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In this research, mango parts (kernel and integument) were loaded into a polylactic acid (PLA) matrix by a casting process to develop biocomposite materials. These materials should present improved mechanical and thermal properties and have the potential to be used as environmentally friendly, biodegradable food packaging material with extended shelf life. For this purpose, the research was divided into two parts: step 1, ground materials of a certain particle size from a previous work1 and step 2, which are the materials from Step 1 ground again. The samples were characterized by x‐ray diffraction, scanning electron microscopy (SEM), laser granulometry, texture tests, and thermal analysis. The difference between them was particle size distribution, impacting the materials' mechanical strength and degradation rate. Three biocomposites were made (PLA/kernel, PLA/integument, and PLA/kernel/integument) in both steps. SEM was used to observe the size distribution of the mango seed and sample morphology. In addition, resistance values increased with the addition of kernel or integument particles. Biocomposite biodegradability was also evaluated. Based on the results of this study, the biocomposites showed high mechanical properties and thermal stability, making them suitable for applications such as food packaging and structural components to help reduce environmental loads and microplastic generation. [ABSTRACT FROM AUTHOR]

This work focuses on the characterization of five palygorskite clays from the Brazilian state of Piaui and their feasibility as eco-friendly adsorbents for the removal of Fe3+ ions from aqueous solutions. For characterization, we applied the techniques of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), size distribution measurements, density measurement by He pycnometry, superconducting quantum interference device (SQUID) magnetometry, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTA), zeta potential measurement, hydrophobicity determination by contact angle, Brunauer–Emmett–Teller surface area analysis (BET technique) and atomic force microscopy (AFM). Batch experiments were performed in function of process parameters such as contact time and initial concentration of Fe3+. The natural palygorskites (Palys) had excellent performance for the removal of Fe3+ from aqueous solutions by adsorption (around 60 mg/g), and the Langmuir is supposedly the best model fitted the experimental data. [ABSTRACT FROM AUTHOR]

Geopolymers are a type of inorganic polymer that typically have a monochromatic appearance. This study investigates the formation of artificial chrysocolla by immersing these materials in Cu(II) ion solutions. The resulting synthetic chrysocolla possesses magnetic properties and characteristic silicate bands in its structure, indicating geopolymerization and a similarity to natural chrysocolla. Furthermore, the inclusion of copper and zinc ferrites in the nano-modified geopolymer matrix enhances its properties and potential antiviral properties. The antiviral test results show that synthetic chrysocolla based on nano-modified geopolymers has a mild antimicrobial effect. However, more testing is needed to determine its effectiveness against bacteriophage, as bacterial growth was observed in the area where the nano-modified geopolymer bacteriophage blend was applied. In addition to its potential antiviral properties, synthetic chrysocolla's porous structure allows it to act as an adsorbent, making it useful in the development of antiviral filters. Artificial chrysocolla can be obtained through a geopolymeric matrix by immersing it in a solution of Cu(II) ions, which can occur by ion exchange of the ions present in the aluminosilicate structure with Cu(II). Neutralization of the geopolymer matrix by washing with distilled water is required prior to immersion to ensure proper formation of chrysocolla and not copper(II) hydroxide on the geopolymer surface. Overall, this study provides evidence for the successful preparation of nano-modified synthetic chrysocolla from geopolymers and ferrites, with properties and chemical composition similar to those of natural chrysocolla. The presence of copper ions in its composition and the incorporation of copper and zinc ferrites can contribute to its use as a resource to combat viral pathogens. [ABSTRACT FROM AUTHOR]

