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

Abstract

With the advancement of additive manufacturing (AM) and the mass adoption of 3D printing technology, it is essential to shift focus to environmentally and economically sustainable materials. As the utilization of renewable feedstocks is quite limited in this context, the utilization of more bio-based raw materials in the ongoing development of AM represents an essential means of achieving this shift. In this work, vat photopolymerization 3D printing has been used to process vegetable oil-based (VO) resins with an ultralow concentration of 0.07 vol % nanocellulose fibrils (NFC) and crystals (NCC). The developed nanocellulose containing bio-based vat photopolymerization resin shows excellent shelf stability, enabling high-resolution printing. Compatibilization of the nanocellulose with the polymer matrix was achieved through the introduction of isocyanate or acrylate groups via reactions of acryloyl chloride (AC) and hexamethylene diisocyanate (HMDI) with cellulose surface hydroxyls. Surface functionalization results in ∼20–30% increases in interfacial adhesion and stress transfer, yielding significant improvements in mechanical performance (4× higher toughness, 2.4× higher tensile strength, and 2× higher tensile strain) in 3D-printed specimens. Fourier-transformation infrared (FTIR) spectroscopy complemented by solid-state nuclear magnetic resonance (NMR) techniques enabled a more detailed study of the chemical structure of these materials as well. Tensile performance comparison with literature data on VO-based natural fiber-reinforced resins showed that this work brought bio-based resins one step closer to competing with petroleum-based resins. The prepared VO/nanocellulose resins are promising candidates for high-performance bio-based resins derived from completely renewable feedstocks.

Synthesis and application of sustainable vegetable oil-based polymers in 3D printing

“…These reinforcement materials include Macadamia nut shells, 148 hydroxyapatite, 149,150 walnut shell, 151 calcium silicate hydrate, 152 and cellulose crystals. 153–155 However, the 3D printing technique has been adapted based on the viscosity of the composite resin and the desired properties of the printed product. In one investigation, formulations containing epoxy linseed oil (ELO) and soybean oil (ESO), as well as different fillers such as walnut shell, tagua, and hemp powder, were examined.…”

A super-tough plant oil based elastomer for UV-light assisted 3D printed soft robotics and shape-memory

“…Our prior investigations have delved into various vegetable oil-based compositions, offering a comprehensive analysis of print resolution and the printability of resins employing the VP technique. 17,31 Incorporating photo-absorbers, coloring agents, or diverse llers can enhance printing precision. These additives improve the structural integrity and endow the prints with functional advantages, such as electroconductivity and luminescence.…”

“…13 On the other hand, plant oilbased resins drew a lot of attention due to their low cost, ease of processing, and potential for chemical functionalization. Nevertheless, the majority of current vegetable oil acrylatecontaining UV-curable resins reported in the literature oen display glassy polymer specichard and brittle behavior, [16][17][18] making them inappropriate for the requirements of so robotics. While there are alternative plant oil-based elastomeric formulations, most of them are incompatible with VP printing methods or have elongation values limited to around 60%.…”

Renewable Photopolymers: Transformation of Biomass Resources into Value-Added Products Under Light

“…The dispersion of methacrylated CNCs in methacrylate malate photocurable resins can lead to a significant increase in the dielectric constant and capacitance, demonstrating great promise in energy storage application . Addition of an ultralow concentration of 0.07 vol % nanocellulose fibrils and crystals in AESO-based resins yielded significant improvements in mechanical performance (4× higher toughness, 2.4× higher tensile strength, and 2× higher tensile strain) in 3D-printed specimens . Another method for methacrylation was reported by the reaction between cellulose acetate butyrate and the monofunctional adduct of isophorone diisocyanate and HEMA .…”

“…101 Addition of an ultralow concentration of 0.07 vol % nanocellulose fibrils and crystals in AESO-based resins yielded significant improvements in mechanical performance (4× higher toughness, 2.4× higher tensile strength, and 2× higher tensile strain) in 3D-printed specimens. 102 Another method for methacrylation was reported by the reaction between cellulose acetate butyrate and the monofunctional adduct of isophorone diisocyanate and HEMA. 103 The product was mixed with diluents and utilized for continuous liquid interface production (CLIP) to print objects with tensile and flexural strengths reaching 44.67 and 64.53 MPa and excellent solvent resistance.…”