Advances in Polymer Technology最新文献

With the increasing incidence of bird damage affecting the reliability of transmission lines, addressing bird pest control has become an important task for the operation and maintenance of transmission lines. A viable solution involves the application of spray-coated polyurea elastomer composite materials to insulate exposed conductive points and weakly insulated connection parts of transmission line towers. To improve the comprehensive performance of polyurea elastomers, in this study, a polyurea curing system was modified by incorporating aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), and (boron nitride) BN nanoparticles. An orthogonal experiment was designed to investigate the influence of different fillers on the comprehensive performance of polyurea elastomers. These nanoparticles partially filled the defects inherent in the polyurea and BN microparticles, improving the alternating current (AC) breakdown strength of these elastomers. Compared with filler-free polyurea elastomers, optimal performance of the polyurea elastomers was achieved when using 5 wt% Al₂O₃, 0.4 wt% SiO₂, and 5 wt% BN, resulting in a 15.75% increase in the AC breakdown strength and a 10.00% enhancement in the thermal conductivity.

Polymethyl methacrylate (PMMA) has garnered significant attention in the field of dentistry due to its wide applications. This paper proposes the incorporation of the nystatin coated copper oxide (CuO) particles having desirable conductivity and antifungal properties, as a filler in the PMMA denture to address their low thermal conductivity, low impact strength, low fatigue resistance, and microbial adhesion. The prepared nystatin coated CuO particles were characterized with several analytical techniques. The nystatin coated CuO particles were mixed in different ratios (0%, 1%, 2%, and 4%) in PMMA corresponding to groups C, E1, E2, and E3, respectively. The prepared samples of composite PMMA with nystatin coated CuO were evaluated to determine their transverse strength, impact strength, Vickers hardness (HV), and thermal conductivity. Furthermore, antifungal properties of CuO particles, nystatin coated CuO particles, and their acrylic composites were evaluated against Candida albicans. Scanning electron microscopy (SEM) analysis confirmed the particles’ spherical and irregular shapes. The particle sizes range from nano to micron level. Fourier-transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX) analysis confirmed the coating of nystatin on CuO. X-ray diffraction (XRD) analysis showed the diffraction patterns and planes of CuO monoclinic shape structure. The composite prepared to have higher values of HV (19.53 ± 0.65, 20.16 ± 0.37, and 21.11 ± 0.75, respectively) as compared to the control. The impact strength values were measured high at 14.12 ± 5.55 kJ/m² for 2% containing nystatin coated CuO acrylic resins compared to control and other groups. The conductivity increased linearly with the addition of CuO particles. The addition of CuO particles causes a reduction in flexural strength as compared to the control group. As the concentration of nystatin coated CuO (1%, 2%, and 4%) in acrylic samples increased, the antifungal properties were improved. Thus, the incorporation of optimized concentrations of nystatin coated CuO particles in acrylic resin resulted in the improved mechanical, thermal, and antifungal properties.

Poly(N-isopropylacrylamide) (PNIPAM) is a versatile polymer known for its phase transition properties, exhibiting a lower critical solution temperature (LCST) of approximately 32°C. Below this temperature, PNIPAM is hydrophilic, while above it, the polymer becomes hydrophobic, making it ideal for thermosensitive drug delivery systems (DDSs). In tissue engineering, PNIPAM provides a biocompatible, nontoxic and stimuli-responsive surface for cell culture. Its nontoxic nature ensures safety in medical applications. PNIPAM enhances biosensing diagnostics through its affinity for biomolecules, improving accuracy. Widely used in hydrogels, smart textiles, soft robotics and various medical applications, PNIPAM adapts to environmental changes. Its straightforward synthesis allows for the creation of diverse copolymers and composites, applicable in selective reactions and conjugations with fluorescent tags or chemical modifications. PNIPAM’s versatility extends to pH-responsive alternatives, broadening its application spectrum. Practical examples include phase separation in water treatment and cleaning processes. This discussion explores PNIPAM’s biomedical and drug delivery applications, particularly in cancer treatment, photothermal therapy (PTT) and photodynamic therapy (PDT), gene delivery and medical imaging. Additionally, it highlights PNIPAM’s noncancerous applications, such as small interfering RNA (siRNA) targeting of oncogenes and detailed imaging of deep and tumour tissues.

