Preparation Of Composite Films Research Articles

Preparation and characterization of graphene oxide-Chitosan composite film for ultrathin hyaluronic acid hydrogels

ABSTRACT Mechanical properties of hyaluronic acid (HA) hydrogels are too poor to be prepared as an ultra-thin hydrogels, so to provide a supporting skeleton for them is important. Herein, the porous film based on chitosan(CS)、PEG-20000 and graphene oxide (GO) were prepared for ultra-thin hydrogels. CS is a suitable polymer to prepare films. The added PEG-20000 endowed the film porosity. And the addition of GO improved the mechanical of the film. When CS:PEG = 3:2 and the GO solution proportion was 15%, the porous film exhibited the best comprehensive properties, with a tensile strength of 5.593 MPa, an elongation at break of 45.833%, a water permeation of 1.4099 g at 12 h, a porosity of 62.3% and an average pore size of 1.88 um. Blood compatibility experiments and cell experiments have proved that the film hydrogel has strong biocompatibility, indicating it can be a promising biomaterial.

Chiral-Induced Ultrathin Covalent Organic Frameworks Nanosheets with Tunable Circularly Polarized Luminescence.

Development of covalent organic frameworks (COFs) with circularly polarized luminescence (CPL) is still challenging. Here we first reported ultrathin COFs nanosheets (NS) based CPL materials using a chiral induced-synthesis strategy. Chiral amines served as chiral inducers to give COF TpBpy with chirality and participated in the modification of TpBpy, inhibiting the fluorescence quenching caused by π-π stacking to form ultrathin luminescent chiral COFs (chirCOFs) NS. The obtained chirCOFs R-/S-TpBpy NS had strong chirality and intense red CPL property with a |glum| of ∼0.02. Afterward, the carboxyl containing green and blue fluorescent dye molecules were postmodified onto the chirCOFs NS (chirCOFs/Dyes) to achieve color-adjustable CPL. Due to the chirality and energy transfer between chirCOFs and dye groups, the obtained chirCOFs/Dyes showed strong chirality and increased and tunable photoluminescence, exhibiting excellent, tunable, and amplified CPL performance with a maximum |glum| of ∼0.1, which was ∼5 times stronger than that of as-prepared chirCOFs NS. Moreover, the corresponding chirCOFs NS were dispersed into a polydimethylsiloxane (PDMS) matrix to form wafer size, highly transparent, and flexible COFs/PDMS films for practical CPL application. This study opens a new strategy to prepare ultrathin chirCOFs NS with strong and tunable CPL by chiral induction and provides a new approach for the preparation of transparent, large size, and flexible COFs composite films in chiral optical applications.

Facile Preparation of Chitosan-Based Composite Film with Good Mechanical Strength and Flame Retardancy.

To improve on the poor strength and flame retardancy of a chitosan (CS)-based functional film, cellulose nanofiber (CNF) was taken as the reinforced material and both ammonium polyphosphate (APP) and branched polyethyleneimine (BPEI) as the flame-retardant additives in the CS matrix to prepare the CS/CNF/APP/BPEI composite film by simple drying. The resulting composite film showed good mechanical strength, with a tensile strength reaching 71.84 Mpa due to the high flexibility of CNF and the combination of CS, CNF and BPEI through strong hydrogen bonding interactions. The flame retardant-performance of the composite film greatly enhanced the limit oxygen index (LOI), up to 32.7% from 27.6% for the pure film, and the PHRR intensity decreased to 28.87 W/g from 39.38% in the micro-scale combustion calorimetry (MCC) test due to the ability of BPEI to stimulate the decomposition of APP, releasing non-flammable gases such as CO2, N2, NH3, etc., and forming a protective phosphating layer to block the entry of O2. Based on the good flame retardancy, mechanical strength and transparency, the CS/CNF/APP/BPEI composite film has a great potential for future applications.

Preparation of graphene-starch composite film and its application in sensor materials

In this work, a composite film was prepared by combining reduced graphene oxide (RGO) and starch nanocrystals (SNC). The results show that SNC can be well dispersed on graphene after mixed with the graphene oxide solutions. SNC had a greater impact on the morphology and microstructure of the composite film. Moreover, the introduction of SNC and the efficient reduction process of graphene oxide (GO) render these composite films good mechanical properties as well as high electrical conductivity. The tensile strength of the composite film was improved after being combined with graphene. However, as the addition rate of SNC increased, the strain-to-failure of the composite film decreased. Therefore, 10% reduced graphene-starch nanocrystals (10%RGO-SNC) was used as multifunctional sensor materials. And it had strong responses to different external stimuli, such as, temperature, humidity, bending/stretching, and solutions.

