title: Urea-montmorillonite-extruded nanocomposites: a novel slow-release material.
abstract: The present study describes the preparation and characterization of a novel urea slow-release nanocomposite, based on urea intercalation into montmorillonite clay by an extrusion process at room temperature. Nanocomposites with urea contents ranging from 50 to 80 wt % were successfully produced and characterized. Analyses by XRD, DTA, and SEM-EDX confirmed the effectiveness of this simple process to exfoliate the clay lamellae into the urea matrix, forming a product that can be classified as a nanocomposite, due to the exfoliation degree attained. Diametral compression tests showed that the samples were very deformable, and the release rate of active components in water showed that the nanocomposite showed a slow release behavior for urea dissolution, even in low montmorillonite amounts (20% in weight).
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, CEP: 13565-905, São Carlos, SP, Brazil.
authors.forename: Elaine I
authors.initials: EI
authors.lastname: Pereira
authors.forename: Fernando B
authors.initials: FB
authors.lastname: Minussi
authors.forename: Camila C T
authors.initials: CC
authors.lastname: da Cruz
authors.forename: Alberto C C
authors.initials: AC
authors.lastname: Bernardi
authors.forename: Caue
authors.initials: C
authors.lastname: Ribeiro
mesh_terms: D000383:Agriculture / Q000295:instrumentation*; D001546:Bentonite / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics*; D005308:Fertilizers / Q000032:analysis*; D007700:Kinetics; D053761:Nanocomposites / Q000737:chemistry*; D014508:Urea / Q000493:pharmacokinetics*
chemical_list: D003692:Delayed-Action Preparations; D005308:Fertilizers; D001546:Bentonite; D014508:Urea