Tri-(butanediol-monobutyrate) citrate plasticizing poly(lactic acid): Synthesis, crystallization, thermal, and mechanical properties

Construction of high-performance and sustainable polylactic acid composites for 3D printing applications with plasticizer

Polylactic acid (PLA) attains much attention because of its biodegradability, biocompatibility, and high strength, but its further application was remarkably hindered by its brittleness. In order to improve the toughness of PLA, a biodegradable composite was prepared by blending ductile polycaprolactone (PCL), stiff microcrystalline cellulose (MCC), and green plasticizer tributyl citrate (TBC) with PLA by melting extrusion. The physicochemical properties and microstructure of PLA composites were thoroughly investigated using FTIR, TGA, DSC, XRD, melting rheology, optical transmittance, 3d printing, tensile tests, and SEM. The tensile tests results show that introduction of TBC exhibited a remarkable improvement effect in the elongation at break of PLA/PCL/MCC (PPM) composite, increasing from 2.9 % of PPM to up to 30 % of PPM/6TBC and PPM/8TBC. Noticeably, the strength of PPM/TBC composites (at least 33.1 MPa) was enhanced compared with that of PPM (28.2 MPa). The plasticization of TBC, enhancing the compatibility of composites, and reinforcing effect of MCC were identified as pivotal factors in toughening and reinforcing PLA. Furthermore, it is observed that the incorporation of TBC contributed to enhanced thermal stability, crystallinity, and rheology property of composites. This research supplies a novel approach to bolstering the toughness of PLA and broaden its potential applications.

Fused Deposition Modelling of Natural Fibre/Polylactic Acid Composites

Fused deposition modelling is a simple additive manufacturing technology utilising fine filament extrusion of predominantly thermoplastic materials to build 3D objects layer by layer. This research explores the feasibility and the factors involved in using fused deposition modelling to produce natural fibre reinforced composite components. Uniform 3-mm filaments of both hemp and harakeke (Phormium tenax) in varying weight percentages within polylactic acid (PLA) polymer were successfully produced and used to print tensile test samples. Tensile test results supported harakeke to be a useful fibre in terms of mechanical properties achieved which surpassed the Young’s modulus and tensile strength of plain PLA samples by 42.3% and 5.4%, respectively.