Development and analysis of cellulose nanocomposite films with in situ generated silver nanoparticles using tamarind nut powder as a reducing agent

Cellulose/Tamarind nut powder (TNP)/Silver nanoparticles (AgNPs) nanocomposites were prepared by in situ generation of AgNPs using regeneration method, followed by solution casting method. In this, TNP was used as a reducing agent. These nanocomposites were characterized using FT-IR spectroscopy, XRD and SEM and studied their mechanical properties and antibacterial activity for medical and packing applications. The FT-IR spectral studies revealed the involvement of functional groups – Polyphenols, Flavonoids and –OH in the process of reducing the metal salts into metal nanoparticles. These nanocomposites showed good antibacterial activity against five bacteria. Improved mechanical properties with good antibacterial activities make these composites suitable for medical, food and packaging applications.     

One-step synthesis of manganese dioxide/polystyrene nanocomposite foams via high internal phase emulsion and study of their catalytic activity

This paper is devoted to the preparation of manganese dioxide/polystyrene nanocomposite foams via a novel and facile one-step method using high internal phase emulsion as templates. Scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analyses (TGA) techniques were used to characterize the resulting composites. SEM measurements revealed the porous network structure, the average pore diameters ranged from 3.8 to 30.4 μm. The presence of manganese dioxide was identified by XPS pattern, XRD, pattern and FT-IR spectra of the resulting composites. The TGA thermograms showed that the maximum content of manganese dioxide in the nanocomposite foams reached about 15.5%. The applications of the nanocomposite in the oxidative degradation of methylene blue exhibited good catalytic activity in the presence of H₂O₂ as an oxidant.     

Microwave-hydrothermal synthesis and photocatalytic properties of biomass charcoal/TiO2 nanocomposites

Biomass charcoal-doped titanium dioxide (C/TiO₂) composites were proposed by microwave-hydrothermal and calcination method using tetrabutyl titanate as the titanium source and lignin as the carbon source. TiO₂ crystals with different morphologies could be successfully adsorbed onto the surface of biomass charcoal. These products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), derivative thermogravimetric (DTG), UV–vis diffuser flection spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET). The photocatalytic activities of the as-obtained composites were checked under visible light irradiation. The results showed that both the microwave-hydrothermal temperature and time played an important role in the microstructure and photocatalytic activity of the samples. The rapid microwave-hydrothermal with the thermal post-treatment provides a promising route for the fabrication of biomass charcoal-doped nanocomposites materials.     

FT-IR,EPR and SEM–EDAX investigation of some accelerated aged painting binders

The results of FT-IR, SEM–EDAX and EPR investigations of some binders used in classical paintings and artificial aged binders, i.e. linseed oil, hen yolk and linseed oil/hen yolk are presented and discussed. Carbon dioxide, sulfur dioxide as well as nitrogen oxides were used as aging agents. Accordingly, the FT-IR spectra of all binders showed a set of characteristic modifications. This makes it possible to select the most representative bands which, acting as sui generis fingerprints, provided evidence of certain specific combinations for each binder and the polluting agents. The EPR spectroscopy was helpful in choosing the most appropriate chemical reactions whose products were identified in the corresponding FT-IR spectra. Moreover, the SEM–EDAX data allowed us to establish that, in the case of CO₂ aging, the patina consists of finely dispersed carbon aggregates. Within this context, the most plausible chemical reactions explaining the observed changes were proposed and discussed.     

Preparation and properties of graphene oxide nanosheets/cyanate ester resin composites

Graphene oxide nanosheets (GONSs)/cyanate ester (CE) resin composites were prepared via a solution intercalation method. The structures of the GONSs and the composites were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The mechanical and tribological properties of the composites were investigated. In addition, the thermal behavior of the composites was characterized by thermogravimetric analysis (TGA). Results show that the GONSs/CE resin composites were successfully prepared. The addition of GONSs is beneficial to improve the mechanical and tribological properties of the composites. Moreover, the composites exhibit better thermal stability in comparison with the CE resin matrix.     