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The effects of concentration and surface modification of two Brazilian bentonite clays on nanocomposites' properties based on polylactic acid – (PLA) were investigated. The samples were prepared by the extrusion/injection method to obtain biodegradable packaging plastics. The raw materials and their bionanocomposites were characterized by various techniques. Natural clay samples presented a size of around 2 μm while the modified ones' size was 5–6 μm, probably due to the presence of cetyltrimethylammonium bromide in the interlayer space. The particle size and the contact angle increased with the treatment and the clay's density decreased. The organoclays were homogeneously dispersed in PLA, which can be associated with the interactions between PLA chains' carbonyl groups and the organoclays. The bionanocomposites present modified clay particles axis aligned to the flow direction of the extruder/injector. Chocolate organoclay acts as a nucleating agent to PLA crystal growth, increasing the sample's crystallinity, while Bofe organoclay interferes with the amorphous chain's mobility and diminishes the sample's crystallization. The addition of both organoclays to PLA diminished the sample's elongation at break and strength, although the organoclays increased the sample's Young modulus, even though Bofe organoclay is more active in PLA amorphous phase and Chocolate organoclay on the crystalline one. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles are widely used in current medicine because their magnetite properties allow several uses as drug delivery systems, contrasts in imaging tests, and even for magnetohyperthermia. However, magnetic nanoparticles possess meager Zeta potential, presenting a strong tendency to agglomerate. For clinical use, they must be covered with a biocompatible material to maintain colloidal stability, without, however, altering its magnetic properties. Thus, for biomedical applications in general, magnetic nanocomposites are more interesting than pure magnetite. The present work applies poly(butylene succinate) (PBS), as a coating on magnetite nanoparticles, aiming to increase their biocompatibility. PBS is a polymer obtained from renewable sources, being entirely suitable for pharmacological uses. In this work, the synthesis of ricinoleic acid from natural castor oil is carried out through the saponification method and subsequent acid hydrolysis. In turn, the synthesis of magnetite nanoparticles is performed by coprecipitation. Then, by an acid‐base reaction, the nanoparticles are treated with ricinoleic acid. Soon afterward, toluene diisocyanate is used to produce bonding between the modified particles and PBS. Fourier‐transform infrared spectroscopy confirms the synthesis of the material. Also, scanning electron microscopy and dynamic light scattering experiments are performed. The obtained results allow inferring the success in the preparation of the pursued hybrid material. [ABSTRACT FROM AUTHOR]

Mango seeds from agro‐industry represents an environmental problem due to the amounts of by‐products produced. Conversely, poly (lactic acid) (PLA) is a potential green alternative to conventional plastics. The goal of this study aimed to develop a biocomposite based on PLA and mango's by‐product for rigid packaging. Six biocomposites are obtained by extrusion/injection processing using formulations with PLA as a matrix and up to 20% by weight of mango seed's by‐products. The materials are characterized by chemical and physical analysis; scanning electron microscopy/energy dispersive X‐ray, X‐ray diffraction; Fourier transform infrared spectroscopy (FTIR); thermal gravimetric analysis/differential thermogravimetry; differential scanning calorimetry (DSC), and mechanical analysis. FTIR bands and DSC transitions related to starch are higher in the kernel, while more cellulose bands are found in the integument. Kernel presented thermal degradation in the biocomposites, the sample PLA+20 wt% kernel. For the other compositions, it is possible to observe that they could keep their morphology. Significant improvements in both mechanical and barrier properties are found in the formulation with 20 wt% integument (up to 38% in elastic modulus). Therefore, this study suggests that biocomposites developed from PLA / Integument / Kernel have potential as a new biomaterial for rigid food packaging systems. [ABSTRACT FROM AUTHOR]

Alginate hydrogels have many attractive characteristics for potential use as wound dressing materials. However, they are not considered to possess any intrinsic activity against microbial infection, often present in neuropathic wounds. To overcome this, the effect of incorporating neomycin or propolis in alginate hydrogels was investigated, both by direct blending alone and also by further addition of loaded alginate microparticles prepared by the extrusion dripping method. The morphological, microstructural, thermal, mechanical, and swelling properties of each film were evaluated, as well as particle size distribution and antimicrobial penetration analysis. Microparticle size was considered suitable for drug delivery applications and incorporation in hydrogel films. The presence of neomycin and propolis, in both blended and microparticle form, interfered with film properties leading to hydrogels with different characteristics. All samples showed swelling degrees up to 100% and mechanical and thermal properties suitable for application as wound dressings. In addition, all samples acted as barriers to microbial penetration. [ABSTRACT FROM AUTHOR]