Microstructure and tribological properties of Ni3Al–Cr3C2/Ni3Al micro-laminate composite films fabricated by electrohydrodynamic atomization technique

Micro-laminate composite films perform better than monomer films due to their small layer-spacing and multi-interface. Armed with this information, this work aims to offer efficient technology for the preparation of micro-laminate composite films and then to study their tribological properties. For this study, both Ni3Al monomer film and Ni3Al–Cr3C2/Ni3Al micro-laminate composite films were deposited on 316L stainless steel via electrohydrodynamic atomization technology. Then, the microstructure and mechanical properties of these two kinds of films were comparatively investigated. Additionally, the wear resistance of the two films was analyzed according to the wear volume, friction coefficient curves, and 3D profiles of the wear tracks. The results revealed that both the mechanical properties and wear resistance of the micro-laminate composite films were superior to the monomer film. This improved wear resistance of the micro-laminate composite films was attributed to the strengthening effects from the Cr3C2 reinforcement phase and the construction of the laminated structure. The worn surface morphologies demonstrated that the wear mechanism of the Ni3Al film was a combination of adhesion wear and abrasive wear, while the wear mechanism of the micro-laminate composite films was abrasive wear.

Preparation and characterization of plasticized polyvinyl chloride composite film based on photochromic intelligent cooling

AbstractIndoor temperature adjustment to maintain a relatively comfortable living environment has resulted in different cooling strategies. Often, these strategies are energy consuming as well as energy wasting because of the complex and changing environment. Materials development to achieve intelligent adjustment of indoor temperature through efficient and energy‐saving methods is essential. Here, we present a strategy to prepare polyvinyl chloride (PVC)/photochromic powders cooling films. By adding different colors of photochromic powders to PVC substrate and utilizing their properties of changing color and light transmittance according to sunlight intensity to achieve the intelligent cooling effect. The indoor sunlight simulation test indicates that the PVC/red photochromic powders composite film possesses the best cooling performance under ultraviolet (UV) irradiation, and the maximum cooling range is about 10°C compared with the control sample, meanwhile the maximum cooling effect is only 2–3°C without UV irradiation. The PVC/red photochromic powders composite film also shows the best cooling effect (6°C) in the outdoor solar irradiation test with strong sunlight, and all films did not exhibit an obvious cooling effect under weak sunlight. Meanwhile, PVC/photochromic powders composite films also solve the shortcoming of the single color of traditional cooling films, which can better meet the demand of people for color diversity. In addition, the stable mechanical properties of PVC/photochromic powders composite films also give it great application value. Therefore, PVC/photochromic powders composite films can provide a promising energy‐saving solution for future intelligent adjustment of indoor temperature.

Preparation and performance of electroless silver composite films based on micro-/nano-cellulose

Preparation and performance of electroless silver composite films based on micro-/nano-cellulose

Study on preparation and properties of edible carrageenan-garlic extract composite film

In order to prepare edible cling film with anti-oxidation and anti-bacteria properties, in this study, a new functional food packaging film was prepared using carrageenan (CA) and garlic extract (GE) as raw materials, then based on identification of morphological and structural characteristics, anti-oxidation analysis and anti-bacteria analysis methods were used to study the optical properties and physical and chemical characteristics of the film materials. Results indicate that the addition of garlic extract has affected the micro-structure and mechanical properties of composite film, where the DPPH free radical scavenging rate significantly increases with the increase of extract concentration. In addition, the film with the mass concentration of 3% has a better anti-oxidation effect and the diameter of inhibition zone increases with the increase of extract concentration. In short, the addition of garlic extract improves the biological activity of carrageenan film, having provided a theoretical basis for the production of garlic extract-carrageenan composite film.

Preparation, Characterization and Dielectric Properties of Alginate-Based Composite Films Containing Lithium Silver Oxide Nanoparticles.

