One-Pot Synthesis of Block Copolymers via ATRP and ROP Using PCL Macroinitiator (original) (raw)
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Journal of Polymer Science Part A: Polymer Chemistry, 2002
Azo-containing polytetrahydrofuran (PTHF) obtained by cationic polymerization was used as a macroinitiator in the reverse atom transfer radical polymerization (RATRP) of styrene and methyl acrylate in conjunction with CuCl 2 / 2,2Ј-bipyridine as a catalyst. Diblock PTHF-polystyrene and PTHF-poly(methyl acrylate) were obtained after a two-step process. In the first step of the reaction, stable chlorine-end-capped PTHF was formed with the thermolysis of azo-linked PTHF at 65-70°C in the presence of the catalyst. Heating the system at temperatures of 100-110°C started the polymerization of the second monomer, which resulted in the formation of block copolymers. The decomposition behavior of the azo-linked PTHF and the structure of the block copolymers were determined by 1 H NMR and gel permeation chromatography (GPC). Kinetic studies and GPC analyses further confirmed the controlled/living nature of the RATRP initiated by the polymeric radicals.
Journal of Polymer Science Part A: Polymer Chemistry, 2014
ABA triblock copolymers were synthesized using two polymerization techniques, polycondensation, and atom transfer radical polymerization (ATRP). A telechelic polymer was synthesized via polycondensation, which was then functionalized into a difunctional ATRP initiator. Under ATRP conditions, outer blocks were polymerized to form the ABA triblock copolymer. Six types of samples were prepared based on a poly(ether ether ketone) or poly(arylene ether sulfone) center block with either poly(methyl methacrylate), poly(pentafluoros-tyrene), or poly(ionic liquid) outer blocks. As polycondensation results in polymers with broad molecular weight distribution (MWD), the center of these triblock copolymers are disperse, while the outside blocks have narrow MWD due to the control afforded from ATRP. V
Reactive and Functional Polymers, 2007
Bifunctional polystyrene macroinitiators, having various molecular weights, were prepared by atom transfer radical polymerization (ATRP), initiated with bifunctional initiator 1,3-bis{1-methyl-1[(2,2,2-trichloroethoxy) carbonylamino]ethyl}benzene in conjunction with CuCl catalyst and polyamine ligands. These macroinitiators were subsequently used for ATRP of tert-butyl acrylate (t-BuA), giving BAB triblocks poly[(t-BuA)-b-(Sty)-b-(t-BuA)] as precursors of amphiphilic copolymers. Both the polymerization steps proceeded as controlled processes with linear semi-logarithmic conversion plots and lengths of the blocks following theoretical predictions. Hydrolysis of outer poly(t-BuA) blocks led to triblock copolymers with the central polystyrene block and outer blocks of poly(acrylic acid), the molecular weights of which ranged from ca. 5 Â 10 3 to almost 1 Â 10 5 Da.
European Polymer Journal, 2021
In this study, we report concurrent ring-opening and atom transfer radical polymerization for synthesis of the block copolymers of L-lactide and styrene. Simultaneous polymerization of two different polymerization mechanisms requires careful selection of reaction conditions and reagents for targeted comparable propagation of both types. Several different di-block copolymers are synthesized having different total molar mass, chemical composition, and individual block lengths. Such simultaneous polymerization mechanisms require different reagents, and the regents required for one type of polymerization may hamper the other parallel mechanism. Hence, synthesized block copolymers are analysed comprehensively using different polymer chromatographic techniques and NMR spectroscopy. Total molar mass and chemical composition of BCPs are determined by size exclusion chromatography and NMR, respectively. PLA block length in PS-b-PLA and quantification of PS homopolymers is revealed by liquid chromatography at critical conditions of PS. For determination of PS block length in PS-b-PLA and quantification of PLA homopolymers, a gradient polymer elution chromatography (GPEC) method is applied. The comprehensive analysis of synthesized PS-b-PLA by parallel polymerization mechanisms revealed uninterrupted simultaneous polymerization of both monomers under applied conditions.
Polymer, 2005
Block copolymers are fascinating and complex materials that have been used in a range of diverse scientific and technological capacities. We demonstrate that a single one-step approach based on dual simultaneous polymerizations is a viable technique for the synthesis of a wide range of block copolymers by combining two dissimilar polymerization systems and using a dual-functional initiator. The main advantage of this methodology is that a simple, one-step, and simultaneous polymerization occurs in the bulk, which makes this process very attractive from both industrial and academic points of view. We plan to study the reaction kinetics and evaluate how well the ring opening catalyst [in this case, Sn(oct) 2 ] works under reverse ATRP conditions. q