PSI - Issue 28

ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com Sci nceDir t Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 28 (2020) 2218–2227

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo Abstract Medical applications of PGLA fibres in the form of scaffolds is dependent on the mechanical and degradation properties of these fibres. Aim of this study is to investigate the mechanical properties of PGLA fibres depending on its degradation rate. Results from this investigation helps to utilise PGLA fibres in a composite cord with different biodegradable filaments. Use of the composite cord helps in tuning the rate of degradation. Further, the information from this study help to design and simulate the Ligament Augmentation Device (LAD) made of different biodegradable filaments for Anterior Cruciate Ligament (ACL) injuries. The effect of strain rate and degradation on various mechanical parameters were studied. Seven degradation stages viz. 0, 5, 10, 15, 20, 30 and 40 days were used for degradation studies at a constant temperature of 37 °C. In-vitro degradation uses Phosphate buffer solution (PBS) as a degradation medium. Five different strain rates viz. 0.0001, 0.001, 0.01, 0.05 and 0.1/s were used to perform the tensile tests of PGLA fibres. Differential Scanning Calorimetry (DSC) was performed to analyse the effect of degradation on the transition temperatures and crystallinity of undegraded and in-vitro degraded PGLA fibres. Mechanical properties first increase up to 15 days of degradation, and then the decay starts due to the chain scission. Change of glassy to rubbery behaviour occurs at a lower temperature. Percentage crystallinity of PGLA fibres throughout degradation stages remains in between 30 – 40 %. Complete deterioration of mechanical properties in PGLA was observed after 40 days of degradation at 37 °C. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo Keywords: Biomaterials; Hydrolytic Degradation; Mechanical Characterization; PGLA; Tissue Engineering 1st Virtual European Conference on Fracture Investigating Mechanical Properties of PGLA Fibres as a Function of Degradation Time Anurag Singh a* , Rui Miranda Guedes a,b,c a Laboratory of Optics and Experimental Mechanics (LOME), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal, b Department of Mechanical Engineering (DEMec), Faculty of Engineering, University of Porto (FEUP), Rua Dr Roberto Frias, 4200-465, Porto, Portugal c LABIOMEP - Porto Biomechanics Laboratory, University of Porto, 4200-450 Porto, Portugal Abstract Medic l applications of PGLA fibres in the form of scaffolds is dependent on the mechanical and degradation properties of these fibres. Aim of this study is to investigate t mechanical properties of PGLA fibres d pending on its degradation rate. Results from this investigation helps to utilise PGLA fibres in com osit cord with different biodegradable filaments. Use of the composite cord helps in tu ing the rate of degradation. Further, the information from this study help to design a d simulate the Ligament Augm ntation Device (LAD) ma of ifferent biodegradable filame ts f r Anterior Cruciate Ligament (ACL) injuries. The eff c of strai rate and degradation on various m chanical p r m ters w re studied. Seven degradat on stages viz. 0, 5, 10, 15, 20, 30 and 40 days were used for degrad t n studies at constan temp rature of 37 °C. In-vitro degradation uses Phosphate buffer solution (PBS) as a d gradation med um. Fiv different str in rates viz. 0.0001, 0.001, 0.01, 0.05 and 0.1/s were used to perform the tensile tests of PGLA fibres. Differential Scanning Calorime ry (DSC) was performed to analyse the effect of d gradation on ransition emperatures and crystallinity of undegraded and in-vitro degraded PGLA fibres. Mechanical properties fi st increase up to 15 days of d gradation, and then the decay sta ts due to the chain scission. Change of glassy to rubbe y b haviour oc urs at a lower temperature. Perce t ge crystallinity of PGLA fibres throughout degradation sta es remains in between 30 – 40 %. Complete det rioration of mechani al properties in PGLA was observed af er 40 days f degradation at 37 °C. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of European Structural Integri y Soci ty (ESIS) ExCo Keywords: Biomaterials; Hydrolytic Degradation; Mechanical Characterization; PGLA; Tissue ngineering 1st Virtual European Conference on Fracture Investigating Mechanical Properties of PGLA Fibres as a Function of Degradation Time Anurag Singh a* , Rui Miranda Guedes a,b,c a Laboratory of Optics and Experimental Mechanics (LOME), Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal, b Department of Mechanical Engineering (DEMec), Faculty of Engineering, University of Porto (FEUP), Rua Dr Roberto Frias, 4200-465, Porto, Portugal c LABIOMEP - Porto Biomechanics Laboratory, University of Porto, 4200-450 Porto, Portugal

* Corresponding author E-mail address: asingh@inegi.up.pt * Corresponding author E-mail address: asingh@inegi.up.pt

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.11.050