Polymers最新文献

This paper describes an evaluation of the mechanical and biological properties of highly porous, biocompatible poly(lactic-co-glycolic acid) (PLGA) scaffolds produced using the antisolvent 3D printing technique under various forming conditions. The dependence of the scaffolds' microstructure, PLGA molecular weight distribution, and cell adhesion properties on temperature and injection nozzle diameter was evaluated. All samples consisted of fibers with different inner polymer distributions formed by specific radial, highly porous structures with a mean pore length of less than 50 μm and a diameter below 10 μm. The microstructure formed using a nozzle with a diameter of 160 μm showed a moderate correlation with printing temperature, while for the 330 μm nozzle, there was no significant difference in microstructures formed at different temperatures. Scaffolds produced at lower temperatures of 4 °C with a thin nozzle showed better compression load characteristics in terms of strength. In contrast, a larger nozzle allowed the production of a PLGA structure with improved elasticity. A 10-17% change in the molecular weight of PLGA was observed during printing, but no influence on biological properties was found. All types of PLGA scaffolds tested demonstrated good biocompatibility and promoted cell adhesion compared to the control.

The increasing complexity of polymer systems in both experimental and computational studies has led to an expanding interest in machine learning (ML) methods to aid in data analysis, material design, and predictive modeling. Among the various ML approaches, boosting methods, including AdaBoost, Gradient Boosting, XGBoost, CatBoost and LightGBM, have emerged as powerful tools for tackling high-dimensional and complex problems in polymer science. This paper provides an overview of the applications of boosting methods in polymer science, highlighting their contributions to areas such as structure-property relationships, polymer synthesis, performance prediction, and material characterization. By examining recent case studies on the applications of boosting techniques in polymer science, this review aims to highlight their potential for advancing the design, characterization, and optimization of polymer materials.

Among the naturally occurring polysaccharides, chitosan is the second-most abundant polysaccharide. It is obtained from chitin through a process known as deacetylation. It is biodegradable, biocompatible, and non-toxic, which made it suitable for various environmental applications. In the present review, the structure, properties, and characteristics of chitosan were discussed. In addition, the modified forms of chitosan (including cross-linked, nanoparticles, functionalized, and grafted forms of chitosan) were enumerated. The applications of these modified forms of chitosan in the adsorption of organic pollutants (such as antibiotics, dyes, pesticides, microplastics, polyaromatic hydrocarbons, parabens, and polychlorobiphenyls) are comprehensively reviewed. Furthermore, the mechanism of adsorption, adsorption isotherm (Langmuir and Freundlich), and the kinetic models are highlighted. Finally, the economic viability assessment and environmental impact of processing tons of shrimp shells into chitosan annually were discussed.

This study aimed to optimize the injection mold for oil production single-screw pump rubber stators. MOLDFLOW2023 analysis post-design determined the optimal gate position and gating system, and it also analyzed the impact of key parameters on quality. The optimization led to a significant improvement in product quality. The most influential factors were mold temperature, melt temperature, and injection time. The best settings were a mold temperature of 100 °C, a melt temperature of 70 °C, an injection time of 30 s, a holding time of 10 s, and a holding pressure of 60 MPa. This resulted in a 1.8-2.7% decrease in volume shrinkage and a 1.3-0.9% decrease in sink index, enhancing the quality of rubber stators and advancing injection molding technology.

The aim of this work was to determine the anisotropy of the electrophysical and mechanical properties of rubber reinforced with a hybrid filler CNTs&CB (carbon nanotubes and carbon black) as a function of CNT content and the technological parameters of the production process. A significant difference in electrical conductivity (σ) and dielectric permittivity (ε) in three perpendicular directions was found for CNT concentrations ranging from 0 to 0.007 in volume fraction. The highest values of σ and ε were observed in the calendering direction, with slightly lower values in the perpendicular direction. This effect was attributed to the orientation of polymer molecules and CNTs along the direction of movement during calendering, as well as the disruption of the cluster structure in the transverse direction. Although the calculated percolation threshold values of the investigated system differed slightly, a correlation was observed between the mechanical and electrophysical properties of CNTs&CB rubber. This correlation enables rubber products to be designed with optimal properties tailored to the desired direction.

Xyloglucan from Tamarindus indica seeds (TISs) is a polysaccharide widely used in the food, biomedical, and pharmaceutical sectors. Nevertheless, the challenge in future research for the food processing industry is to provide adequate knowledge regarding natural product extraction, chemical modifications, interactions, and potential applications according to sustainability issues. The goal of this work was to implement a sustainable method for xyloglucan extraction from TISs at a semi-industrial scale and carry out the characterization of this hydrocolloid, to compare the effect of the technique of decorticating of seeds on the chemical composition and physicochemical properties of xyloglucan. The TISs were decorticated using soaking (DS) and roasting (DR) methods, and, then, the xyloglucan was extracted applying a semi-industrial mechanical separation process. Subsequently, the extraction yield, chemical content, Fourier transform infrared analysis, color, morphology, molecular weight (MW), viscosity, texture, Z potential, particle size, and thermal properties were evaluated. Xyloglucan extraction from TISs at a semi-industrial scale was demonstrated for the first time. The xyloglucan yield by DR (44.04%) was significantly higher (p < 0.05) compared with DS (41.42%), while separation efficiency was similar in both methods (~97%). Significant differences (p < 0.05) in fat, ashes, crude fiber, calcium, total phenolic content, and antioxidant capacity in xyloglucan samples were observed by applying DS and DR. The method of decorticating promoted changes in the MW and particle size of xyloglucan samples, which were reflected in the viscosity, particle size, texture attributes, Z potential, and thermal properties of xyloglucan. These results show that the decorticating method is an important issue to be considered in the resultant chemical and physicochemical properties of xyloglucan extracted from tamarind seeds, for suitable applications of the xyloglucan in the food processing and pharmaceutical industries.

