Investigating the Mechanical Behaviour of Biodegradable Substrates

The amount of electronics waste is increasing rapidly, and replacing traditional electronics materials with biodegradable alternatives is essential where possible. In this research work, PLA (polylactic acid) based substrates with different fillers (pure PLA and ones filled with Licocene<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">™</sup>, wool fibres or keratin powders) and with different thicknesses (ranging from 0.9 to 1.9 mm) were investigated from their mechanical point of view. The mechanical behaviour was addressed by measuring the flexural behaviour of these substrates with a 3-point bending test. The bending tests were carried out loosely following EN ISO 178 and IEC 60068-2-21 standards. These demand the precise measurement of the test specimen’s deflection and the required force. For this purpose, a custom measurement equipment was developed, in which the deflection is measured by a Balluff incremental linear encoder and a deflection gauge, whereas the force was measured with an L6P aluminium planar beam having a combined error of $\leq \pm 0.023 \% \mathrm{FS}$ at 450 N maximum load. The force sensor was calibrated up to 120 N using reference weights. The samples were tested then at two loading speeds to address time-dependent behaviour and measure the flexural modulus. A motorised stage was also developed to aid the repeatability of the measurements.