Chemo-Mechanics of Biodegradable Polymers

可生物降解聚合物的化学力学

• 批准号: MR/W006995/1
• 负责人: Laurence Brassart
• 金额: $ 184.46万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FW006995%2F1
• 关键词: Chemo; Mechanics; Biodegradable; Polymers

Biodegradable polymers are materials designed to gradually break down into harmless constituents, and eventually disappear after having fulfilled their structural function. They are attracting enormous interest as potential replacements to traditional inert plastics in an attempt to address the plastic pollution problem. Applications include sustainable packaging, agricultural films and fishing nets, among others. Biodegradable polymers are also materials of choice for the design of temporary biomedical implantable devices (e.g. stents, sutures, or orthopaedic fixtures), thanks to their biocompatibility and tunable mechanical properties. From an engineering design perspective, biodegradable polymers introduce new challenges due to seemingly contradictory requirements: they need to degrade relatively fast after having completed their intended function, but they must also maintain suitable mechanical properties (stiffness, strength, toughness) during service. Addressing these challenges requires a fundamental understanding of the coupled chemo-mechanical effects that dictate the performance of these materials. On the one hand, chemical degradation in water progressively decreases the mechanical properties of the material and causes swelling. On the other hand, mechanical stresses arising from externally-applied loads or geometrical imperfections significantly impact the degradation rate. The proposed research aims to elucidate the role of mechanics in the chemical degradation of polymers in aqueous environment. This will be achieved by integrating systematic experiments on model polymers (PLA) degrading under loads and new physics-based constitutive models coupling mechanics and chemistry (hydrolysis reaction and diffusion of water and reaction products). The proposed models will be implemented within robust computational tools enabling the in-silico testing of biodegradable components under complex loading conditions up to failure. Ultimately, the research aims to answer the following question: "can we harness mechanical effects to control the degradation rate and failure mode for specific applications?". The new knowledge, models and computational tools delivered by this project will be directly relevant for a broad range of applications in packaging, engineering and healthcare. Benefits include guidelines for the formulation of polymer systems with targeted mechanical and degradation properties, as well as design guidelines and predictive simulation tools at component level. These will reduce the need for costly and time-consuming trial-and-error experimental approaches, and improve performance and safety of biodegradable devices.

生物可降解聚合物是一种旨在逐渐分解成无害成分的材料，并在完成其结构功能后最终消失。它们正吸引着巨大的兴趣，作为传统惰性塑料的潜在替代品，试图解决塑料污染问题。应用领域包括可持续包装、农用薄膜和渔网等。生物可降解聚合物由于其生物兼容性和可调的机械性能，也是设计临时生物医学可植入装置(如支架、缝合线或矫形固定器)的首选材料。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，但它们还必须在使用过程中保持适当的机械性能(刚性、强度、韧性)。应对这些挑战需要对决定这些材料性能的化学机械耦合效应有一个基本的了解。一方面，水中的化学降解会逐渐降低材料的机械性能，并导致膨胀。另一方面，由外加载荷或几何缺陷引起的机械应力对退化速率有显著影响。这项拟议的研究旨在阐明力学在水环境中聚合物化学降解中的作用。这将通过整合模型聚合物在负载下降解的系统实验和新的基于物理的本构模型来实现，该模型耦合了力学和化学(水和反应产物的水解、反应和扩散)。建议的模型将在强大的计算工具中实施，从而能够在复杂加载条件下对生物可降解组件进行硅胶测试，直到发生故障。最终，这项研究旨在回答以下问题：我们能否利用机械效应来控制特定应用的退化速度和失效模式？该项目提供的新知识、模型和计算工具将与包装、工程和医疗保健中的广泛应用直接相关。好处包括具有目标机械和降解性能的聚合物体系的配方指南，以及组件级别的设计指南和预测性模拟工具。这些将减少对昂贵和耗时的反复试验方法的需求，并提高可生物降解设备的性能和安全性。

项目成果

A reaction-diffusion framework for hydrolytic degradation of amorphous polymers based on a discrete chain scission model.

基于离散断链模型的无定形聚合物水解降解的反应扩散框架。

• DOI: 10.1016/j.actbio.2023.06.021
• 发表时间: 2023
• 期刊: Acta biomaterialia
• 影响因子: 9.7
• 作者: Pan Z

Shear yielding and crazing in dry and wet amorphous PLA at body temperature

• DOI: 10.1016/j.polymer.2023.126477
• 发表时间: 2023-11-17
• 期刊: POLYMER
• 影响因子: 4.6
• 作者: Chen，Huanming;Pan，Zhouzhou;Brassart，Laurence
• 通讯作者: Brassart，Laurence