Macromolecular Materials and Engineering最新文献

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.

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.

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.

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.

This study presents an amphiphilic shape-memory hydrogel (SMH) based on poly(acrylic acid-co-n-hexadecyl acrylate) [P(AAc-co-C16A)] that integrates pH and temperature responsiveness within a single molecular network. The hydrophobic C16 side chains form reversible crystalline domains that act as physical cross-links, imparting thermal shape-memory and mechanical strength, while ionizable acrylic acid units provide pH-dependent swelling and charge regulation. An optimal composition containing 30 mol % C16A exhibited a balanced combination of mechanical robustness (E ≈ 15 MPa), a high shape-recovery ratio (>93 %), and a thermoresponsive transition near physiological temperature (37°C–39°C). Ibuprofen-loaded SMHs demonstrated strongly pH-dependent and thermally accelerated drug release, with enhanced release under mildly acidic conditions and further acceleration upon shape recovery. Cytocompatibility assays confirmed the hydrogels’ safety for normal fibroblasts, while selective cytotoxicity toward MDA-MB-231 breast cancer cells underscored their therapeutic potential. Overall, P(AAc-co-C16A) SMHs provide a molecularly tunable platform that couples shape-memory functionality with controlled, dual-stimulus drug delivery. Their combination of reversibility, biocompatibility, and mechanical resilience offers new opportunities for localized and on-demand release systems in cancer therapy and next-generation 4D-printed biomedical devices.

Poly(2-oxazoline)-imidazole (POZ-Im) polymers were synthesized by one-pot termination of 2-ethyl, 2-propyl-, and 2-phenyl-2-oxazoline homopolymers with imidazole and evaluated as thermal latent curing agents (TLCs) for one-component epoxy resins (OCERs). ¹H NMR, FTIR, and MALDI-TOF confirmed successful synthesis of polymers. The polymers were amorphous, exhibiting glass transition temperatures of 43°C (PEOZ-Im), 24°C (PPrOZ-Im), and 91°C (PPhOZ-Im) and showed thermal stability with onset degradation at 364°C–375°C. When incorporated into DGEBA at a fixed 5 phr Im-to-epoxy ratio, their miscibility and curing performance varied with side-chain chemistry. PPhOZ-Im was fully miscible, PPrOZ-Im was partially miscible, and PEOZ-Im formed fine dispersed domains. Dynamic DSC revealed left-limit temperatures of 91.75°C (PEOZ-Im), 94.22°C (PPhOZ-Im), and 103.28°C (PPrOZ-Im). Rheological analysis showed that PPrOZ-Im/DGEBA exhibited the longest gelation time, followed by PEOZ-Im/DGEBA and PPhOZ-Im/DGEBA. Shelf-life estimations based on viscosity doubling times and Arrhenius extrapolation indicated stability of 88 days (PPrOZ-Im/DGEBA), 34 days (PEOZ-Im/DGEBA), and 32 days (PPhOZ-Im/DGEBA) at −20°C. These results demonstrate that POZ-Im polymers provide tunable latency and curing behavior suitable for advanced composite applications.

Mallotumide A (MA) is a novel cycloheptapeptide isolated from the roots of Mallotus spodocarpus Airy Shaw. It exerts anticancer activity by downregulating several lipogenic enzymes and cellular respiration, particularly in triple-negative breast cancer. However, MA has poor water solubility and is highly toxic to both cancer and normal cells, limiting its therapeutic applications. To address these drawbacks, MA was encapsulated within poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and coated with riboflavin (Rf)-modified chitosan (CR), creating (MA)PLGA/CR NPs. This study characterized the NPs and investigated their encapsulation efficiency of MA, cellular uptake, and anticancer activity in two breast cancer (MDA-MB-231 and MCF-7) and normal (MCF-10A) cell lines. The NPs were spherical with an average size of 300 ± 6.64 nm and a zeta potential of +11.96 mV. The PLGA/CR NPs exhibited enhanced cellular uptake in both cancer cells in a dose- and time-dependent manner, while reducing toxicity in normal cells. Furthermore, the (MA)PLGA/CR NPs inhibited the viability, migration, and invasion of MDA-MB-231 cells, thereby demonstrating their potential as a targeted anticancer delivery system.