Facile synthesis of Cu2O nanocube/polycarbazole composites and their high visible-light photocatalytic properties

Cu₂O nanocube/polycarbazole composites have been prepared by an one-pot solvothermal process using carbazole as a reductant. The polycarbazole layer not only protected and stabilized Cu₂O particles, but also prohibited the recombination of photogenerated electrons-holes pair and facilitated interfacial charge transfer between polycarbazole and Cu₂O. The composition, structure and morphology of the obtained products was systematically studied by X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer. Furthermore, the visible-light photocatalytic behavior of the Cu₂O nanocube/polycarbazole composites on the methyl orange was investigated.     

Thermal and microstructural characterization of compatibilized polystyrene/natural fillers composites

Composites of polystyrene (PS) with cellulose microfibres and oat particles, obtained by melt mixing, were examined. The compatibilization of the composites was carried out by addition of maleic anhydride-functionalized copolymers (SEBS-g-MA, PS-co-MA) and poly(ethylene glycol) to improve the fibre–matrix interfacial interactions. The plain components and their composites were characterised by FT-IR, DSC, TGA, SEM microscopy and mechanical tests. The properties of the various systems were analysed as a function of both fibre and compatibilizer amount. The compatibilized PS composites showed enhanced fibre dispersion and interfacial adhesion as a consequence of chemical interactions between the anhydride groups on the polymer chains and the hydroxyl groups on the fibres, as demonstrated by FT-IR spectroscopy. DSC analysis pointed out a neat increase of T _g of composites on addition of SEBS-g-MA, as compared to PS-co-MA. The thermal stability of composites was also influenced by the type and amount of fibres, as well as by the structure and concentration of compatibilizer. The effect of the reactive copolymers on the composites properties was accounted for on the basis of the polymer–polymer miscibility and chemical interactions at the matrix/filler interface.     

Comparison of the photonic effects of Mn-CNT/TiO<Subscript>2</Subscript> composites modified by different oxidants

Manganese-carbon nanotubes (CNTs) on titania (TiO₂) composites modified by different oxidants (KMnO₄, (NH₄)₂S₂O₈ and m-chlorperbenzoic acid (MCPBA)) were prepared with a sol-gel method. These composites were comprehensively characterized by the Brunauer-Emett-Teller (BET) method, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy EDX, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. The photoactivity of these materials prepared under visible light irradiation was tested using methylene blue in aqueous solution. The result shown that among the three oxidants, the MCPBA was the best one for the surface functionalization of CNTs and the manganese treated CNT/TiO₂ composite can enhance the photocatalytic activity. The proposed mechanism of the photodegradation of methylene blue on Mn-CNT/TiO₂ composites was present.     

Optical Properties of Swift Heavy Ion Beam Irradiated Polycarbonate/Polystyrene Composites Films

Polycarbonate/polystyrene composites films were irradiated by 55 MeV Carbon ion beam with fluence ranging from 1 × 10¹¹ to 1 × 10¹³ ions/cm². The polymer composites films were prepared by solution mixing method. The effects of ion beam on structural, optical and surface morphology of PC/PS composites films were investigated by X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FT-IR) and Optical Microscope. The XRD pattern shows the average crystallite size, percentage of crystallinity and inter-chain separation, which decreases with increase in ion fluences. UV-vis spectra show that the energy band gap and transmittance decreases while number of carbon atoms increases with fluences. The FT-IR spectra evidenced very small change in cross linking and chain scissoring at high ion fluences, while the optical microscopy shows a color change with ion fluence.     

