Multiwalled Carbon Nanotube Reinforced Bio-Based Benzoxazine/Epoxy Composites with NIR-Laser Stimulated Shape Memory Effects

Abstract

Smart materials with light-actuated shape memory effects are developed from renewable resources in this work. Bio-based benzoxazine resin is prepared from vanillin, furfurylamine, and paraformaldehyde by utilizing the Mannich-like condensation. Vanillin-furfurylamine-containing benzoxazine resin (V-fa) is subsequently copolymerized with epoxidized castor oil (ECO). When the copolymer is reinforced with multiwalled carbon nanotubes (MWCNTs), the resulting composite exhibits shape memory effects. Molecular characteristics of V-fa resin, ECO, and V-fa/ECO copolymers are obtained from Fourier transform infrared (FT-IR) spectroscopy. Curing behavior of V-fa/ECO copolymers is investigated by differential scanning calorimetry. Dynamic mechanical properties of MWCNT reinforced V-fa/ECO composites are determined by dynamic mechanical analysis. Morphological details and distribution of MWCNTs within the copolymer matrix are characterized by transmission electron microscopy. Shape memory performances of MWCNT reinforced V-fa/ECO composites are studied by shape memory tests performed with a universal testing machine. After a significant deformation to a temporary shape, the composites can be recovered to the original shape by near-infrared (NIR) laser actuation. The shape recovery process can be stimulated at a specific site of the composite simply by focusing NIR laser to that site. The shape recovery time of the composites under NIR actuation is four times faster than the shape recovery process under conventional thermal activation. Furthermore, the composites possess good shape fixity and good shape recovery under NIR actuation.

Metal Complexes of the Porphyrin-Functionalized Polybenzoxazine

“…Because strong inter- and intramolecular hydrogen bonds exist after the thermal ROP of BZ units, formed among the tertiary amino and phenolic units in the Mannich bridges, the polymerization products can possess low dielectric constants, low surface free energies, low degrees of shrinkage, and high thermal stabilities and char yields [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Flexibility in molecular design—by varying the structures of the phenolic and amino groups—has allowed the introduction of a range of functional groups (e.g., allyl, propargyl, crown ether) [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] or inorganic nanomaterials (such as polyhedral oligomeric silsesquioxane, graphene, carbon nanotube) [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ] into the BZ matrix.…”

Effects of graphene nanoplatelets on bio-based shape memory polymers from benzoxazine/epoxy copolymers actuated by near-infrared light

“…The first tan d peak (lower temperature region) was attributed to the rich phased ECO in the V-fa/ ECO copolymers, while the other tan d peak (higher temperature region) was the T g of the rich phased V-fa in the V-fa/ECO copolymers. The rich phased ECO acted as a reversible switching unit and the rich phased V-fa in the V-fa/ECO copolymers was permanent netpoint (Hombunma et al, 2020;Prasomsin et al, 2019). The T g obtained from the maximum of the tan d peak of the unfilled V-fa/ECO copolymers was 84°C, while the addition of GNPs tended to increase the T g of the copolymers because of restriction in molecular chain mobility, reducing the free volume in the copolymer matrix (Lashgari et al, 2016).…”

“…However, the shape fixity and shape recovery values slightly decreased after repeated fold-deploy in cycle 4. During the repeated fold-deploy of V-fa/ECO copolymers, the crosslinking of V-fa/ECO copolymers could be increased due to the low curing temperature of the copolymers (Prasomsin et al, 2019). The higher crosslinking of copolymer chains might limit their mobility, resulting in the lower shape memory performance after some cycles of use.…”

“…For example, benzoxazine/epoxy copolymers can be prepared in the way that benzoxazine resin can act as a latent curing agent (Ishida et al, 1996). The shape memory properties of benzoxazine/epoxy copolymers have been studied and demonstrated (Prasomsin et al, 2019). Traditionally, the raw materials used for the synthesis of benzoxazine resin are obtained from petroleum resources.…”

“…Accordingly, the use of bio-based raw materials to prepare bio-based benzoxazine resin has become a research hotspot. Bio-based materials including vanillin, eugenol, cardanol, furfurylamine, stearylamine, and guaiacol have been used for the synthesis of benzoxazine resins (Prasomsin et al, 2019).…”