No abstract

Thermoplastic polyurethane/graphene nanocomposites were successfully prepared by mixing masterbatches with neat polymers using the melt compounding process. Graphene was obtained from graphite by the chemical mean. Graphite was initially converted into graphite oxide which was then converted to graphene oxide. Graphene oxide was then reduced by L-ascorbic acid to obtain graphene. The effects of graphene addition on thermal and morphological properties of nanocomposite were studied by a differential scanning calorimeter, a thermal gravimetric analyzer and a scanning electron microscope. TPU/graphene nanocomposites showed higher melting temperature compared to TPU. On the other hand, heat of fusion of nanocomposites was lowered. TPU and TPU/graphene nanocomposites have two steps of decomposition. The first degradation of TPU occurred at higher temperature compared with nanocomposites but the second degradation showed the opposite results. The percentage of residue after thermal degradation of nanocomposites was lower than that of TPU. For surface morphology, nanocomposite exhibited the rougher surface comparing with TPU and well graphene dispersion in TPU phase was achieved. Nevertheless, there were some agglomeration of graphene.

In this research, we developed 3D printing filaments from polyhydroxybutyrate (PHB)/poly(lactic acid) (PLA) blends to further its use in a fused filament fabrication (FFF) 3D printing technique as an alternative feedstock for manufacturing bone scaffold model. The filaments were fabricated with blending ratios of PHB/PLA at 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100 %wt. using an extrusion process. Furthermore, 10 phr of polypropylene glycol (PPG) was added as a processing aid to enhance the processability. The results of MFR showed that the suitable temperature for 3D printing of all blended filaments is 190 °C. The changes in thermal properties indicate the partial compatibility between PHB and PLA in the blends. PLA plays a vital role in improving the mechanical properties of PHB. 3D printing filament from PHB/PLA blends has been successfully developed.