The Effects of Self-Polymerized Polydopamine Coating on Mechanical Properties of Polylactic Acid (PLA)–Kenaf Fiber (KF) in Fused Deposition Modeling (FDM)

Abstract

This research examines the impact of self-polymerized polydopamine (PDA) coating on the mechanical properties and microstructural behavior of polylactic acid (PLA)/kenaf fiber (KF) composites in fused deposition modeling (FDM). A biodegradable FDM model of natural fiber-reinforced composite (NFRC) filaments, coated with dopamine and reinforced with 5 to 20 wt.% bast kenaf fibers, was developed for 3D printing applications. Tensile, compression, and flexural test specimens were 3D printed, and the influence of kenaf fiber content on their mechanical properties was assessed. A comprehensive characterization of the blended pellets and printed composite materials was performed, encompassing chemical, physical, and microscopic analyses. The results demonstrate that the self-polymerized polydopamine coating acted as a coupling agent, enhancing the interfacial adhesion between kenaf fibers and the PLA matrix and leading to improved mechanical properties. An increase in density and porosity was observed in the FDM specimens of the PLA–PDA–KF composites, proportional to their kenaf fiber content. The enhanced bonding between kenaf fiber particles and the PLA matrix contributed to an increase of up to 13.4% for tensile and 15.3% for flexural in the Young’s modulus of PLA–PDA–KF composites and an increase of up to 30% in compressive stress. The incorporation of polydopamine as a coupling agent in the FDM filament composite led to an improvement in tensile, compressive, and flexural stresses and strain at break, surpassing that of pure PLA, while the reinforcement provided by kenaf fibers was enhanced more by delayed crack growth, resulting in a higher strain at break. The self-polymerized polydopamine coatings exhibit remarkable mechanical properties, suggesting their potential as a sustainable material for diverse applications in FDM.

Sonochemical synthesis of bioinspired graphene oxide–zinc oxide hydrogel for antibacterial painting on biodegradable polylactide film

“…Besides, elongations at break of PLA films coated with Zn(OH) 2 paint and GO-ZnO paint were lower than that of blank PLA films. In scientific literature, coating effects on the decrease of materials elongation were also reported [67][68][69]. During tensile process, cracks appreared in the brittle coatings and propagated into the substrates.…”

Empowering Rehabilitation: Design and Structural Analysis of a Low-Cost 3D-Printed Smart Orthosis

“…A particularity of this unconventional process is the adhesion of the coating using polymer materials. Layer adhesion refers to the cohesive bonds formed between consecutive layers of material during the additive manufacturing process, ensuring the structural integrity and stability of the printed object [25][26][27][28]. with a Grid infill, the Flexure load at Tensile Strength recorded a value of 300 N. Utilizing a Gyroid infill pattern resulted in recorded forces reaching a value of 379 N, whereas the employment of a Triangles infill pattern yielded forces measuring at 232 N. All values are presented in Tables 3 and 4.…”

“…A particularity of this unconventional process is the adhesion of the coating using polymer materials. Layer adhesion refers to the cohesive bonds formed between consecutive layers of material during the additive manufacturing process, ensuring the structural integrity and stability of the printed object [25][26][27][28]. In the second test, the joint consisted of components obtained through 3D printing utilizing PLA as the material.…”

Preparation of MoS2@PDA-Modified Polyimide Films with High Mechanical Performance and Improved Electrical Insulation

“…Feng et al [25] found that the interfacial interaction between filler and polyarylene ether nitrile was enhanced by a coreshell structural composite (MoS 2 @PDA). Sanusi Hamat et al [26] found that a coupling agent (PDA) could increase the tensile Young's modulus, flexural Young's modulus, and compressive stress of kenaf fibers and the PLA matrix by 13.4%, 15.3%, and 30%, respectively. Therefore, the use of MoS 2 @ PDA core-shell structure nanoparticles doped with modified PI materials is expected to further enhance the mechanical and friction properties of the composites, as well as effectively improve the electrical insulation properties of the composites.…”