Papers by Keyword: Composite Film

Abstract: This study investigates the fabrication and potential application of novel sustainable energy materials from poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/amethyst composite films. Solution processing and casting techniques were employed to prepare these composites with varying amethyst content (0 – 0.5 phr). The film characteristics, including appearance, dispersion, morphology, density, and mechanical properties, were comprehensively analyzed. Optical microscopy (OM) revealed good dispersion of amethyst at low loadings, while higher loadings exhibited a tendency towards agglomeration. Notably, the mechanical properties of the composites improved with increasing amethyst content. Tensile strength increased from 5.57 to 13.04 N/mm², strain at break increased from 4.33 to 15.74%, and Young's modulus increased from 156.00 to 258.21 N/mm². The combined properties of PVDF-HFP and amethyst suggest their potential for application in sustainable energy generation. Future work will be directed towards exploring this possibility through further characterization relevant to energy applications.

Abstract: Polyimide/Al₂O₃ films were prepared by the surface modification with different hydrolysis time, ion exchange technique and heat treatment using polyimide films as the substrates and aluminum chloride as the precursor of Al₂O₃. The morphology, thermal properties and electrical properties of the composite films were characterized and tested. The results indicated the alumina distributed in certain thickness on the surface of the films and there was a clear interface layer between the alumina layer and the substrate. The breakdown strength of the composite films maintains the excellent properties of the pristine film while the thermal and corona-resistant time properties of composite films were better than the pristine film due to introducing aluminum oxide. The composite film which used KOH to treat for 90 min has the longest corona-resistant time (101.2 min), which was almost 10 times longer than the pristine film.

Abstract: The electrospinning/spray technique is a promising approach to fabricate composite films for many applications in flexible electronic devices. In this study, an elastic film with remarkable conductivity is synthesized by electrospinning TPU (thermoplastic polyurethanes) fibers and electrospraying graphene nanosheets into the single collector. This technique allows the graphene nanosheets to adhere uniformly to a carbon textile matrix for promoting its conductivity. But the graphene is possible to be oxidized into graphene oxide during electrospray, which is attributed to the high-voltage field, the rapid evaporation of the solvent and the full exposure to air. And the spinning fibers have the potential to induce the behavior as well. The instability of graphene during the process can make an impact on the overall conductivity and uniformity of composite films. So, we set up a series of experiments on the study of oxidization behavior of graphene and its influence on the performance of composite films. With different parameters, some samples are synthesized to conduct Raman spectroscopy analysis as well as take the measurements of overall conductivity through a 4-point probe electrical conductivity device. The oxidization behavior of graphene during the electrospinning/spray process can be well characterized by the results from the Raman spectrums. And the results of electrical conductivity measurements can provide powerful evidence to ensure the great conductivity of composite films via electrospinning/spray process.

Abstract: Poly(butylene succinate) (PBS) was blended with poly(butylene adipate-co-terephthalate) (PBAT) in weight ratios of 80/20 and 70/30 wt%. Zeolite4A and zeolite13X of 1, 2, and 3 wt% were added which polyethylene glycol (PEG) was used to improve compatibility. The blends and composites were compounded and extruded into thin films. Mechanical, thermal, and morphological properties were studied. Water absorption was also investigated. The results showed that adding PEG enhanced elongation at break of the PBS70/PBAT30 film due to plasticizing effect. Better miscibility between PBS and PBAT was observed after adding PEG. Nevertheless, zeolite particles reduced elongation at break of composite films. The composite films with zeolite13X had higher tensile strength but lower elongation at break than those with zeolite4A. The degree of crystallinity increased significantly in the PBS70/PBAT30 film. The 24-hour water absorption of the blends was higher than that of neat PBS film and was higher with respect to zeolite content.

