PSI - Issue 28

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Anurag Singh et al. / Procedia Structural Integrity 28 (2020) 2218–2227 Anurag Singh/ Structural Integrity Procedia 00 (2019) 000–000

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Figure 3: Monomer and polymeric unit (a) Lactides and Polylactic Acid (PLA) (b) Glycolic Acid and Polyglycolic Acid (PGA)

In the case of the ligaments, the main task is the long-term load-bearing capabilities and subsequently strengthen torn tissue during the rehabilitation and lose the mechanical properties while gradually transferring the load. As a result, the load-bearing capability as a function of degradation time becomes significant. In this work, a study of the mechanical properties of PGLA fibres during several in-vitro degradation stages at human body temperature. PGLA is a blend of PLA and PGA; PLA has a slow rate of degradation; comparatively, PGA has a high rate of degradation. This research uses a PGLA blend of 90:10, where PGA is 90%, and PLA is in 10% concentration. This work helps in understanding the long-term behaviour of this PGLA blend (90:10). The main objective is to analyse the evolution of mechanical properties along several stages of degradation at human body temperature. 2. Materials and Methods 2.1 Materials PGLA fibres were used for the mechanical characterisation and degradation stages as received. PGLA is a blend of PGA and PLA, with a concentration of 90:10, respectively as shown in table 1. Figure 4 shows the SEM (Scanning Electron Microscopy) images of PGLA fibres, the single fibre in the PGLA has a diameter of 13.84 microns, whereas the multifilament has a diameter of 323.1 microns. On visual inspection, the structure of PGLA is like the multifilament yarn; cylindrical casing encloses this multifilament yarn. 2.2. Degradation Protocol PGLA samples subjected to 5, 10, 15, 20, 30 and 40 days of degradation. Specimens were degraded by submerging the samples in Phosphate Buffer Solution (PBS), samples were weighed and placed in 50 ml bottles at a constant temperature of 37°C and submitted to different stages of degradation. For PGLA, the sample to solution ratio of 1:5 mg/ml was maintained for every sample to ensure an equal amount of soaking in PBS.