Structural, morphological and thermal properties of nanocomposites poly(GMA)/clay prepared by ultrasound and in-situ polymerization

In Situ Preparation of Silver Nanoparticles/Organophilic-Clay/Polyethylene Glycol Nanocomposites for the Reduction of Organic Pollutants

This work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples. The results showed that the catalyst with the highest molecular weight of polyethylene glycol had the highest AgNP content. Catalyst mass, NaBH4 concentration, and type of catalyst were shown to have a significant influence on the conversion and rate constant. The material with the highest silver nanoparticle content was identified as the optimal catalyst for the reduction of both pollutants. The measured rate constants for the reduction of methylene blue (MB) and 4-nitrophenol (4-NP) were 164 × 10-4 s-1 and 25 × 10-4 s-1, respectively. The reduction of MB and 4-NP in the binary system showed high selectivity for MB dye, with rate constants of 64 × 10-4 s-1 and 9 × 10-4 s-1 for MB and 4-NP, respectively. The reuse of the best catalyst via MB dye reduction for four cycles showed good results without loss of performance.

Antimicrobial Properties of Azole Functional Silica Nanocomposites

Silica nanoparticles have become more attractive due to their surface characteristics, versatility, biocompatibility, and morphological and physicochemical properties. For this reason, their use in biological applications has been expanding in recent years. In this study, after functionalizing silica nanoparticles with glycidyl methacrylate monomer, nanocomposites were formed by attaching 1,2,4‐Triazole, 3‐Amino‐1,2,4‐Triazole, and 5‐Aminotetrazole particles to the surface. Notably, the thermal degradation temperature of all nanocomposites was determined to surpass 200 °C. However, it is worth mentioning that despite the favorable water uptake rates observed for MT(7.64 %) and M3(5.98 %) nanocomposites, MT did not exhibit resistance against Fenton chemicals and experienced degradation. It is important to note that the material loss in M3 nanocomposites is minimal, measuring less than 1 %. In order to reveal the antifungal and antibacterial activity of the synthesized nanoparticles, Minimum inhibitory concentration(MIC), as well as Minimum Fungicidal Concentration(MFC) against the yeast strain Saccharomyces cerevisiae, and Minimum Bactericidal Concentration(MBC) values against bacteria strains, Staphylococcus aureus, Enterococcus faecalis and Escherichia coli were determined. The findings of the study indicated that MP, M3, and M5 nanocomposites displayed a moderate level of antibacterial activity. It is noteworthy, however, that the antibacterial activity diminished when triazole was combined with MP at concentrations exceeding 100 mg/mL.

Green Copolymers and Nanocomposites from Myrcene and Limonene Using Algerian Nano-Clay as Nano-Reinforcing Filler

In this work, we report a new facile method for the preparation of myrcene-limonene copolymers and nanocomposites using a Lewis acid as a catalyst (AlCl₃) and organo-modified clay as a nano-reinforcing filler. The copolymer (myr-co-lim) was prepared by cationic copolymerization using AlCl₃ as a catalyst. The structure of the obtained copolymer is studied and confirmed by Fourier Transform Infrared spectroscopy, Nuclear Magnetic Resonance spectroscopy, and Differential Scanning Calorimetry. By improving the dispersion of the matrix polymer in sheets of the organoclay, Maghnite-CTA⁺ (Mag-CTA⁺), an Algerian natural organophilic clay, was used to preparenanocomposites of linear copolymer (myr-co-lim). In order to identify and assess their structural, morphological, and thermal properties, the effect of the organoclay, used in varyingamounts (1, 4, 7, and 10% by weight), and the preparation process were investigated. The Mag-CTA⁺ is an organophylic montmorillonite silicate clay prepared through a direct exchange process in which they were used as green nano-reinforcing filler. The X-ray diffraction of the resulting nanocomposites revealed a considerable alteration in the interlayer spacing of Mag-CTA⁺. As a result, interlayer expansion and myr-co-lim exfoliation between layers of Mag-CTA⁺ were observed. Thermogravimetric analysis provided information on the synthesized nanocomposites' thermal properties. Fourier transform infrared spectroscopy and scanning electronic microscopy, respectively, were used to determine the structure and morphology of the produced nanocomposites (myr-co-lim/Mag). The intercalation of myr-co-lim in the Mag-CTA⁺ sheets has been supported by the results, and the optimum amount of organoclay needed to create a nanocomposite with high thermal stability is 10% by weight. Finally, a new method for the preparation of copolymer and nanocomposites from myrcene and limonene in a short reaction time was developed.

