Characteristics Of Composite Films Research Articles

Preparation and characteristics of composite films with functionalized graphene/polyimide

AbstractPolyimide (PI) has the inherent defect of poor intrinsic thermal conductivity and cannot meet the increasing demand for rapid heat dissipation in the thermal management introduction. To improve the thermal conductivity of PI, in this study, thick sheet graphene‐ionic liquid (TSG‐IL) functionalized graphene has been prepared by a one‐step ultrasonic‐chemical method. Under the action of mechanical force, IL is successfully modified on the surface of TSG, and TSG is peeled to some extent. TSG‐IL/PI has been prepared the typical method of solution casting followed by thermal imidization. The structure, morphology, thermal conductivity, and mechanical properties of the composites are evaluated by Fourier‐transform infrared spectroscopy, x‐ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, and Hot Disk thermal conductivity tests. When the amount of TSG‐IL is 0.3 wt%, the thermal conductivity of TSG‐IL/PI (0.18 W·m−1·k−1) than pure PI and TSG (ultrasonication)/PI increased by 50.0% and 28.6%, respectively. Moreover, it can maintain good mechanical properties, and its tensile strength (121.5 MPa) is 6.5% and 3.5% higher than that of pure PI and TSG (ultrasonication)/PI, respectively. The potential for application in the preparation of composites with high‐thermal conductivity is promising.

Effect of synergism between sodium alginate and xanthan gum on characteristics of composite film and gloss of areca nut coating

In this study, two polysaccharides of sodium alginate (SA) and xanthan gum (XG) were compounded in proportions of 100:0, 75:25, 50:50, 25:75, 0:100 with 1% total mass concentration and then coated on areca nuts. The effects of their synergistic interactions on the optical appearance of the edible coating were investigated for the first time. Areca nuts coated by 50:50 SA-XG presented the highest gloss (2.69 GU) and maximum spreading coefficient (−33.95 mN/m), indicating the improved wettability of the coating solution on the fruit's surface. The polarized light microscopy exhibited the unique birefringence phenomenon caused by the liquid crystal state, resulting in the better optical properties of the coating. UV–vis transmittance, Fourier transform infrared, and scanning electron microscopy indicated the good compatibility of SA and XG. The SA-XG film was more compactly arranged and had a denser microstructure due to hydrogen bonding. Additionally, the SA-XG combination improved the mechanical properties and water resistance compared to a single polysaccharide films and enhanced the water retention properties for the areca nut coating. Therefore, the SA-XG combination is promising to prepare edible films with improved optical properties for areca nuts.

Characteristics and properties of chitosan/alginate/lovastatin composite films

This study aims to learn about the preparation and properties of alginate/chitosan polyme films blend carrying lovastatin drug. Some characteristics of composite films have been investigated by many methods, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimeter and swelling capacity. The results show that the composite had a relatively homogeneous distribution of lovastatin. The chararcteristic signs in the FTIR of each agent still appeared in the FTIR spectra of the composite films however they had a slightly shift. This proved that the alginate, chitosan and lovastatin had strong interaction together by the dipole-dipole interaction and hydrogen bonding between the amine and hydroxyl groups in chitosan with the carboxyl group in alginate. The melting temperature of the composite films were lower than these of lovastatin and the films were able to swell in water for 3-4 hours, then disintegrate over time as alginate dissolved.

MoS2 Additives for Enhancing Tribological Performance of Hydroxypropyl Methylcellulose Biopolymer

This study demonstrates the influence of MoS2 additives on the tribological performance of Hydroxypropyl methylcellulose composite films. Biopolymers have numerous potential applications, as they can be relatively quick and easily prepared and possess characteristics that are easy to optimize. The tribological characteristics of composite films can be enhanced by controlling the thickness of the film and by adding MoS2 particles. An appropriate film thickness can optimize the tribological characteristics and service life of the film. MoS2 nanoparticle additives can alter the surface morphology of a film, thus, affecting its tribological behavior. The addition of an appropriate quantity of MoS2 can alter the surface roughness and load-carrying capacity of the film. The mechanism by which MoS2 enhances the tribological characteristics of a composite film is dependent on the uniform dispersion of MoS2 particles within the film and the optimization of the surface roughness of the film.

