Synthesis, spectral characterization and DFT calculations of novel macro MADIX agent: mechanism of addition-fragmentatio
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Synthesis, spectral characterization and DFT calculations of novel macro MADIX agent: mechanism of addition‑fragmentation reaction of xanthate compound Ümit Yildiko1 · Ahmet Cagri Ata2 · İsmail Cakmak2 Received: 2 June 2020 / Accepted: 3 September 2020 © Springer Nature Switzerland AG 2020
Abstract In this study, the macromolecular design was performed via interchange of xanthates (MADIX) polymerization. The macro RAFT/MADIX agent containing the structure of polytetrahydrofuran (PTHF) (average Mn ~ 1000 g/mol) was synthesized to use in the polymerization. PS-b-PTHF-b-PS triblock copolymer was obtained by styrene-controlled radical polymerization using the RAFT/MADIX agent. The plot of ln [M]o/[M] versus monomer concentration versus polymerization time exhibits first-order kinetic behavior. Block copolymer formation has a controlled character. The formation of the narrow molecular weight polymer controlled by the styrene’s RAFT/MADIX polymerization is confirmed by the increase in the polymerization time of the molecular weight. The results are in good agreement with theoretical values. Block copolymers having a narrow molecular weight distribution and a predetermined average molecular weight have been obtained using this polymerization process. The synthesized RAFT/MADIX agents, polymer, and copolymers were characterized by NMR and FT-IR spectroscopy, GPC, and differential scanning calorimetry. Based on the vibration analysis, the thermodynamic properties of the compound were also calculated. Optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were analyzed by DFT calculations. As a result of the DFT study with trimer and hexamer; although the chain length is increased, the energy parameters obtained are very proximate to each other. Keywords MADIX polymerization · Block copolymer · PTHF · DFT · NBO
1 Introduction The synthesis of various types of macromolecules, including block copolymers, is usually obtained by reversible-deactivation radical polymerization [1]. In recent years, significant developments have occurred in the synthesis chemistry, such as the ability to obtain innovative polymeric materials [2, 3], by controlling molecular properties [4, 5], chain length distribution, stereogenicity, copolymer composition, block copolymer alignment, lengths and functional
group addition [6–11]. Controlled/living radical polymerization (CRP) are known as living polymerization techniques [12–14]. The CRP mechanisms consist of different polymerization mechanisms which are used to obtain polymers with controlled molecular weight growth and a narrow molecular weight distribution [15–19]. The most commonly used CRP techniques are nitroxide mediated radical polymerization (NMP) [20–22], atom transfer radical polymerization (ATRP) [6, 23, 24], reversible addition-fragmentation chain transfer (RAFT), and macromolecular design via interchange of
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s42452-020-03495-3) contains
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