Search Results (131)

Interfacial polymerization (IP) has been widely utilized to synthesize composite membranes. However, precise control of this reaction remains a challenge due to the complexity of the IP process. Herein, an optical three-dimensional microscope was used to directly observe the IP process. To construct copolyesteramide containing phthalazine moiety films, rigid monomer 4-(4′-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ) and flexible monomer piperazine (PIP) were used as aqueous phase monomers, and trimesoyl chloride (TMC) served as the organic phase monomer. Multilayer cellular structures were observed for the copolyesteramide films during the IP process. The effects of multiple factors including the ratio between flexible and rigid monomers, co-solvents, and the addition of phase transfer catalysts on the film growth and the morphologies were investigated. This research aims to deepen our understanding of the IP process, especially for the principles which govern polymer film growth and morphology, to promote new methodologies for regulating interfacial polymerization in composite membrane preparation. Full article

The growing accumulation of plastic packaging waste poses severe environmental and health challenges. To address these issues, significant research has been devoted to developing biodegradable films; however, their weak mechanical and barrier properties limit their practical utility. This study introduces an innovative multilayer film production method, combining electrospun polycaprolactone (PCL) fibers with a chitosan matrix. Two configurations were investigated: (1) nonwoven PCL layers placed between chitosan sheets and (2) a chitosan sheet sandwiched between two nonwoven PCL layers. Both systems were evaluated using PCL fibers derived from medical-grade and technical-grade polymers. The chitosan/polycaprolactone/chitosan (CH/PCL/CH) configuration demonstrated superior performance, achieving enhanced interlayer cohesion and significantly improved mechanical strength, durability, and barrier properties. Notably, this configuration achieved tensile strength and elongation at break values of 57.1 MPa and 36.3%, respectively—more than double those of pure chitosan films. This breakthrough underscores the potential of multilayered biopolymer films as eco-friendly packaging solutions, offering exceptional promise for sustainable applications in the food packaging industry. Full article

Polymer residues can be reused in civil construction by partially replacing mineral aggregates in concrete, thereby reducing the extraction of natural resources. This study aimed to evaluate the use of powdered poly (ethylene terephthalate) (PET) and polyethylene (PE) residues, accumulated in shaving-mill filters during the extrusion of multilayer films used in food packaging, in the production of sealing masonry blocks. The PET/PE residues were characterized by Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Cylindrical specimens were produced in which part of the sand, by volume, was replaced with 10, 20, 30, 40 and 50% polymer residue. The cylindrical specimens were evaluated for specific mass, water absorption and axial and diametral compressive strengths. The 10% content provided the highest compressive strength. This formulation was selected for the manufacture of concrete blocks, which were evaluated and compared with the specifications of ABNT NBR 6136:2014. The concrete blocks showed potential for applications without structural function and were classified as Class C. The results, in line with previous investigations on the incorporation of plastic waste in concrete, underscore the promising application potential of this strategy. Full article

The application of graphene nanoplatelets (GNPs) in polymer composites is a challenge due to their high tendency to agglomerate and restack during processing. In this work, alkyl phosphonium-based ionic liquid was used to assist the dispersion of GNP in an ethylene-vinyl acetate (EVA) matrix, through a melt-mixing procedure. The mechanical properties and creep resistance of the films prepared by the film extrusion process were evaluated. The results demonstrated that the noncovalent treatment of GNP with the ionic liquid (IL) enhanced the electrical conductivity and creep stability of the EVA composites. The microwave absorbing properties were studied in the X-band and Ku-band. A reflection loss (RL) of −15 dB for EVA containing 0.5 wt% of GNP and 1:1 wt% of GNP/IL was achieved. The use of a multi-layered structure containing thin film layers was efficient for enhancing the microwave absorbing performance, with a minimum RL of −24.6 dB and effective absorption bandwidth of 4.3 GHz. This result is attributed to the internal reflection and scattering of the radiation between layers. The use of simple, low-cost materials and procedures, combined with the system’s excellent mechanical and electrical properties, makes it a promising candidate for multifunctional applications as electrostatic dissipative and microwave absorbing materials for electronic packaging and other electronic devices. Full article

