Influence of Castor Oil-Based Polyurethane on Physico-Chemical Properties of Calcium Silicate Cement
Eduardo R. Magdaluyo, Jr., Clodualdo M. Aranas, Jr., and Jovilyn D. Masiglat
Department of Mining, Metallurgical and Materials Engineering
University of the Philippines, 1101 Diliman, Quezon City, Philippines
Polyurethane from castor oil and toluene diisocyanate was activated in the presence of calcium silicate cement paste, with varying equivalent free isocyanate (NCO) to equivalent free hydroxyl (OH) moiety and cement to water ratio. It was shown that as the NCO/OH ratio and percent cement mixture were increased, the compressive strength and bulk density of the obtained polymer-modified calcium silicate cement materials improved significantly. The increase in the strength and density is explained by low porosity and the presence of polyurethane hard segments in the polymer structure. Moreover, the powder x-ray diffraction and surface morphology investigations of the castor oil-based polyurethane-reinforced cement composites revealed the interpenetration of the polymer macromolecules in the cementitious matrix. The Ca2+ from the portlandite phase was readily available to react with the hydroxyl groups from the polyurethane macromolecule and excess monomer resulting in calcium oxide-terminated diisocyanate.
One of the most widely used construction materials includes conventional cement and concrete. The materials have low flexural strength and failure strain as well as susceptible to chemical damage in spite of their good physical properties and relatively low cost. This problem can be solved by fabricating composite material wherein an organic polymer is added to the inorganic cement powder. The two different phases are continuously interpenetrated and can be optimized for producing lightweight components with interesting potential applications in the field of non-structural and construction materials . . . . . . . . .
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