In vitro and in vivo evaluation of the chitosan/Tur composite film for wound healing applications

We have developed tourmaline/chitosan (Tur/CS) composite films for wound healing applications. The characteristics of composite films were studied by optical microscope, infrared spectra and X-ray diffraction. Tur particles were uniformly distributed in the CS film and the crystal structure of CS was not remarkably changed except the decrease of crystallinity. The influence of Tur on wound healing applications was characterized by modulating Tur concentrations in the Tur/CS composite film prepared by loading Tur powder into CS matrix with different proportion (0, 1/40 and 1/10). Then L929 cells were co-cultured on the composite films to access the cytotoxicity in vitro. Tur concentrations strongly influenced cell process extension. Tur/CS composite film with 1/40 mass ratio could promote the cell adhesion and proliferation. Fewer and shorter processes were observed at high Tur density. When the composite films were transplanted on porcine full-thickness burn wounds, histological results demonstrated that the Tur/CS group with 1/40 mass ratio had a significantly higher number of newly-formed and mature blood vessels, and fastest regeneration of dermis. Based on the observed facts these films can be tailored for their potential utilization in wound healing and skin tissue engineering applications.

Influence of the temperature on current-voltage characteristics of composite materials fabricated based on a polypropylene matrix and carbon fillers

A composite material based on a polypropylene matrix and carbon fillers has been fabricated in the form of films and blocks. It has been shown that the dependence of the resistivity of the composite on the filler weight fraction has a threshold character. The current-voltage characteristics of composite films have been measured at different temperatures in the range of 80–360 K. The temperature dependence of the resistivity of the composites at different filler weight fractions has been found. A theoretical description of current-voltage characteristics at different temperatures has been presented.

Pyroelectric Properties of PVDF:MWCNT Nanocomposite Film for Uncooled Infrared Detectors and Medical Applications

The biocompatible and flexible polyvinylidene fluoride (PVDF) has a number of interesting pyroelectric and piezoelectric properties with fast, dynamic response for use in touch/tactile sensors, infrared detectors and thermal vidicon/imaging devices. Pyroelectric multi-walled carbon nano-tubes:polyvinylidene fluoride nano-composite films were fabricated via the solution casting technique. The dielectric, pyroelectric and piezoelectric characteristics of composite films were measured. Using foregoing parameters, figures-of-merit for infrared detectors, and thermal-vidicons were calculated. The results indicated figures-of-merit of the composite film that were higher than pristine polyvinylidene fluoride film. The potential applications of composite films in medical devices are also discussed.

Reflective and Magnetic Properties of Photonic Polymer Composite Materials Based on Porous Silicon and Magnetite Nanoparticles

Photonic polymer composite materials exhibiting both reflective and magnetic properties were prepared by the replication of rugate porous silicon (PS) using polystyrene and magnetite nanoparticle (Fe3O4). Rugate PS prepared by applying a computer-generated pseudo-sinusoidal current waveform resulted in a mirror with high reflectivity in a specific narrow spectral region and served as a template for replicating its nanostructure with polystyrene containing the magnetic nanoparticles of magnetite. The composite films replicated a sharp photonic resonance with full-width at half maximum (FWHM) of 20 nm from rugate PS in the reflectivity spectrum as well as displayed a magnetic property of magnetite nanoparticles in SQUID magnetometry. Optical characteristics of composite films indicated that the surface of polymer film had a negative structure of rugate PS. The composite films were stable in aqueous solutions for several days without any degradation.

Evaluation of the optical characteristics of composite films with carbon fillers in the IR range of wavelengths

The applicability of the Bouguer—Lambert—Beer law was demonstrated for determining the optical characteristics of composite films in analyzing absorption of laser radiation with introduction of the corresponding corrections. The validity of using Eq. (5) for composite films with carbon fillers was demonstrated and is very important in analyzing reflection of laser radiation from the investigated composites. The optical characteristics of the composite films with carbon fillers are not only a function of the filler content, but also of the filler type.

408 高配向CNTを有するコンポジットフィルムの諸特性(高分子/高分子基複合材料)

408 高配向CNTを有するコンポジットフィルムの諸特性(高分子/高分子基複合材料)

Preparation and characterization of thick magnetostrictive films

In this paper, magnetostrictive thick films are prepared by screen-printing and sintering. The morphology, magnetic character and magnetostriction prepared at different temperatures are studied. Characteristics of composite films thus prepared are compared with the original magnetostrictive blocks.

Morphological Characteristics of Composite Films

For the testing of methods for morphological analysis of composite films, a computer experiment was suggested. Two models were prepared to study the possibility of at least partial reconstruction of 3D structures from their 2D projections or sections. The importance of some morphological characteristics for the reconstruction of size and/or spatial distribution of objects is shown in the paper. It illustrates the usage and significance of the integral transform method for the unfolding of the structures, too.