Advances in Polymer Technology最新文献

This study investigates the effects of different extraction methods—water retting and alkali treatments using 5% and 10% NaOH—on the properties of Carica papaya fibers (CPFs) for sustainable composite applications. Physical, chemical, thermal, and mechanical properties of the fibers were analyzed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and tensile testing. Results showed that alkaline treatment enhanced fiber purity, crystallinity, and thermal stability, with 5% NaOH offering the best compromise between strength and flexibility. Crystallinity index (CI) reached 64.06%, and tensile strength improved significantly (276.98 MPa for CPF5 compared to 116.88 MPa for untreated fibers). Thermal degradation onset increased by 13.5°C compared to retted fibers. Analysis of variance (ANOVA) and Tukey HSD tests confirmed statistically significant improvements. Although no composites were fabricated, the thermal and mechanical properties of treated CPF suggest compatibility with thermoplastic matrices such as polypropylene and PLA. These findings demonstrate that Carica papaya (CP) pseudostem, an agricultural residue, can be a promising reinforcement source for biodegradable composites. Further investigation is needed to optimize fiber–matrix interactions and long-term durability under environmental stress.

The increasing need for environmentally friendly substitutes for petroleum-based polymers has positioned plant-based biopolymers as potential candidates for additive manufacturing, especially in the context of fused deposition modeling (FDM). Though plant-based biopolymers have limited thermal stability, poor mechanical properties, and variable printability, limiting their industrial use. This review seeks to overcome such limitations by examining the intersection of plant biotechnology and polymer engineering, with a particular focus on the optimization of biopolymer performance through genetic engineering, recombinant DNA (rDNA) technologies, and new processing technologies. A multicriteria decision-making (MCDM) approach, integrated with machine learning (ML) algorithms, is suggested to enable optimal material selection based on printability, biodegradability, and mechanical properties. The research consolidates knowledge from recent developments in genetic modification, enzymatic polymerization, and artificial intelligence (AI)–based computational modeling to demonstrate improved polymer characteristics, such as improved tensile strength, improved interlayer adhesion, and improved thermal resistance. The main findings highlight the revolutionary role of AI-aided design loops, digital twins, and biofabrication in the achievement of scalable and high-performance biopolymers. Future research directions focus on integrating synthetic biology, autonomous laboratories, and closed-loop recycling systems toward achieving eco-efficient and next-generation additive manufacturing platforms.

Bone diseases and consequent defects present a significant challenge in the orthopedics. Synthetic scaffolds mimic bone porose structures and can be substituted in bone defects. In this study, we designed and evaluated four scaffold models with different architectures (regular Voronoi (Rv), irregular Voronoi (Iv), Star (S), and Vintiles (V) structures). Additionally, the scaffolds were designed with four different porosities (50%, 60%, 70%, and 80%), and 16 scaffold models were designed and manufactured using the three-dimensional (3D) printing (3DP) method. The models were fabricated using two photosensitive resins (50% PLA-Pro resin and 50% P-CROWN [zirconia and ceramic]). Thus, the models’ mechanical properties were tested using compression tests. The results showed porosity plays an essential role in scaffold mechanical behavior. Moreover, the architecture was effective in the mechanical performance of the models. The elastic modulus of the models was 4–30 MPa, which is close to trabecular bone mechanical properties. The S-50 model showed a maximum stress of 17.75 MPa, which was 20 times higher than the S-80 model. Similar results were visible in other groups of scaffolds. In all four groups, 50% and 80% porosity scaffolds showed the highest and lowest mechanical strength, respectively. The results of this study showed that the Voronoi structure mimics bone morphology with a stochastic porosity and demonstrated a mechanical property similar to the scaffold with regular structures, which confirms its compatibility with bone tissue engineering. The outcomes of this study shed more light on scaffold design and fabrication for bone defects.

Epoxy resins have attracted considerable attention as versatile adhesives due to their structural stability, chemical inertness, and excellent resistance to oxidation. Their performance can be further enhanced through the incorporation of various additives designed for specific applications. In the present study, cellulose nanocrystals (CNCs), recognized for their high mechanical properties, were employed as a reinforcing agent. CNCs were incorporated into the epoxy resin at loading ratios of 0.0625%, 0.125%, 0.25%, and 0.5% to produce the nanocomposites. According to the obtained results, the lowest reductions observed in flexural and tensile strengths were 13% and 16%, respectively, while the highest increases in flexural and tensile modulus were 18% and 50%, respectively. Morphological analyses revealed that CNCs were not homogeneously distributed within the matrix, particularly at higher concentrations, where agglomeration likely contributed to the observed declines in mechanical performance. Thermogravimetric analysis (TGA) indicated a slight improvement in thermal stability at lower CNC loadings; however, thermal stability diminished at higher CNC concentrations. X-ray diffraction (XRD) analysis demonstrated that the neat epoxy exhibited the highest crystallinity index (CI, 62%), which progressively decreased with increasing CNC content, resulting in a more amorphous nanocomposite structure.

In this study, silica nanoparticles (SiNPs) with a flower-like wrinkled morphology were synthesized via a green method using rice husk (RH) as a sustainable silica precursor. The synthesis was performed without hazardous chemicals, highlighting the environmental compatibility and cost-effectiveness of the process. The structural and physicochemical properties of the nanoparticles were characterized using FTIR, XRD, scanning electron microscopy (SEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), UV–vis, thermogravimetric analysis (TGA), and Differential scanning calorimetry (DSC) analyses. FTIR confirmed the presence of Si─O─Si and Si─OH groups, while XRD revealed that the synthesized particles exhibit a crystalline quartz structure rather than the amorphous form commonly obtained from RH. SEM images showed petal-shaped particles with hierarchical morphology. Thermal analysis indicated high stability up to 800°C. These findings suggest that the developed green synthesis method can yield structurally defined SiNPs suitable for further application in catalysis, adsorption, and nanomaterials development.

