Preparation Of Composite Films Research Articles

Preparation and characterization of poly(hydroxybutyrate) and hollow glass microspheres composite films: morphological, thermal, and mechanical properties

In this work, of poly(hydroxybutyrate) (PHB) and glass microspheres (HGM) in different compositions with polypropylene-grafted-maleic anhydride (PP-g-MA) composites were developed by melt intercalation, and then, films from the composites and the polymer matrix were obtained. Subsequently, the morphological, thermal, and mechanical properties were evaluated. A good distribution and intermediate dispersion of the filler throughout the matrix with the formation of some agglomerates was observed, while adhesion between the components was not achieved. The HGM did not affect significantly the thermal properties of the systems; there were discrete variations in the initial degradation temperature (Tonset), peak temperature (Tp), and melting temperature (Tm). However, the degree of crystallinity decreased with the addition of the HGM, and the film with 3% HGM had a variation above 11%. Additionally, it was noticed that the composites (regardless of the presence of PP-g-MA) presented small values of elongation and ultimate stress compared with those of pure PHB.

Facile Preparation of a Novel Transparent Composite Film Based on Bacterial Cellulose and Atactic Polypropylene

Abstract A transparent bacterial cellulose/atactic polypropylene (BC/at-PP) composite film was prepared by a very facile “sandwich” hot-press method. The resulting BC/at-PP composite film exhibited good transparency, hydrophobicity, and significantly enhanced mechanical properties, indicating its tremendous potential as transparent film for food packaging and optoelectronics applications.

Enhancement of Graphite Functionality in Renewable Polymer Composite Properties

The preparation and characterization of composite thin films of renewable polymer graphite (PG) is disclosed. Thin films ~ 0.1 mm thick are prepared using a simple solution mixing with mass proportion of 2/1 (renewable monomer/ Methylene Diphenyl Diisocyanate, MDI), upon differ graphite content (PG0, PG5, PG10, PG15, PG20, PG25 andPG30) and drop casting at room temperature. The morphology-structure relations of renewable PG composites with respect to electrical conductivity were diagnosed using Optical microscope (OM), Fourier transform infra-red spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The homogeneous random dispersion and strong interface between the graphite in the classical insulating renewable polymer matrix were observed. Thus resulting of enhancements in thermal stability with slight shift of decomposition temperature and better mechanical properties through the modulus and tensile strength increment up to ~440% and ~100% respectively. The result shows that it can simultaneously leads to renewable PG conductivity (σ) where the percolation threshold occurs at higher graphite content (PG20, PG25 andPG30) of 103 - 104 S/m. Thus, this non-petroleum based renewable polymer graphite composites have remarkably more to offer as conducting polymer composites material in multidisciplinary applications.

Preparation of polyethylene glycol diglycidyl ether (PEDGE) crosslinked chitosan/activated carbon composite film for Cd2+ removal

Preparation and characterization of polyethylene glycol diglycidyl ether (PEDGE) crosslinked chitosan/activated carbon composite film have been conducted. PEDGE was used as crosslinking agent and activated carbon as a filler on composite film preparation. The composite films were produced with several ratios of chitosan/PEDGE/activated carbon. Tensile test, Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD) and Scanning electron Microscope (SEM) were used to study the structure and properties of PEDGE crosslinked chitosan/activated carbon composite film. Tensile test results showed crosslinking and filler influenced the tensile strength of composite films. The best composite film was obtained at 0.70/0.10/0.20 mixing ratio of chitosan/PEDGE/activated carbon. FTIR, SEM and XRD analysis confirmed the formation of PEDGE crosslinked chitosan/activated carbon composite films. The obtained PEDGE crosslinked chitosan/activated carbon composite film was used for adsorption of Cd2+. The highest adsorption capacity of Cd2+ was obtained at pH 5 and 40 min contact time. Based on Langmuir adsorption isotherm model, the maximum adsorption capacity (Q) of Cd2+ by PEDGE crosslinked chitosan/activated carbon composite film was 357.14 mg/g. Regeneration studies showed the PEDGE crosslinked chitosan/activated carbon composite film can be used repeatly with high performance.

