Blendas de PEBD/amido termoplástico utilizando nanosílica silanizada como compatibilizante

• Autor(a) principal: Lopes, Fernando Luis Panin
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3599
• topic: Amido termoplástico; Blendas de amido termoplástico; Polietileno de baixa densidade; Nanosílica silanizada; Compatibilizante; Propriedades mecânicas; Blendas poliméricas; Brasil.; Thermoplastic starch; Low density polyethylene; Polymer blends; Silanized nanosilica; Brazil.; Engenharias; Engenharia Mecânica

Starch presents mechanical properties, chemical and physical interesting of viewpoint of processing and application. One form found to improve starch properties and has been successfully employed in the manufacture of industrial products is the starch composition with other polymers to give polymer blends. Among the polymers of greatest interest to form blends with the thermoplastic starch (TPS) stands low density polyethylene (LDPE) having low cost, being one of the materials used in the production of packaging films, films for agriculture and other applications . Thus, it is noted that several studies with thermoplastic starch blends have been made in search of better results in the mechanical tests and aiming a decrease in the hydrophobicity of the starch to develop a biomaterial that can be used commercially. Given the above, this study aimed to obtain TPS blends with LDPE using nanosílica silanized (nSS) as compatibilizer. We conducted a factorial study 22 with center point and morphological analysis to evaluate the influence and interaction of nanosílica and plasticizer glycerol in getting a TPS with hydrophobic characteristics, evaluating the properties of water absorption, solubility and contact angle. From this it is concluded that the sample of TPS with 30% glycerol and 5% nanosílica better results. The blends with LDPE and TPS were obtained in a second step by extrusion and injection processing mixtures in mass proportions of 80, 60 and 40% of LDPE with pure TPS and TPS modified silanized nanosílica (nSS). The composition of the blends contained pure TPS and with addition of 5% NSS, both with 30% glycerol. The blends were analyzed and characterized as Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), tensile strength, flexural strength, Izod impact strength, Shore hardness D, scanning electron microscopy (SEM) and degradation test, in addition to the tests listed in the factorial study.. The blends containing nanosílica as compatibilizer had lower solubility compared the blends of pure TPS. From the traction resistance tests it was concluded that the greater the amount of low TPS is the maximum stress at rupture and elongation, however it noted that blends of the same amount, but containing the nanosílica obtained an increase of the maximum tension rupture elongation and reduction. The modulus of elasticity is noted also that the higher the amount of TPS and nSS the blend is stiffer. In relation to mechanical impact test it was found that the blends with higher silica with TPS are less impact resistant, however the blend with improved performance was the lowest amount of TPS containing silica. The testing of hardness and bending it appears that blends with nanosílica showed improvement in these properties when compared to blends without nanosílica, demonstrating that the inclusion nSS increases the hardness and stiffness of these samples. Finally, it is concluded that the presence of nanosílica contributes to reducing the hydrophilicity of the starch improving LDPE / TPS interaction. In the biodegradation test blends were grounded and 60 for 30 days and then were analyzed for tensile strength, in which the maximum voltage decreases with increasing time of exposure to soil for most formulations. As for the results of elastic modulus observed drastic reduction in these values for the polymer blends. In scanning electron microscopy, it noticed some visual effect of environmental degradation on the surface of LDPE. However for the blends buried for 30 to 60 days there is a great concentration of defects on the surface of samples, indicating a higher biodegradability of the blends compared to pure starch.