MMBOP: Multiphysics Modelling of BiOdegradable Polymers

该研究旨在开发新的基于物理的建模和仿真工具，以了解和预测可生物降解聚合物的机械响应。这些材料可以逐渐分解成无害的成分，并最终在完成其结构功能后消失。在医疗保健应用中，材料的生物降解性是一个理想的特征，因为它能够制造不需要移除手术的临时植入式器械，例如心血管支架、缝线或骨科固定器械。近年来，生物可降解聚合物也引起了人们的极大关注，因为它们有可能取代传统的惰性塑料，以解决塑料污染问题。可生物降解的聚合物对于减少对石油的依赖也是有吸引力的，因为许多可生物降解的聚合物是天然来源的。从工程设计的角度来看，生物可降解聚合物由于看似矛盾的要求而带来了新的挑战：它们需要在完成其预期功能后相对快速地降解，但它们还必须在使用时保持合适的机械性能。这与传统的设计工程策略形成对比，在传统的设计工程策略中，人们通常希望尽可能延迟退化的发生。在缺乏可靠的工程设计准则的情况下，目前的做法基本上依赖于试错法，考虑到降解的时间尺度相对较长（大约数月或数年），这种做法特别耗时且成本高昂。因此，需要可靠的建模和模拟工具，以补充实验研究和开发。本项目将提供一个连续建模平台和本构模型，以描述可生物降解聚合物的变形和化学降解。该项目的重点是水解降解（即在水的攻击下聚合物链的断裂），这是生物医学聚合物的主要降解途径。该模型将考虑水诱导的溶胀、断链造成的渐进性损伤和降解产物释放造成的质量损失。该模型将被实施到强大的计算工具，以模拟复杂的负载条件下的任意形状的设备的退化。该项目将产生关于影响生物降解聚合物的机械性能和寿命的各种因素的作用的新知识。最终，该项目将为学术和工业受益者提供合理的设计工具，以提高研究和开发的生产力，并提高可生物降解设备的可靠性和性能。

The proposed research aims to develop new physics-based modelling and simulation tools to understand and predict the mechanical response of biodegradable polymers. Such materials can gradually break down into harmless constituents and eventually disappear after having fulfilled their structural function. In healthcare applications, materials biodegradability is a desirable feature, because it enables the fabrication of temporary implantable devices that do not require removal surgery, such as cardiovascular stents, sutures, or orthopaedic fixation devices. In recent years, biodegradable polymers have also attracted enormous attention due to their potential to replace traditional inert plastics in an attempt to address the plastic pollution problem. Biodegradable polymers are also attractive to reduce reliance on oil, since many biodegradable polymers are naturally sourced. From an engineering design perspective, biodegradable polymers introduce new challenges due to seemingly contradictory requirements: they need to degrade relatively fast after they have completed their intended function, but they must also maintain suitable mechanical performance while in use. This contrasts with traditional design engineering strategies, where one usually wants to delay the onset of degradation as much as possible. In the absence of reliable engineering design guidelines, current practice essentially relies on trial and error, which is particularly time-consuming and costly given the relatively long timescales for degradation (of the order of months or years). There is thus a need for reliable modelling and simulation tools to complement experimental research and development. Physics-based models are also needed to elucidate the complex interplay between mechanics and chemistry in load-bearing biodegradable devices.This project will deliver a continuum modelling platform as well as constitutive models to describe concurrent deformation and chemical degradation in biodegradable polymers. The project focuses on hydrolytic degradation (i.e. the breaking of polymer chains under the attack of water), which is the primary degradation pathway in biomedical polymers. The model will account for water-induced swelling, progressive damage by chain scission, and mass loss by release of the degradation products. The models will be implemented into robust computational tools to simulate the degradation of devices of arbitrary shape under complex loading conditions. The project will generate new knowledge on the role of various factors impacting the mechanical performance and lifetime of biodegradable polymers. Ultimately, this project will equip academic and industrial beneficiaries with rational design tools to boost productivity in research and development, and improve reliability and performance of biodegradable devices.