Estudo da correlação estrutura-propriedade de blendas de polietileno linear de baixa densidade (PELBD) com polietileno de ultra alto peso molecular (PEUAPM) modificadas por peroxido

• Ano de defesa: 2018
• Autor(a) principal: Cardoso, Pollyana da Silva Melo
• Orientador(a): Ueki, Marcelo Massayoshi
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Ciência e Engenharia de Materiais
• Palavras-chave em Português: Ciência dos materiais; Polímeros; Aditivos; Polietileno; Blenda; Reticulação; Polietileno linear de baixa densidade (PELBD); Polietileno de ultra alto Peso Molar (PEUAPM); Desgaste dos materiais
• Palavras-chave em Inglês: Blend; Crosslinking; Linear low density polyethylene (LLDPE); Ultra high molecular weight polyethylene (UHMWPE); Wear
• Área do conhecimento CNPq: ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/11302

The chemical modification of polymers with the use of peroxide additives has been increasingly evaluated for the alteration of properties, and in particular increased impact resistance for application in rotomolded parts and wear resistance for application in orthopedic prostheses. For this work the development of chemically modified LLDPE/UHMWPE blends with 1% and 2% peroxide was carried out. Initially, crosslinking parameters were determined by peroxide application in the LLDPE. Then, the modification of the properties with addition of peroxide in the LLDPE and UHMWPE were evaluated separately. Finally, peroxide-modified LLDPE/UHMWPE blends were prepared, using proportions of 15%, 30% and 45% of UHMWPE for the formation of the blend, and the chemical modification with 1% and 2% peroxide. All blends were prepared by hot compression and the samples were then immersed in water for 1 hour at a controlled temperature of 90°C to relieve stresses from the forming process. The results obtained showed an increase in the impact resistance for the crosslinked blends, however the mechanical properties did not identify significant changes. For the thermal properties a decrease in crystallinity and the occurrence of two peaks of crystallization temperature were identified for the crosslinked blends. The morphologies obtained by means of SEM showed the occurrence of two phases in the formation of the blends and with peroxide addition a better phase adhesion was identified. The abrasion resistance of the reticulated blend showed an increase in relation to the LLDPE, and the wear mechanism found was of the abrasion type.