Extrusion-based 3D printing is widely used to fabricate precise and accurate 3D structures with nanocellulose suspensions due to its excellent material flow control and system stability. The current issues related to high concentration nanocellulose 3D structures are low printability, layers adhesion, shape fidelity, and mechanical strength. Herein, the issues associated with 3D printed concentrated nanocellulose structures were resolved by mixing different concentrations of tannic acid. The printing parameters of a twin-screw extruder, tannin acid content, and drying conditions were optimized for concentrated nanocellulose paste. The mechanical results showed that tannic acid effectively improved the adhesion between printed layers, as confirmed by a scanning electron microscope.
Piezoelectric ceramics, lead zirconate titanate (PZT), have been widely used for sensors and actuators due to their high electromechanical properties. However, the brittle nature of ceramics limits their applications to only small deformations as the flexibility and durability of these materials are the main essential factors required for practical applications. The flexible piezoelectric materials can be developed by blending PZT with flexible polymeric materials such as nanocellulose fibers. The bio-based nanocellulose fibers (CNF) have been reported as a type of electroactive polymer with a piezoelectric response exhibiting excellent mechanical strength and modulus. In this regard, the present study focuses on enhancing the mechanical strength and load-bearing capability of PZT by blending 20 and 30wt% of PZT powder with 80 and 70wt% CNF to obtain a flexible piezoelectric composite film via 3D printing. The 3D printed films' structural, morphological, and mechanical properties were investigated through XRD, SEM, and tensile tests. The SEM images and XRD analysis demonstrated that the PZT powder was uniformly dispersed in the CNF films and showed the morphotropic phase boundary (MPB) in PZT/CNF films. The addition of CNF in PZT has improved the mechanical strength significantly.
Recently, extrusion-based 3D printing has been widely used to manufacture precise and accurate 3D structures with high nanocellulose concentrations due to excellent materials flow control and system stability. With the extrusion-based 3D printing technique, the main challenges for precision and accuracy in high concentration nanocellulose 3D printed structures are proper printing parameters and appropriate adhesion between printed layers. Therefore, this study aims to improve the adhesion between high content nanocellulose printed layers by blending different lignin concentrations and optimizing the twin-screw extruder printing parameters. The lignin concentrations are optimized in nanocellulose paste by assessing the mechanical properties, shape retention, and shrinkage of 3D printed structures. To ease shape retention, the 3D printed structures are dried at controlled humidity (45%) and temperature (25oC). The surface morphology of the 3D printed structures is observed by scanning electron microscope.
KEYWORDS: 3D printing, 3D modeling, Structural engineering, Scanning electron microscopy, Manufacturing, Humidity, Electron microscopes, Computer simulations, Additive manufacturing
3D printing, commonly referred to as additive manufacturing (AM), is a rapid technique of making three-dimensional structures from a computer-based design model. Various materials have been used to manufacture 3D structures for different engineering applications, including synthetic and natural materials. In the case of natural materials for 3D printing, nanocellulose gain much attention as a feedstock material for AM techniques due to its high strength, lightweight, and biocompatibility. However, the mechanical properties exhibited in high concentration nanocellulose printed 3D structures are unsatisfactory, as demonstrated in their building blocks due to drying issues. Therefore, this research aims to optimize the proper drying conditions for 3D printed high concentration nanocellulose structures. The 3D printed structures are dried at different humidity and temperature conditions and evaluated their mechanical properties. The scanning electron microscope is utilized to observe the morphology of 3D printed high concentration nanocellulose structures. The research results will significantly help nanocellulose-based industries to overcome the drying issues in 3D printed high concentration nanocellulose structures.
Cellulose is attractive for in fabricating renewable triboelectric nanogenerators (TENGs) due to its lightweight, flexibility, renewability, and biodegradability. However, the insufficient functional groups and weak polarization on the surface restrict its progress towards high-performance TENGs. Therefore, this research has developed flexible environment-friendly TENGs with significant output performance based on polyvinyl alcohol (PVA)/graphene oxide (GO) and cellulose films. Furthermore, the specific contact surface area of the films is improved by patterning rectangular dots using a photolithography technique. Moreover, the concentration of GO, size of friction layers, and thickness are optimized in terms of triboelectric output performance. The scanning electron microscope is used to observe the surface morphology of the prepared TENGs films. We believe that the fabricated TENGs have the potential to be applied for self-powered biomedical applications.
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