Polyurethane foams with the contribution of products of hydroxyalkylation of N,N′‐bis(2‐hydroxyalkyl)oxamides with alkylene carbonates—obtaining and properties

Abstract

In the reactions of N,N 0 -bis(2-hydroxyethyl)oxamide (BHEOD) with an excess of ethylene carbonate (EC) and N,N 0 -bis(2-hydroxypropyl)oxamide (BHPOD) with an excess of propylene carbonate (PC), the hydroxyethoxy and hydroxypropoxy derivatives of oxamide (OD) were obtained, respectively, distinguished by an increased thermal stability. First time, these derivatives were used as polyol components to obtain foamed polyurethane plastics with the contribution of 4,4 0 -diisocyanate diphenylmethane (MDI). The rigid polyurethane foams of a slight water uptake, good stability of dimensions, enhanced thermal stability, and compression strength were obtained.

Oligomers with structural elements of imidazolidinetrione obtained from oxamic acid and oxamide: polyurethane foams modified by structural elements of imidazolidinetrione

“…On the DTG curve of the products of BHPOD reaction with PC, also two peaks were observed, but at slightly lower temperatures, i.e., 220°C and 300°C [25]. With the increase of PC excess, the first peak decreased and shifted towards higher temperatures (240°C at 10 molar excess), and the second one remained unchanged (300°C) [25].…”

“…With the increase of PC excess, the first peak decreased and shifted towards higher temperatures (240°C at 10 molar excess), and the second one remained unchanged (300°C) [25].…”

“…The resulting rigid foamed polyurethane plastics exhibited glass transition temperatures above room temperature [33], located within the range of 75-145°C [25][26][27][28][29][30][31].…”

“…The hydroxyalkylated derivatives of oxamic acid [26] and oxamide [25,27] as well as parabanic acid [28] and urea [29][30][31] were used as polyol components for the preparation of foamed polyurethane plastics. The influence of the amount of catalyst (triethylamine), isocyanate (4,4′-diisocyanate diphenylmethane with 30 wt% content of triisocyanates), foaming agent (water) and the kind of hydroxyalkyl derivative on the foaming process, has been investigated.…”

“…In the present paper, based on earlier reports [20][21][22][23][24][25][26][27][28][29][30][31], syntheses of the aforementioned oligomers in reactions of oxamic acid and oxamide with alkylene carbonates are described. The applications of oligomers with oxamidoester and oxamide groups, as well as with oxamidoestercarbamidoimide and carbamide groups as polyol components for preparation of thermally stable foamed polyurethane materials are described.…”