Macromolecular Materials and Engineering最新文献

In this study, we fabricated 3D-printed scaffolds based on gelatin (GEL), methylcellulose (MC), and varying concentrations of hexagonal boron nitride h-BN nanoplatelets. The GEL/MC/BN hydrogel inks were prepared with optimized rheological properties for extrusion-based 3D printing and chemically crosslinked using EDC/NHS. The printability, pore fidelity, and strut geometry of the scaffolds were characterized, revealing consistent architectures with adequate mechanical robustness. FTIR, swelling behavior, degradation, and contact angle measurements demonstrated successful h-BN nanoplatelet incorporation and favorable hydrogel network stability. Mechanical tests indicated that h-BN nanoplatelet addition preserved the compressive modulus and flexibility. In vitro assays using MC3T3-E1 pre-osteoblasts demonstrated that the scaffolds supported % cell viability and proliferation. Remarkably, h-BN nanoplatelet incorporation triggered calcium phosphate formation both in SBF and Alizarin Red staining studies. FTIR and SEM-EDS analysis demonstrated that apatite formation was triggered with h-BN. Apatite formation is possibly due to the negative charge of h-BN nanoplatelets in the medium which triggered calcium phosphate deposition. Antibacterial testing against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus revealed a significant, species-specific bactericidal effect at ≥5% BN content, especially against Gram-negative strains. Overall, these findings indicate the potential of h-BN-incorporated GEL/MC scaffolds as a promising platform for infection-resistant, cytocompatible, and structurally stable bone grafts.

All cellulose composites (ACCs) containing a cotton-based reinforcement and a cellulose matrix are prepared either by the impregnation of the textile with a pre-formed cellulose solution in a solvent, i.e., a mixture of ionic liquid and dimethylsulfoxide (route 1), or by direct impregnation of the textiles with this solvent to form the matrix by the partial dissolution of the reinforcement fibers (route 2). The fabrication route 2, allowing the control of the dissolution process of the fibers with an adequate solvent, has the higher potential to lead to generation of materials with superior properties. Because too long dissolution time or too high processing temperature may lead to an advanced dissolution of the fibers with negative impact on the mechanical properties, both temperature and duration of the impregnation process are key control factors. Therefore, it is essential to perform experiments to determine their optimal values for maximizing the mechanical properties. The number of layers constituting the composites seems also to play an important role on their mechanical properties. The highest tensile strength of > 100 MPa is obtained for the 2-layer composites fabricated by impregnation with pure solvent under moderate conditions.

Melt-spun electrically conductive polymer fibers often face trade-offs among conductivity, mechanical strength, and processability. This study introduces a synergistic SWCNT/carbon black (CB) hybrid strategy where spherical CB particles appear to maintain connectivity within aligned SWCNT networks. PA6 composites with optimized ratios (PA6/1% SWCNT/3% CB) were systematically characterized for electrical, rheological, thermal, and processing behavior. Percolation thresholds (φc, SWCNT ≈ 0.1–0.25 wt.%, φc, CB ≈ 2–2.5 wt.%) confirmed the superior efficiency of SWCNTs in network formation. The hybrid system maintained resistivity of ∼10²–10⁴ Ω·cm despite drawing (DDR 2–4), while single-filler SWCNT systems failed (>10⁹ Ω·cm). Complex viscosity (∼1400 Pa·s at 270°C) remained within processable ranges despite elevated values, exhibiting stable shear-thinning behavior. Mechanical properties showed tenacity of 4–6 cN/dtex with 100%–150% elongation. These structure-property relationships demonstrate the potential of hybrid nanofiller systems for producing conductive filaments suitable for smart textile applications, positioning hybrid SWCNT/CB systems as promising candidates for scalable smart textile manufacturing.

This study elucidates the mechanism by which alkali treatment enhances the transparency of delignified wood, with a focus on the cellulose microfibril skeleton. Following delignification, the resulting material remains translucent due to light scattering from preserved lumens. Subsequent potassium hydroxide (KOH) treatment further removes hemicellulose and exchanges carboxyl-group counterions, which collectively soften the cell walls. This process allows the cellulose microfibril skeleton to undergo greater densification during drying, thereby reducing light scattering and yielding a highly transparent material without the need for polymer impregnation. We discovered that the inherent anisotropic structure of the wood's skeleton causes differential swelling between tangential and radial sections. The tangential sections, with their lower swelling ratio, undergo a more complete collapse of cell lumens, leading to higher density and superior transparency compared to the radial sections. This optical anisotropy, a direct consequence of the cellulose microfibril arrangement, was also evident in transparent wood-polymer composites. These findings highlight the fundamental role of the wood's underlying structure in determining its optical properties.

