Mechanical properties of rigid polyurethane foams at room and cryogenic temperatures

Abstract

Studies on the effect of the foams’ polymeric matrix’ properties on the tension and compression properties of pour rigid polyurethane (PUR) foams, apparent core density 65—70 kg/m3, at 296 and 77 K were carried out. PUR foams were produced by the hand mixing method from polyol systems that comprised polyether, polyester polyols, and chain extenders. To produce PUR foams, crude MDI was used, and Solkane 365 mfc/227 ea was used as a blowing agent. The molecular weight per branching unit (Mc) of the polymeric matrix of PUR foams was varied in the range 300—1150. Cohesion energy densities of the blocks forming the polymeric matrix were calculated. The effect of Mc on the formation of hydrogen bonds between the urethane groups was estimated from FTIR spectroscopy data and ratio NHbonded /NHfree. It has been found that, with increasing polymeric matrix’ Mc, the tensile strength and elongation at break of PUR foams at 296 and 77 K increases, while Young’s modulus decreases. The increase in the parameter Mc promotes the decrease in the compressive strength and modulus of elasticity of PUR foams at 296 K, while compressive strength indices at 77 K are higher for the foams, whose polymeric matrix has the highest Mc. With increasing polymeric matrix’ M c, the concentration of the urethane groups bonded with hydrogen bonds increases. Structural and mechanical properties of layered spray polyurethane foams, apparent core density approx. 48 kg/m3, having two layers and polymeric matrix’ Mc = 740 were investigated.

Tensile, flexure, and compression properties of anisotropic microchannel epoxy foams

“…As a final comparison, the properties of our microchannel polymers are plotted alongside the reported compressive moduli of other low‐density polymer foams As previously mentioned, literature reports typically contain data across only a very limited density range, and generally only the compressive moduli are reported. The data we gathered are shown collectively in Figure , and the density and compressive moduli are not normalized to neat material values because these values were not provided in the literature.…”

“…Power‐law relationship between Young's Modulus (E* C ) and density (ρ*) for microchannel epoxy and other porous polymer materials, from a collection of references . [Color figure can be viewed at wileyonlinelibrary.com]…”

Synthesis and Characterization of Functionalized Calix[4]arene Derivatives and Preparation of Rigid Polyurethane Foams by the Incorporation of Calixarene

“…The mechanical properties of PU are very important regarding its broad range of application in industry . Linul et al have comprehensively investigated the mechanical properties of PU composite such as Young's modulus, yield stress, and plateau stress indicating that these parameters are strictly dependent upon the density .…”

“…Linul et al have comprehensively investigated the mechanical properties of PU composite such as Young's modulus, yield stress, and plateau stress indicating that these parameters are strictly dependent upon the density . Strinal et al have studied the temperature effects on mechanical properties of PU foams at room and cryogenic temperatures . These compounds have a simply variable structure during chemical reactions and are noticeably stable at high temperatures.…”

Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

“…They are extensively used as thermal insulation in construction industry, in domestic appliances and refrigerators, as space filling material [1] as well as for transportation of liquefied natural gas and for insulation of cryogenic space launchers [2]. PU foams have excellent properties such as closed-cell structure, low thermal conductivity, low water adsorption and moisture permeability, and relatively high compressive strength.…”