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Mechanical performance of 3D printed polylactide during degradation

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journal contribution
posted on 02.02.2021, 13:50 by Amirpasha Moetazedian, Andy GleadallAndy Gleadall, Xiaoxiao Han, Alper Ekinci, Elisa MeleElisa Mele, Vadim SilberschmidtVadim Silberschmidt
© 2021 Elsevier B.V. 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.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Additive Manufacturing

Volume

38

Publisher

Elsevier BV

Version

AM (Accepted Manuscript)

Rights holder

© Elsevier

Publisher statement

This paper was accepted for publication in the journal Additive Manufacturing and the definitive published version is available at https://doi.org/10.1016/j.addma.2020.101764

Acceptance date

06/12/2020

Publication date

2020-12-18

Copyright date

2021

ISSN

2214-8604

eISSN

2214-8604

Language

en

Depositor

Mr Andy Gleadall Deposit date: 1 February 2021

Article number

101764