Application of cesium hydroxide monohydrate for ring opening polymerization of monosubstituted oxiranes: characterizatio
- PDF / 964,626 Bytes
- 12 Pages / 439.37 x 666.142 pts Page_size
- 68 Downloads / 140 Views
Application of cesium hydroxide monohydrate for ring opening polymerization of monosubstituted oxiranes: characterization of synthesized polyether‑diols Zbigniew Grobelny1 · Justyna Jurek‑Suliga2 · Sylwia Golba2 Received: 12 December 2018 / Revised: 29 October 2020 / Accepted: 6 November 2020 © The Author(s) 2020
Abstract Cesium hydroxide monohydrate (CsOH·H2O) activated by cation complexing agents, i.e., 18C6 or C222 was applied as initiator of monosubstituted oxiranes polymerization. Propylene oxide (PO), 1,2-butylene oxide (BO), styrene oxide (SO) and some glycidyl ethers were used as monomers. All processes were carried out in tetrahydrofuran solution at room temperature. Such polymers, as PPO-diols, PBO-diols and PSO-diols, are unimodal and have molar masses Mn = 2000–5100. Their dispersities are rather high (Mw/Mn = 1.17–1.33). Moreover, PPO-diols and PSO-diols are not contaminated by monools with unsaturated starting groups. Poly(glycidyl ether)s are, in general, polymodal. For example, poly(isopropyl glycidyl ether)-diols are bi- or trimodal, whereas poly(allyl glycidyl ether)-diols possess two or even six fractions. Molar masses of main fraction are 4200–6400, and the second fraction is much lower, namely 600–2600. Dispersities of some fractions are very low (Mw/Mn = 1.01–1.07). Polymodality of polymers obtained was discussed in terms of the formation of two or more species propagating with different rate constants. Graphic abstract
Extended author information available on the last page of the article
13
Vol.:(0123456789)
Polymer Bulletin
Keywords Cesium hydroxide monohydrate · Ring opening polymerization · Monosubstituted oxiranes · Polyether-diol
Introduction Polyethers are an important class of synthetic polymers, which have many applications, e.g., as impact modifiers, surfactants, de-emulsifiers, dispersant agents, fuel additives, lubricants, biomedical materials or adhesives [1–5]. Especially interesting are polyether- and copolyether-diols or triols prepared from oxiranes, i.e., ethylene oxide (EO), propylene oxide (PO) or 1,2-butylene oxide (BO), which are applied for fabrication of polyurethane elastomers or foams [6]. Many initiators were used for anionic ring-opening polymerization of oxiranes, e.g., potassium hydroxide [7, 8] or potassium alkoxides [9–15]. In industry, the most frequently used are KOH/1,2propylene glycol or glycerol systems, which allow to obtain PPO-diols or PPO-triols with Mn = 2000–6000 at 110 °C [6, 16]. The polymers possess low unsaturation due to excess of hydroxylic compound used, which strongly limited chain transfer reaction to monomer. On the other hand, PPOs with Mn = 9000 and high unsaturation were prepared in the polymerization initiated with anhydrous KOH in THF solution at room temperature [8]. It was proposed, that in this case deprotonation of the monomer by initiator and active centers of growing chains occur to a wide extend. KOH, RbOH and CsOH are effective catalysts, while LiOH and Na OH are ineffective [17, 18]. Unsaturation of PPOs depends st
Data Loading...
