Although widely-used biodegradable polymers have been extensively studied for conventional manufacturing processes, this is the first study considering the effect of interfacial bonds between extruded filaments – the most important aspect related to additive manufacturing – on degradation at 37 °C. Its results improve the confidence in the material extrusion additive manufacturing process and negate one of the crucial unknown factors for bioresorbable products, by demonstrating that the interface degrades in a similar manner to the bulk polymer material. To do this, specially designed micro-tensile specimens were developed to analyse the degradation of 3D-printed parts for the first time at 37 °C and accelerated temperatures. The mechanical properties of the interface between extruded filaments (Z specimen) were compared against the control, i.e. along filaments (F specimen), under medically relevant testing conditions (submerged at 37 °C). Monitoring the degradation of tensile strength showed that both specimen types behaved similarly, exhibiting an initial delay followed by a reduction in properties. Comparison of thermal and chemical properties revealed that during the early stage of degradation, crystallinity was the dominating factor, whilst at later stages, mechanical properties were mainly defined by the molecular weight and autocatalytic degradation. The findings suggest that understanding developed in the long-standing field of polymer degradation can be applied to additive-manufactured medical devices, which unavoidably contain interlayer interfaces.

尽管已经对常规制造过程中广泛使用的可生物降解聚合物进行了广泛研究，但这是第一个考虑到挤出长丝之间的界面键（与增材制造有关的最重要方面）对37°C降解的影响的研究。通过证明界面以与本体聚合物材料相似的方式降解，其结果提高了材料挤出添加剂制造工艺的信心，并消除了生物可吸收产品的关键未知因素之一。为此，开发了专门设计的微拉伸试样，以首次在37°C和加速温度下分析3D打印零件的降解。将挤出的长丝（Z样品）之间的界面的机械性能与对照进行了比较，即 在医学上相关的测试条件下（浸没在37°C下）沿着细丝（F样品）。监测抗拉强度的下降表明，两种样品的行为相似，表现出最初的延迟，随后性能下降。热和化学性质的比较表明，在降解的早期，结晶度是主要因素，而在后期，机械性能主要由分子量和自催化降解决定。这些发现表明，在聚合物降解的长期研究领域中发展起来的理解可以应用于增材制造的医疗器械，这些医疗器械不可避免地包含夹层界面。监测抗拉强度的下降表明，两种样品的行为相似，表现出最初的延迟，随后性能下降。热和化学性质的比较表明，在降解的早期，结晶度是主要因素，而在后期，机械性能主要由分子量和自催化降解决定。这些发现表明，在聚合物降解的长期研究领域中发展起来的理解可以应用于增材制造的医疗器械，这些医疗器械不可避免地包含夹层界面。监测抗拉强度的下降表明，两种样品的行为相似，表现出最初的延迟，随后性能下降。热和化学性质的比较表明，在降解的早期，结晶度是主要因素，而在后期，机械性能主要由分子量和自催化降解决定。这些发现表明，在聚合物降解的长期研究领域中发展起来的理解可以应用于增材制造的医疗器械，这些医疗器械不可避免地包含夹层界面。结晶度是主要因素，而在后期阶段，机械性能主要由分子量和自催化降解决定。这些发现表明，在聚合物降解的长期研究领域中发展起来的理解可以应用于增材制造的医疗器械，这些医疗器械不可避免地包含夹层界面。结晶度是主要因素，而在后期阶段，机械性能主要由分子量和自催化降解决定。这些发现表明，在聚合物降解的长期研究领域中发展起来的理解可以应用于增材制造的医疗器械，这些医疗器械不可避免地包含夹层界面。