Thermal and electrical properties of polyimide/PANI nanofiber composites prepared via in situ polymerization

Abstract Polyimide/polyaniline nanofiber composites were prepared by in situ polymerization with various weight percentages of polyaniline (PANI) nanofibers. X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), proved the successful preparation of PANI nanofiber composite films. In addition, thermal stability of PI/PANI nanofiber composites was superior relative to PI, having 10 % gravimetric loss in the range of 623 °C to 671 °C and glass transition temperature of 289 °C to 297 °C. Furthermore, the values of the loss tangent tanδ and AC conductivity σAC of the nanocomposite films were notably higher than those of pure polyimide. The addition of 5 wt.% to 15 wt.% PANI nanofiber filler enhanced the activation energy of PI composites from 0.37 eV to 0.34 eV.

3D‐Printed Microfluidic Devices for Materials Science

AbstractMicrofluidics (MFs) has emerged as a valuable and in some cases, unique platform for the synthesis and assembly of inorganic and polymeric materials. 3D printing enables time‐, labor‐, and cost‐efficient prototyping of MF devices, their durability during operation, and the ability to implement complex designs, however the applications of 3D‐printed MF devices in materials science are still in their infancy. Here, the synthesis and assembly of a diverse range of materials, including spraying‐based synthesis of inorganic NPs and conductive filaments, extrusion‐based fabrication of hydrogel fibers and sheets, and the preparation of composite solid films are reported. The properties are examined and potential applications of these materials are shown, the advantages of material fabrication in 3D‐printed MF devices are highlighted, and the directions for their further development are identified.

A Hydrogel-Film Casting to Fabricate Platelet-Reinforced Polymer Composite Films Exhibiting Superior Mechanical Properties.

The fabrication of mechanically superior polymer composite films with controllable shapes on various scales is difficult. Despite recent research on polymer composites consisting of organic matrices and inorganic materials with layered structures, these films suffer from complex preparations and limited mechanical properties that do not have even integration of high strength, stiffness, and toughness. Herein, a hydrogel-film casting approach to achieve fabrication of simultaneously strong, stiff, and tough polymer composite films with well-defined microstructure, inspired from a layer-by-layer structure of nacre is reported. Ca2+ -crosslinked alginate hydrogels incorporated with platelet-like alumina particles are dried to form composite films composed of horizontally aligned alumina platelets and alginate matrix with uniformly layered microstructure. Alumina platelets are evenly distributed parallel without precipitations and contribute to synergistic enhancements of strength, stiffness and toughness in the resultant film. Consequentially, Ca2+ -crosslinked alginate/alumina (Ca2+ -Alg/Alu) films show exceptional tensile strength (267 MPa), modulus (17.9 GPa), and toughness (3.60 MJ m-3 ). Furthermore, the hydrogel-film casting allows facile preparation of polymer composite films with controllable shapes and various scales. The results suggest an alternative approach to design and prepare polymer composites with the layer-by-layer structure for superior mechanical properties.

Preparation and characterization of starch-based composite films reinforced by cellulose nanofibers

The current study deals with the preparation and characterization of polysaccharide-based biocomposite films acquired by the incorporation of cellulose nanofiber within glycerol plasticized matrix formed by starch. The application of starch-based films is limited due to highly hydrophilic nature and poor mechanical properties. These problems are solved by forming a nanocomposite of thermoplastic starch (TPS) as matrix and cellulose nanofiber (CNF) as reinforcement. CNF is successfully prepared from short henequen fibers which consist of almost 60% cellulose by a chemo-mechanical process. TPS/CNF composite films are prepared by the polymer solution casting method, and their characterizations are obtained by water vapor transmission rate (WVTR), atomic force microscopy (AFM), oxygen transmission rate (OTR), X-ray diffraction, light transmittance and tensile test. The 0.4 wt% CNF loaded TPS films showed approximately the maximum improvement in tensile strength. Tensile strength and elastic modulus increased by up to 80% and 170% respectively. Above 0.5 wt% CNF, tensile strength starts to deteriorate. WVTR and OTR results show improvement in water vapor barrier properties of TPS matrix. The AFM analysis shows the topography of the surface of the nanocomposite. The morphology of nanofibers is studied by using the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM).

