Experimental Study on the Effect of Pentanediol as a Chain Extender on the Mechanical Properties of MDI Polyurethane Foams

Energy-absorbing materials and structures have many uses, especially in protecting human lives. As a result, interest in discovering the applied new materials have increased. Polyurethane foams are used in a variety of energy absorbers. In this study, the mechanical properties of a pentanediol-reinforced methylene diphenyl diiscocyanate (MDI) polyurethane foam have been investigated.

Foams were prepared by direct mixing of the reactants. Standard samples have been developed to study the compressive and tensile properties. The specimens were made by adding 5 and 10% pentanediol to a same polyurethane compound. Quasi-static strength and compression tests have been performed and the results have been reported. The microstructure of the foam has been investigated using scanning electron microscopy (SEM).

Comparison of the results showed that, despite the strengthening of the compressive strength of the polyurethane foams by adding some other chain-extenders, the compressive properties of polyurethane foams, including the strength and absorbed energy with the pentanediol as an additive, are not significantly altered, but the elastic modulus and plateau modulus increased significantly. The specific absorbed energy of foam is also increased by adding 5 and 10 percent pentanediol to 11.7% and 12.6%, respectively. The results of tensile tests also showed a high sensitivity to the addition of pentanediol. With addition of 10% pentanediol, strength, fracture strain and foam toughness increased by 37.9%, 57.1% and 137.5%, respectively. The elastic modulus of the tensile samples was also increased by 6.9% in adding 10% pentanediol. Also, the results showed that the substance exhibited smaller cells and a more uniform structure by adding 1,5-pentane diol.