Novel biobased polymers based on lignin building blocks are synthesized and systematically characterized. The three prominent aromatic aldehydes that can be obtained from oxidative degradation of lignin, namely p-hydroxybenzaldehyde (H), vanillin (V), and syringaldehyde (S), are chemically modified into radically polymerizable styrenic monomers presenting either a methoxy or butoxy (-OBu) group at the para-position. The transformation of these molecules is accomplished and optimized individually on each compound. Subsequently, polymers are successfully prepared by free radical polymerization in homogeneous conditions (in solution using ethyl lactate as green solvent) and in heterogeneous conditions (in aqueous emulsion using a biosourced surfactant). Novel polymeric materials with high thermal stability and a glass transition temperature (Tg) tunable between 40°C and 110°C are obtained, depending on the monomer used.

To address the issue of safety operation being affected by surface icing on wind turbine blades in extremely cold environments, this paper employs a spraying technique to prepare a de-icing coating. This coating utilizes a PDMS base material (0.1 g) + curing agent (0.01 g) and PVDF (0.5 g) as the organic bonding framework, doped with functional particles including GPE (0.65 mg), MWCNTs (25 mg), and modified SiO2 (0.25 g), ultimately enabling the conversion of light and electrical energy into thermal energy. This coating exhibits excellent superhydrophobic properties, with a contact angle of approximately 167.0° and a sliding angle of about 4.0°. Under conditions of photothermal heating and electrothermal heating, the surface temperature of the coating can rapidly rise to high levels of approximately 68.0°C and 48.5°C within 200 and 150 s, respectively. The water droplet freezing experiments and de-icing experiments demonstrate that the coating can significantly delay the freezing time of liquid droplets, reduce the adhesion strength of ice, and exhibit excellent de-icing capabilities under the action of light and electrical current. Additionally, various durability tests, including acid-alkali immersion and friction-wear tests, are conducted on the coating to prove its outstanding stability and durability.

Polymer mats are prepared by electrospinning and coated with a single-walled carbon nanotube dispersion by simultaneous electrospraying, creating a conductive nanotube network on and between fibres. The resulting mats act as p-type thermoelectric materials due to the properties of the nanotubes and also serve as highly sensitive acetone vapour sensors that exhibit pronounced resistance changes when exposed to vapour. More details can be found in the Research Article by Beate Krause and co-workers (DOI: 10.1002/mame.202500358).

Poly(trimethylene terephthalate) (PTT) is a widely used engineering polyester, but its petroleum-derived monomers conflict with current efforts to reduce reliance on fossil feedstocks. Poly(trimethylene 2,5-furandicarboxylate) (PTF), a fully bio-based analogue with properties comparable to PTT, is a promising alternative, yet the impact of chemical modifications such as copolymerization remains poorly explored. This work combines mathematical modeling with experimental characterization to predict and validate key thermal and structural properties of bio-based polyesters and copolyesters. This study underlined the successful synthesis of two series of bio-based copolymers, i.e. poly(trimethylene terephthalate-co-trimethylene glutarate) PTT-co-PTG and poly(trimethylene 2,5-furandicarboxylate-co-trimethylene glutarate) (PTF-co-PTG) via melt polycondensation. The chemical structure and composition of the copolymers were confirmed with the use of ¹H NMR spectroscopy. Limiting viscosity numbers (LVNs) ranging from 0.643 to 0.759 dL/g were obtained, indicating that the desired values were achieved. The influence of the incorporation of PTG units on thermal properties and morphology was investigated using differential scanning calorimetry (DSC). There were no significant differences in thermal stability and activation energy between the homopolymer and the corresponding copolymers.

The methacrylation of Beech organosolv Lignin with methacrylic anhydride (MA) at 65°C under [4- (dimethylamino) pyridine] (DMAP) base catalysis is monitored by the FTIR OH-stretch at 3340cm⁻¹ and the C═C vibrations associated with the methacrylate group at 780, 810, 945, and 1637 cm⁻¹. Methacrylation extent increases with the MA: lignin OH molar ratio, the DMAP: MA wt%, and their interactions. Monitoring these vibrations over 48 h suggests side reactions, liberating new OH functionalities and, in turn, new grafting sites. Under these conditions, zero- and second-order kinetics fit the kinetics of lignin methacrylation equally well. Lignin methacrylate derivatives cure readily under UV light, and both the cure rate and full cure extent increase with increasing methacrylate conversion of lignin OH. The Sestak-Berggren autocatalytic kinetic model successfully describes UV-photocure, whereby the product autocatalytic (m) and reactant's exhaustion retardation (n) effects decrease with increasing methacrylation extent, from ca. 0.34 to 0.28 and from ca. 1.05 to 0.67, respectively. Lignin methacrylation can thus be tuned to adjust rheological and photocuring properties of methacrylate lignins for UV light induced processing, such as 3D printing.