LED polymer multilayer films offer clear advantages over single-layer coatings, such as minimized particle settling, finer control over particle distribution, and more precise spectral tuning. However, the standard “coat–dry–coat” process for these multilayer systems often traps air bubbles, degrading film quality and uniformity. This study investigates the air entrainment mechanism in multilayer film formation. Bubbles form when the cured bottom layer exhibits a low contact angle, which destabilizes the advancing liquid front. High-speed microscopy captured these interfacial dynamics, and contact-angle measurements quantified the wetting behavior. Numerical simulations further demonstrated that reduced wettability and vortex formation drive air entrainment. To mitigate air entrainment, a semi-cured slot die coating approach was proposed to modify the surface wettability and suppress the flow instabilities. Incorporating temperature-dependent viscosity into the simulation model improved its predictive accuracy, cutting the error in predicted coating-gap limits from 11.49% to 4.99%. This combined strategy delivers reliable, bubble-free multilayer films and paves the way for more consistent, high-quality LED polymer applications. Full article

Energy storage polymers are critical to modern microelectronics, electric vehicles, and wearable devices. Capacitor energy storage devices are the focus of contemporary research, with film dielectric capacitors being the focus of mainstream research. Research on polymers—particularly polypropylene—has yielded numerous innovations, but their energy storage performance and breakdown resistance under extreme conditions remain unsatisfactory. Numerous reports have proposed various solutions, but systematic reviews, classifications, and investigations regarding the effects of processing on polypropylene films remain lacking. This study collects and organizes the latest research reports on dielectric-related polypropylene films with the aim of addressing this issue by providing a comprehensive review of the research on polypropylene thin film materials that exhibit high dielectric stability and high energy storage density under extreme conditions. These conditions include mixing and doping, surface modification, designing new molecular structures, and constructing multilayers. This study analyzes how polypropylene’s dielectric properties can be enhanced. It reviews the impacts of processing on the dielectric properties of biaxially oriented polypropylene and the underlying mechanisms. The paper is concluded with a summary of the current research progress and shortcomings in industrial production and performance, as well as discussions of future prospects. It offers valuable references for enhancing the dielectric properties of biaxially oriented polypropylene films and optimizing film processing. Full article

In two-dimensional (2D) materials research, exfoliating 2D transition metal dichalcogenides (TMDs) from their growth substrates for device fabrication remains a significant challenge. Current methods, such as those involving polymers, metals, or chemical etchants, suffer from limitations like contamination, defect introduction, and a lack of scalability. Here, we demonstrate a selenium capping-based exfoliation technique. Its advantage lies in its ability to enable the clean, contamination-free exfoliation and transfer of TMD films. We successfully exfoliated and transferred monolayer and multilayer TMD films, including WSe₂ and MoSe₂. The selenium capping layer not only enables seamless exfoliation but also protects the film from oxidation, as confirmed by X-ray photoelectron spectroscopy and Raman spectroscopy. This approach is versatile and applicable to a range of TMDs and thicknesses, paving the way for the high-quality, scalable integration of 2D materials into nanoelectronic devices. Full article

Polyelectrolyte multilayers (PEMs) deposited on non-porous and porous blend substrates were studied. Films, prepared from two biodegradable polymers poly (D-lactic acid) (PDLA) and poly(ε-caprolactone) (PCL) and their blends were used as substrates in the present paper. All films were initially charged in a corona discharge (positive or negative corona). After charging, the initial surface potential of the samples V₀ was measured and the normalized surface potential was calculated. The dependencies on time of the normalized surface potential for electrets, possessing either positive or negative charges, were studied. It was found that the steady-state values of the normalized surface potential for the porous substrates were higher than those of the non-porous ones, independently of material type and corona polarity. It was also shown that the values of the normalized surface potential for the PCL electrets were the highest and decreased when the content of PDLA increased. Scanning electron microscopy (SEM) was utilized for the determination of the substrates’ surface morphology. With the largest pore size, PCL substrates allowed for a greater capture of charges on their surface and facilitated the retention of said charges for prolonged periods of time. Differential scanning calorimetry (DSC) measurements were performed to determine the degree of crystallinity, which was very high for PCL substrates, when compared to the other investigated substrates. The wettability of the investigated substrates was measured using the static water contact angle method. The obtained results demonstrated that the created blends were more hydrophilic than the pure films. The two chosen polyelectrolytes were layered onto the surface of the substrates with the use of the layer-by-layer (LbL) technique and benzydamine hydrochloride was loaded in the multilayers as a model drug. Its loading efficiency and release profile were carried out spectrophotometrically. It was determined that for non-porous substrates, independently of the corona polarity, the best fitting model was Korsmeyer-Peppas, while for the porous substrates the best fitting model was Weibull. Full article