The physical, mechanical, thermal and barrier properties of starch nanoparticle (SNP)/polyurethane (PU) nanocomposite films synthesised by an ultrasound-assisted process

This article reports on the ultrasound-assisted acid hydrolysis for the synthesis and evaluation of starch nanoparticles (SNP) as nanofillers to improve the physical, mechanical, thermal, and barrier properties of polyurethane (PU) films. During the ultrasonic irradiation, dropwise addition of 0.25 mol L^-1 H₂SO₄ was carried out to the starch dispersion for the preparation of SNPs. The synthesized SNPs were blended uniformly within the PU matrix using ultrasonic irradiation (20 kHz, 220 W pulse mode). The temperature was kept constant during the synthesis (4 °C). The nanocomposite coating films were made with a regulated thickness using the casting method. The effect of SNP content (wt%) in nanocomposite coating films on various properties such as morphology, water vapour permeability (WVP), glass transition temperature (Tg), microbial barrier, and mechanical properties was studied. The addition of SNP to the PU matrix increased the roughness of the surface, and Tg by 7 °C, lowering WVP by 60% compared to the PU film without the addition of SNP. As the SNP concentration was increased, the opacity of the film increased. The reinforcement of the SNP in the PU matrix enhanced the microbial barrier of the film by 99.9%, with the optimal content of SNP being 5%. Improvement in the toughness and barrier properties was observed with an increase in the SNP content of the film.

Synthesis and Characterization of Copolymers and Nanocomposites from Limonene, Styrene and Organomodified-Clay Using Ultrasonic Assisted Method

In the present work, we report a simple synthesis method for preparation of copolymers and nanocomposites from limonene and styrene using clay as a catalyst. The copolymerization reaction is carried out by using a proton exchanged clay as a catalyst called Mag-H⁺. The effect of temperature, reaction time and amount of catalyst were studied, and the obtained copolymer structure (lim-co-sty) is characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H-NMR) and differential scanning calorimetry (DSC). The molecular weight of the obtained copolymer is determined by gel permeation chromatography (GPC) and is about 4500 g·mol⁻¹. The (lim-co-sty/Mag 1%, 3%, 7% and 10% by weight of clay) nanocomposites were prepared through polymer/clay mixture in solution method using ultrasonic irradiation, in the presence of Mag-CTA⁺ as green nano-reinforcing filler. The Mag-CTA⁺ is organophilic silicate clay prepared through a direct exchange process, using cetyltrimethylammonuim bromide (CTAB). The prepared lim-co-sty/Mag nanocomposites have been extensively characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). TEM analysis confirms the results obtained by XRD and clearly show that the obtained nanocomposites are partially exfoliated for the lower amount of clay (1% and 3% wt) and intercalated for higher amounts of clay (7% and 10% wt). Moreover, thermogravimetric analysis (TGA) indicated an enhancement of thermal stability of nanocomposites compared with the pure copolymer.

Review of Clay-Based Nanocomposites as Adsorbents for the Removal of Heavy Metals

