A mixture design of experiment (DoE) was used to guide the fabrication and analysis of sustainable poly­(lactic acid) (PLA) and biobased poly­(butylene succinate) (BioPBS) 3D-printing filaments. The statistical DoE approach was employed to investigate the correlation between the mechanical properties of the PLA/BioPBS blends at different PLA and BioPBS wt % and to obtain the linear regression models of the mechanical properties. The statistical models help to design PLA/BioPBS blends with the desired mechanical properties. The PLA/BioPBS filaments with different composition ratios were 3D-printed via fused deposition modeling (FDM). The 3D-printability of the polymer blends was determined by the flowability and dimensional stability of the filaments, provided by fundamental rheological and coefficient of linear thermal expansion (CLTE) studies. Preliminary research found that the 3D-printability of PLA/BioPBS filaments with BioPBS content higher than 50 wt % was unsuccessful due to high viscosity and low thermal stability. These findings were verified with rheological tests for a range of PLA/BioPBS blend ratios and thermomechanical studies. Rheological results show a significant increase of the blend viscosity when BioPBS content in the blend was >50%. Additionally, the CLTE drastically increased with higher contents of BioPBS, making the PLA/BioPBS filaments thermally unstable during FDM processing. These results confirmed that the 3D-printability of PLA/BioPBS filaments is greatly influenced by the blend viscosity and the printing temperature. Rheological studies revealed that the viscosity range of a 3D-printable PLA/BioPBS filament lies within 1000–100 Pa·s. Scanning electron microscopy (SEM) and polarized optical microscopy (POM) images confirmed that PLA and BioPBS are immiscible. However, the addition of BioPBS improved the ductility and the crystallinity of PLA. The 3D printed PLA/BioPBS (90/10) blend showed an interesting result in that it obtained higher tensile and impact strengths than the neat PLA, which was attributed to crystallinity and morphological factors.

Commercially available biocarbon (BC) derived from Miscanthus was activated by potassium hydroxide (KOH) at different BC/KOH ratios of 1:3, 1:4, and 1:5. The structural and morphological changes and the porosity developed in the resultant products were investigated. In addition, the electrochemical performance of the assembled electric double layer capacitors (EDLCs) incorporating these carbonaceous materials was determined using galvanostatic, voltammetric, and impedance spectroscopy techniques. Compared with pristine BC samples, these KOH-activated BC samples exhibited a significant increase in the surface area from 98 to 3024 m 2 g −1 , which was mainly attributed to the well-developed micropores. By employing the activated BC as an electrode material for EDLCs, comparable capacitance values up to 110.8 F g −1 at a scan rate of 0.05 V s −1 and 65.4 F g −1 at a current density of 1 A g −1 were obtained during operation in an organic electrolyte. The variations in the electrochemical behavior were considered in relation to the surface area and the porous characteristics.

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