Multi-layer films are one of the most challenging classes of polymer waste for recycling, as they consist of a mixture of constituent materials like polyethylene (PE), polyamide 6 (PA6), and ethylene vinyl alcohol (EVOH). This study investigates the characterization, washing, and mechanical properties of recycled blends derived from such multi-layer films. Raman spectroscopy and Differential Scanning Calorimetry (DSC) were used to characterize the individual components in single- and multi-layer films, and distinct properties of LDPE, LLDPE, PA6, and EVOH were observed. Mechanical properties enhanced by proper shredding, washing procedures, and multiple combinations of polyethylene blends were investigated to optimize the mechanical characteristics of the recycled materials, especially strain at break. Additionally, the shrinkage behavior of the recycled films was compared to commercial shrink films, demonstrating their potential for use in industry packaging applications. These results highlight a more sustainable possibility for multi-layer packaging applications. Full article

Multilayer flexible packaging wastes (MFPWs) consist of complex materials composed of multiple plastic films, which are often laminated with aluminum foil, and they constitute a large portion of packaging waste. The use of several polymeric layers is essential to achieve the desired technical and mechanical performance of the packaging; however, this makes layer separation and recycling challenging. Currently, this type of waste is predominantly incinerated or landfilled; non-industrial recycling processes have recently been developed, but they mostly rely on traditional solvent-based treatments, which can be problematic. We present a versatile process for recycling MFPWs using switchable hydrophilicity solvents (SHSs). By treating waste with SHSs through a temperature-controlled process, we efficiently recovered the polymeric layers as sorted transparent films, effectively removing all additives while preserving the original properties of the polymers. Aluminum was recovered as well. N,N-dimethylcyclohexylamine was the best solvent for the delamination of the 26 different packaging materials tested, containing polypropylene, polyethylene, polyethylene terephthalate, and aluminum. The main advantage of this method is the straightforward recovery of the different components that can be efficiently delaminated and easily removed from the solvent, even from highly variable input material. Moreover, by exploiting the CO₂-triggered switchable behavior of the solvent, its purification and recovery can be achieved, maintaining its delamination efficacy over several cycles. Full article

Background/Objectives: Oral diseases causing mucosal lesions are normally treated with local or systemic anti-inflammatory, analgesic and antimicrobial agents. The development of topical formulations, including wound-healing promoters, might speed up the recovery process, improving patients’ quality of life, and reduce the risk of deterioration in health conditions. In this study, a mucoadhesive multilayer film, including a novel biocompatible substance (solubilized eggshell membrane, SESM), was rationally designed. Methods: The SESM preparation procedure was optimized and its biological effects on cell proliferation and inflammation marker gene expression were evaluated in vitro; preformulation studies were conducted to identify the most promising polymers with film-forming properties; then, trilayer films, consisting of an outer layer including chlorhexidine digluconate as a model drug, a supporting layer and a mucoadhesive layer, incorporating SESM, were prepared using the casting method and their mechanical, adhesion and drug release control properties were evaluated. Results: SESM proved to possess a notable wound-healing capacity, inducing a wound closure of 84% in 24 h without inhibiting blood clotting. The films revealed a maximum detachment force from porcine mucosa of approx. 1.7 kPa and maximum in vivo residence time of approx. 200–240 min; finally, they released up to 98% of the loaded drug within 4 h. Conclusions: The formulated trilayer films were found to possess adequate properties, making them potentially suitable for protecting oral lesions and favoring their rapid healing, while releasing antimicrobial substances that might be beneficial in reducing the risk of bacterial infections. Full article

Polyimides (PIs) have been extensively used in thin film and micro-electromechanical system (MEMS) processes based on their excellent thermal and mechanical stability and high glass transition temperature. This research explores the development of a novel multilayer and multifunctional polymer composite electro-piezomagnetic device that can function as an energy harvester or sensor for current-carrying wires or magnetic field sensing. The devices consist of four layers of composite materials with a polyimide matrix. The composites have various nanoparticles to alter the functionality of each layer. Nanoparticles of Ag were used to increase the electrical conductivity of polyimide and act as electrodes; lead zirconate titanate was used to make the piezoelectric composite layer; and either neodymium iron boron (NdFeB) or Terfenol-D was used to make the magnetic and magnetostrictive composite layer, which was used as the proof mass. A novel all-polymer multifunctional polyimide composite cantilever was developed to operate at low frequencies. This paper compares the performance of the different magnetic masses, shapes, and concentrations, as well as the development of an all-magnetostrictive device to detect voltage or current changes when coupled to the magnetic field from a current-carrying wire. The PI/PZT cantilever with the PI/NdFeB proof mass demonstrated higher voltage output compared to the PI/Terfenol-D proof mass device. However, the magnetostrictive composite film could be operated without a piezoelectric film based on the Villari effect, which consisted of a single PI-Terfenol-D film. The paper illustrates the potential to develop an all-polymer composite MEMS device capable of acting as a magnetic field or current sensor. Full article

