RT Journal Article T1 Isocyanate-functionalized castor oil as a novel bitumen modifier A1 Cuadri Vega, Antonio Abad A1 García Morales, Moisés A1 Navarro Domínguez, Francisco Javier A1 Partal López, Pedro AB The use of biomaterials from renewable sources in the synthesis of polyurethane-derived polymers is lately receiving great attention from social, environmental and economic standpoints. In this work, prepolymers having different -NCO/-OH ratio were synthesized, by reaction of 4,4´-diphenylmethane diisocyanate (MDI) with castor oil (CO), to be used as modifying agent of asphaltic bitumen. Reactions between MDI and CO, performed with -NCO/-OH molar ratios of 8:1 and 4:1, have led to suitable bitumen modifiers. Modification has been related to chemical reactions between -NCO groups, some bitumen compounds and air moisture (or added water), which gave rise to binders with enhanced resistance to permanent deformation. The results showed that a 2 wt.% of MDI-CO prepolymer leads to binders with higher viscosity than that corresponding to a 3 wt.% Styrene-Butadiene-Styrene (SBS) block copolymer, a polymer and concentration widely used in the paving industry. Furthermore, the resulting prepolymers are liquids that can be easily mixed with bitumen at 90 ºC, which significantly lowers the typical temperature used for commercial SBS-modified bitumen (about 180 ºC). This fact may represent energy savings, reduce bitumen oxidation and result in improvements of health and safety conditions during the product manufacture. However, if high processing temperatures are required, MDI-CO based modifiers have demonstrated much higher thermal stability than prepolymers derived from crude oil (e.g. based on polyethylene glycol). As a result, NCO-terminated prepolymers obtained from biomass-derived polyols (castor oil in this article) may become a promising alternative to the use of other petrochemicals in the paving industry. PB Elsevier SN 0009-2509 SN 1873-4405 (electrónico) YR 2013 FD 2013 LK http://hdl.handle.net/10272/12112 UL http://hdl.handle.net/10272/12112 LA eng NO Cuadri Vega, A.A., García Morales, M., Navarro Domínguez, F.J., Partal López, P.: "Isocyanate-functionalized castor oil as a novel bitumen modifier". Chemical Engineering Science. Vol. 97, págs. 320-327, (2013). DOI: 10.1016/j.ces.2013.04.045 NO This work is part of a research project sponsored by Junta de Andalucia-CEIC (TEP6689) and also by “Ministerio de Educacion” through its Research Mobility Programme (Ref. PR2010-0593) and through the Cuadri’s F.P.U. research grant (AP2008-01419). Authors gratefully acknowledge their financial support. DS Repositorio Institucional de la Universidad de Huelva RD 1 jun 2026