Self-Assembled Composite Langmuir Films via Fluorine-Containing Bola-Type Derivative with Metal Ions

The design and preparation of functional bolaamphiphile-based composite films are of key importance for application in a wide variety of fields. This study demonstrates a new approach to constructing composite films by the Langmuir-Blodgett (LB) method using a fluorine-containing bola-type diacid derivative with different metal ions. The bola-type molecule we used could be spread on water surfaces and metal ion subphases to fabricate various nanostructured ultrathin films. The obtained data demonstrated that the employed metal ions, including Ag(I), Cu(II), and Eu(III) ions in subphase solutions, can regulate the organized molecular stacking and form interfacial nanostructures deposited in LB films. It was found that the interfacial coordinating interactions can easily occur between carboxyl groups in a molecular skeleton with metal ions in the formed composite films. The formation of composite films was confirmed by changes in the surface pressure-area isotherms, morphologies, and spectra of the transferred LB films. While various research works have achieved the regulation of functions and nanostructures of sophisticated bola-type compounds, we here demonstrate a simple routine to modulate the nanostructures and organized packing of bola-type compounds composite films by changing the metal ions in subphase solutions.

Gold-supported magnetron sputtered Ir thin films as OER catalysts for cost-efficient water electrolysis

This work presents a research on the preparation of thin composite catalytic films in which an essential part of the efficient but expensive Ir is substituted by Au sub-layer using the preparation method of direct current magnetron sputtering (DCMS). The aim is to investigate the influence of the Au sub-layer on the catalytic activity toward oxygen evolution reaction (OER) of water electrolysis. The properties of the sputtered films are studied using X-ray diffraction (XRD) and electrochemical methods of cyclic voltammetry, quasi steady state polarization and chronoamperometry. It is found that by proper variations in the films thickness it is possible to realize synergetic effects leading to essential decrease in Ir loading and the cost of catalysis without sacrifice in efficiency.

Preparation, biocompatibility, and biotribological properties of TiN-incorporated graphite-like amorphous carbon bio-ceramic composite films

In this work, TiN-incorporated graphite-like amorphous carbon (a-GLC) bioceramic films were successfully fabricated on Ti alloy (Ti6Al4V) using the magnetron sputtering technique. The biocompatibility and biotribological properties of the TiN/a-GLC-coated Ti alloy were evaluated. Based on the clinical application, the microstructure, biocompatibility, histomorphological observation, and mechanical properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nanoindentation test, and in vitro and in vivo tests including MTT, cell adhesion test, and slice observation of hard tissues. These techniques confirmed that there was strong bonding between the Ti alloy and the TiN/a-GLC film. In addition, face-centered cubic TiN and hexagonal close-packed Ti were clearly detected in the TiN/a-GLC films. A partial nanocomposite structure, comprised of homogeneous nanoclusters and crystalline particles, was detected in the amorphous matrix. Cell adhesion and MTT test results indicated that the TiN/a-GLC film could promote cell attachment and proliferation. Phase composition and the film morphology were determined to be the crucial factors that contributed to the improved biocompatibility. The biotribological property test showed that the TiN/a-GLC film with a Ti content of 7.8at% had the lowest coefficient of friction (COF) of 0.076 and the lowest wear rate of 1.76 × 10–6mm3(Nm)–1. The low COF was attributed to the superior mechanical properties of the TiN/a-GLC composite film. The TiN/a-GLC-coated Ti alloy implants were placed subcutaneously into rabbits for different time periods, and the tissue response decreased significantly as compared to that of the pure a-GLC film. The excellent biocompatibility and function reliability of the TiN/a-GLC bioceramic films showed that they are potential candidates for bone tissue implants.

Preparation and Characterization of Porous Scaffold Composite Films by Blending Carboxymethyl Chitosan and Gelatin for Tissue Engineering

In this research work, gelatin-carboxymethylchitosan (CMC) based biodegradable composites films were prepared by solution casting method. Chitosan from waste prawn shell was the basic raw materials of CMC synthesis. Five sets of CMC-gelatin composites (5-25 wt% CMC) along-with pure gelatin were prepared in solution casting method. Incorporation of CMC into gelatin significantly altered some of the properties. The CMC and gelatin-CMC composites formation was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Surface morphology of the films was investigated by Scanning Electron Microscopy (SEM) and SEM micrograph revealed that composites were porous and CMC was homogenously dispersed into gelatin. The porous surface of the composites is one of the criterions for new cells growth. Thermal stability of composites were investigated by thermogravimetric analysis (TGA) and composites more thermal stable (less weight loss) than pure gelatin. Antimicrobial and cytotoxicity tests found all composites were performed microbial safe and no cytotoxic effect. The physico-chemical analyses and others analyses of scaffolds revealed for their application as a wound dressing material or artificial skin.

