Macromolecular Materials and Engineering最新文献

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.

Layer multiplying co-extrusion (LMCE) is a versatile and scalable technology for manufacturing polymeric composites with micro- and nano-scale templated features. While previous studies have primarily focused on applications with neat polymers, incorporation of solid fillers into layered structures at high loading levels would enable new types of polymeric composites and templated precursors to dense solids. In this initial study, processing conditions and limitations of the LMCE process with respect to highly filled systems are explored using a model system of glass microsphere fillers in a polyolefin binder. Scanning electron microscopy of film cross-sections indicates that layering persists for viscosity-matched systems even as layer thicknesses approach the characteristic particle size of the fillers. However, when there is a significant viscosity mismatch between the filled and unfilled layers, an interfacial instability arises which disrupts the layer structure in high shear regions. These results demonstrate the feasibility of LMCE for highly filled systems and point to processing guidelines for the stable production of filled microlayer structures.

Lanthanide-doped upconversion nanoparticles (UCNPs) exhibit unique luminescence properties, making them promising for applications in displays, sensors, security labels, and solar cells. Embedding UCNPs in polymer films can enhance their functionality; however, the properties of the polymer matrix significantly influence the dispersion and loading capacity of UCNPs, ultimately affecting optical performance. In this study, we investigate the incorporation of UCNPs into two distinct polymer matrices, poly(3-hexylthiophene) (P3HT) and poly(methyl methacrylate) (PMMA), via spin coating at different speeds. Our findings demonstrate that UCNP dispersion and monodispersity are governed by polymer polarity, viscosity, and UCNP concentration in the suspension. To enhance UCNP loading, multiple spin coatings were explored. In UCNP−P3HT films, the volume fraction of UCNPs increased from 26.1% to 51.4% after three consecutive spin coatings, while maintaining a uniform distribution. In contrast, the lower miscibility and higher viscosity of PMMA restricted UCNP loading to 12.0% before significant clustering occurred. Although multiple spin coatings increased the total UCNP content in PMMA films, the volume fraction decreased to 8.0% due to film thickening. This comparative analysis highlights the critical role of polymer matrix properties in UCNP embedding and provides valuable insights for optimizing UCNP−polymer composites for advanced optical applications.

This study introduces a multilayered biofunctional tumor dressing designed for localized treatment after tumor resection. The system incorporates three therapeutic agents: doxorubicin (DOX) for anticancer action, amoxicillin (AMOX) for antibacterial protection, and ibuprofen (IBU) for anti-inflammatory support. These drugs were loaded into polyvinyl alcohol (PVA) and polycaprolactone (PCL) matrices via a hybrid method combining 3D printing, electrospinning, and electrospraying. FTIR, SEM, and optical microscopy confirmed structural integrity. in vitro release at pH 7.4 and 37°C showed rapid DOX and AMOX release within 240 min, while IBU exhibited sustained release over 120 h. Mathematical modeling (zero-order, first-order, Higuchi, and Korsmeyer–Peppas) indicated diffusion-driven, matrix-controlled kinetics. Encapsulation efficiencies exceeded 98%, affirming fabrication reliability. Antibacterial tests showed stronger activity against Staphylococcus aureus than Escherichia coli. Cytotoxicity results demonstrated selective toxicity, with 42.86% viability in CCD1072-Sk fibroblasts and lower survival in MCF-7 (25.63%) and A549 (23.76%) cancer cells. This multifunctional dressing enables spatial and temporal control over drug release to effectively manage residual tumor cells, infection, and inflammation, offering a promising strategy for postoperative cancer therapy with minimized systemic side effects.

Additive Manufacturing (AM), particularly stereolithography (SLA), offers great flexibility for producing complex structures. However, the limited availability of photocurable and sustainable resins remains a major challenge. Therefore, the development of ‘greener’ alternatives is imperative to establish a sustainable cycle within the AM industry. To address this, we developed a novel terpene-based monomer, monoperillyl maleate (PeryMal), which is both degradable and cross-linkable, offering a greener alternative to traditional petroleum-based acrylic resins. The synthesis was carried out using the bio-derived solvent 2-methyltetrahydrofuran (2-MeTHF) to further enhance sustainability. PeryMal was blended with the water-soluble monomer ACMO at various ratios and successfully 3D printed. The ACMO-blend 60, with the highest PeryMal content, showed excellent printability, a glass transition temperature (Tg) of 25°C–30°C, and thermal stability up to 400°C. It also demonstrated full degradation in alkaline conditions (pH 9) within 24 h and partial degradation at pH 2 over 28 days. To further improve sustainability, PeryMal was also blended with bio-based isobornyl methacrylate (iBoMA). The resulting iBoMA-blend 60 also printed well (PS 5) and exhibited a higher Tg of 65°C–90°C. These results highlight the potential of PeryMal-based systems for creating sustainable, functional materials for SLA printing.

Reversible cross-linking of thermoplastic materials allows thermoplastic processing before and after cross-linking, while improving the mechanical and thermal properties after cross-linking during the use phase. Hence, reversible cross-linking can play an important role in establishing circularity by enabling mechanical recycling of a cross-linked material after de-linking. This exploratory study investigates 1-(5-(Aminoethyl)-2-nitrophenyl)ethanol as a photolabile cross-linker (PXL) for polyamide 6 (PA6). The PXL is melt-mixed with PA6 in two concentrations and processed into samples, which are investigated by Dynamic Mechanical Analysis (DMA) and Differential Scanning Calorimetry (DSC) before and after UV-exposure. The addition of the PXL increases the storage modulus from 1.585 MPa for neat PA6 to 2.550 MPa for PA6 with 3 wt.% PXL and 3.470 MPa for PA6 with 6 wt.% PXL, respectively. Exposure to UV radiation decreases the storage modulus with increasing exposure time. The crystallinity decreases from 33,32% for neat PA6 to 30,71% for PA6 with 3 wt.% PXL and to 29,71% for PA6 with 6 wt.% PXL When the samples with PXL are exposed to UV-radiation, an increase in the crystallinity is observed. The results of this exploratory study indicate that PA6 can be cross-linked with 1-(5-(Aminoethyl)-2-nitrophenyl)ethanol and that de-linking through UV-exposure is possible.

