Macromolecular Materials and Engineering最新文献

3D printing, particularly bioprinting, has emerged as a transformative technology in tissue engineering and regenerative medicine, enabling the precise layer-by-layer fabrication of living tissues and complex biomaterials. Bioprinting has evolved through advances in printing methods such as fused deposition modeling (FDM), stereolithography (SLA), powder bed fusion (PBF), and jetting techniques, each offering distinct advantages for producing high-resolution, functional constructs. Central to bioprinting is the development of bioinks, primarily composed of natural and synthetic polymers and microbial polysaccharides, which must balance biocompatibility, mechanical integrity, and printability to support viable cell encapsulation and tissue formation. Despite remarkable progress, challenges persist, including optimizing bioink viscosity, cell viability, scaffold structural and functional complexities (vascularization, in vivo functionality), degradation rates, and scalability, as well as addressing regulatory and ethical concerns. Recent innovations, such as cryogenic printing, offer promising solutions by preserving cell viability and enhancing structural fidelity under ultra-low temperatures. While 3D printing holds immense potential to revolutionize personalized medicine, organ fabrication, and sustainable manufacturing, current technological, biological, and economic constraints temper expectations. Continued interdisciplinary research, material innovation, and refinement of printing technologies are essential to translate 3D bioprinting from experimental platforms to clinical and commercial realities, fulfilling its promise as a cornerstone of next-generation regenerative therapies and advanced manufacturing.

Material Extrusion Additive Manufacturing (MEAM) offers the ability to manufacture complex geometries through layer-by-layer deposition. MEAM involves fast heating and cooling of polymers, processes that involve thermal expansion and contraction of materials that may undergo phase transitions. These phenomena may lead to warpage: distortion of the printed parts or deviation from the intended geometry, which significantly compromises the dimensional accuracy and functionality of parts. Mitigation or even cancelling warpage has become one of the roadblocks toward further widespread application of MEAM technology, a target that requires a thorough understanding of the phenomenon. To contribute to this goal, this review presents and discusses the current knowledge of warpage in MEAM, starting with a general presentation of the technology and its intrinsic features, followed by details of the fundamental mechanisms of warpage, highlighting the crucial interaction between processing parameters, material characteristics, and part geometry. A thorough analysis of the experimental methodologies used to quantify warpage is presented, alongside a comparative exploration of warpage behavior in amorphous and semicrystalline polymers. The state-of-the-art of current modeling approaches aimed at predicting the warpage phenomenon is also presented and discussed, with a focus on the capability to effectively consider the complex thermo–mechanical history specific to MEAM.

Poly(aryl piperidinium)s containing both alkaline stable ether-free aromatic polymer backbone and heterocyclic quaternary ammonium groups are currently considered as one of the best candidates for the development of anion-exchange membranes. The branching modification strategy allows accelerating the polymerization process and receiving the polymers with high molecular weight and enhanced characteristics. So far, the application of asymmetric branching agents is very limited. In this study, 4-biphenylyl trifluoromethyl ketone (BTK) was used as AB₂-type structuring monomer in superacid-catalyzed Friedel-Crafts polyhydroxyalkylation together with p-terphenyl which is B₂-type monomer, and N-methyl-4-piperidone which is A₂-type monomer. Polymers with different degrees of branching (1.5 and 3 equivalents of BTK) are synthesized. The presence of unreacted terphenyl, revealed by ¹H NMR and wide-angle X-ray diffraction, is highlighted, and measures are proposed to prevent its occurrence. On the basis of neutral polymers (NB-PTP-1.5 and NB-PTP-3), their quaternized counterparts (QB-PTP-1.5 and QB-PTP-3) with excellent film-forming properties are obtained. Static light scattering measurements show that the values of molecular weight of different polymers are close, whereas particle size is bigger for a more branched polymer (according to dynamic light scattering analysis). Thermooxidative resistance of quaternized branched polymers is higher than that of linear polymers. Alkaline stability of polymers is confirmed by ¹H NMR.

In this study, we examined the effect of matrix viscosity on the properties of thermoplastic dynamic vulcanizates (TDV) produced using devulcanized ground tire rubber (dGTR) and polypropylene (PP). Polypropylenes with substantially different MFI were used to demonstrate the effect of viscosity on the properties of the resulting TDV. We examined the temperature dependence of the viscosity ratio of the components during dynamic vulcanization and found that if the viscosity of PP is closer to that of the dGTR blend, more time is allowed for the crosslinked rubber particles to disperse. We examined the TDVs thoroughly, performing tensile, acoustic emission, falling weight tests, morphological, and rheological analysis. We found a clear trend between scorch viscosity ratio and the main mechanical properties: all properties improved with increasing scorch viscosity ratio. We also found a significant decrease in rubber grain size distribution in connection with the increasing matrix viscosity, leading to improved toughness.