Preparation and characterization of natural corn starch-based composite films reinforced by eggshell powder

ABSTRACTThe aim of this work is to study the effect of eggshell powder (ESP) on the properties of corn starch (CS) films. It was found that the addition of ESP significantly improved the tensile strength, elongation at break, water vapor and oxygen barrier properties compared to the control film. There was an inductive effect between the C–C bonds on cornstarch skeleton and the O–C–O bond on CaCO3 in the ESP and the number of hydrogen bands increased between starch molecules and ESP particles, which indicated a strong interaction and biocompatibility between the two components. In addition, the organic compounds on the surface of ESP increased the adhesion between CaCO3 particles and CS films matrix. In summary, the ESP, as an enhancement factor, is a good candidate for the development of green food packaging material.

Simple preparation of fluorescent composite films based on cerium and europium doped LaF3 nanoparticles

The combination of materials to form hybrids with unique properties, different from those of the isolated components, is a strategy used to prepare functional materials with improved properties aiming to allow their application in specific fields. The doping of lanthanum fluoride with other rare earth elements is used to obtain luminescent particles, which may be useful to the manufacturing of electronic devices’ displays and biological markers, for instance. The application of the powder of nanoparticles has limitations in some fields; to overcome this, the powder may be incorporated in a suitable polymeric matrix. In this work, lanthanum fluoride nanoparticles, undoped and doped with cerium and europium, were synthesized through the co-precipitation method in aqueous solution. Aiming the formation of solid state films, composites of nanoparticles in an elastomeric matrix, the nitrile rubber (NBR), were prepared. The flexibility and the transparency of the matrix in the regions of interest are advantages for the application of the luminescent composites. The composites were applied as films using the casting and the spin coating techniques and luminescent materials were obtained in the samples doped with europium and cerium. Scanning electron microscopy images showed an adequate dispersion of the particles in the matrix in both film formation techniques. Aggregates of the particles were detected in the samples which may affect the uniformity of the emission of the composites.

Preparation of Composite Films of Methacryloyl-modified Lignocresol and Polylactic Acid

Methacryloyl chloride was grafted onto lignocresol to increase the acyl content of lignocresol and to enhance the interfacial compatibility of lignocresol and polylactic acid. The physical and mechanical properties of the modified lignocresol sample were studied. The methacryloyl-modified lignocresol was characterized by infrared spectroscopy (IR), ultraviolet-visible (UV) spectroscopy, and gel permeation chromatography (GPC). Unmodified and modified lignocresol samples were used to prepare composite films with polylactic acid, and its tensile strengths and elongations at breaks were analyzed after film formation. Thermal stabilities were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that methacryloyl group was successfully grafted onto lignocresol, and that the optimum dosage of methacryloyl chloride required was 0.5 mL per 0.5 g of lignocresol. When unmodified lignocresol was added to polylactic acid, the tensile strength gradually decreased as the amount of lignocresol increased. However, the composite films prepared from the methacryloyl-modified lignocresol exhibited a slower decline in tensile strength and displayed an increased elongation at break. The optimum mechanical properties were found using a 10% blend of modified lignocresol with polylactic acid.

Preparation and Properties of Composite Films of Silk Fibroin/Carboxymethyl Chitosan

Preparation and Properties of Composite Films of Silk Fibroin/Carboxymethyl Chitosan

Preparation of optical functional composite films and their application in protein detection

In this work, an optical functional composite film was prepared through self-assembly technique for specific protein detection. The Au nanostructures with metal enhanced fluorescence (MEF) effect were prepared via the in situ reduction of Au ions in a filter paper. Then, a multilayer film was prepared on the Au nanostructures by layer-by-layer adsorption of poly-(ethylenimine), poly-(glycolic acid) and biotinylated poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG-biotin). Through adjusting the structure of multilayer film, an optimum interaction distance between Au nanostructures and fluorophores for the MEF effect was achieved. Meanwhile, the surface PLL-g-PEG-biotin layer allows the film to capture specific streptavidin through biotin-streptavidin interaction. Owing to the MEF effect of Au nanostructures, a significant enhancement in the fluorescence of fluorescein isothiocyanate (FITC) that labeled streptavidin was successfully obtained. This optical functional composite film with enhanced fluorescence could be used to recognize specific protein in a facile and efficient way.