This paper investigates the effect of poly(butylene adipate-co-terephthalate) (PBAT) on the mechanical and morphological properties of poly(lactic acid) (PLA) when the PLA is blended with 10%, 20%, and 30% PBAT and subjected to different draw ratios (DRs), followed by annealing at a fixed length. Results indicate that PBAT functions more as a strengthening agent than a toughening agent when the blend is drawn. Furthermore, both undrawn and most drawn samples exhibit higher crystallinity and lower cold crystallization temperatures (T_cc) (in proportion to PBAT ratio) compared to the unblended material, with crystallinity equilibrating at the highest measured draw ratio (DR) of 4, as determined by differential scanning calorimetry (DSC). The crystallinity of the annealed samples equilibrates at 45%–47%, demonstrating the effectiveness of heat treatment at the cold crystallization temperatures of the samples, as measured by DSC, which decreases with increasing DR. However, X-ray diffraction (XRD) results show that heat treatment at the original T_cc, specific to the undrawn PLA, results in higher crystal orientation.

Solvent-free polyurethane dispersions (PUDs), which disperse without the use of organic solvents, present a sustainable alternative for textile coating applications. The release of organic solvents into the environment has raised concerns because of their association with extreme weather events and their deleterious effects on human health. This study used an ecofriendly solvent-free process, along with polyester polyols derived from corn and other natural materials, to synthesize a series of PUDs with varying biomass contents (60, 50, 40, 30, and 0 wt.%). The successful synthesis of PUDs was verified using fourier transform infrared spectroscopy, and experiments were performed to determine their mechanical and thermal properties, nanoparticle characteristics, zeta potential, physical stability, and textile coating applications. The results of this study demonstrate the potential of the synthesized PUDs for enhancing the performance of textiles.

This study investigates the machining behavior of a sisal/bamboo fiber reinforced polyester matrix hybrid composite (10%/20%/70% weight ratio, unidirectional 0° orientation) through drilling and milling operations. Taguchi methods and Gray Relational Analysis (GRA) were employed to optimize machining parameters (spindle speed, feed rate, tool diameter, and depth of cut) while considering delamination, surface roughness (R_a), and material removal rate (MRR). ANOVA (analysis of variance) was utilized to analyze the influence of the parameters. Drilling results showed that spindle speed influenced entry delamination, while tool diameter significantly impacted exit delamination. Optimal drilling parameters (A₁B₃C₃: 380 rpm, 0.25 mm/rev, 10 mm) minimized delamination (DFentry = 1.10, DFexit = 1.50) while maximizing MRR (19.63 mm³/min). In milling, feed rate was the dominant factor influencing both delamination and R_a. Higher feed rates led to increased delamination and R_a. Higher spindle speeds reduced R_a. The optimal milling parameters (S₃F₃d₂: 1180 rpm, 0.06 mm/rev, 3 mm) minimized delamination (1.41) and R_a (0.17) while maximizing MRR (2548.8 mm³/min). Although feed rate showed the largest influence on MRR, none of the factors were found to be statistically significant in influencing MRR based on ANOVA. This study provided valuable insights for optimizing machining parameters to enhance performance and reduce defects in processing the biocomposite.

Brewer’s spent grains (BSGs) are lignocellulosic sources that can be considered promising economic alternatives to wood as biofillers to produce wood–plastic composites (WPCs). Given the high protein content (25 wt.%) of BSGs, alkaline hydrolytic solid–liquid (S/L) extractions were carried out at different pHs, with the goal of extracting as much protein as possible without altering or compromising the quality of the lignocellulosic matrix. Biocomposites with 10–50 wt.% biofiller were produced by blending polybutylene succinate (PBS) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBH) with native BSG (BSG), BSG treated at pH 10.5 (BSG-S2_T2) and BSG treated at pH 12 (BSG-S2_T3). The injection-molded compounds were characterized in terms of structural, rheological, mechanical, morphological, and thermal properties to investigate the potential impact of different biofillers on the overall compatibility of the two different biopolymer matrices as an alternative to conventional wood flour-based WPCs. Fourier transform infrared (FT-IR) spectra, thermal (differential scanning calorimetry [DSC]), and morphological (scanning electron microscope [SEM]) analyses revealed only minor interactions. The melt flow rate (MFR) analyses showed the increased viscosity in PBS-based biocomposites when the filler concentration increased. In contrast, for PHBH-based composites, an increase in MFR values was obtained under the same test conditions, with a maximum peak of 97% for S2_T3 30 wt.% filler. From a mechanical point of view, the addition of reinforcing fibers led to a more significant increase in Young’s modulus (E) in PBS-based composites as the biofiller content increased, up to 98%, compared to pure PBS. On the contrary, in PHBH-based composites, the addition of fillers led to a significantly lower increase, with values between 14% and 20% compared to pure PHBH. The tensile strength (σ_B) and elongation at break (ε_B) decreased proportionally in the two biopolymer matrices as the percentage of natural filler increased, with properties similar to traditional WPCs. These results are consistent with the literature and support the application of PBS and PHBH biocomposites filled with BSG as an environmentally friendly alternative to conventional plastics.