Confecção e caracterização de material biocompatível de polipropileno e elastômero para telas a serem aplicadas em cirurgias de peritoniostomias

Abstract

This research aimed to manufacture and characterize a mesh as a substitute for peritoneum in peritoniostomy surgeries using a polymer blend of elastomer and polypropylene. To prepare the blends, Elastomer and Polypropylene were used, which were mixed and subjected to extrusion at an average temperature of 146.75ºC. Twenty grams of these blends were used in concentrations of 70/30 of Elastomer/Polypropylene; 80/20 Elastomer/Polypropylene; 90/10 of Elastomer/Polypropylene that went through a hydraulic press heated to 140ºC and with 3.5 tons of pressure, which formed 250 μm and 400 μm thick screens. The screens were analyzed and characterized using scanning electron microscopy to identify complete or partial polymer mixtures. Later, specimens of different concentrations of blends and materials in their pure form were made for tensile, rheological and differential scanning calorimetry analysis to verify degradation temperature. The screens were subjected to a cleaning process with polyhexamethylene biguanide hydrochloride and seeded in a culture medium for further microbiological analysis. The same process was replicated in the blends after the ethylene oxide sterilization process. Through the analysis of electron microscopy, it was observed the formation of a heterogeneous blend without porosities or irregularities. In the rheology test it was proven that the blends have more elastic characteristics compared to plastic. In the tensile tests it was evidenced that at the 90/10 concentration of Elastomer/Polypropylene it has an average elasticity of 178.89 (MPa) which corresponds to that it supports up to 10 times more pressure on its surface in relation to the biological peritoneum, as well. as it requires 343% more energy on its surface to cause rupture when compared to biological peritoneum. Through the Differential Scanning Calorimetry test, it was identified that the melting temperature of the materials occurred between 135/155 °C, and the degradation temperature occurred above 350 °C, which generates safety when materials are placed in contact with biological tissue, as degradation is a triggering factor for inflammatory response and tissue toxicity, a characteristic that is avoided in biomaterials. In blends submitted only to the cleaning process with polyhexamethylene biguanide hydrochloride, after microbiological testing, Staphylococcus epidermidis was evidenced, and after sterilization with the ethylene oxide method, the blends showed absence of microorganisms, suggesting that this is the safest and most effective method for sterilization of this polymeric biomaterial, because it works at lower temperatures and does not change the physical structure of the materials, such as irregularities on their surfaces.