Due to rapid industrialization, urbanization, and surge in modern human activities, water contamination is a major threat to humanity globally. Contaminants ranging from organic compounds, dyes, to inorganic heavy metals have been of major concern in recent years. This necessitates the development of affordable water remediation technologies to improve water quality. There is a growing interest in nanotechnology recently because of its application in eco-friendly, cost-effective, and durable material production. This study presents a review of recent nanocomposite technologies based on clay, applied in the removal of heavy metals from wastewater, and highlights the shortcomings of existing methods. Recently published reports, articles, and papers on clay-based nanocomposites for the removal of heavy metals have been reviewed. Currently, the most common methods utilized in the removal of heavy metals are reverse osmosis, electrodialysis, ion exchange, and activated carbon. These methods, however, suffer major shortcomings such as inefficiency when trace amounts of contaminant are involved, uneconomical costs of operation and maintenance, and production of contaminated sludge. The abundance of clay on the Earth’s surface and the ease of modification to improve adsorption capabilities have made it a viable candidate for the synthesis of nanocomposites. Organoclay nanocomposites such as polyacrylamide-bentonite, polyaniline-montmorillonite, and β-cyclodextrin-bentonite have been synthesized for the selective removal of various heavy metals such as Cu2+, Co2+, among others. Bacterial clay nanocomposites such as E. coli kaolinite nanocomposites have also been successfully synthesized and applied in the removal of heavy metals. Low-cost nanocomposites of clay using biopolymers like chitosan and cellulose are especially in demand due to the cumulative abundance of these materials in the environment. A comparative analysis of different synthetic processes to efficiently remove heavy metal contaminants with clay-based nanocomposite adsorbents is made.

An Investigative Study on the Progress of Nanoclay-Reinforced Polymers: Preparation, Properties, and Applications: A Review

Nanoclay-reinforced polymers have attracted considerable universal attention in academic and industrial research due to their outstanding properties and their ever-expanding utilization in diversified applications. In that regard, in the present review, the structure of layered silicate clay, as well as procedures for clay material modification, are outlined. We also discuss the general characterization techniques, synthesis methods, and various properties of polymer-clay nanocomposites (PCNs), and some examples likewise are depicted from the scientific literature. The study's primary goal is to provide an up-to-date survey of polymer-clay nanocomposites and their specific applications in industries such as automotive, flame-retardant, and biomedical applications, coating, and packaging.

Low-Frequency Ultrasound Coupled with High-Pressure Technologies: Impact of Hybridized Techniques on the Recovery of Phytochemical Compounds

The coupling of innovative technologies has emerged as a smart alternative for the process intensification of bioactive compound extraction from plant matrices. In this regard, the development of hybridized techniques based on the low-frequency and high-power ultrasound and high-pressure technologies, such as supercritical fluid extraction, pressurized liquids extraction, and gas-expanded liquids extraction, can enhance the recovery yields of phytochemicals due to their different action mechanisms. Therefore, this paper reviewed and discussed the current scenario in this field where ultrasound-related technologies are coupled with high-pressure techniques. The main findings, gaps, challenges, advances in knowledge, innovations, and future perspectives were highlighted.

Design and synthesis of transparent and flexible nanofibrillated cellulose films to replace petroleum-based polymers

Nanofibrillated cellulose films have garnered attention due to their interesting proprieties such as transparency and high mechanical strength. However, they are brittle, very hydrophilic, which is decreasing their potential applications. We have successfully achieved a simple and effective chemical modification based on polymer grafting and through plasticizer additions to increase the performance of the films as well as to improve the compatibility within conventional polymer. A preliminary study shows the possibility of using this film as an interlayer in safety glazing and/or bulletproof glass with polyvinyl butyral (PVB). The modified NFC films displays high optical transmittance (93 %), increases tensile stretch and is more hydrophobic (83°). A higher flexibility was also achieved, as the film was greatly stretched and bended without cracking or breaking. The NFC / PVB composite has three times more elongation at break, 13 % more specific energy absorbed with a half-tensile stress compared to an interlayer of PVB.

