initiators6, 7 or exploit modern methods of controlled radical polymerization, such as nitroxide‐mediated polymerization,8 radical addition‐fragmentation chain transfer,9 single‐electron transfer living radical polymerization (SET‐LRP)10 and, in particular, atom transfer radical polymerization (ATRP) 11–13. The ATRP and SET‐LRP methods allow for an extensive control over the copolymer architecture by introduction of initiation sites into the cellulose chains in the first step, giving rise to a macroinitiator, followed by polymerization of a chosen monomer in the second step.…”