Effect of Chemical Modifications of Fibers on Tensile Properties of Epoxy Hybrid Composites

Treatment of oil palm empty fruit bunch (EFB) and jute fibers is carried out by using 2-hydroxy ethyl acrylate (2-HEA) to increase the interfacial bonding of fibers with the epoxy matrix. Fourier transform-infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to measure the change of surface composition of the fibers after treatment. Modified oil palm and jute fibers were used as reinforcements for epoxy matrix to fabricate hybrid composites by the hand lay-up technique. Tensile and morphological properties of hybrid composites were studied, and tensile properties of hybrid composites prepared from chemically treated oil palm/jute fibers were found to be better than those of untreated hybrid composites. SEM micrographs disclose that interfacial bonding between fiber and matrix significantly improved in the hybrid composites. Developed hybrid composites can be exploited as alternative materials for development of automotive and structural components instead of synthetic fiber–reinforced polymer composites.     

聚吡咯/氧化石墨烯层状复合材料的制备及其在超级电容器中的应用(英文)

通过将吡咯单体在低温下与氧化石墨烯进行原位聚合,获得聚吡咯/石墨烯(Ppy/CRGO)复合材料.采用场发射电子显微镜(FESEM)、红外(FT-IR)和热重分析(TGA)对复合物的表面形貌、结构进行表征.FESEM结果表明,通过控制氧化石墨烯(GO)和吡咯单体的质量比例,可以对复合物的层状和厚度进行调控.FT-IR和TGA结果表明,聚吡咯(Ppy)是通过化学键合的方式与氧化石墨烯复合在一起.通过机械冷压法将粉末状Ppy/CRGO复合物压成圆片电极,并探讨了石墨烯和聚吡咯复合比例、反应时间、烘干温度和孔隙率等因素对Ppy/CRGO复合物电极的电学和电化学性能的影响.结果表明,Ppy与CRGO质量比为10∶1所制得的Ppy/CRGO复合物的电容量为421 F·g-1,通过在电极中引入孔隙,电容量能进一步提升为509 F·g-1.     

MOF-808/BiOCl复合材料的制备及其光催化性能

将高稳定性的MOF-808与BiOCl结合,采用简便的水热法制备出新型MOF-808/BiOCl复合异质结材料。以环丙沙星(CIP)为污染物,探究复合材料MOF-808/BiOCl对CIP的光催化性能。发现含有10% MOF-808的复合材料(MOF-808/BiOCl-10%)表现出最佳的光催化活性。在紫外光照射20 min内,MOF-808/BiOCl-10%对CIP的光催化降解效率高达94.7%。通过X射线粉末衍射、扫描电镜、红外光谱、荧光光谱、紫外可见漫反射光谱、光电流、电化学阻抗等表征技术来考察材料的物相组成、形貌以及光电化学性质。紫外可见漫反射光谱的结果表明,MOF-808/BiOCl-10%材料光吸收范围得到提高。同时进行了自由基捕获实验。基于以上实验数据,提出了MOF-808/BiOCl复合材料可能的光催化机理。     

Effects of gamma irradiation and accelerated aging on GO/UHMWPE nanocomposites

This article investigates irradiated and accelerated aged graphene oxide (GO)/ultrahigh molecular weight polyethylene (UHMWPE) nanocomposites. The prepared GO/UHMWPE nanocomposites are gamma-irradiated at a high irradiation dose in a vacuum and then accelerated aging procedure is performed at 80°C in an air oven for 21 days. Irradiated and aged samples are characterized by Raman spectrum, Fourier transform infrared (FT-IR) spectrum, differential scanning calorimetry, contact angle, and gel content. Filling GO reduces the intensity of Raman spectrum of UHMWPE and irradiation or aging cannot affect vibrational modes of UHMWPE and GO/UHMWPE. The result of the FT-IR spectrum shows that UHMWPE and GO/UHMWPE basically have the same oxidation index values, whether with irradiation or accelerated aging. Irradiation or aging can slightly increase the melting temperature. GO, irradiation, or aging can significantly increase the crystallinity and improve wetting properties. In irradiated GO/UHMWPE, GO is able to maintain the efficiency of the cross-linking. However, after aging, the cross-linking density of GO/UHMWPE is reduced significantly. According to the above results, it is proposed that GO shows a very weak scavenging free radicals capacity in GO/UHMWPE composites and cannot display antioxidant capacity.     

