2- ethyl methacrylate, ATRP

Fig. 5.8 Examples of polymers grafted from nanocarbons, (a) An ATRP initiator covalently attached to RGO via nitrene and carbodiimide chemistry was used for the growth of poly(2-(ethyl (phenyl)amino)ethyl-methacrylate). (b) A RAFT chain transfer agent is covalently attached to GO prior to polymerization of vinylcarbozole.

The first diblock copolymer brushes synthesized in our group were made by a combination of carbocationic polymerization and ATRP (Scheme 1) [46]. Zhao and co-workers [47] synthesized diblock copolymer brushes consisting of a tethered chlorine-terminated PS block, produced using carbocationic polymerization, on top of which was added a block of either PMMA, poly(methyl acrylate) (PMA) or poly((Ar,M -dimethylamino)ethyl methacrylate) (PDMAEMA), synthesized using ATRP. The thickness of the outer poly(meth)acrylate block was controlled by adding varying amounts of free initiator to the ATRP media. It has been reported that the addition of free initiator is required to provide a sufficiently high concentration of deactivator, which is necessary for controlled polymerizations from the sur-... 

We have recently evaluated the ATRP of a wide range of hydrophilic monomers such as 2-sulfatoethyl methacrylate (SEM), sodium 4-vinylbenzoate (NaVBA), sodium methacrylate (NaMAA), 2-(dimethylamino)ethyl methacrylate (DMA), 2-(iV-morpholino)ethyl methacrylate (MEMA), 2-(diethylamino)ethyl methacrylate (DEA), oligo(ethylene glycol) methacrylate (OEGMA), 2-hydroxyethyl methacrylate (HEMA), glycerol monomethacrylate (GMA), 2-methacryl-oyloxyethyl phosphorylcholine (MPC), and a carboxybetaine-based methacrylate [CBMA]. Their chemical structures and literature references (which contain appropriate experimental details) are summarised in Table 1. 

Controlled free-radical polymerization methods, like atom-transfer radical polymerization (ATRP), can yield polymer chains that have a very narrow molecular-weight distribution and allow the synthesis of block copolymers. In a collaboration between Matyjaszewski and DeSimone (Xia et al., 1999), ATRP was performed in C02 for the first time. PFOMA-/)-PMMA, PFOMA-fr-PDMAEMA [DMAEMA = 2-(dimethylamino)ethyl methacrylate], and PMMA-/)-PFOA-/)-PM M A copolymers were synthesized in C02 using Cu(0), CuCl, a functionalized bipyridine ligand, and an alkyl halide initiator. The ATRP method was also conducted as a dispersion polymerization of MMA in C02 with PFOA as the stabilizer, generating a kine-... 

In this paper, we first present a model study on blending a a,co-3,5-dinitrobenzoate PDMS and free 9H-carbazole-9-ethanol, in order to check whether the recently proposed 1 1 stoechiometry between carbazole and dinitrobenzoate molecules indeed applies (Scheme 1). [26] Then, we describe the preparation of triblock copolymers, poly[2-(N-carbazolyl)ethyl methacrylate]-fc-PDMS-fc-poly[2-(N-carbazolyl)ethyl methacrylate] (P(CzEMA)-fe-PDMS-fc-P(CzEMA)), using Atom Transfer Radical Polymerization (ATRP), and their blending with the acceptor-functionalized PDMS. In both studies, the physical association and thermal reversibility of these were followed by different techniques, including UV-Vis spectroscopy, DSC or Rheology. 

The polymerization of CzEMA by ATRP, starting from the PDMS macroinitiator, was adapted from the protocol described by Zeng et al. [27] applied to the ATRP of 2-(dimethylamino)ethyl methacrylate, which has a stmctnre qnite similar to the CzEMA, i.e. in THE at 60°C nsing HMTETA and CnBr. The desired triblock copolymer PCzEMA-( -PDMS-fc-PCzEMA was obtained in very good yields (monomer conversion >99%), and the final prodnct analyzed by SEC (not shown) and H-NMR (Eig. 8). 