ABSTRACT: Water contaminated by oil poses challenges to the management of water resources. Magnetic nanoparticles has been issue of different potential applications including remotion oil from water. Magnetic polystyrene–palygorskite nanocomposites were prepared by a heterogeneous phase polymerization for the removal of organic contaminants from water. The organo‐Fe3O4‐palygorskite nanoparticles were coated with polystyrene, forming water repellent and oil absorbing surfaces to promote the removal of oil from the surfaces of nanocomposites by applying an external magnetic field. X‐ray fluorescence, X‐ray diffraction, scanning electron microscopy, zeta potential and size distribution measurement, surface area determination by BET, density measurement by He pycnometry, carbon grade determination, thermogravimetric analysis, Fourier‐transform infrared spectroscopy, Raman spectroscopy, and evaluation of hydrophobicity by contact angle were used to characterize the nanoparticles. The magnetic nanocomposite obtained showed excellent hydrophobicity, around 78° contact angle. In addition, oil removal capability tests were also performed, according to which the preliminary results indicated removal of approximately 98% of oil in synthetic oily water samples. The oil–water separation using this magnetic nanocomposite provides a promising alternative strategy for water treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46162. [ABSTRACT FROM AUTHOR]

The organophilization of clays to increase interfacial interactions is a typical practice when the objective is its encapsulation with a polymer. This work intend to synthesize and characterize an organo-palygorskite-Fe 3 O 4 , to change the hydrophilicity of the material and investigate its efficiency in the removal of two anionic dyes from aqueous solution with the aim to use this material to treat wastewater contaminated with dyes. The organophilization of modified palygorskite–Fe 3 O 4 was done with a cationic surfactant (cetyl trimethylammonium bromide, CTAB) and the material obtained was characterized by XRF, SEM, XRD, FTIR, Nano Zetasizer, density, BET surface area, TGA/DTA and contact angle measurements. XRF and FTIR confirmed the presence of carbon in the modified palygorskite–Fe 3 O 4 nanoparticles while XRD showed new crystalline phases from CTAB. Furthermore, a positive zeta potential value appeared and an inversion in the nanoparticles' hydrophobicity happened due to the increase of organic carbon content in the organo-palygorskite-Fe 3 O 4 . The adsorbed anionic dye on organo-palygorskite-Fe 3 O 4 may be completely recovered by the action of a magnet, showing an excellent adsorptive property and economical alternative adsorbents to treat dye wastewater. The negative values calculated for the free energies of adsorption indicate that the adsorption of methyl orange and indigo carmine on the active sites of organo-palygorskite-Fe 3 O 4 surface was spontaneous and that the indigo carmine had the best interaction with the magnetic organo clay. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is a biodegradable polymer used in packaging, but its properties can be improved by manufacturing composite matrixes. The combination of PLA, starch, and nano‐montmorillonite leads to materials with superior mechanical properties. Mango lump is rich in cellulose and starch. The goal of this study is to develop and characterize biocomposites based on PLA, mango waste, and nano‐organo‐montmorillonite for packaging. The samples were microstructurally, morphologically, and mechanically characterized. Physical interaction between the phases was observed. The mango components displaced the PLA X‐ray diffraction peaks and the clays altered their intensity, by interfering with chain packing. The addition of single components to PLA increased the samples' transition temperatures, but the addition of multiple components diminished them. PLA showed adhesiveness to cellulose fibers and nonadhesiveness to starch granules. Thicker samples presented better mechanical properties. PLA–mango–"chocolate clay" samples are relatively stable materials, while PLA–mango–"bofe clay" samples could represent promising highly biodegradable materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47512. [ABSTRACT FROM AUTHOR]

In this work, intelligent materials were developed from the cotton fabric modified with polyaniline (PAni). PAni was used in different oxidation states (Emeraldine Salt, Emeraldine, Leucoemeraldine and Pernigraniline Base). The obtained materials were tested as colorimetric hydrogen sulfide gas sensors. The intelligent fabrics were analyzed by Infrared Spectrometry (FTIR), X‐ray powder diffraction (XRD), Thermogravimetric Analysis (TGA), Energy Dispersive X‐Ray Spectroscopy (EDS), Optical Microscopy and Electrical Resistivity Analysis. Smart fabrics were exposed to hydrogen sulfide gas, and colorimetric analyses were performed before and after exposure to identify fabrics capacity of detection. The obtained results allowed inferring that the best material was the one modified with Emeraldine base. This low‐cost material can be easily obtained, constituting a valuable hydrogen sulfide gas detection tool. [ABSTRACT FROM AUTHOR]