ABSTRACT
The aromatic polyols (ex. Mannich polyols), due to their intinsique aromaticity, lead to rigid polyurethane foams with high physico-mechanical, thermal and flame proofing properties. In the present paper has been studied the synthesis of new aromatic polyols having the structure of totally substituted amides and the substituents at the amidic nitrogens are hydroxyalkyl (hvdroxyethyl, hydroxypropyl etc.). The aromatic am id it polyols are obtained by the reaction of dialkanolamines (diethanolamine, diisopropanolamine etc.) with dicarboxylic or polycarboxyl ic aromatic acids or their esters or anhydrides. Thus, by the condensation reaction of dimethylterephthalate (DMT), dimethyl isophthalate, dimethylphthalate, methylbenzoate, methyl salycilate or of the corresponding acids with diethanolamine are obtained condensation products, under form of glassy solids at room temperature, but stirrable viscous liquids at the normal temperatures of alkoxylation (90–130°C). By the polyaddition of propyleneoxide or ethyleneoxide to the synthesised condensation producs are obtained new liquid amidic polyols, having convenient viscosities and with hydroxyl number of 300–500 mgKOH/g, exactly in the domain frequently used in the rigid polyurethane foams. The reactions involved are: https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429332609/b489e897-3e47-4364-b629-cdcef395eff2/content/page607_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
Using the synthesised amidic polyols were obtained rigid polyurethane foams with excellent physico-mechanical, thermal and flame retardant properties. As compared with amino-polyols, the reactivity of the amidic polyols it is not so high, because the catalytic effect of amidic groups are minor, much lower than those of aminic groups. The paper presents the properties of the synthesised aromatic amidic polyols and of the resulted rigid polyurethane foams as compared with standard polyols. Due to the accessibility and convenient cost of raw materials, due to the simplicity of the synthesis which needs only conventional apparatus for 608condensation and alkoxylation, the studied new amidic polyols present a real applicative potential for high performance rigid polyurethane foams.