Effect of Polythiophene Content on Thermomechanical Properties of Electroconductive Composites

The thermal, mechanical and electrical properties of polymeric composites combined using polythiophene (PT) dopped by FeCl₃ and polyamide 6 (PA), in the aspect of conductive constructive elements for organic solar cells, depend on the molecular structure and morphology of materials as well as the method of preparing the species. This study was focused on disclosing the impact of the polythiophene content on properties of electrospun fibers. The elements for investigation were prepared using electrospinning applying two substrates. The study revealed the impact of the substrate on the conductive properties of composites. In this study composites exhibited good thermal stability, with T₅ values in the range of 230–268 °C that increased with increasing PT content. The prepared composites exhibited comparable PA T_g values, which indicates their suitability for processing. Instrumental analysis of polymers and composites was carried out using Fourier Transform Infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM).     

Preparation and Characterization of Polypropylene Carbonate Bio-Filler (Eggshell Powder) Composite Films

In recent years, biodegradable polymer composites have attracted considerable attention due to inadequate and depleting petroleum resources and to replace nonbiodegradable synthetic polymers posing environment problems. In the present work, biodegradable composites based on polypropylene carbonate (PPC)/eggshell powder (ESP) were prepared by the solution-casting method using chloroform as the solvent. Polypropylene carbonate was loaded with 1 to 5 wt% of eggshell powder (particle size < 40 µm). Characterization of the composites was accomplished by Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) analysis, and morphological studies were carried out by optical microscopy (OM) and scanning electronic microcopy (SEM). The tensile properties of the composite films were found to be higher than those of neat PPC matrix and increased with ESP content up to 4 wt.% and then decreased. This work offers an easy path to manufacture ecofriendly PPC/eggshell powder composite films with improved properties, and reducing, in some cases, the demand for petroleum-based plastics such as polyolefins.     

氧化石墨烯-Ag纳米粒子/聚酰亚胺混合基质膜及其渗透汽化性能

以聚乙二醇（PEG-400）为还原剂,AgNO₃为前驱体,采用浸渍-还原法合成氧化石墨烯-Ag纳米粒子（GO-AgNP）复合物,再通过共混法制备氧化石墨烯-Ag纳米粒子/聚酰亚胺（GO-AgNP/PI）混合基质膜,用于苯/环己烷混合物的渗透汽化分离。使用透射电子显微镜、红外吸收光谱、拉曼光谱、热失重以及X射线光电子能谱等分析表征GO-AgNP复合物、GO-AgNP/PI混合基质膜的形貌和结构;探讨了Ag掺杂量对GO-AgNP复合物的结构以及GO-AgNP/PI混合基质膜的结构和渗透汽化性能的影响。结果发现,Ag⁺被还原形成AgNP的同时,GO失去了部分含氧官能团;Ag掺杂破坏了GO的结构,使其无序度增加,但改善了GO-AgNP复合物在混合基质膜中的分散性,提升了GO-AgNP/PI混合基质膜的苯/环己烷渗透汽化性能。然而过量的Ag掺杂将使GO片层上产生Ag粒子团聚,从而降低混合基质膜的渗透汽化性能。当Ag掺杂量为15%时,GO-AgNP/PI混合基质膜渗透汽化性能最佳,渗透通量为1 404 g·m^-2·h^-1,分离因子可达36.2。     