Abstract: Indium sulfide and zinc oxide (In₂S₃-ZnO) films have successfully synthesized by doctor blading method coupling with low temperature precipitation-reflux rout. The weight ratio of In₂S₃ was varied from 0-70 wt.%. Physical characterization results obtained from various analytical techniques exhibit the well crystallinity phase of cubic β-In₂S₃ and wurtzite ZnO structure from XRD patterns. TEM micrograph of 35% In₂S₃-ZnO sample showed the small ZnO particles are embedded into β-In₂S₃. The obtained results exhibited the phase well crystallinity of cubic β-In₂S₃. A strong adsorption spectra shifted toward visible light region and the narrower optical band gap results of In₂S₃-ZnO composite films suggesting that synthesized samples could be used as the visible-light-driven photocatalyst. The photocatalytic activity of rhodamine B had been investigated over entire composite films under visible light illumination. It can be seen that the entire In₂S₃-ZnO composite catalyst films revealed degradation of rhodamine B performance obviously higher than pure ZnO and pure In₂S₃. Moreover, the highest photocatalytic activity was found from 35% wt. In₂S₃-ZnO film which showed 69.5% degradation within 4 h under visible light irradiation.

Abstract: Lignin was extracted from sugarcane bagasse using alkali treatment process. The antimicrobial activity of sugarcane bagasse lignin (LNB) was evaluated against two pathogenic bacteria, Staphylococcus aureus and Escherichia coli by broth dilution method. The MIC and MBC values of LNB are 10,000 μg/ml and 20,000 μg/ml, respestively in both pathogenic bacteria. The composite film between polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) blending with LNB at five different amounts (1%, 3%, 5%, 10% and 15%) were produced by solvent casting. The chemical interactions of composite films were investigated using FTIR. The IR spectra indicates the formation of strong intermolecular hydrogen bonds between the hydroxyl groups of PVA or PVP and lignin. Furthermore, the overall migration was investigated. The migration results revealed that the PVA films blending with lignin up to 3% and the PVP films blending with lignin up to 5% could be considered suitable for application in fatty food packaging field.

Abstract: In this paper, we intended to study and improve the mechanical properties of poly (lactic acid) (PLA) composites with cellulose fibers from recycled newspapers. The influence of cellulose fiber content on tensile mechanical properties and swelling behavior of biocomposite films were investigated. In addition, the morphological property of biocomposite films was determined by scanning electron microscopy (SEM). It was found that the cellulose fibers have directly affected to the swelling behavior of biocomposite films. In addition, it was found that the cellulose fibers were found embedded between PLA matrices, which resulting to the improvement and increase the mechanical properties of biocomposite films. These findings illustrate that the cellulose fibers from recycled newspaper possesses good fillers and could be a good alternative reinforcement for biopolymer composites.

Abstract: Current research efforts toward achieving ceramic/polymer composites which fulfill the balance between sufficiently high dielectric constant (ε) and low dielectric loss (tanδ) are presented. In this paper, ceramic/polymer composite films made of CaCu₃Ti₄O₁₂ (CCTO) powder as filler, which is modified by silane coupling agent vinyltrimethoxysilane (A-171), and polyvinylidene fluoride (PVDF) copolymer as matrix were prepared by solution casting method. The morphology and dielectric properties (DP) were studied by transmission electron microscopy (TEM) and impedance analyzer. The effect of pH and ethanol concentration on the dielectric properties of A-171@CCTO/PVDF were studied. The results show that constant could reach 54.17 and loss 0.05 when mass fraction of A-171 is 0.4% at 1 kHz. pH=4 and using anhydrous ethanol are the optimal conditions.

Abstract: A simple process was developed for preparation of highly photoactive Fe and S codoped TiO₂-SiO₂-ZnO composite film. The Brunauer–Emmett–Teller (BET) surface area results showed that the specific surface area of the composite TiO₂ sample was 432.5m²g^-1, while that of the pure TiO₂ was 103.4m²g^-1. The diffuse reflectance measurements exhibited an extension of light absorption into the visible region for the composite TiO₂. The photoluminescence (PL) spectra analysis indicated that the electron-hole recombination rate was effectively inhibited in the composite TiO₂. The photocatalytic activities of the TiO₂ films were evaluated by the photocatalytic decomposition of methyl green in aqueous solution. The composite TiO₂ film exhibited excellent photocatalytic activities compared to pure TiO₂ film.

Abstract: In this study, corncob hemicelluloses were extracted by hot water to investigate its potential for film production. Extracted hemicelluloses were mixed with PVA 30 wt%, the prepared films had a smooth、uniform and continuous surface and dense cross section without the phase separation, as characterized by SEM. Besides, the mechanical properties and thermal characteristics tests showed that the films had a tensile strength of 4.6 MPa, elongation at break of 6.4%, and a nice thermally stability.