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

• Published in: Polymer testing Vol. 32; no. 4; pp. 665 - 672
• Main Authors: Ribeiro da Silva, Virginia, Mosiewicki, Mirna A., Yoshida, Maria Irene, Coelho da Silva, Mercês, Stefani, Pablo M., Marcovich, Norma E.
• Format: Journal Article
• Language: English
• Published: Kindlington Elsevier Ltd 01-06-2013; Elsevier
• Subjects: Applied sciences; Ashes; Cellular; Composites; Compressive strength; Density; Dynamics; Exact sciences and technology; Fillers; Foams; Forms of application and semi-finished materials; Mechanical properties; Polymer industry, paints, wood; Polyurethane foam; Rice; Technology of polymers; Tung oil; Tung oil; Mechanical properties; Polyurethane foam; Cell structure; Storage modulus; Thermal transition; Vegetable oil; Dispersion reinforced material; Compressive strength; Experimental study; Cellular plastic; Rice by product; Polyaddition; Dynamic mechanical properties; Polyurethane; Concentration effect; Crosslinked polymer; Agricultural waste; Plastics; Rheological properties
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2013.03.010

Viscoelastic polyurethane (PU) foams based on modified tung oil, ethylene glycol and polymeric MDI, and reinforced with rice husk ash (RHA), were prepared by a free-rise pouring method and characterized in terms of density, compression and dynamic mechanical behavior. The density of foams ranged between 50 and 90 kg/m3, depending on the position of the sample with respect to the foam rise direction and filler content. As revealed by dynamic mechanical tests, the foams exhibited two different and broad thermal transitions, the temperature of their maxima depending on filler concentration. Compression modulus, compressive strength and storage modulus increase as foam density increases but decreases as rice husk ash concentration increases due to the detrimental changes induced by the filler in the foam cellular structure. However, densification strain exhibits the opposite behavior, indicating that reinforced foams can sustain slightly higher deformations without collapsing, probably due to a reduced reactivity of the components induced by the filler.