Evaluation of Thermal Endurance Characteristics of Thermosetting Polyurethane Elastomers and Polyurethane Foams by Dynamic Compression Modulus

In the present work polyurethane foams containing various content loadings of kenaf fiber and recycled tire rubber particulates were prepared and studied, with the objective of developing alternative composite rigid foams. The influence of the filler content on the foam microstructure and its physical and mechanical behavior has been studied for three different polyurethane resin densities. Microstructural observation on fracture surface of composites was carried out using scanning electron microscopy. It has shown closed spherical cells with reduced size when the fillers are added. Nevertheless, the incorporation of kenaf fiber and recycled tire rubber particulates that refined at 80 mesh led to higher mechanical properties than that unfilled polyurethane foam. A 6% filler content loading exhibited the optimum compression stress and compression modulus, while further increase of filler content loading resulted in decline in mechanical behavior. The presence of larger filler content deteriorated the polyurethane system cellular structure and lead to poor composites strength. Overall, the use of kenaf fiber and recycled tire rubber particulates gives composite foams with comparable mechanical behavior for the studied filler reinforcement level.

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Preliminary Mechanical Characterization of Reinforced Rigid Polyurethane Foams

Recent Advances in Mechanics of Solids and Structures ◽

10.1115/imece2003-43397 ◽

2003 ◽

Author(s):

Nagesh Kasichainula ◽

Sanjeev K. Khanna

Keyword(s):

Mechanical Properties ◽

Glass Fibers ◽

Tensile Modulus ◽

Compression Modulus ◽

Layered Composite ◽

Polyurethane Foams ◽

Rigid Polyurethane Foams ◽

Structural Applications ◽

Glass Fiber Reinforcement ◽

Static Mechanical

Rigid polyurethane foams are very widely used in a variety of structural and non-structural applications. For example, it may be used as an insulator, in sandwich layered composite panels, and as filler for improving the stiffness of lightweight components, such as thin metal tubes. Rigid foams do not show any recovery after impact and typically are crushed or crumble. They also tend to degrade over a period of time. Thus in this investigation, reinforced rigid polyurethane foams have been developed and characterized for their quasi-static mechanical properties. Rigid polyurethane foam was reinforced with short, 0.47 mm length, milled E-glass fibers. It has been observed that short glass fiber reinforcement helps in improving the mechanical properties, such as tensile modulus, breaking strength, and compression modulus, of the reinforced foam as compared to monolithic foam.

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Density and shrinkage as guiding criteria for the optimization of the thermal conductivity of poly(urethane)-class aerogels

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-019-05161-6 ◽

2019 ◽

Vol 93 (1) ◽

pp. 149-167 ◽

Cited By ~ 1

Author(s):

Sylwia Członka ◽

Massimo F. Bertino ◽

Jan Kośny ◽

Nitin Shukla

Keyword(s):

Thermal Conductivity ◽

Physical Properties ◽

Dynamic Compression ◽

Monomer Concentration ◽

Volume Ratio ◽

Compression Modulus ◽

Toluene Diisocyanate ◽

Solubility Parameters ◽

K Index ◽

Freeze Dried

Abstract We investigated the effect of gelation solvent, monomer type, and monomer concentration on the physical properties of freeze-dried poly(urethane)-poly(isocyanurate) (PUR-PIR) aerogels, with particular emphasis on their thermal conductivity. It was found that the gelation solvent considerably affects aerogel morphology and physical properties. Aerogels with the lowest thermal conductivity were obtained using a mixture of tetrahydrofuran (THF) and acetonitrile, in a 50% volume ratio. The influence on thermal conductivity of polyol and isocyanate structure and of their concentration was also investigated. Rigid precursors, phloroglucinol (POL), and an aromatic polyisocyanate based on toluene diisocyanate (Desmodur RC) yielded the lowest thermal conductivity. Our results were compared with recent work reporting on parameters that could be used as predictors of thermal conductivity and other physical properties of organic aerogels. None of these parameters were found to be satisfactory predictors of aerogel properties. For example, no systematic correlation between solvent solubility parameters and aerogel properties was observed. We also examined the role of the K-index. This index, defined as the ratio between porosity and contact angle, was shown recently to be a good predictor of the properties of polyurea aerogels. While the thermal conductivity scaled with the K-index, the scaling was different for each of the isocyanate monomers considered in our experiments. Thermal conductivity, instead, scaled well with the product of density and shrinkage of aerogels, independent of monomer type. The reasons of this dependence on shrinkage and density are discussed, and the use of these parameters to guide experimentation on other systems is discussed. Physical properties such as static and dynamic compression modulus and thermal stability of the most promising formulations were also examined.

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