Mechanically and Thermally Enhanced 3D-Printed Photocurable Polymer Nanocomposites Containing Functionalized Chitin Nanowhiskers by Stereolithography

Abstract

Additive manufacturing, or simply 3D printing (3DP), where objects are built through layer-wise material deposition, has gained significant academic and industrial attention as a result of the development of advanced and functional materials requiring rapid, customized, and flexible solutions. In the context of green manufacturing, diversifying environmentally and economically sustainable material portfolios is an essential endeavor for the success of 3DP technology that uses widely available, highly valuable, and renewable materials. In this study, we used stereolithography (SLA) for processing methacrylate-based photocurable resins containing crab shell-derived chitin nanowhiskers (CNWs), which are surface-functionalized by reactive acrylate groups. Results from full spectral, thermal, structural, and topological analyses corroborate not only the surface functionalization of CNWs but also indicate the presence of these photocurable CNW (pCNW) fillers in the 3D-printed nanocomposites. Owing to the strong interfacial bond induced by the physical and chemical crosslinking between the pCNW and methacrylate (MA) polymer matrix, the internally formulated nanocomposites displayed enhanced thermomechanical properties (e.g., storage modulus and glass transition temperature) compared to those of commercially available pure SLA resins. For instance, the inclusion of 0.5 wt % pCNW improved the tensile strength and stiffness to up to 78 and 71%, respectively, without compromising the toughness and ductility of the printed material. Accordingly, this result also evidences the compatibility between the filler and resin materials. Consequently, the formation of a crosslinked network in the nanocomposite structure results in a higher thermal stability and activation energy (i.e., up to ∼79%) for all the hybrid materials than the pristine MA. The high-resolution SLA print features, dimensional accuracy, and enhanced mechanical performance of our microstructure-forming functionalized chitin-based nanocomposites make them promising materials for a wide range of robust and high-performance industrial applications.

Vat Photopolymerization of Nanocellulose-Reinforced Vegetable Oil-Based Resins: Synergy in Morphology and Functionalization

“…As for VO/NFA, an increase in the strength of the loss modulus peak indicates that the increased number of chain segments inhibits the relaxation process within the composite. A similar effect was reported by Maalihan et al for methacrylate/acrylated chitosan NCC composites …”

“…FTIR was used to analyze the UV-curing of SLA resins and the macromolecular network chemical structure of the polymer. FTIR is reported to be an effective and widely used technique to investigate the UV-curing reaction of polymer resins. ,, All FTIR spectra from uncured resin and printed samples are shown in Figure S4. Peaks at 810, 980, 1409, and 1629 cm –1 indicate the vinyl bonds, which are characteristic of acrylic groups .…”

“…Up to 0.5 wt %, NCCA yielded an increase of strength and strain on NCCA vs neat NCC, while addition of 1 wt % led to a 4-fold decrease in properties. 39,55 Compared to the VO, VO/NCI showed 144% and 52% increases in tensile strength and strain, respectively. The chosen functionalization improves the wettability and adhesion between VO and NCCI.…”

“…A similar effect was reported by Maalihan et al for methacrylate/acrylated chitosan NCC composites. 39 Figure 5c presents tan δ curves, which represent damping properties and indicate the balance between the elastic and viscous phases in the composite. 51 In line with the observed increases in cross-link densities (Table 1), a clear decrease in tan δ around the glass transition was observed for all composites as compared to the VO.…”

3D-Printed Photocurable Resin with Synergistic Hydrogen Bonding Based on Deep Eutectic Solvent

“…The sample of PCR-1/6/3 exhibited the highest T g value of 160 °C, which was higher than the values exhibited by most PCRs used for vat polymerization in 3D printing. 46,47 Thus, PCR-1/6/3 could increase the upper limit of temperature used for 3D printing. In addition, the motion of the molecular segments was restricted in PCR-1/6/3, leading to a narrower intensity peak in the glass-transition range of the curve.…”