Biodegradable poly(lactic acid) (PLA) filaments have been widely used in the fused deposition modeling (FDM) 3D printing technology. However, PLA has low toughness and low thermal resistance that affects printability and restricts its industrial applications. In this study, PLA was compounded with 0 to 40 wt% of poly(butylene adipate-co-terephthalate) (PBAT) and varied content of nano talc at 0 to 40 wt% in a twin screw extruder. The compounds were reextruded to filaments using a capillary rheometer. PLA/PBAT blends and their composite filaments were printed with a FDM 3D printing machine. Morphology, rheological behaviour, thermal characteristic, surface roughness, and mechanical property of 3D printing of the blends and the composites were investigated. Complex viscosity of the blends and the composites increased with increase of the PBAT and the nano talc contents. The incorporation of the nano talc enhanced crystallization temperature and reduced the coefficient of volume expansion of the composites. It was found that the PLA/PBAT blends and composites were excellent in both printability and dimension stability at PBAT content 10-30 wt% and nano talc up to 10 wt%. Interestingly, it was possible to print the composite filaments at an angle up to 75° during the overhang test without a supporter. From the vertical specimens, the surface roughness improved due to the incorporation of the nano talc. Tensile strength of the blends and the composites decreased, whereas elongation at break increased when the PBAT and the nano talc contents were increased. The reduction of tensile strength was attributed to agglomeration of the PBAT dispersed phase and less adhesion between the nano talc and the matrix. It can be noted that the composite 3D printing product showed superior elongation at break up to 410% by adding nano talc 1 wt%. This result suggests that the ductile 3D printable PLA/PBAT blend and the PLA/PBAT-nano talc composite products can be prepared, which shows potential for the commercialized scale.

Polymer surface modification that mimicks natural behaviors has been a subject of great interest. Fabrication of polymer nanofiber arrays with various applications has been studied intensively. Avoidance of chemical solvents, reduction of processing time, improvement of the nanofiber size distribution and aspect ratios, and improvement of reproducibility have been sought for industrial value creation. This study examines an alternative fabrication methods for polymer nanofiber arrays using a combination of anodic aluminum oxide (AAO) nanoporous template and thermal nanoimprinting lithography for simple, precise processing. Based on those results, nanofiber arrays were fabricated with 40‐µm‐thick film and 50–100 nm fiber diameter polystyrene (PS) and polypropylene (PP). For this study, 50‐nm diameter PS nanofibers with 50 µm maximum length and a maximum aspect ratio of 1,000 were produced in addition to PP nanofibers having 130 µm maximum length and an aspect ratio of 2,600. The nanofiber lengths were affected considerably by molten polymer flow related to imprint processing conditions, polymer properties, AAO properties, and surface wettability between AAO and molten polymers. Moreover, AAO nanoconfinement demonstrated molecular orientation alignment of polymers that affect thermal properties, crystallinity, and mechanical properties of the obtained polymer nanofiber arrays. POLYM. ENG. SCI., 57:214–223, 2017. © 2016 Society of Plastics Engineers

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One-dimensional (1D) composite nanostructures, or vertically aligned composite nanostructures (VACNs), of polystyrene (PS) and graphene nanoplatelets (GNPs) (1.0-5.0 wt%) were precisely replicated by thermal nanoimprint with an anodic aluminum oxide (AAO) template. In this study, we fabricated VACNs of PS-GNPs (1.0-5.0 wt%) with a diameter of 100 nm and length of 10-70 μm, depending on the imprinting conditions. The obtained PS-GNPs 5.0 wt% VACNs showed enhancement of flat film water contact angle increasing from 87±3°to 132±2°. The nanostructures of PS-GNPs exhibit improved surface mechanical properties when compared with the neat PS. The evaluated surface mechanical properties included friction coefficient, surface durability, surface modulus, and hardness. The glass transition temperature (T g ) of PS-GNPs nanostructures increased about 1 to 4°C as compared with their bulk composites because of the immobilization the polymer chain owing to confinement in the AAO template and also due to the surface interfacial interaction effects between PS and GNPs. Moreover, the maximum thermal conduction of 1D PS-GNPs 5.0 wt% nanostructures were obtained with a value up to 1.8 W/m.K due to the control of filler orientation. The PS-GNPs nanostructures showed a higher thermal stability than that the PS nanostructures.