ABSTRACT
Bone injury represents an urgent clinical problem, and implantable bioscaffolds offer suitable means for replacing and regenerating damaged tissues. This paper proposes an in-situ foaming printing method employing material extrusion additive manufacturing technology and physical foaming to prepared poly(lactic acid)/chitin nanocrystals (CHNCs) microporous composite scaffolds, featuring pore sizes ranging from 9 ± 5 µm. This method offers a novel strategy for the preparation of poly(lactic acid)-based scaffolds with good biocompatibility. Material characterization and mechanical property testing demonstrated that the in-situ foaming printed PLA scaffolds exhibited excellent foam printability, and the expansion ratio and compression properties of the scaffolds could be adjusted by modifying the CHNCs concentration and the printing speed, achieving a compression modulus between 39.2 MPa and 54.3 MPa. Furthermore, at equivalent foaming multiplicity (1.5-2.6 times), the compression modulus increased by nearly 100 % compared to previously reported PLA-based foam scaffolds. Importantly, the PLA/CHNCs scaffolds produced via in-situ foaming exhibited superior biocompatibility compared to directly printed PLA scaffolds. This PLA/CHNCs composite scaffold provides a promising approach to addressing and repairing bone defects.
ABSTRACT
Digital light processing (DLP) techniques are widely employed in various engineering and design fields, particularly additive manufacturing. Acrylate resins utilized in DLP processes are well known for their versatility, which enables the production of defect-free 3D-printed products with excellent mechanical properties. This study aims to improve the mechanical and thermal properties of 3D-printed samples by incorporating mica as an inorganic filler at different concentrations (5%, 10%, and 15%) and optimizing the dispersion by adding a KH570 silane coupling agent. In this study, mica was introduced as a filler and combined with epoxy acrylate resin to fabricate a 3D-printed sample. Varying concentrations of mica (5%, 10%, and 15% w/w) were mixed with the epoxy acrylate resin at a concentration of 10%, demonstrating a tensile strength increase of 85% and a flexural strength increase of 132%. Additionally, thermal characteristics were analyzed using thermogravimetric analysis (TGA), and successful morphological investigations were conducted using scanning electron microscopy (SEM). Digital light-processing technology was selected for its printing accuracy and cost-effectiveness. The results encompass comprehensive studies of the mechanical, thermal, and morphological aspects that contribute to the advancement of additive manufacturing technology.
ABSTRACT
Polymer-based dielectric composites are of great importance in advanced electronic industries and energy storage because of their high dielectric constant, good processability, low weight, and low dielectric loss. FDM (Fused Deposition Modeling) is a greatly accessible additive manufacturing technology, which has a number of applications in the fabrication of RF components, but the unavoidable porosity in FDM 3D-printed materials, which affects the dielectric properties of the materials, and the difficulty of large-scale fabrication of composites by FDM limit its application scope. This study's main focus is on how the matrix, filler, interface, and FDM 3D printing parameters influence the electrical properties of FDM-printed polymer-based dielectric composites. This review article starts with the fundamental theory of dielectrics. It is followed by a summary of the factors influencing dielectric properties in recent research developments, as well as a projection for the future development of FDM-prepared polymer-based dielectric composites. Finally, improving the comprehensive performance of dielectric composites is an important direction for future development.