Synthesis, Heat Resistance, and Mechanical Properties of Cross-Linked Urethane–Imide Copolymers Containing Blocks of Two Structurally Different Aliphatic Fragments (Polyether and Polyester) in the Backbone
А. Л. Диденко, А. Г. Иванов, E.A. Bogdanova, V. E. Smirnova, Gleb Vaganov, Е. Н. Попова, Denis A. Kuznetsov, Ilya Kobykhno, E. S. Vasil’eva, О. В. Толочко, В. М. Светличный, V. E. Yudin, V. V. Kudryavtsev
Abstract
Multiblock (segmented) copoly(urethane–imides) were prepared using as monomers toluene 2,4-diisocyanate-terminated aliphatic polyether and polyester [poly(propylene glycol), poly(1,6-hexanediol/neopentylene glycol-alt-adipic acid)], aromatic diamines [1,4-bis(4'-aminophenoxy)biphenyl sulfone or 4,4'-bis(4''-aminophenoxy)biphenyl in a mixture with 3,5-diaminobenzoic acid], and 1,3-bis(3',4-dicarboxyphenoxy)benzene dianhydride. Each of the polymers contains two structurally different soft polyether/polyester segments and two identical hard imide segments, into one of which the reactive carboxy group is introduced. The covalent cross-linking of the copolymers was performed by the reactions of the carboxy groups with aromatic diisocyanates (toluene 2,4-diisocyanate, biphenylmethane 4,4'-diisocyanate) and 1,2,5,6-diepoxycyclooctane. The cross-linked polymer systems obtained were studied by thermal gravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The kind of cross-linking agent influences the properties of cross-linked copoly(urethane–imides). Variation of the mechanical loss tangent tan δ and width of the temperature interval of the transition from glassy to rubber-elastic state in relation to the chemical structure of copoly(urethane–imides) was analyzed. For the polymers under consideration, the maximal tan δ values exceed 0.3, which indicates that these polymers exhibit the damping ability.