Nanocompósitos de poliuretano comercial e nanopartículas híbridas de núcleo Fe3O4 funcionalizado com capa orgânica de Poli(1,4-Butanodiol)
Pessan, Cibele Carneiro
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The use of inorganic nanoparticles in polymer nanocomposites allows gain in mechanical resistance and new properties. However, the incorporation of organic layer functionalized nanoparticles alters the material’s properties in a not fully understood manner. This work has the objective of analyzing the nature of interaction between the organic layer functionalized nanoparticles and the commercial polyurethane adhesive matrix (Adcote 555) and the consequences over physical-chemical properties in relation to the mass percentage of nanoparticles added. The nanoparticles were synthesized with a magnetite core and a poly(1,4-butanediol) organic shell. The mixtures were divided in two groups: low nanoparticles concentration, from 0,05%wt to 5,0%wt, and highly concentrated, up to 90%wt. Tensile and DSC tests allowed the nanocomposites mechanical and thermal properties analysis, respectively. MET imaging and SAXS analysis allowed to determine inorganic core and organic shell sizes, respectively. The nanocomposites’ mechanical behavior wasn’t the expected for conventional nanocomposites. On the contrary, the organic shell seems to have a camouflage effect over the inorganic core and the mechanical and thermal behavior seem the be guided more strongly by the volumetric fraction of the nanoparticles organic shell than their inorganic cores. Thus, it was concluded that the nanocomposites’ properties are ruled by the interphase between matrix and organic shell. The magnetite core’s contribution was to attribute magnetic properties to the highly concentrated nanocomposites.