氧化石墨烯-Ag纳米粒子/聚酰亚胺混合基质膜及其渗透汽化性能

以聚乙二醇(PEG-400)为还原剂,Ag NO3为前驱体,采用浸渍-还原法合成氧化石墨烯-Ag纳米粒子(GO-Ag NP)复合物,再通过共混法制备氧化石墨烯-Ag纳米粒子/聚酰亚胺(GO-Ag NP/PI)混合基质膜,用于苯/环己烷混合物的渗透汽化分离。使用透射电子显微镜、红外吸收光谱、拉曼光谱、热失重以及X射线光电子能谱等分析表征GO-Ag NP复合物、GO-Ag NP/PI混合基质膜的形貌和结构;探讨了Ag掺杂量对GO-Ag NP复合物的结构以及GO-Ag NP/PI混合基质膜的结构和渗透汽化性能的影响。结果发现,Ag+被还原形成Ag NP的同时,GO失去了部分含氧官能团;Ag掺杂破坏了GO的结构,使其无序度增加,但改善了GO-Ag NP复合物在混合基质膜中的分散性,提升了GO-Ag NP/PI混合基质膜的苯/环己烷渗透汽化性能。然而过量的Ag掺杂将使GO片层上产生Ag粒子团聚,从而降低混合基质膜的渗透汽化性能。当Ag掺杂量为15%时,GO-Ag NP/PI混合基质膜渗透汽化性能最佳,渗透通量为1 404 g·m-2·h-1,分离因子可达36.2。     

聚苯胺/聚丙烯酰胺/镍锌铜铁氧体复合物的制备及电磁性能

采用溶液聚合法制备了聚苯胺/聚丙烯酰胺/镍锌铜铁氧体(PANI/PAM/Zn0.4Ni0.5Cu0.1Fe2O4)三元复合物. 利用X射线衍射仪、红外光谱仪、扫描电子显微镜和振动样品磁强计分别表征了样品的结构、形貌和磁性能, 用阻抗/材料分析仪测定了复合物在1 MHz～1 GHz的频率范围内的磁损耗和介电损耗, 并研究了聚苯胺和引发剂的相对含量对复合物的磁损耗和介电损耗的影响. 结果表明复合物中磁性粒子和聚合物之间具有一定的相互作用, 复合物在1 MHz～1 GHz的频率范围内具有较大电磁损耗能力.     

石墨烯/钴镍双氢氧化物复合材料的制备及其超电容特性

采用氧化石墨(GO)还原法制备石墨烯(GNS),以氨水为沉淀剂,在石墨烯存在的情况下,通过Co²⁺和Ni²⁺化学共沉积的方法合成了石墨烯/钴镍双氢氧化物复合电极材料,采用红外光谱(FT-IR)、X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、比表面积测试(BET)等技术手段表征了产物的组成、结构和形貌,用循环伏安、恒电流充放电等测试方法对复合材料的电化学性能进行了研究。 研究发现,石墨烯纳米片均匀分散在钴镍双氢氧化物中,改善了钴镍双氢氧化物的传导性和结构稳定性。 电化学测试表明,在1 A/g的电流密度下,复合材料比电容高达2770 F/g,且循环500次后,比电容仍能保持93.4%,呈示该复合材料具有优异的电化学性能。     

Thermal,structural and morphological assessment of PVP/HA composites

Composites of poly(vinyl pyrrolidone)/hydroxyapatite (PVP/HA), at variable proportions (100/0; 80/20; 50/50; 20/80 wt%) were prepared and characterized by Fourier transformer-infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetry/differential thermogravimetry (TG/DTG). PVP carbonyl stretching was slightly shifted to lower frequency in composites indicating the formation of hydrogen bonding with HA hydroxyl groups. At the first cycle of heating, the calorimetric curves revealed a broad peak the intensity of which was reduced insofar as the amount of PVP decreased in the composites. This peak was attributed to the PVP enthalpy relaxation. According to the TG/DTG curves, PVP degraded into two steps sharply perceivable in the composites. The first decay was ascribed to the release of the pyrrolidone pendant groups and the following one concerned the burning of the hydrocarbon chains. The HA molecules seem to exert a catalytic action on the PVP degradation.