This research is aimed at studying the properties of polymer anticorrosion coatings based on ED-20 resin widely used in practice and industrial wastes. In this work, three basic types of nanoscale nanofillers were chosen: dispersed particles—microsilica, microspheres obtained at Kazakh enterprises, and carbon nanotubes. Physicochemical research methods were used in the research: a laser analyzer for studying the dispersibility of industrial waste and spectrometric research methods. The properties of materials were investigated by standardized methods. The obtained results show that the introduction of microsilica and microspheres obtained at Kazakhstani enterprises, used as additives, improves both the physical and mechanical properties of epoxy composites compared to the standard (control) material. The results of experiments have shown that the optimal content of additives of microsilica and microspheres provides an improvement in the physical and mechanical properties of epoxy composites in comparison with the standard (control) material. Studies have shown that the introduction of microspheres into ED-20 polymer increases impact toughness. The introduction of microsilica into the matrix contributes to the increase of elastic modulus. Experimental studies of optical properties of samples of carbon composite polymer films based on polystyrene (PS) with additives of carbon nanotubes C₆₀ and C₇₀ and multilayer carbon nanotubes were also carried out. The experimental results obtained for the optical properties of polymer composites based on basic polymers from solid waste and carbon nanotubes showed that the optical properties of polymer composites undergo noticeable changes. Full article

Biobased and biodegradable plastics have emerged as promising alternatives to conventional plastics offering the potential to reduce environmental impacts while promoting sustainability. This study focuses on the production of multilayer blown films with enhanced functional properties suitable for food packaging applications. Films were developed through co-extrusion in a three-layer film configuration, with Polybutylene Succinate (PBS) and Polybutylene Succinate Adipate (PBSA) as the external and internal layers, respectively. The functional layer consisted of Polyhydroxybutyrate (PHB) enhanced with nanoclays Cloisite^® 30B at varying weight ratios. Films were also processed by manipulating the extruder screw speed of the functional layer to investigate its impact on the functional properties. Rheology, mechanical strength, and barrier performance were characterised to establish correlations between processing conditions and functional layer blends (Cloisite^® 30B/PHB) on the properties of the resultant films. Rheological test results indicated that the system with 5% Cloisite^® had the best polymer/nanofiller matrix dispersion. Mechanical and permeability tests showed that by varying the process conditions (the alteration of the thickness of the functionalized layer) resulted in an improvement in mechanical and barrier properties. Furthermore, the addition of the nanofiller resulted in a stiffening of the film with a subsequent decrease in permeability to oxygen and water vapour. Full article

Silver nanoparticles (AgNPs) possess unique characteristics ideal for enhancing device sensitivity, primarily due to their high surface-to-volume ratio facilitating heightened interaction with analytes. Integrating AgNPs into polymers or carbon-based materials results in nanocomposites with synergistic properties, enabling the detection of minute changes in the environment across various applications. In this study, we investigate the adsorption kinetics of AgNPs within multilayered layer-by-layer (LbL) structures, specifically examining the impact of AgNPs concentration in the LbL film formation that is further explored as sensing units in an impedimetric microfluidic e-tongue. Although absorption kinetic studies are infrequent, they are crucial to optimize the AgNPs adsorption and distribution within LbL structures, significantly influencing upcoming applications. Through systematic variation of AgNPs concentration within identical LbL architectures, we applied the films as sensing units in a microfluidic e-tongue capable of distinguishing food enhancers sharing the umami taste profile. Across all tested scenarios, our approach consistently achieves robust sample separation, evidenced by silhouette coefficient, principal component analyses, and long-term stability. This work contributes to exploring controlled nanomaterial-based developments, emphasizing the importance of precise parameter control for enhanced sensor performance across diverse analytical applications. Full article