Formação e decaimento de carga superficial em cânulas de teflon no estado de eletretos

• Ano de defesa: 1971
• Autor(a) principal: Spinelli, Isa M Muller
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: eletretos
• Link de acesso: https://teses.usp.br/teses/disponiveis/18/0/tde-20250528-103215/

The greatest problem founded in a cardiovascular implant is the thrombus formation and we will try to prevent this using Teflon grafts in electret state for prothesis in vena cava of dogs. To put these grafts in an electret state we used a corona discharge in air and homocharge was formed predominantly. To measure the formed surface charge the oscillating capacitor technique was used. Our initial system had plane geometry and we constructed a new system with cylindrical geometry. In the electret state tlle grafts showed an initial den sity of charge of 10-C/cm2 and we measured the charge decay and time decay of the samples under, many conditions. We found two activation energies, 2= 0,17 eV and 3 = 1. 12 eV, due to rapid and slow decay, respectively. The charged grafts were sterilized with ethilene gas oxide and this process apparently did not influence the charges. No theoretical model was proposed in the area of antithrombogenic surfaces, since the work is essencially technological. The surgical and biological experiments related to this work will be carried out at the surgical Department of the School of Medicine of Ribeirão Preto.