Synthesis of Novel Coordination Polyurethanes

Abstract

ABSTRACT:New coordination polyurethanes based on novel diols bis [N-[[2-hydroxyphenyl]methylene]hydroxylethyleneamino]-copper (II), cobalt (II), and nickel (II) were synthesized successfully. The products are elastomeric materials or powders. Similar to other polyurethane elastomers, the block copolymers synthesized in this paper exhibit two-phase microstructure and thermoplastic properties. Some samples show a Schlieren pattern under the polarizing optical microscope. The geometric structure of the ionic domains, which plays an important role in the properties of these materials, was determined by the nature of the metal ions.KEY WORDS Polyurethane I Metal Ions I Synthesis I Coordination I Macromolecule metal complexes have been studied extensively for several decades. This kind of material, which has many special chemical and physical properties, has attracted scientific and commercial attention. 1 • 2 Polyurethane ionomers are well-known examples of ion-containing materials. 3 Both carboxylated and sulfonated polyurethanes containing pendent ionic groups on the side of polyurethane backbone have been synthesized and studied at our laboratory. 4 • 5 However, polyurethanes contain pendent groups and metal ions in the main chain were not studied to any great extent. Only a few reports of these polymers are known. 6 Recent studies show that some metal complexes offer potentially mesogenic molecular structures. Some coordination polymers having liquid crystalline properties 7 • 8 have been achieved. In this paper, a new kind of polyurethane which is metal coordinated low molecular weight compounds, was synthesized and characterized. EXPERIMENTAL Synthesis of Metallic Dials and PolyurethanesThe synthesis of metallic diols and polyurethanes are summarized in Scheme I.In Scheme !(Ia) stoichiometric ethanolamine was added to a solution of salicylaldehyde in 200 ml of boiling absolute ethanol. Then stoichiometric sodium acetate in 20 ml water was added to the above reaction system. Finally I 00 ml boiling ethanol solution containing a stoichiometric amount of metal acetate were added. The reaction mixture was kept boiling for 15 min. The crystal precipitates from the solution after cooling and a second crystallization occurred from ethanol solution. The product was dried under an infra-red lamp for 24 hours.The coordination polyurethanes were synthesized in N,N'-dimethylformamide (DMF) under nitrogen atmosphere, using 0.5% by weight of stannous octoate catalyst. The poly(tetramethylene oxide) (PTMO Mn = 980) was first reacted with 4,4' -bis(isocyanatophenyl)ether (ODI) or 4,4'-bis(diisocyanatophenyl)methane (MDI) for 30 min at 70oC. The coordination chain extender in DMF solution was then added to the reaction along with 0.5 wt% stannous octoate catalyst. To ensure compJete reaction, the mixture was maintained at 70oC for 4 hours. The product was recovered by precipitation in hot water and further washed with ethanol to remove any residual small molecule products. The films were cast from DMF in Teflon-casting dishes...

Novel Metal‐Containing Polyurethane Elastomers Prepared Using Tetradentate Schiff Base Metal Complexes

“…A few monographs4 and reviews5 have been published in which the synthesis, properties, and applications of variety of metal‐containing polymers have been described. Metal‐containing polyurethanes and polyurea is the subject of extensive research6–20 as these polymers exhibit low viscosity, liquid crystalline properties, and unusual thermal properties.…”

“…Metals are usually incorporated into polyurethane chain by means of ionic bond18–21 or through coordination 6–10. Sandwich of the metal with polyurethane structure is less often encountered 16,17.…”

“…Chantarasiri et al6,7 prepared hexadentate Schiff base metal complexes with amine functional group and used them for the preparation of metal‐containing polyurethane‐ureas. Metal‐coordinated tetradentate Schiff base diol monomer for the preparation of metal‐containing polyurethanes is also reported 8–10. Such kind of monomers could be synthesized with vast number of structural variations and are having many applications.…”

Thermotropic poly(azomethine-urethane)s with non linear optical properties: Synthesis and characterization

“…The later pathway has been uti lized to a larger extent due to the ease in synthesis and handling [4][5][6]. A few information are available on liquid crystalline poly(azomethine urethane)s based on biphenyl diols with azomethine groups and aro matic diisocyanates [7]. Azomethine group incorpo rated either in diacarboxalic acids or in aromatic diiso cyanates has exhibited liquid crystalline behavior [8].…”

“…TGA thermograms of PU MDI series PU MDI 1 (1), PU MDI 2 (2), PU MDI 3 (3), PU MDI 4 (4), PU MDI 5 (5), PU MDI 6 (6), PU MDI 7(7).…”