Premium
Rigid polyurethane foams: A model of the foaming process
Author(s) -
Rojas A. J.,
Marciano J. H.,
Williams R. J.
Publication year - 1982
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760221310
Subject(s) - blowing agent , polyurethane , materials science , polyol , isocyanate , composite material , mixing (physics) , copolymer , silicone , evaporation , nucleation , foaming agent , mold , boiling , chemical engineering , polymer , thermodynamics , physics , quantum mechanics , porosity , engineering
A model of the manufacture of rigid polyurethane foams by free rising is presented. The extent of cream and rise periods as well as the amount of blowing agent necessary to give the desired foam density are theoretically predicted. The rate of blowing agent evaporation is calculated from an experimental boiling temperature vs. composition curve. Experimental runs were carried out with a formulation consisting of a polymeric isocyanate, a polyether polyol based on sorbitol, a silicone‐polyol block‐copolymer as surfactant, dibutyltin dilaurate as catalyst, and trichlorofluoromethane as blowing agent. Mixing was performed in situ in the mold using a commercial foaming machine. Experimental results gave a satisfactory agreement with model predictions. A diagram containing all the relevant information may be theoretically built and used for the selection of adequate operating parameters for a given formulation.