An effective description of the mechanical behavior of biodegradable copolymers suture threads requires the analysis of their response under cyclic loading and the prediction of the fundamental damage and residual stretches effects. In this paper we propose a micromechanically-based model adopting a new form of Worm Like Chain free energy for the copolymer chains, which takes care of the insurgence of residual stretches on the basis of a rigorous statistical mechanics result. Under the affinity hypothesis we subsequently derive the macroscopic response of the material. The obtained model has a clear physical interpretation and depends on a small number of parameters, which can be fitted by a simple uniaxial test. The effectiveness of the theoretical results has then been verified by performing cyclic tests on Monocryl® monofilament sutures and showing the ability of the model in predicting with high accuracy the history dependence, the damage and permanent deformations in the obtained response.

有效描述可生物降解的共聚物缝合线的力学性能，需要分析其在循环载荷下的响应，并预测基本损伤和残余拉伸效应。在本文中，我们提出了一种基于微机械的模型，该模型采用一种新型的蠕虫状链自由能用于共聚物链，该模型在严格的统计力学结果的基础上考虑了残余拉伸的发生。在亲和力假设下，我们随后得出材料的宏观响应。所获得的模型具有清晰的物理解释，并且依赖于少量参数，可以通过简单的单轴测试进行拟合。