Polimerização in-situ de poliuretano em meio de óxido de grafeno

• Autor(a) principal: Avancini, Milena
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do Mackenzie
• Texto Completo: http://dspace.mackenzie.br/handle/10899/26442
• topic: óxido de grafeno; espuma de poliuretano; nanocompósito; CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA

The use of graphene derived nanomaterials for composites production is increasing. This is because graphene and its derivatives have excellent mechanical, thermal and electrical properties, consequently promoting a gain of properties in the matrix in which it is applied. To this end, different ways of producing and incorporating these materials and their derivatives have been studied since the insulation of graphene in 2010. However, some difficulties have been encountered regarding the incorporation methods of these nanomaterials, because each matrix has a specific need, and for the nanocomposite to be produced effectively, the incorporation process must ensure the material’s incorporation into the matrix without points of agglomeration or separation. Therefore, this work proposes the effective incorporation of graphene oxide (GO) in a polymeric matrix, a flexible foam based on polyurethane, through the method of polymerization in-situ, aiming to obtain a nanocomposite with mechanical properties superior to foam without GO. For this, the GO used was produced through the modified Hummers method and the foam production followed the steps of a conventional industrial process. Different concentrations of GO were evaluated in the preparation of the composite (0.0010; 0.0015; 0.0030; 0.0090; 0.02; 0.03 and 0.05%), and the best gains in mechanical properties were achieved by using 0.03% (m/m) of GO the PU polymeric matrix. The addition of this small amount of GO during the in-situ polymerization process allowed an increase of 16.78% in the tensile strength of the material and 11.80% in the tear strength property compared to the pure PU sample. In addition, the PU@GO samples 0.03%, showed an elongation of only 133.9% before rupture (when applying 127.0 KPa) compared to the pure PU sample 172.8% (when applying 108.8 KPa), thus proving that the incorporation of GO sheets in the polymeric matrix promotes an increase in the rigidity of the polymeric chain. The Indentation hardness tests (IFD) at 40% showed that the PU@GO nanocomposite (0.03% of GO), showed a significant increase of 91.40% in the value of IFD, compared to the pure PU sample. The method proposed in this work to incorporate 0.03% of GO to the PU polymeric matrix did not cause changes in the comfort factor of the foams and much less in the production process, thus enabling the industrial scheduling of the nanocomposite. Thus, the nanocomposite developed in this work presents a great technological potential and can be used in several sectors of the polyurethane industry, generating materials with longer life, less wear and high mechanical resistance.