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Owing to its robustness, ability to achieve complex geometries, and ease of use, 3D printing has become one of the noteworthy applications in the field of engineering. Polycarbonate has become a thermoplastic of interest due to its excellent mechanical and optical properties. Especially when infused with nanosilica, polycarbonate becomes a potential candidate for 3D printing with enhanced properties. Polycarbonate nanocomposite filaments infused with AEROSIL (nanosilica) have been melt extruded with various filler loadings of 0.5, 1, and 3 wt% and are then 3D printed. The thermal analysis of the filaments has shown that thermal stability of the filaments increases with increase in filler loading. Tensile tests have shown that addition of nanosilica have enhanced the mechanical properties of the filaments as well as 3D printed films. The addition of silica in low concentrations exhibit higher transmittance of UV light, as silica restricts the mobility of polycarbonate. Despite 3D printing causing voids in bulk materials, silica at low concentration (0.5 and 1 wt%) can improve the mechanical and optical properties. These improvements are promising for applications in thin film interfaces and the automotive industry. 

A novel approach is demonstrated for the synthesis of the high entropy transition metal boride (Ta, Mo, Hf, Zr, Ti)B2 using a single heating step enabled by microwave-induced plasma. The argon-rich plasma allows rapid boro-carbothermal reduction of a consolidated powder mixture containing the five metal oxides, blended with graphite and boron carbide (B4C) as reducing agents. For plasma exposure as low as 1800 °C for 1 h, a single-phase hexagonal AlB2-type structure forms, with an average particle size of 165 nm and with uniform distribution of the five metal cations in the microstructure. In contrast to primarily convection-based (e.g., vacuum furnace) methods that typically require a thermal reduction step followed by conversion to the single high-entropy phase at elevated temperature, the microwave approach enables rapid heating rates and reduced processing time in a single heating step. The high-entropy phase purity improves significantly with the increasing of the ball milling time of the oxide precursors from two to eight hours. However, further improvement in phase purity was not observed as a result of increasing the microwave processing temperature from 1800 to 2000 °C (for fixed ball milling time). The benefits of microwave plasma heating, in terms of allowing the combination of boro-carbothermal reduction and high entropy single-phase formation in a single heating step, are expected to accelerate progress in the field of high entropy ceramic materials. 

Abstract Forcespinning technique was used to fabricate sub-micron size polycaprolactone (PCL) fibers. Forcespinning method uses centrifugal forces for the generation of fibers unlike the electrospinning method which uses electrostatic force. PCL has been extensively used as scaffolds for cell regeneration, substrates for tissue engineering and in drug delivery systems. The aim of this study is to qualitatively analyze the force spun fiber mats and investigate the effect of the spinneret rotational speed on the fiber morphology, thermal and mechanical properties. The extracted fibers were characterized by scanning electron microscopy differential scanning calorimetry, tensile testing and dynamic mechanical analysis. The results showed that higher rotational speeds produced uniform fibers with less number of beads. The crystallinity of the fibers decreased with increase in rotational speeds. The Young’s modulus of the forcespun fibers was found to be in the range of 3.5 to 6 MPa. Storage and loss moduli decreased with the increase in the fiber diameter. The fibers collected at farther distance from spinneret exhibited optimal mechanical properties compared to the fibers collected at shorter distances. This study will aid in extracting fibers with uniform geometries and lower beads to achieve the desired nanofiber drug release properties.