The evolution of the structure and mechanical properties of fully bioresorbable polymer-glass composites during degradation

Fully bioresorbable polymer matrix composites have long been considered as potential orthopaedic implant materials, however their combination of mechanical strength, stiffness, ductility and bioresorbability is also attractive for cardiac stent applications. This work investigated reinforcement of p...

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Bibliographic Details
Published in:arXiv.org 2021-12
Main Authors: Oosterbeek, Reece N, Zhang, Xiang C, Best, Serena M, Cameron, Ruth E
Format: Article
Language:English
Subjects:
Biocompatibility
Biomedical materials
Crystallization
Degradation
Ductility
Enthalpy
Evolution
Glass fiber reinforced plastics
Mechanical properties
Orthopaedic implants
Orthopedics
Phosphate glass
Polylactic acid
Polymer matrix composites
Polymers
Stents
Stiffness
Surgical implants
Water absorption
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Summary:Fully bioresorbable polymer matrix composites have long been considered as potential orthopaedic implant materials, however their combination of mechanical strength, stiffness, ductility and bioresorbability is also attractive for cardiac stent applications. This work investigated reinforcement of polylactide-based polymers with phosphate glasses, addressing key drawbacks of current polymer stents, and examined the often-neglected evolution of structure and mechanical properties during degradation. Incorporation of 15 - 30wt.% phosphate glass led to modulus increases of up to 80% under simulated body conditions, and 15wt.% glass composites retained comparable ductility to pure polymers, crucial for stent applications where ductility and stiffness are required. Two-stage degradation was observed, dominated by interfacial water absorption and glass dissolution. Polymer embrittlement mechanisms (crystallisation, enthalpy relaxation) were suppressed by glass addition, allowing composites to achieve a more controlled loss of mechanical properties during degradation, which could allow gradual transfer of loading to newly healed tissue. These results provide a valuable new system for understanding the structural and mechanical changes occurring during degradation of fully bioresorbable polymer matrix composites, providing important new data to underpin the design of effective cardiac stent materials.
ISSN:2331-8422
DOI:10.48550/arxiv.2112.07326