Improving the shape stability and enhancing the properties of layer dependent material extruded biodegradable polylactic acid for thin implants

Purpose – This paper aims to establish an appropriate annealing method, which is necessary for shape stability and to evaluate their potential degradation performance of 1-, 3- and 5-layer material extruded polylactic-acid specimens by enhancing their thermal and mechanical properties. Design/methodology/approach – The distortion of each layered printed specimen subjected to degradation was calculated in x- and y-direction. Each layered specimen was subjected to annealing at 70°C, 80°C and 90°C for 2 h and at 80°C for 1, 4, 8 and 16 h. Thermal, molecular weight and mechanical properties were calculated using, differential scanning calorimetry, gel permeation chromatography and tensile testing machine, respectively. Findings – In the x-direction, distortion was 16.08 mm for one-layer non-annealed printed specimens and decreased by 73% and 83% for 3- and 5- layer, respectively, while each layered non-annealed specimen subjected to degradation at 37°C for one month. Within the outlined study, annealing treatment enhances properties such as the degree of crystallinity (%x) up to 34%, Young’s modulus (E) by 30% and ultimate tensile strength by 20% compared to the non-annealed specimens. Practical implications – The future research accomplishments will be concentrated on the design, development and optimisation of degraded biomedical implants using material extrusion thin films including drug delivery system and fixation plates. Originality/value – The printed thin specimens subjected to degradation were investigated. This research developed a new understanding of the effect of the annealing temperature and time on the mechanical, thermal and molecular weight properties for each layered specimen.