Simultaneous optimization of mechanical properties of braided polyethylene terephthalate suture subjected to hot-stretching treatment

Abstract

Braided polyethylene terephthalate sutures are the first used braided suture. They have to undergo several manufacturing steps including hot stretching. However, there is a lack of literature describing precisely braided suture manufacturing process. Hot-stretching treatment was reported to have positive impact on suture mechanical properties. The main objective of this work is the simultaneous improvement of different mechanical properties related to this treatment. Obtained results show that polyethylene terephthalate suture hot stretching leads to a uniform compact suture with high ultimate tensile strength and low friction coefficient. However, during this treatment suture becomes stiff. By increasing temperature and drawing ratio, suture becomes flexible. Below 200℃, polyethylene terephthalate braided suture shows low friction coefficients difference and low Young’s modulus. Performing overlaid contours plot permitted to determine optimal values for significant manufacturing parameters in order to manufacture polyethylene terephthalate braided suture having at the same time high ultimate tensile strength, low friction coefficient, low extension at break, low rigidity, and high yield point values. In this study, optimal conditions for hot-stretching suture in main heat zone are defined. Reported results show also optimized conditions of suture preliminary hot stretching in order to obtain further best mechanical properties. Results approve that suture hot stretching in main heat zone after preliminary heat without tension involved the best suture mechanical properties.