Degradation mechanism of biodegradable polymer structures processed by a 3D printer

Abstract

Poly (lactic acid) (PLA) is used in medicine especially tissue engineering. The biodegradable polymer structure is often constructed by 3D printing methods in recent years. However, strength characteristics associated with hydrolysis may be different between scan patterns of the nozzle. The purpose of this research is to elucidate the mechanism for the decline of strengths associated with hydrolysis by comparing quantities of water absorption and strengths. The strength characteristics were evaluated by the tensile strength test method. Test pieces made by a 3D printer were prepared by four different scan patterns of the nozzle, (i) Parallel, (ii) Vertical, (iii) Parallel and Vertical, and (iv) Cross to longitudinal direction. In the degradation test, test pieces were soaked in saline and placed incubator set at 310K. This paper shows results of quantities of water absorption and maximum stresses on the bases of different scanning pattern and different fabrication methods.