Relationship Between Dip-Coating Fabrication Parameters and the Elastic Properties of Rubber Latex Prosthesis
- PDF / 908,173 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 91 Downloads / 196 Views
W11.9.1
Relationship Between Dip-Coating Fabrication Parameters and the Elastic Properties of Rubber Latex Prosthesis
W.F.P. Neves-Junior, T. C. dos Santos, M. Ferreira, M. Mulato, and Departamento de Física e Matemática, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil J. Coutinho-Netto Departamento de Bioquímica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil ABSTRACT In the present work we are mainly interested in the use of the natural latex extract from the Hevea brasiliensis for medical applications. This presentation focuses on the influence of the fabrication parameters on the final elastic properties of the tubes obtained by dip-coating. The elastic properties of the prosthesis were investigated using tension-deformation experiments. The influence of important fabrication parameters were studied, such as: dip-coating velocity, final prosthesis thickness (which was varied as a function of the number of baths), and thermal treatment. Single and cycled tension-deformation experiments were performed with closed and opened samples considering longitudinal and axial directions. A model is proposed for the anisotropy of the elastic behavior, which involves the sulfur bonds between polymeric chains. INTRODUCTION Natural rubber latex extracted from the Hevea brasiliensis is a poly-dispersed system containing about 40-45% weight of rubber molecules (cis-polyisoprene), 4-5% weight nonrubber constituents such as protein, lipids, carbohydrates and sugar and 50% of water [1]. It is an important raw material for a large range of industrial applications such as tires, automobile, shoes and aircrafts. The use of the natural rubber latex as a biomaterial has been investigated in recent years [2]. This material has all the requisites to be used in contact or inside the human body, being biologically compatible. In addition, it performs a biological action being a powerful stimulator of cicatrisation [2-4]. Besides, natural rubber presents high resistance, elasticity and is an easy-shaping material, what increases its appeal for the fabrication of vascular prosthesis. The present study shows the results about the manufacturing process and physical characterization of rubber tubes that could be used as substitutes for damaged arteries or veins. The fabrication procedure is based on the dip-coating technique, which is a very simple, fast, cheap and reproducible process. We studied the main variables involved in this procedure such as different mold diameters, wall thickness and temperature drying process. The elastic properties of the prosthesis were investigated by tension versus deformation experiments. The processing parameters were characterized and evaluated to improve the fabrication and development of vascular prosthesis. Another important issue regarding the design of vascular prosthesis is the porosity. There are evidences that the tubes must have a porous wall to function as a scaffol
