Polyurethane foams based on modified tung oil and reinforced with rice husk ash II: Mechanical characterization

V. RIBEIRO DA SILVA; M.A. MOSIEWICKI; M.I. YOSHIDA; M. COELHO DA SILVA; P.M. STEFANI; N.E. MARCOVICH

POLYMER TESTING

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2013 vol. 32 p. 665 - 672

0142-9418

Viscoelastic polyurethane (PU) foams based on modified tung oil, ethylene glycol andpolymeric MDI, and reinforced with rice husk ash (RHA), were prepared by a free-risepouring method and characterized in terms of density, compression and dynamic mechanicalbehavior. The density of foams ranged between 50 and 90 kg/m3, depending onthe position of the sample with respect to the foam rise direction and filler content. Asrevealed by dynamic mechanical tests, the foams exhibited two different and broadthermal transitions, the temperature of their maxima depending on filler concentration.Compression modulus, compressive strength and storage modulus increase as foam densityincreases but decreases as rice husk ash concentration increases due to the detrimentalchanges induced by the filler in the foam cellular structure. However, densificationstrain exhibits the opposite behavior, indicating that reinforced foams can sustain slightlyhigher deformations without collapsing, probably due to a reduced reactivity of thecomponents induced by the filler.