Triblock polymers synthesis

As had been observed in the synthesis of carbohydrate-substituted polymers of different lengths, the reactivity of the monomers was an important parameter in generating the triblock polymers. If the mannose-substituted 7-oxanor-bornene derivative was first polymerized, followed by the galactose-derivatized norbornene and the mannose-substituted norbornene monomers, two distinct sets of products were observed. These were identified by modification of the resulting polymers by acetylation, and analysis of the products by GPC. With this protocol, it was found that the product was composed of short polymers (DP=... 

Fig. 22 Images and data representing development and application of DLS on a chip a one iteration in the design of a microfluidic DLS fabricated from aluminum with the surface anodized black to reduce surface reflections b image of a microfluidic chip that integrates polymer synthesis with DLS. The machined channels have been covered by a Kapton sheet fixed with adhesive c data for temperature depended micelle formation of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (Pluronic P85) at 2% by volume in water. (Derived from [106] with permission)...

Hadjichristidis N, Iatrou H et al (2005) Linear and non-linear triblock terpolymers. Synthesis, self-assembly in selective solvents and in bulk. Progr Polym Sci 30 725-782... 

Hosono N, Pitet LM, Palmans ARA, Meijer EW (2014) The effect of pendant benzene-1,3,5-tricarboxamides in the middle block of ABA triblock copolymers synthesis and mechanical properties. Polym Chem 5(4) 1463-1470... 

Only a few of the radical cations formed in this way dimerize, however, to the corresponding dications. Consequently, in contrast to anionic polymerizations, electron transfers are poor methods of synthesis for living cationic polymerizations to triblock polymers. However, dications can be produced in a single-stage process from trifluoromethane sulfonic anhydride with, for example, tetrahydrofuran ... 

A simple, versatile synthesis of triblock polymers was demonstrated. 

RAFT-CTAs can be prepared in a similar way and thus combined with ROMP for the synthesis of well-defined block copolymers. ABA-type triblock polymers of 1,5-cyclooctadiene (by ROMP) and St or tBA (by RAFT) were synthesized by Mahanthappa et In the first step of the process, the synthesis of telechelic PBs possessing trithiocarbonate-functionalized termini was performed using the specially designed difanctional CTA containing double bond in the middle. The RAFT polymerizations of conventional monomers mediated by the telechelic polymers gave rise to PSt-b-PB-l7-PSt and PtBA-l -PB-l7-PtBA (Scheme 68). 

Even M, Haddleton DM, Kukulj D. Synthesis and characterization of amphiphUic triblock polymers by copper mediated living radical polymerization. Eur Polym J 2003 39 633-639. 

Guo JB, Sun J, Cao H, Zhao DY, Yang H. Synthesis and characterization of functionalized triblock polymer the prepared polymer is cholesteryl terminated and chain-extended PCL. J Appl Polym Sci 2007 105 3505-12. 

Yuan L, Chen W, Li J, Hu J, Yan J, Yang D. PEG-i>-PtBA-f>-PHEMA weU-defined amphiphilic triblock copolymer synthesis, self-assembly, and apphcation in drug dehvery. J Polym Sci, Part A Polym Chem 2012 50 4579-88. 

Bao S, Ni H, Wu Q, Gao H, Liang G, Zhu F, Wu Q (2014) Waterborne redox-active helix-coil-helix triblock metallopolymers synthesis, disassembly and electrochemical behaviors. Polymer 55 2205-2212... 

RAFT polymerization has emerged as one of the most important methods for imparting living characteristics to radical polymerization. RAFT has been shown to be robust and has applicability to the majority of monomers that are subject to radical polymerization. However, selection of the RAFT agent for the monomers to be polymerized and the choice of reaction conditions are crucial for success. With these provisos, RAFT polymerization can be used in the synthesis of well-defined homo-, gradient, diblock and triblock polymers as well as more complex architectures which include higher order blocks, stars and polymer brushes. 

AABB polyimides, synthesis of, 300-302 AA-BB-type polymers, 135 AA-BB-type sulfonylation, 330 AA monomers, 11-12 A-B-A triblock copolymers, 7 A-B copolymers, 7 AxBy monomers, 8 AB polyamides, 173-180 AB polyimides, 304-307 syntheses of, 306 Abrasion resistance test, 243-244 ABS. See Acrylonitrile-... 

The gel permeation chromatogram shown in Fig. 6 illustrates the purity of a block copolymer obtained by ion coupling. It is seen that about 5% of uncoupled block copolymer contaminates a triblock copolymer of narrow molecular weight distribution. The synthesis of star block polymers owes its recent development to the use of new coupling agents412. ... 

Triblock copolymers of ABA type, where B is the central elastomeric block and A is the rigid end-block, are well-known commercially available polymers [7,8]. The chemical structures of some common TPEs based on styrenic block copolymers are given in Eigure 5.1. Synthesis of such ABA-type polymers can be achieved by three routes [9] ... 

The anionic method of polymerization is most useful for the synthesis of low molecular weight hydroxy-terminated oligomers and polymers that are to be further processed. For example, the treatment of hydroxy-terminated oligomers with isocyanates has been used to obtain polyester-urethanes (9,20), while triblock copolymers (PCL-PEG-PCL) are prepared by initiating the polymerization of e-caprolactone with the disodium alcoholate from polyethylene glycol (26). 

Several excellent books and review articles have been published covering this particular area of polymer science [1-3]. Nevertheless, this review will highlight recent (2000-2004) advances and developments regarding the synthesis of block copolymers with both linear (AB diblocks, ABA and ABC triblocks, ABCD tetrablocks, (AB)n multiblocks etc.) and non-linear structures (star-block, graft, miktoarm star, H-shaped, dendrimer-like, and cyclic copolymers). Attention will be given only to those synthetic methodologies which lead to well-defined and well-characterized macromolecules. 

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