Polymer electrolyte-based lithium-ion batteries have garnered a lot of interest because of their potential to improve flexibility and safety. However, the economic and environmental sustainability of these electrolytes remains a critical factor in material selection. To address these concerns, polymer electrolytes derived from natural materials such as soybean oil have been explored for their affordability, abundance, environmental compatibility, and the presence of electron-donating functional groups. Additionally, interfacial instability between the electrolyte and electrodes is one of the major challenges limiting the performance of lithium-ion batteries. So, epoxidized soybean oil (ESO), as a bio-based polymer, provides good film-forming ability, mechanical flexibility, and compatibility with lithium salts, characteristics that are suitable for application in polymer electrolytes. In this work, crosslinked gel polymer electrolytes are prepared using ESO and bisphenol A diglycidyl ether (DGBEA), with citric acid serving as the crosslinking agent. The resulting polymer electrolytes exhibited a wide electrochemical stability window (up to 4.2 V), ionic conductivity in the range of 10⁻⁴ S cm⁻¹, and a cation transference number between 0.47 and 0.76, demonstrating its potential for improving the electrochemical performance and stability of lithium-ion batteries.

MXenes are gaining popularity in biomedicine, energy storage, electronics, and environmental applications. When combined with electrospun polymers, their simple and large-scale manufacturing potential makes them ideal for obtaining multifunctional, photothermally active hybrid nanofibers. Here, a combination of biodegradable and biocompatible polymers, poly(L-lactide-co-ε-caprolactone) (PLCL) and polyethylene glycol (PEG), was used to fabricate nanofibers loaded with MXenes. Various weight ratios of MXene were incorporated into nanofibers, and the photothermal response of the resulting hybrid materials was studied using a low-power NIR-LED light source. Additionally, physicochemical properties of the nanofibers were studied to identify their fundamental properties, such as morphology, thermal, and surface characteristics. The incorporation of MXene enabled the nanofibers to function as highly efficient photothermal receptive materials. A direct correlation between photothermal activity and MXene concentration was observed. Significant photothermal activity, with a temperature difference of up to 20°C in heating performance, was demonstrated for nanofibers containing 10% of MXenes. The photothermal stability, demonstrated through multiple irradiation cycles, makes it an attractive, low-cost, and low-energy platform for biomedical purposes such as photothermal therapy.

Photoresponsive polymers have emerged as a dynamic class of materials exhibiting a response to light. On the other hand, amphiphilic polymers are materials possessing both hydrophobic and hydrophilic sides in their macromolecular structure. The particularity of amphiphilic polymers is that they can simultaneously interact with hydrophobic and hydrophilic environments, leading to self-assembly. The combination of these intriguing photosensitive and amphiphilic properties has spurred the development of amphiphilic photoresponsive polymers with adaptable features. Exposure to light triggers changes in the polymers’ properties, which can be exploited to influence the formation and stability of diverse nanoscale structures such as core–shell micelles, worm-like micellar assemblies, vesicles, and other complex macromolecular architectures. This precise control over polymer behavior has propelled these materials to the forefront of research and innovation. This review sheds light and classifies the main photosensitive chemical groups used to design such photoresponsive polymers. Furthermore, a concise overview and a discussion about the synthesis pathways of photoresponsive polymers, with or without amphiphilic behavior, are presented, followed by a projection of potential opportunities raised by these polymers to improve controlled agrochemicals release area.

Microgels combine the strengths of hydrogels and microparticles. The multiple advantages of microgels, including control of drug release, excellent loading efficiency, high stability, and biocompatibility, make them an ideal vehicle for biotherapeutics. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan which is used in many clinical applications, including formulation. Batch synthesis of cross-linked HA microgels has been reported, but frequently leads to large polydisperse particles. In this study, we investigated the synthesis of divinyl sulfone cross-linked HA microgels using a coaxial flow reactor to enable tuning of particle properties and continuous manufacture. The experimental parameters were optimized using Taguchi orthogonal arrays as a design of experiment (DoE) method. The DoE method allowed efficient exploration of reaction space, giving conditions which lead to hydrodynamic particle diameters from 230 to 1623 nm and polydispersity indices (PdIs) between 0.19 and 0.86. The DoE also allows extraction of effect sizes of the parameters on both particle size and PdI. It was found that all parameters included in the experiment design influenced the outcomes of the experiment, highlighting the advantages of taking this statistical approach to experiment design. From an initial DoE, a second orthogonal array was selected based on parameters that minimized size. This second array resulted in production of microgels with desirable properties for potential drug delivery applications (hydrodynamic diameter 261 nm, PdI 0.19) under the optimized conditions.

To address the high-efficiency energy dissipation requirements of flexible protective materials, this study developed cellulose nanocrystal (CNC)-reinforced waterborne polyurethane (WPU) nanocomposites through an interface hydrogen bond regulation strategy. Utilizing the strong interfacial interactions between WPU chains and surface hydroxyl groups of CNC, a CNC/WPU system with a homogeneous dispersion structure was fabricated by the solution casting method. Fourier transform infrared spectroscopy results confirmed the formation of a high-density hydrogen-bonded crosslinked network between CNC and WPU. Dynamic mechanical analysis revealed that CNC predominantly interacted with hard segments of WPU through hydrogen bonding. Split Hopkinson pressure bar tests demonstrated that the composite containing 0.5 wt.% CNC exhibited optimal dynamic impact performance: elastic modulus increased by 59.6% to 5.57 ± 0.46 GPa, energy absorption improved 29.9% to 165.2 ± 6.7 MJ·m⁻³, and maximum engineering stress grew by 36.2% to 545.5 ± 17.5 MPa. This enhancement originated from the well-dispersed CNC and robust hydrogen-bonded networks in CNC/WPU nanocomposites, which forced molecular chain orientation during dynamic impact and induced remarkable strain-hardening behavior.