Polymer composites have found applications in diverse areas, ranging from the manufacturing of portable electronic devices to the fabrication of bioactive agent carriers. This article reports the preparation of composite films consisting of sodium alginate (SA) and lithium silver oxide (LAO) nanoparticles. The films are generated by solution casting; whereas the nanoparticles are fabricated by using the hydrothermal method. The effects of the nanoparticles on the morphological, thermal, and dielectric properties of the films are examined by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Electrical measurements are also performed to determine the dielectric constant (ε′), dielectric loss (ε″), AC conductivity (σac), electrical moduli (M′ and M″), and impedance (Z' and Z″). The composite films are shown to be crystalline in nature, with nanoparticles having a diameter of 30–45 nm effectively disseminated in the polymer matrix. They also display good dielectric properties. Our results suggest that the films warrant further exploration for possible use in microelectronic applications.

Preparation, Microstructure and Thermal Properties of Y2O3 Hollow-Sphere Composite Films

Preparation, Microstructure and Thermal Properties of Y2O3 Hollow-Sphere Composite Films

Preparation of Explicit and Recessive Composite Anti-Counterfeiting Film Based on Epoxy Resin

Preparation of Explicit and Recessive Composite Anti-Counterfeiting Film Based on Epoxy Resin

Preparation and thermal conductivity properties of high-temperature resistance polyimide composite films based on silver nanowires-decorated multi-walled carbon nanotubes

Preparation and thermal conductivity properties of high-temperature resistance polyimide composite films based on silver nanowires-decorated multi-walled carbon nanotubes

Preparation of tuna skin collagen-chitosan composite film improved by sweep frequency pulsed ultrasound technology

To produce a natural food packaging film from tuna skin collagen (TSC) and chitosan (CTS) and improve its mechanical and physicochemical properties, the sweep frequency pulsed ultrasound (SFPU) was introduced as a new technology and compared with the conventional method. The optimum preparation conditions of the SFPU-TSC-CTS film were sweep frequency of 28 ± 0.5 kHz, power density of 100 W/L, sweep frequency cycle of 100 ms, pulse duty ratio of 77%, and ultrasonic time of 10 min. Significant increases in the tensile strength (27.14%) and elongation at break (16.54%) and a significant decrease in the water vapor permeability (12.15%) were observed by sonication. Thus, a moderate SFPU treatment can significantly improve the moisture resistance and mechanical properties of the film. These enhancements were achieved by a more ordered and compact structure, a good crystallinity and a higher thermostability of SFPU-TSC-CTS film, which were verified by the Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal stability indexes. Moreover, SFPU-TSC-CTS film also presented good antioxidant and antibacterial activities. Therefore, SFPU was an effective auxiliary technology for improving the quality of food packaging film and can be deeply explored.

Preparation and characterization of polydimethylsiloxane-based composite films

Abstract In this study, we aimed to find the characteristic properties of the neat and the composite polydimethylsiloxane (PDMS) films. The composite films were prepared by adding 5 A and NaY zeolites and nano-TiO2 to PDMS polymer matrix. In the preparation of the composite polymer films, the inorganic additives were added by 10 wt.-%. The structural and thermal characteristics of the prepared homogenous PDMS film and composite PDMS films were determined by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The glass transition temperature of the films was found by differential scanning calorimetry (DSC). Finally, the mechanical properties of the films were obtained through tensile tests. The effects of 5 A and NaY zeolites and TiO2 on the neat PDMS films were investigated.

Preparation, optical properties, and thermal stability of polyvinyl butyral composite films containing core (lanthanum hexaboride)–shell (titanium dioxide)-structured nanoparticles

Abstract Nano-sized lanthanum hexaboride (LaB6)@ titanium dioxide (TiO2) particles with a core–shell structure has been successfully synthesized via a simple sol–gel method. LaB6@TiO2 particles were used as filler in polyvinyl butyral (PVB) matrix and performance of the TiO2 shell was evaluated. The core–shell nanoparticles were characterized for morphology and structure properties. X-ray diffraction and transmission electron microscope testing results confirm the formation of LaB6–TiO2 core–shell structure. In composite film, LaB6 improved the thermo-decomposing temperature of PVB matrix from 369.2 to 372.8°C, while the same amount of LaB6@TiO2 further increased the temperature to 381.0°C. In addition, TiO2 shell redshifted the maximum transmittance of the film from 605 to 669 nm in the visible region. In the near infrared region, its absorption peak shifted from 1,466 to 1,476 nm. This result will be helpful for the development of transparent and thermal insulating materials.

