Low molecular weight homopolymers of methylmethacrylate and tertbutylmethacrylate were polymerized by the controlled process of ATRP- Atom Transfer Radical Polymerization. The procedure for initiation of an ATRP reaction employs a molecule, either a small molecule, macromolecule, or a functionalized surface, with one or more transferable atoms or groups, most often a (pseudo)halide, that undergoes a one electron redox reaction with a transition metal catalyst forming the reactive species.
In all of the published literature on ATRP this RBr molecule has been called the initiator even though in contrast to standard free radical polymerization the molecule is an inherently thermally stable entity and is incorporated in its entirety into the final polymer.
This sequence can repeat itself, until the desired level of consumption of the monomer is reached, resulting in the synthesis of polymers with predetermined molecular weights (DPn = ^[M]/[RBr]0) and low polydispersities (Mw/Mn < 1.5).The advantage of ATRP is that it provides great freedom for the choice of both initiator and catalyst complex.
P(methylmethacrylate) was further used as a macroinitiator in the polymerization of tertbutylmethacrylate resulting in the copolymer P(methylmethacrylate)-b-P( tertbutyl methacrylate). P(tertbutylmethacrylate) was also used as macroinitiator in the polymerization of P(methylmethacrylate) resulting in the copolymer P(tertbutylmethacrylate-b-P(methylmethacrylate).
N-Hydroxysuccinimidemethacrylate monomer was synthesized and successfully used in homopolymer.
The initiating system was composed of a ligand, a copperhalogen and a initiator. N,N,N1,N11,N111-heksametyltrietylentetramin and N,N,NI,NII, NII-pentametyldietylentriamin were used as ligand, copper(I)bromide and copper(I)chloride were used as metalhalogen and ethyl 2-bromoisobutyrate, trichloroethanol and para-toluensulfonylchloride as initiator.
The main part of the reactions was carried out using N,N,N1,N11,N111-heksametyltrietylentetramin, copper(I)bromide and para-toluene sulfonylchloride. They were chosen because the initiator was easy to analyse and the ligand gave reproducable results. The complex ligand/copper structure is not readily fully understood. Para-toluene sulfonylchloride was also chosen as initiator due to hydrolysis of ethyl 2-bromoisobutyrate and problems with characterizing the product when using trichloroethanol.