Brushes with diblock side chains have been prepared by the same concept as illustrated in Figure 13. In this case either a polystyrene block or a poly-(n-butylacrylate) block was grafted first by atom transfer polymerization, ATRP, on a poly(2-bro-mopropanoyl ethyl methacrylate), pBPEM, on which in a second step the other monomer was polymerized as the second block.189 Table 4 summarizes the molecular structure of the corresponding polymers, i.e., (i) the macroinitiator or mere backbone molecule (pPBEM) from which (ii) a brush with pnBuA homopolymer side chains (pBPEM-g—pnBuA), (iii) a... 

Hyperbranched polymers synthesized by ATRP using mixed monomers , structures that contain combinations of (meth)acrylates with a-haloesters [262], have also been reported. For example, 2-(2-bromopropionyloxy)ethyl methacrylate (BPEM) contains the methacrylate and bromopropionate groups which form tertiary and secondary radicals, respectively. Likewise, the monomer 2-(2-bromoisobutyryloxy)ethyl acrylate (BIEA) contains the secondary acrylate group with a tertiary 2-bromoisobutyrate fragment. With these monomers, highly branched macromolecules were obtained. In a similar way, macroinitiators were used to reduce the proportion of branched units [263]. They may be considered a segmented block copolymers. 

Pan et al. prepared a macroinitiator by chloromethylation of a commercially available AB block copolymer of poly (styrene-fe-ethylene-co-propylene) (SEP) and used it as a macroinitiator for the ATRP of ethyl methacrylate (EM A) [302]. The kinetic plot showed little evidence of termination during the reaction and the molecular weight of the graft copolymer increased linearly with the monomer conversion, resulting in a final Mn=73,200 and Mw/Mn=1.22. The weight ra-... 

Several ligands were used with allyl-type and vinyl-type initiators, such as 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMDETA), NJJyN JJ jN -pentamethyldiethylenetriamine (PMDETA), or compound 7 in Scheme 66. Zeng et al. showed that the combination of initiator 1 in Scheme 66 with BA6TREN or initiator 4 in Scheme 66 with BA6TREN gave the best control of the molar mass for the ATRP of 2-(dimethylamino)ethyl methacrylate. These allylic macromonomers are then able to copolymerize with acrylamide. 

There are only a few cases in which polyelectrolyte stars have been prepared by the arm-first strategy. Qiao et al. prepared pH responsive poly(acrylic acid) stars by the MI method using atom transfer radical polymerization (ATRP), which was used to form layer-by-layer (LBL) polyelectrolyte multilayers with linear cationic polyelectrolytes [54], Matyjaszewski et al. obtained cationic poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) stars and anionic PAA stars also using the MI method, which formed all-star LBL layers [55], Ishizu et al. obtained... 

Figure 11 Facing page) (a) Structural formula of pH-responsive triblock copol3uner consisting of poly[(diisopropylamino)ethyl methaciylate]-6-pol3Kmethacryloyloxyethyl phosphorylcholine)-6-poly[(diisopropylammo)ethyl methacrylate] prepared by ATRP technique, (b) Formation of macroscopic gels of concentrated solution of triblock copolymer, (c) Drug release behavior from triblock copolymer gels at 37°C and at pH 7.4. (From Ref. 72.)...

Figure 4.2 Synthesis of the compatibilizer (P2) and schematic illustration of non-covalent functionalisation of MWNTs by P2. Reproduced with permission from Mandal and Nandi." EBIBT- 3-[l-ethyl-2(2-bromoisobutyrate)] thiophene DMAEMA- 2-(dimethylamino ethyl methacrylate) HMTETA- 1,1,4,7,10,10-hexamethyltriethylenetetra-mine ATRP- atom transfer radical polymerization.

The synthesis of an interesting DHBC, namely poly (4-vinylbenzoic acid-block-2-(diethylamino)ethyl methacrylate) (PVBA-PDEAEMA), has been presented by Armes and Liu [13], The synthesis was performed by ATRP using protecting group chemistry in three steps. Initially the polymerization of a tert-butyl protected PVBA macro-initiator was performed followed by the polymerization of the second monomer, DEAEMA. Finally the hydrolysis of the tert-butyl protected block was realized giving rather monodisperse block copolymers. 

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