To improve the deteriorated performance caused by CO₂ release during the curing process of traditional moisture-crosslinked polyurethane or polyurea and poor flame retardancy, this work realized an effective in situ crosslinking technique triggered by moisture for poly(urethane-urea) with intrinsic flame retardancy, through the incorporation of trimethoxysilane and phosphorus groups via a continuous two-stage process. Moisture-triggered crosslinking reaction of trimethoxysilane groups resulted in the establishment of a robust Si─O─Si network, as confirmed by Fourier transform infrared spectroscopy (FTIR) test. The structure transformation considerably enhanced the material’s strength, with the stress at break increasing from 1.0 to 3.2 MPa and modulus from 32.9 to 46.9 MPa. The flame retardant properties of PUUS1 (poly(urethane-urea) sample) were investigated through limiting oxygen index (LOI) and cone calorimeter (CCT) analysis, demonstrating satisfactory flame resistance, as evidenced by high LOI value of 29%, high char yield of 46.2%, and controlled smoke production. Combining thermogravimetric analysis-infrared spectrometry (TG-IR), X-ray photoelectron spectroscopy (XPS), and flame retardant performance, it is speculated that the generation of phosphorus-free radical scavengers in gas phase from diethyl bis(2-hydroxyethyl) aminomethyl phosphonate (DBHAP), coupled with the barrier effects of charred layer and distinctive Si─O─Si framework in condensed phase inhibited combustion and toxic gas emission. The results highlight the successful synthesis of a moisture-crosslinkable poly(urethane-urea) with intrinsic flame retardancy, promising for applications necessitating moisture-crosslinkable materials with superior flame resistance.

This article explores the multifaceted potential of pullulan-based films across food-packaging, pharmaceutical, biomedical, and cosmetic applications. In food-packaging, pullulan films serve as transparent, flexible, and high-oxygen barrier materials, effectively preserving the freshness and quality of a wide range of fruits and vegetables. Edible pullulan films extend the shelf life and enhance food safety, while active pullulan films inhibit microbial growth and oxidation, thus supports food preservation. In the pharmaceutical industry, pullulan-based films offer promising solutions for oral drug delivery, providing biodegradable and rapid disintegration for enhanced solubility and bioavailability of drugs. Additionally, due to their mechanical strength, biocompatibility, and antimicrobial properties, pullulan films demonstrate potential in wound dressings and tissue engineering applications. Furthermore, pullulan’s utility extends to the cosmetic industry, where it is used widely in various ingredients in skincare products, cosmetics, and personal care items. Its moisturizing, stabilizing, and film-forming properties make pullulan an attractive component in the industry. Future research directions should focus on cost-effective production methods and expanding industrial applications to further enhance their effectiveness and versatility. This in-depth analysis highlights the significant potential of pullulan-based films across multiple industries and underscores the importance of continued research and development efforts to fully unlock their diverse applications and benefits.

Chicken eggshells (ESs) consist of 96%–97% calcium carbonate, while about 3%–4% consists of organic substances, mainly in the form of protein-based membranes and occluded organic matter. Recently, ESs have been studied as a filler in polymer composite materials, which represents an innovative solution to address ES valorization. In this study, thermal and chemical treatments were investigated for membrane removal since the membrane may alter various properties when the ES fillers are added to the composite material. A nanoindentation method was used to measure changes in the ES mechanical properties. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier-transform infrared (FT-IR) spectroscopy were used to characterize the ES membrane removal through chemical treatment. The results showed that even at a heating temperature of 100°C, the ES mechanical properties were negatively affected, while a low concentration of bleach solution (25% bleach solution and 10 min of holding time) was able to remove the membrane without reducing the ES mechanical properties. The chemical treatment method offers a means for ES membrane removal while conserving the quality of the mineral fraction (calcite; CaCO₃).

To achieve sustainable and energy-efficient CO₂ capture processes, it is imperative to develop membranes that possess both high CO₂ permeability and selectivity. One promising approach involves integrating high-aspect-ratio nanoscale fillers into polymer matrices. The high-aspect-ratio fillers increase surface area and improve interactions between polymer chains and gas molecules passing through the membrane. This study focuses on the integration of cellulose nanocrystals (CNCs) with an impressive aspect ratio of around 12 into rubbery polymers containing polyethylene oxide (PEO), namely PEBAX MH 1657 (poly[ether-block-amide] [PEBA]) and polyurethane (PU), to fabricate mixed-matrix membranes (MMMs). By exploiting the interfacial interactions between the polymer matrix and CNC nanofillers, combined with the surface functionalities of CNC nanofillers, the rapid and selective CO₂ transport is facilitated, even at low filler concentrations. This unique feature enables the development of thin-film composites (TFCs) with a selective layer around 1 μm. Notably, even at a filling ratio as low as 1 weight percent, the resulting membranes exhibit remarkable CO₂ permeability (>90 Barrer) and CO₂/N₂ selectivity (>70). These findings highlight the potential of integrating CNCs into rubbery polymers as a promising strategy for the design and fabrication of highly efficient CO₂ capture membranes.

