MMBOP: Multiphysics Modelling of BiOdegradable Polymers

这项拟议的研究旨在开发新的基于物理的建模和模拟工具，以了解和预测可生物降解聚合物的机械响应。这种材料可以逐渐分解成无害的成分，并在完成其结构功能后最终消失。在医疗保健应用中，材料的生物降解性是一个理想的特征，因为它使不需要移除手术的临时可植入设备的制造成为可能，例如心血管支架、缝合线或矫形固定设备。近年来，可生物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，试图解决塑料污染问题。可生物降解聚合物在减少对石油的依赖方面也很有吸引力，因为许多可生物降解聚合物都是天然来源的。从工程设计的角度来看，生物可降解聚合物带来了新的挑战，因为似乎相互矛盾的要求：它们需要在完成预期功能后相对较快地降解，但在使用中还必须保持适当的机械性能。这与传统的设计工程策略不同，在传统的设计工程策略中，人们通常希望尽可能地推迟退化的开始。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，鉴于退化的时间相对较长(大约几个月或几年)，这特别耗时且代价高昂。因此，需要可靠的建模和模拟工具来补充实验研究和开发。还需要基于物理的模型来阐明承载生物降解设备中力学和化学之间的复杂相互作用。该项目将提供一个连续介质建模平台和本构模型来描述生物可降解聚合物中的同时变形和化学降解。该项目的重点是水解性降解(即在水的攻击下聚合物链的断裂)，这是生物医用聚合物的主要降解途径。该模型将考虑水引起的膨胀、链断裂造成的渐进性损伤以及降解产物的释放造成的质量损失。这些模型将被应用到稳健的计算工具中，以模拟复杂加载条件下任意形状设备的退化。该项目将在影响可生物降解聚合物的机械性能和寿命的各种因素的作用方面产生新的知识。最终，该项目将为学术界和工业界的受益者配备合理的设计工具，以提高研发效率，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.