Impact of hot-stretching treatment on physical and mechanical properties of braided polyamide suture

Abstract

Suture is the most used implant in the human body, but it is not yet perfect. Braided polyamide sutures have to undergo several manufacturing steps, including hot-stretching. The main objective of this work was to analyze physical structural changes of polyamide fibers after the hot-stretching step and to highlight mechanical property changes related to this treatment. The obtained results showed that hot-stretching of polyamide braided suture allows one to obtain uniform and compact suture. In this paper, modification of mechanical properties due to hot-stretching has been correlated to macromolecular properties, such as crystallinity, crystal size and macromolecular chain orientation. Hot-stretching braided suture at a temperature higher than 200℃ and the medium value of drawing ratio resulted in the best braided suture properties. Below 180℃, polyamide braided suture undergoes thermal shrinkage during hot-stretching, leading to an increase in breaking extension. Hot-stretching suture ameliorated fabricated braided suture crystallinity reached 33%, with the creation of numerous crystals with smaller size. Using an overlaid contours plot, we have determined optimal values for significant manufacturing parameters in order to manufacture polyamide braided suture that has high ultimate tensile strength, low extension at break, low rigidity and high crystallinity.