Continuous Blown Film Preparation of High Starch Content Composite Films with High Ultraviolet Aging Resistance and Excellent Mechanical Properties.

Starch/PBAT blown films with high ultraviolet aging resistance and excellent mechanical properties were prepared by introducing lignin with polyurethane prepolymer (PUP) as a starch modifier and physical compatibilizer and 4,4′–methylene diphenyl diisocyanate (MDI) as a crosslinker. Starch was modified by reacting the NCO groups of the PUP with the OH groups of the starch to form a carbamate bond. The mechanical properties, hydrophobic properties, ultraviolet barrier, ultraviolet aging properties and microscopic morphology of starch/PBAT films with different contents of lignin were investigated. The results showed that the starch/PBAT films were blown continuously. The addition of lignin did not decrease the mechanical properties. On the contrary, the film with 1% lignin possessed the excellent mechanical properties with longitudinal tensile strength of 15.87 MPa and the elongation at a break of 602.21%. In addition, the higher the lignin content, the better the UV blocking effect. The introduction of lignin did not affect the crystalline properties but improved the hydrophilic properties and sealing strength of the high starch content composite films.

Preparation and properties of antibacterial PVDF composite thin films

As medical dressings, polyvinylidene fluoride (PVDF) thin films loaded with antimicrobial agents offer excellent wound infection control. In this study, PVDF/tea polyphenol (TPs) and PVDF/TPs/Ag composite thin films were prepared by electrically assisted three-dimensional (3D) printing method. The surface morphology, hydrophilicity, and antibacterial properties of the composite thin films were studied. The results showed that the presence of appropriate amount of TPs promoted the crystallinity and β-phase content of the PVDF thin films, and TPs played an important role in the formation of abundant holes on the surface of PVDF films. It facilitated the deposition of silver nanoparticles on the surface of PVDF thin film and improved the uniformity of their distribution. The Escherichia coli (E. coli) inhibition rate of the PVDF/TPs composite thin film reached 97.22%. The antibacterial activity of this composite thin film improved significantly after the deposition of silver nanoparticles, and the E. coli inhibition rate of the PVDF/TPs/Ag composite thin film was 99.58%.

Preparation and characterization of chitosan-based antioxidant composite films containing onion skin ethanolic extracts

Preparation and characterization of chitosan-based antioxidant composite films containing onion skin ethanolic extracts

Preparation and Characterization of Ginger Essential Oil Microcapsule Composite Films.

New food packaging has shown research significance in the face of increasing demand for high-quality foods and growing attention paid to food safety. In this study, ginger essential oil microcapsule composite films were prepared by combining microcapsules prepared by a complex coacervation method with gelatin films, and the mechanical properties and active functions of the composite films were analyzed. Fourier-transform infrared spectroscopy and differential scanning calorimetry confirmed the successful encapsulation of ginger essential oil. The scanning electron microscopy of the composite films showed the microcapsules and gelatin film matrix were highly compatible. During the entire storage period, the antioxidant capacity of the ginger essential oil microcapsule films weakened more slowly than ginger essential oil microcapsules and could be maintained at a relatively high level for a long time. The microcapsule films had excellent inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. Therefore, the direct addition of microcapsules to a film matrix can broaden the application range of microcapsules and increase the duration of the release of active ingredients. Ginger essential oil microcapsule films are potential biodegradable food packaging films with long-lasting activity.

Preparation, structural investigation and optical properties determination of composite films based on PAZO polymer doped with GeTe4-Cu chalcogenide particles

The work presents preparation, structural investigation and optical properties determination of composite films based on the azopolymer (poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt]), shortly PAZO, doped with 1 wt.% particles of the previously synthesized by us new tellurium containing chalcogenide system (GeTe4)100-xCux, wherex = 5, 10, 15 and 20 mol.%. X-Ray diffraction (XRD) was applied to analyze the structure of the chalcogenide bulk material. Transmission electron microscopy (TEM) has been used to study the particles and the composite films morphology. The transmittance coefficient (T), the reflectance coefficient (R), the refractive index (n), the extinction coefficient (k), the optical absorption coefficient (α) and the optical band gap (Egopt) of the composite films were determined. Birefringence was induced by a He-Cd laser with a wavelength 442 nm and measured with probe Diode Pumped Solid State (DPSS) laser at 635 nm. The influence of the dopants concentration on the optical performance of the composite films has been discussed.