Thermal and flammable properties of rigid PUR-PIR foams obtained by using new compounds based on 2-hydroxypropane-1,2,3-tricarboxylic acid

Rigid polyurethane-polyisocyanurate foams were synthesized using newly obtained compounds: tris(4-hydroxybutyl) 2-hydroxypropane-1,2,3-tricarboxylate and tris(3-hydroxybutyl) 2-hydroxypropane-1,2,3-tricarboxylate. The industrial Rokopol-551 used as polyol was gradually substituted for the new compounds in the polyol premix in new foams. The authors examined the effect of those compounds on the foams' combustibility, thermal properties and changes in linear dimensions, volume and weight after 48h of thermostating in ventilated drier at 120 degrees C. Changes in linear dimensions, volume, or weight did not occur at all or were not substantial. A slight decrease in foams' heat conductivity can be noticed when using new polyols in comparison to the reference foam (P0). The addition of polyols to the foams affects the foams' burning process. The values of those temperatures were decreasing along with the increasing amount of the used polyols in the foams, from 661 degrees C (P0 reference foam, not containing new polyol), to 612 degrees C (P6.5 foam, containing 0.5 equivalent of tris(4-hydroxybutyl) 2-hydroxypropane-1,2,3-tricarboxylate] and to 643 degrees C [P11.5 foam, containing 0.5 equivalent of tris(3-hydroxybutyl) 2-hydroxypropane-1,2,3-tricarboxylate).