The importance of solvent polar character on the synthesis of PMMA-b-PBA block copolymers by atom transfer radical polymerization
TL;DR: In this article, the synthesis of diblock copolymers using atom transfer radical polymerization (ATRP), of methyl methacrylate (MMA), and butyl acrylate(BA), is reported.
About: This article is published in Polymer.The article was published on 2001-11-01. It has received 37 citations till now. The article focuses on the topics: Radical polymerization & Atom-transfer radical-polymerization.
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TL;DR: In this article, a series of diblock copolymers with poly(N-isopropylacrylamide) as a hydrophilic block and poly(tert-butyl methacrylate) as an hydrophobic block were synthesized using RAFT polymerisations.
138 citations
TL;DR: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed as discussed by the authors.
Abstract: Summary: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed. Homopolymers were prepared at relatively low temperatures using ethyl 2-bromoisobutyrate (EBrIB) as the initiator and copper halide (CuX) with N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The high polymerization rate in the bulk did not permit polymerization control. However, homopolymerization in solution enabled us to explore the effects of different experimental parameters, such as temperature, solvent (toluene vs. diphenyl ether) and initiator concentration, on the controllability of the ATRP process. SEC analysis of the homopolymers synthesized confirmed the importance of solvent character on molecular weight control, the lowest polydispersity indices () and the highest efficiencies being found when the polymerizations were performed in diphenyl ether in combination with a mixed halide technique. A novel poly(glycidyl methacrylate)-block-poly(butyl acrylate) (PGMA-b-PBA) diblock copolymer was prepared through ATRP using PGMA-Cl as a macro-initiator. This chain growth experiment demonstrated a good living character under the conditions employed, while simultaneously indicating a facile synthetic route for this type of functional block copolymer. In addition, the isotacticity parameter for the PGMAs obtained was estimated using 1H NMR analysis which gave a value of σGMA = 0.26 in agreement with that estimated in conventional radical polymerization.
SEC chromatograms of PGMA-Cl macroinitiator and PGMA-b-PBA diblock copolymer.
109 citations
TL;DR: In this article, the use of DMSO as solvent for transition metal mediated living radical polymerization was investigated using copper (I) bromide/N-(n-propyl)-2-pyridyl-methanimine catalyst system and ethyl-2-bromoisobyrate as initiator.
Abstract: The use of DMSO as solvent for transition metal mediated living radical polymerization was investigated using copper (I) bromide/N-(n-propyl)-2-pyridyl-methanimine catalyst system and ethyl-2-bromoisobutyrate as initiator. The best conditions for polymerization in DMSO of different methacrylates (MMA, BMA, DMAEMA, HEMA) were determined. In all cases, the measured number-average molar mass of the product increased linearly with monomer conversion in agreement with the theoretical Mn with low polydispersity products (1.16 < PDI < 1.4) achieved. Solvent was found to play a crucial role in the process. The effect of the polar solvent has been investigated and it was shown that DMSO could coordinate copper (II), increasing the activation process, or copper (I), changing the nature of the copper catalyst by competitive complexation of ligand and DMSO. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6299–6308, 2004
83 citations
TL;DR: Block copolymers based on PDMAEMAQ were synthesized containing hydrophobic segments of poly(butyl methacrylate) to improve the antimicrobial activity and glycomonomer units with the aim of decreasing the cytotoxicity of the polymers.
76 citations
TL;DR: The BC nanofiber sleeving was clearly demonstrated by SEM imaging, and its extent can be tuned by controlling the amount of initiating sites and the monomer feed.
70 citations
References
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TL;DR: A review of the development of controlled/living radical polymerization methods can be found in this article, where the authors give a brief overview of recent developments in controlled radical polymerizations and describe in more depth the progress that has been made in the development.