A study of dielectric behavior of manganese doped barium titanate–polyimide composites

AbstractIn this work, a series of BaTi1−xMnxO3–polyimide films were prepared by simple solution casting method. For the preparation of composite films firstly, manganese doped barium titanate, BaTi1−xMnxO3 (where x = 0.00, 0.01, 0.03, 0.05) was synthesized by sol‐gel process. The effect of Mn doping on its structural and dielectric properties was nicely explained. The highest dielectric constant value of 7,104 was obtained for BaTi0.99Mn0.01O3 (BTMn) nanoparticles with low dielectric loss value 2.44. It was observed that Mn‐doping concentration on barium titanate influences its crystal structure. Improved dielectric properties were reported for nanocomposite thin films containing BaTi0.99Mn0.01O3 and polyimide (PI). A series of five homogeneous nanocomposite films were successfully prepared and were characterized thoroughly. The dielectric properties were studied as a function of frequency and loading percentage of BTMn in PI. The dielectric constant of the BTMn/PI nanocomposite films increased from 3.23 to 8.63 with the increase in loading percentage of ceramic from 0 to 5 wt%, respectively. The nanocomposite films were flexible with good mechanical properties and the flexibility decreased with increase in loading percentage of BTMn. The films showed high thermal stability in nitrogen atmosphere up to 571°C with 10% weight loss and also exhibited high glass transition temperature up to 337°C.

Preparation and characterization of starch-based composite films reinfoced by polysaccharide-based crystals

Starch based films, reinforced by two types of polysaccharide-based crystals, were prepared and compared. The films were transparent and their surface was smooth in appearance. Addition of crystals increased the Young's modulus and tensile strength of starch-based materials and decreased elongation at break. Scanning electron microscopic observation indicated good compatibility between starch matrix and the reinforcing fillers due to same chemical unit (glucose). Cellulose crystals have higher thermal stability than that of starch crystals; this provides better processibility and superior mechanical properties to starch films filled with cellulose crystals. On the other hand, starch films filled with starch crystals demonstrated higher protection againstUV radiation. Since all the components used in this work belong to food sources, the prepared films are biodegradable, safe for food packaging and can also be used to developed ible films (such as wrappers for candies) and medicinal capsules (both soft and hard capsules).

Fabrication of homogeneous and enhanced soybean protein isolate-based composite films via incorporating TEMPO oxidized nanofibrillated cellulose stablized nano-ZnO hybrid

Soybean protein isolate (SPI) is well-suited to the preparation of composite films due to its abundance, renewability, biodegradability, and favorable film-forming capacity. In this study, different SPI-based composite films were prepared by incorporating nano-ZnO and 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO) oxidized nanofibrillated cellulose (TNFC) separately or together. Nano-ZnO was introduced to endow the films with multifunction capability, while TNFC was introduced to stabilize the nanoparticles. Both the macro optical characterization and micro scanning electron microscope with energy dispersive X-ray (SEM–EDX) analysis indicated that TNFC could significantly decrease nano-ZnO aggregation and improve its dispersibility in the SPI matrix due to the mechanical restriction and physical adsorption effect of TNFC to the nano-ZnO. In addition to the improved dispersibility, incorporating nano-ZnO and TNFC benefitted the mechanical properties and thermo stability of the SPI-based composite films. The tensile strength and Young’s modulus increased by 73 and 57%, respectively, and the maximum degradation temperature increased by 10 °C, compared to that of the unmodified SPI film. These results can be attributed to the hydrogen bonds formed among SPI components, TNFC, and nano-ZnO, which were further examined by attenuated total reflectance-fourier transform infrared spectroscopy and X-ray diffraction analysis. After the incorporation of nano-ZnO, the SPI-based composite films also possessed excellent UV-shielding capacity and superior antimicrobial ability. To this effect, this work provides a valuable reference for nanoparticles dispersion and application in regards to polymer enhancement and multi-functionalization.