Polyurethane (PU) is one of the most commonly used plastics, typically synthesized from diisocyanates and polyols derived from non-renewable or unsustainable sources. This study proposes a synthesis route for polyurethanes that originates from bio-based polyols. The polyols were obtained through the metathesis depolymerization of butadiene rubber using fatty alcohol and Hoveyda-Grubbs second-generation catalyst (HG2), resulting in hydroxyl-terminated polybutadiene (HTPB). FT-IR and GPC analyses confirmed the successful synthesis of polyols, indicating molecular weights between 535 and 2200 g/mol. Three polyurethanes (PU1, PU2, and PU3) were synthesized using these bio-based polyols, while a fourth polyurethane (PU0) was produced with polyethylene glycol as a standard polyol for comparative property analysis. FT-IR analysis identified the characteristic signals and functional groups of the polyurethanes. TGA and DSC evaluated the thermal properties of the polyurethanes, revealing decomposition temperatures (T_max) between 300 and 450°C. PU materials were practically amorphous, as shown by XRD. SEM micrographs illustrated the varying morphologies of the polyurethanes, providing deeper insights into their properties. This synthesis process is vital for recycling rubber waste, transforming it into hydroxy-terminated compounds, HTPB, or polyols using vegetable oils and renewable resources. When integrated into PU synthesis, these compounds promote the development of sustainable materials and significantly contribute to environmental conservation and the sustainable production of adhesives, paints, and coatings, among other valuable products.

Recently, additive manufacturing has become increasingly available for personalized biomedical applications; still, the material science is one of the primary contentions. Polyamide (PA) has several beneficial characteristics, including mechanical strength, biocompatibility, and flexibility, making it an excellent candidate for biomedical applications. Based on that, this systematic review aims to summarize and critically evaluate the state-of-the-art knowledge of 3D printed polyamide and its composites with respect to material sciences and biomedical applications. Medline, Embase, Scopus, Cochrane, and Web of Science databases were searched for biomedical applications of additively manufactured polyamide. Overall, 1889 papers were screened, and 114 articles were finally selected to be included in this review. This work consists of three sections aiming at a comprehensive biomedical evaluation of the material, starting with mechanical characteristics of polyamide and its composites, considering distinct 3D printing technologies, followed by tissue engineering, drug delivery, and personalized biomedical solutions. Finally, biomedical educational and patient information applications are discussed with insights into future medical applications. Based on the results, polyamide and its composites are suggested to be excellent candidates for biomedical applications. However, this systematic approach highlighted the distinct need for thorough mechanical analysis and clinical trials based on universal standards for future biomedical applications.

Electrospinning and additive manufacturing (AM) are key technologies for fabricating bone tissue engineering scaffolds, each with unique strengths and limitations. Electrospinning produces nanoscale fibers that promote cell attachment and affinity on 2D surfaces but offer limited mechanical strength. In contrast, AM creates 3D scaffolds with enhanced mechanical properties through precise control of topological structures, but the capability to stimulate and guide cell growth is limited compared to electrospun nanoscale fibers. Combining both methods holds potential for next-generation scaffold development with desirable mechanical and biological properties. This study investigates the fabrication of multi-scale and multi-material scaffolds by integrating extrusion-based AM and solution electrospinning. Polycaprolactone (PCL), a biocompatible and biodegradable polymer, served as the base material, while graphene nanosheets were incorporated as functional fillers to enhance mechanical, electrical, surface, and biological properties. Solution electrospinning was first optimized, and hybrid scaffolds were fabricated, with an image-based optimization method, obtaining 87% of the fibres well-aligned with the designed direction. Optimal scaffold composition (PCL nanofibers with 1 wt.% graphene + PCL microfibers with 3 wt.% graphene) was also identified based on 2D mesh characterization results (186% enhancement of the mechanical property and 23% enhancement of the cell proliferation result, compared with neat PCL). The findings demonstrate the potential of this hybrid fabrication approach for developing advanced polymer-carbon nanomaterial scaffolds for bone tissue regeneration applications.

The development of polymer-based Lab-on-a-Chip devices is increasingly benefiting from advanced prototyping techniques that provide exceptional precision and adaptability. This study introduces an innovative fabrication approach that integrates simulations, femtosecond laser processing, and experimental validation to optimize microfluidic channel design. The proposed method relies uniquely on scanning speed as the laser control parameter, a strategy not previously reported in the literature. This approach ensures reproducibility, rapid processing, and excellent precision, making it a highly efficient and scalable solution for Lab-on-a-Chip production. Specifically, we present the fabrication of a microfluidic device with a trapezoidal cross-section, which has demonstrated outstanding efficiency in its intended application. The device is fabricated using polymethylmethacrylate and exploits inertial effects in a spiral microchannel with asymmetric outlets to achieve size-based particle separation. The device successfully separates 20 µm and partially 6 µm particles, mimicking circulating tumor cells and red blood cells respectively, in agreement with the simulation predictions. This simulation-driven design approach highlights critical insights into the laser-based fabrication process, demonstrating it being an efficient method for producing functional devices. With its low-cost materials, customizable design, and strong potential for biological applications, this fabrication technique holds significant promise for commercialization and point-of-care diagnostics.