The objective of this study is to characterize the effect of in situ heat treatment on polylactic acid (PLA) and plasticized PLA during fused deposition modelling (FDM) with the motivation to improve their mechanical, thermal and physical properties. The in situ heat treatment was formed during the FDM by adjusting the bed temperature to 70°C, 90°C and 120°C. The performance of 3D, the printed samples, was compared with the compression moulded samples treated at the same temperature using a vacuum oven. PLA was plasticized with poly (ethylene glycol) (PEG) at different compositions of 0, 5 and 10 wt% of PEG. The properties of PLA, plasticized PLA and FDM-printed sample were analysed using Instron, differential scanning calorimeter (DSC) and X-ray diffraction (XRD). It was found that the addition of PEG into PLA decreased the tensile strength, elongation at break and tensile modulus of the materials. However, after heat treatment in the vacuum oven and FDM, the properties were generally higher at 90°C and this was believed to be primarily due to the effect of crystallization. This can be proved by formation of double melting peak, correspond to melt-crystallization mechanism, observed in DSC. The formation of different crystal was supported by XRD analysis where the amorphous peak had transformed into sharp peak at 16.9° and 19.3°, which indicates an improved crystallinity. Comparison between the compression moulded sample and FDM demonstrated that the in situ heat treatment in FDM had the most significant impact on tensile modulus.

(Ethylene‐propylene‐diene monomer)/(recycled ethylene‐propylene‐diene monomer) (EPDM/r‐EPDM) blends filled with constant mica loading were compounded at various blends ratios (i.e., 90/10, 80/20, 70/30, 60/40, and 50/50). Results indicated that scorch time decreased with increasing r‐EPDM content, whereas curing time, minimum torque, and maximum torque show the opposite trend. The tensile strength, stress at 100% elongation, and elongation at break value increased with increasing r‐EPDM loading in the blend systems and the optimum properties occurred at 70/30 EPDM/r‐EPDM blends ratio. The thermal stability of EPDM/r‐EPDM blends increased with increasing r‐EPDM content in the blends but the swelling percentage showed the opposite trend with a greater addition of r‐EPDM content in the blends. J. VINYL ADDIT. TECHNOL., 21:1–6, 2015. © 2014 Society of Plastics Engineers

In this work, the comparison effect of mica and talc as filler in EPDM composites on curing, tensile, thermal properties was studied. EPDM/mineral fillers composites were compounded using two roll mill at various filler loading (i.e., 100/0, 100/10, 100/15, 100/30, 100/50, 100/70) and curing characteristics were carried out at 160°C using a Monsanto Moving Die Rheometer. The tensile and thermal properties as well as fracture surfaces of composites were tested using Instron Universal Testing Machine, Thermal Gravimetric Analysis (TGA) and Emission Scanning Electron Microscope (SEM). The results indicated that the optimum cure time (t 90), scorch time (t s2) decreased, while maximum torque (M H) increased for both composites with increasing filler loading. The tensile properties of EPDM/mica and EPDM/talc composites increased with increasing filler loading and the optimum tensile strength and tensile modulus for both mineral fillers occurred at 50 phr. EPDM/mica composites showed better tensile properties due to strong interfacial interaction between filler and matrix than EPDM/talc composites. In addition, thermal stability of both composites improved with increasing filler loading.

No abstract

No abstract