Effects of the composition ratio on the properties of PCL/PLA blends: a kind of thermo-sensitive shape memory polymer composites

Polycaprolactone (PCL) / Polylactic acid (PLA) blend composite, as one of the most used matrix composites for FDM printing, whose shape memory property was little being concerned. This research focuses on the effects of the composition ratio on the shape memory property, PCL/PLA blend samples with different compositions were fabricated by FDM printer and used to test the properties of blend composites. Subsequently, the performances including thermal property, surface morphology, mechanical property and shape memory property of the printed samples were investigated, and the effects of the composition ratio on their properties were also elaborated, so as to screen out the optimal composition of PLA/PCL composites for FDM printing the shape memory devices. TGA and FTIR testing results show that the PCL/PLA blends are thermostable and without thermal decomposition phenomenon during 3D printing, that’s to say the 3D printing process does not affect the performance of the composites. The results of mechanical properties show that the toughness increases and tensile strength decreases with the increase of PCL content in blend composites, which shows a good agreement with the morphology observation results from SEM images. Moreover, the glass transition temperature and the melting point of each composite were examined by DSC testing, from which the programming temperature range of the shape memory measurement can be confirmed. Finally, the shape memory testing results indicate compared with other compositions of blend composites, PCL3/PLA1 possesses the highest shape memory recovery ratio of 95.37%, along with programming temperature of 90 ℃. This work can provide some experimental foundation and process guidance for FDM printing PCL/PLA thermo-sensitive intelligent devices.