Deep-sea equipment is generally made of lightweight and pressure-resistant materials in order to meet the requirements of the actual work. In order to explore marine resources better, it is necessary to research lightweight buoyancy materials for loading on mining equipment. These buoyancy materials contribute not only to providing adequate buoyancy to the mining equipment but also to reducing economic expenses. In this paper, hollow glass microspheres reinforced epoxy hollow spheres (HGMSs-EHSs) were prepared by the rolling ball method using expanded polystyrene (EPS), epoxy resin (EP), and HGMS as raw materials. Epoxy syntactic foam (ESF) was manufactured by blending EP, curing agent, HGMS, and HGMS-EHS with molding method. Basalt fiber (BF) reinforced ESF was fabricated by adding BFs to form a fiber network inside the syntactic foam. The results revealed that the density and compressive strength of ESF increased progressively with the number of HGMS-EHS layers. The density and compressive strength of ESF decreased prospectively with the increase of the stacking volume fraction of HGMS-EHS. The density and compressive strength of ESF increased gradually with the enlargement of the length and content of BF. In the range of influencing factors mentioned above, the density of ESF remains around 0.3 g/cm³, which has a low density. When the number of layers of HGMS-EHS was two, the stacking volume fraction was 90%, the length of BF was 12 mm, the content of BF was 4%, the density of BF-ESF was 0.316 g/cm³, and the compressive strength was 6.93 MPa. The compressive strength of prepared buoyancy material can meet the pressure resistance requirements for operations in waters of a certain depth. With a density of only 0.316 g/cm³, it provides sufficient buoyancy to balance the gravity of the equipment. Compared with the current study, in this paper, BFs were used as the reinforcing phase to prepare solid buoyancy foam with low density and high compressive strength. The experimental results demonstrate that this economical fiber material can effectively improve the compressive strength of buoyancy materials. This buoyancy material may be suitable for loading on small equipment for extracting marine resources. This work provides a reference for the preparation of low-density solid buoyancy materials.

Enhancing the hydrophobicity of chitosan through acylation enables the encapsulation of water-insoluble drugs within the polymeric carrier cores. In this study, hydrophobically modified chitosan was synthesized by reacting low-molecular-weight chitosan with acyl chloride (C18–C24) using an agitation method under mild conditions. The structure of acylated chitosan was analyzed using FTIR and ¹H-NMR spectroscopy. The degree of substitution (DS) varied between 56% and 69% for different long-chain N-acylated chitosan, with N-stearoyl chitosan (ChC18) exhibiting the highest DS. The incorporation of capecitabine (CAP) into extended acylated chitosan increased particle size and decreased zeta potential. N-lignoceroyl chitosan (ChC24) exhibited the highest zeta potential value of −27 mV for 0.2 mg of CAP, indicating that the most extended acyl group was the most stable in the suspension. Transmission electron microscope images revealed that all acylated chitosan particles were spherical, with sizes ranging from 100 to 200 nm, and existed as stand-alone entities, indicating excellent stability in suspension. The loading of CAP increased in particle size but did not alter particle shape, except for ChC24, which exhibited agglomeration. SEM images revealed that the individual arrangement of particles in CAP-ChC18 made it more stable than other acylated chitosan. In contrast, the formation of clusters in CAP-ChC24 can be attributed to strong hydrophobic interactions. X-ray photoelectron spectroscopy results show that there is no nitrogen atom in ChC18, which means that the acyl group is oriented inward and bound to the stearoyl group via van der Waals forces. At different drug weight-to-carrier ratios, the encapsulation efficiency (EE) of CAP with varying acyl group lengths ranged from 85% to 97%. The drug loading (DL) capacity and EE increased as the amount of drug in the carrier increased. However, the length of the acyl group did not significantly affect DL and EE, even when the carrier-to-drug ratio was consistently maintained. Sustained release was observed in CAP-loaded ChC24, indicating a significant influence of the extended chain on chitosan. Consequently, extended N-acylated chitosan possesses enormous potential as a drug delivery system for CAP.

Process parameter optimization and selection play a crucial role in additive manufacturing, particularly in determining the quality and characteristics of the final product. Among these parameters, the infill pattern holds significant importance as it directly influences the structural integrity, production time, and material usage efficiency of the printed object. This research focuses on identifying the most suitable 3D printing infill pattern process parameters for thermoplastic polyurethane (TPU) material, specifically for applications in pipeline construction. The criteria considered for process parameter selection include printing time, ultimate tensile strength, ultimate flexural strength, and surface defect minimization. Various infill patterns, including hexagonal, line, solid, triangle (35°), triangle (55°), and line patterns, are evaluated as alternatives. Utilizing the multi-criteria decision-making technique known as analytical hierarchy process (AHP), a systematic approach is employed to determine the optimal printing pattern. The findings of this study reveal that the hexagonal infill pattern outperforms other selected patterns in terms of meeting the criteria set forth for pipeline construction using TPU material. This research contributes to enhancing the efficiency and quality of additive manufacturing processes in pipeline applications, emphasizing the importance of informed parameter selection for achieving desired performance outcomes.