Abstract: The development of new polymeric materials is based on the availability of methods, principally living polymerizations, that allow well-defined polymers to be prepared. Living polymerizations are chain-growth polymerizations that proceed in the absence of irreversible chain transfer and chain termination. Provided that initiation is complete and exchange between species of various reactivities is fast, one can adjust the final average molecular weight of the polymer by varying the initial monomer-to-initiator ratio (DPn = D[M]/[I]0) while maintaining a narrow molecular weight distribution (1.0 < Mw/Mn < 1.5). [8,9] Also, one has control over the chemistry and structure of the initiator and active end group, so polymers can be end-functionalized and block copolymerized with other monomers. Thus, using only a few monomers and a living polymerization, one can create many new materials with vastly differing properties simply by varying the topology of the polymer (i.e., comb, star, dendritic, etc.), the composition of the polymer (i.e., random, periodic, graft, etc.), or the functional groups at various sites on the polymer (i.e., end, center, side, etc.) (Fig. 1). Examples of such materials prepared by atom transfer radical polymerization (ATRP) are shown later in this review. Much of the academic and industrial research on materials development has focused on coordination, cationic, anionic, and ring-opening polymerizations due to the availability of controlled/living polymerizations of these types. Free-radical polymerizations accounted for approximately half of the total production of polymers in the United States in 1995. Despite its tremendous utility, a significant drawback to free-radical polymerization is the lack of macromolecular structure control due to near diffusion-controlled radical coupling and disproportionation. Therefore, the development of controlled/living radical polymerization methods has been a long-standing goal in polymer chemistry. The last five years have seen the realization of this goal and the rapid growth in the development and understanding of new controlled radical polymerizations. In this discussion, we give a brief overview of recent developments in controlled radical polymerizations and describe in more depth the progress that has been made in the development of ATRP.
876 citations
TL;DR: In this article, three multidentate amines, tetramethylethylenediamine (TMEDA), N,N,NN, N',N' and N'N' were used as new ligands in the copper mediated atom transfer radical polymerization (ATRP) of styrene, methyl acrylate and methyl methacrylate.
Abstract: Three multidentate amines, tetramethylethylenediamine (TMEDA), N,N,N‘,N‘,N‘‘-pentamethyldiethylenetriamine (PMDETA) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) have been successfully used as new ligands in the copper mediated atom transfer radical polymerization (ATRP) of styrene, methyl acrylate and methyl methacrylate. All the polymerizations were well controlled with a linear increase of molecular weights (Mn) with conversion and relatively low polydispersities throughout the reactions. Compared to the 2,2‘-bipyridine (bipy) based ligands, most multidentate amines are less expensive and the polymerization mixtures are less colored. In particular, the use of the tridentate PMDETA and the tetradentate HMTETA as the ligands resulted in faster polymerization rates for styrene and methyl acrylate than those using bipy as the ligand. This may be in part attributed to the fact that the coordination complexes between copper and the simple amines have lower redox potentials than the copper−bipy co...
428 citations
TL;DR: In this article, the fundamental principles of controlled/living radical polymerization are given together with a discussion of selected initiating/catalytic systems which provide structural, compositional, and functionality control during radical polymerisation.
Abstract: Fundamentals of controlled/“living” radical polymerization are given together with a discussion of selected initiating/catalytic systems which provide structural, compositional, and functionality control during radical polymerization. Four systems which enable the synthesis of polymers with low polydispersities (Mw/Mn 10 000), and high degrees of functionality are: nitroxide-mediated polymerization of styrene and styrene copolymers; organometallic compounds used for polymerization of acrylates; atom transfer radical polymerization of various monomers; and the degenerative transfer process. Also important in this field are new structural features and potential applications of controlled radical polymerization.
402 citations
365 citations
TL;DR: In this article, multifunctional initiators derived from cyclotriphosphazenes, cyclosiloxanes and organic polyols were used in the synthesis of styrenic and (meth)acrylic star polymers by atom transfer radical polymerization (ATRP).
Abstract: Multifunctional initiators, derived from cyclotriphosphazenes, cyclosiloxanes, and organic polyols, were used in the synthesis of styrenic and (meth)acrylic star polymers by atom transfer radical polymerization (ATRP). Conditions were identified in each system which provided linear first-order kinetics for polymers with narrow, monomodal molecular weight distributions. Molecular weight measurements relative to linear polystyrene standards showed that the star polymers had lower molecular weights than theoretically predicted. Triple detection SEC measured on poly(n-butyl acrylate) samples demonstrated that the absolute molecular weight matched the theoretical valuethe smaller relative chain length was due to lower hydrodynamic volumes of the star-branched polymers relative to linear analogues. Kinetic arguments were used to demonstrate that each alkyl halide moiety bound to the initiators was participating in ATRP. Well-defined poly(methyl acrylate) stars of molecular weights Mn > 500 000 and low polydispe...
364 citations