This work investigates the optimization of aniline content in polyaniline (PANI)/sago starch blends prepared via in situ oxidative polymerization under ultrasonic irradiation. Building upon our previous optimizations of pH and sonication time, this study focuses on the effect of aniline concentration (5-65 wt%) on electrical conductivity, morphological dispersion, and thermal stability. Various characterization techniques, including field emission scanning electron microscopy (FE-SEM), ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA), confirm that a well-connected, conductive network forms at about 35 wt% aniline. Electrical conductivity measurements reveal a pronounced rise from ~1.6 × 10^-8 to ~2.2 × 10^-3 S/cm between 5 wt% and 35 wt% aniline. Conductivity stabilizes above this threshold due to PANI agglomeration. Morphological assessments confirm a shift from smooth, uniform blends at low aniline to rougher, void-filled surfaces when aniline exceeds 50 wt%. TGA shows improved thermal stability with increasing aniline content. These findings highlight an optimum aniline loading of ~35 wt% to achieve synergy between conductivity and structural integrity in biopolymer-based PANI/sago starch composites, offering a pathway to sustainable, high-performance biopolymer-based conductors for applications in sensors, flexible electronics, and electromagnetic shielding.

Polydimethylsiloxane (PDMS) is known for its exceptional mechanical properties, chemical stability, and flexibility. Recent advancements have focused on developing functional PDMS composites by integrating various functional fillers, including polymers, ceramics, and metals, for advanced applications such as electronics, medical devices, and aerospace. Consequently, there is a growing need to investigate PDMS composites to achieve higher filler loadings offering enhanced mechanical performance. This study addresses this need by utilizing the high molecular weight (MW) PDMS resin we have developed, offering its high elongation capacity of up to >6500%. We incorporated boron (B), hollow glass microballoons (HGMs), and tungsten-coated hollow glass microballoons (WHGMs) into the developed high MW PDMS. The resulting composites demonstrated excellent elastic properties and significant compression resilience (35-80%) and elastic modulus (1.28-10.15 MPa) at high filler loadings (~60 vol.%). Specifically, B/PDMS composites achieved up to 67.6 vol.% of B, HGM/PDMS composites held up to 68.6 vol.% of HGM, and WHGM/PDMS composites incorporated up to 54.0 vol.% of WHGM. These findings highlight the potential of high MW PDMS for developing high-performance PDMS composites suitable for advanced applications such as aerospace, automotive, and medical devices.

Cassava peels are rich in polysaccharides but highly unexplored and underutilized, as they could be used to meet the increasing demand for clean-label foods. This study investigated the effect of temperature on the solubilization of cassava peel during hydrothermal treatment to determine the emulsifying ability of solubilized cassava peel (SCP). Subcritical water conditions were employed via hydrothermal (120-200 °C; 2 MPa) or autoclave (127 °C; 0.2 MPa) treatments to solubilize cassava peels. The composition of the SCPs was determined, and their emulsifying ability was assessed using interfacial tension and zeta potential measurements. Under the best treatment conditions (140 °C at 2 MPa [hydrothermal]; 127 °C at 0.2 MPa [autoclave]), SCPs reduced interfacial tension against soybean oil to 12.9 mN/m and 13.4 mN/m, respectively. A strengthened co-emulsifier system was developed by incorporating SCPs with Quillaja saponins (QS) or Tween 20 to enhance the performance. Dynamic interfacial tension and zeta potential measurements revealed synergistic interactions, showing a remarkable reduction in interfacial tension from 12.94 to 5.33 mN/m. This suggests that the SCP has a surfactant-like structure owing to its amphiphilic structure and hydrophobic chains (nonpolar region) attached to the -OH functional group (polar region). Combining a second surface-active compound or co-emulsifier results in an additive effect, reducing the interfacial tension. These findings provide novel insights into carbohydrate-saponin binding and elucidate the impact of peel composition, concentration, and hydrothermal treatment conditions on co-emulsifier system performance, which will assist in the development of emulsifiers, contributing to the advancement of clean-label food technologies, effectively replacing synthetic emulsifiers in food formulations, and offering both sustainability and functionality. A systematic investigation of processing conditions and co-emulsifier interactions provides a practical framework for developing high-performance natural emulsifiers from agricultural waste.

Glucose oxidase (GOX) is widely used in bakery applications to improve dough rheology and bread quality. However, its direct addition to formulations limits its functionality due to premature enzymatic activity. This study used electrospraying to encapsulate GOX using chia mucilage and sodium alginate as biopolymeric wall materials. Three drying methods-critical point drying (CPD), Lyophilization/freeze-drying (LC), and oven drying (OD)-were compared to evaluate their impact on encapsulation efficiency (EE), enzymatic activity retention, and microstructural integrity. Our findings reveal that CPD preserved the porous structure of the microcapsules, minimizing enzymatic leakage and yielding the highest EE (70%). In contrast, LC induced ice crystal formation, disrupting the polymer network and leading to a moderate EE (27.43%), whereas OD resulted in extensive capsule shrinkage, causing significant enzyme loss (57.1%). The release kinetics of GOX during mixing were best described by the Korsmeyer-Peppas model (R² = 0.999), indicating a non-Fickian diffusion mechanism influenced by polymer relaxation. These results demonstrate that drying technique selection plays a crucial role in encapsulated enzymes' stability and release behavior, providing new insights for optimizing enzyme delivery in bakery applications.