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Polymers
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Block Copolymers Synthesis by Advanced Polymerization Techniques
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Block Copolymers Synthesis by Advanced Polymerization Techniques

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Chemistry".

Deadline for manuscript submissions: closed (31 March 2020) | Viewed by 7629

Special Issue Editor

Dr. Sofia Rangou

E-Mail Website
Guest Editor
Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str.1, 21502 Geesthacht, Germany
Interests: polyimides; block copolymer membranes; crosslinking of polymer membranes; gas/liquid separations
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Block copolymer research has attracted great interest over the past few decades. The diversity of these materials has enabled their applications in numerous ways in the fields of chemistry, physics, material, biological, and medical sciences. A large number of advances in experimental techniques regarding the precise synthesis and characterization of block copolymers has been reported up to date. Block copolymers with specified molecular chain parameters (molecular weight and distribution), composition, chain architectures, and properties were developed through advanced chain growth polymerization techniques like living anionic polymerization, controlled/“living” radical polymerization, various transition metal catalyzed polymerization, etc.

The Special Issue aims to expand the knowledge in the area of block copolymer synthesis by advanced polymerization techniques. Typical topics include precise synthesis of new block copolymers, insights into the polymerization chemistry/mechanism, reaction engineering/modeling, method development, new catalyst technologies, polymer characterization, properties, and applications.

Dr. Sofia Rangou
Guest Editor

Keywords

  • block copolymers
  • synthesis
  • anionic polymerization
  • radical polymerization
  • metal catalyzed polymerization
  • block copolymer characterization
  • properties of block copolymers
  • applications of novel block copolymers

Published Papers (2 papers)

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21 pages, 4833 KiB  
Article
Synthesis and Properties of Bioresorbable Block Copolymers of l-Lactide, Glycolide, Butyl Succinate and Butyl Citrate
by Natalia Śmigiel-Gac, Elżbieta Pamuła, Małgorzata Krok-Borkowicz, Anna Smola-Dmochowska and Piotr Dobrzyński
Polymers 2020, 12(1), 214; https://doi.org/10.3390/polym12010214 - 15 Jan 2020
Cited by 10 | Viewed by 3535
Abstract
The paper presents the course of synthesis and properties of a series of block copolymers intended for biomedical applications, mainly as a material for forming scaffolds for tissue engineering. These materials were obtained in the polymerization of l-lactide and copolymerization of l [...] Read more.
The paper presents the course of synthesis and properties of a series of block copolymers intended for biomedical applications, mainly as a material for forming scaffolds for tissue engineering. These materials were obtained in the polymerization of l-lactide and copolymerization of l-lactide with glycolide carried out using a number of macroinitiators previously obtained in the reaction of polytransesterification of succinic diester, citric triester and 1,4-butanediol. NMR, FTIR and DSC were used to characterize the materials obtained; wettability and surface free energy were assessed too. Moreover, biological tests, i.e., viability and metabolic activity of MG-63 osteoblast-like cells in contact with synthesized polymers were performed. Properties of obtained block copolymers were controlled by the composition of the polymerization mixture and by the composition of the macroinitiator. The copolymers contained active side hydroxyl groups derived from citrate units present in the polymer chain. During the polymerization of l-lactide in the presence of polyesters with butylene citrate units in the chain, obtained products of the reaction held a fraction of highly branched copolymers with ultrahigh molecular weight. The reason for this observed phenomenon was strong intermolecular transesterification directed to lactidyl side chains, formed as a result of chain growth on hydroxyl groups related to the quaternary carbons of the citrate units. Based on the physicochemical properties and results of biological tests it was found that the most promising materials for scaffolds formation were poly(l-lactide–co–glycolide)–block–poly(butylene succinate–co–butylene citrate)s, especially those copolymers containing more than 60 mol % of lactidyl units. Full article
(This article belongs to the Special Issue Block Copolymers Synthesis by Advanced Polymerization Techniques)
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13 pages, 2493 KiB  
Article
Synthesis of a Smart Conductive Block Copolymer Responsive to Heat and Near Infrared Light
by Silvestre Bongiovanni Abel, Kevin Riberi, Claudia R. Rivarola, Maria Molina and Cesar A. Barbero
Polymers 2019, 11(11), 1744; https://doi.org/10.3390/polym11111744 - 24 Oct 2019
Cited by 15 | Viewed by 3580
Abstract
A method for the synthesis of a linear block copolymer (PNIPAM-b-PANI), containing a thermoresponsive block (poly(N-isopropylacrylamide), PNIPAM) and a Near Infrared (NIR) light-absorbing block (polyaniline, PANI), is reported. The synthetic approach involves a two-step successive polymerization reaction. First, the [...] Read more.
A method for the synthesis of a linear block copolymer (PNIPAM-b-PANI), containing a thermoresponsive block (poly(N-isopropylacrylamide), PNIPAM) and a Near Infrared (NIR) light-absorbing block (polyaniline, PANI), is reported. The synthetic approach involves a two-step successive polymerization reaction. First, the radical polymerization of NIPAM is done using 4-aminothiophenol as a chain transfer agent for the obtention of thermosensitive block terminated with an aniline (ANI) moiety. Second, the oxidative polymerization of ANI is initiated in ANI moiety of thermosensitive block to grow the second conductive PANI block. 1H nuclear magnetic resonance (NMR) and FT-IR spectroscopy shows the characteristics peaks of both polymeric blocks revealing the successful copolymerization process. Static Light Scattering (SLS) and UV-Visible combined measurements allowed the determination of the Mw for PNIPAM-b-PANI macromolecule: 5.5 × 105 g mol−1. The resulting copolymer is soluble in water (8.3 g L−1) and in non-aqueous solvents, such as ethanol, formic acid, acetonitrile, and others. Both polymer blocks chains show the properties of the polymer chains. The block copolymer shows a lower critical solution temperature (LCST) at the same temperature (32–34 °C) than PNIPAM, while the copolymer shows pH dependent UV-vis-NIR absorption similar to PANI. The PNIPAM block suffers a coil to globule transition upon NIR light irradiation (785 nm, 100 mW), as shown by turbidimetry and Atomic Force Microscopy (AFM), due to local heating (more than 9 °C in 12 min) induced by the NIR absorption at the PANI block. Furthermore, the electrical conductivity of PNIPAM-b-PANI thin films is demonstrated (resistivity of 5.3 × 10−4 Ω−1 cm−1), indicating that the PANI block is present in its conductive form. Full article
(This article belongs to the Special Issue Block Copolymers Synthesis by Advanced Polymerization Techniques)
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