Green Nanocomposites from Rosin-Limonene Copolymer and Algerian Clay

Green nanocomposites from rosin-limonene (Ros-Lim) copolymers based on Algerian organophilic-clay named Maghnite-CTA⁺ (Mag-CTA⁺) were prepared by in-situ polymerization using different amounts (1, 5 and 10% by weight) of Mag-CTA⁺ and azobisisobutyronitrile as a catalyst. The Mag-CTA⁺ is an organophilic montmorillonite silicate clay prepared through a direct exchange process; the clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide in which it used as green nano-filler.The preparation method of nanocomposites was studied in order to determine and improve structural, morphological, mechanical and thermal properties ofsin.The structure and morphology of the obtained nanocomposites(Ros-Lim/Mag-CTA⁺) were determined using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electronic microscopy and transmission electronic microscopy. The analyses confirmed the chemical modification of clay layers and the intercalation of rosin-limonene copolymer within the organophilic-clay sheets. An exfoliated structure was obtained for the lower amount of clay (1% wt of Mag-CTA⁺), while intercalated structures were detected for high amounts of clay (5 and 10% wt of Mag-CTA⁺). The thermal properties of the nanocomposites were studied by thermogravimetric analysis (TGA) and show a significant improvement inthe thermal stability of the obtained nanocomposites compared to the purerosin-limonene copolymer (a degradation temperature up to 280 °C).

In situ polymerization of styrene–clay nanocomposites and their properties

Abstract

This work focuses on the preparation and characterization of polystyrene/organoclay nanocomposites. The effects of the nature of the organoclays and the method of preparation were studied in order to evaluate their morphological, thermal and mechanical properties. X-ray diffraction (SAXS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM, TEM), atomic force microscope (AFM) were used to determine the characteristics of the resulting materials. Initially, cetyltrimethylammonium bromide was used as an organomodifier to modify the clay to form an organic clay. After that, polystyrene/organoclay nanocomposites were synthesized by an in situ mass polymerization process in which styrene was polymerized in the presence of different proportions of organoclay ranging from 1 to 15% by weight. The results obtained confirm the intercalation of cetyltrimethylammonium bromide (CTA) surfactant in the clay layers, while the nanocomposites obtained showed morphologies in which the exfoliated forms were obtained. Nanocomposites showed a significant improvement in thermal stability compared to unmodified polystyrene. The highlighting of the modification was examined by mechanical tests (shock, traction). The Charpy impact test showed an increase in impact resilience, and this is mainly due to a better interfacial adhesion of the matrix. The tensile test showed an improvement in stiffness.

Graphic abstract

The preparation of polystyrene–clay nanocomposites containing various amounts of organoclays ranging from 1 to 15% using the mass polymerization technique has shown the positive effect of the introduction of a cetyltrimethylammonium bromide surfactant chain on the thermal stability of the nanocomposites. Exfoliated morphologies were obtained for the majority of the prepared nanocomposites. A structure, surface and thermal property relationship was established based on TGA, XRD and TEM/SEM analyses.

Preparation and properties of amphiphilic hydrophobically associative polymer/ montmorillonite nanocomposites

In this research, a novel amphiphilic hydrophobically associative polymer nanocomposite (ADOS/OMMT) was prepared using acrylamide (AM), sodium 4-vinylbenzenesulfonate (SSS), N, N'-dimethyl octadeyl allyl ammonium bromide (DOAAB) and organo-modified montmorillonite (OMMT) through in situ polymerization. Both X-ray diffraction patterns and transmission electron microscopy images verified the dispersion morphology of OMMT in the copolymer matrix. Then, the effect of the introduction of OMMT layers on the copolymer properties was studied by comparing with pure copolymer AM/SSS/DOAAB (ADOS). The thermal degradation results demonstrated that the thermal stability of the ADOS/OMMT were better than pure copolymer ADOS. During the solution properties tests, ADOS/OMMT nanocomposite was superior to ADOS in viscosifying ability, temperature resistance, salt tolerance, shear resistance and viscoelasticity, which was because OMMT contributed to enhance the hydrophobic association structure formed between polymer molecules. Additionally, the ADOS/OMMT nanocomposite exhibited more excellent interfacial activity and crude oil emulsifiability in comparison to pure copolymer ADOS. These performances indicated ADOS/OMMT nanocomposite had good application prospects in tertiary recovery.

Ultrasound-induced synthesis of an imidazolium based poly(ionic liquid) in an aqueous media: A structural, thermal and morphological study

Here we describe an efficient and rapid way for the polymerization of the 3-Octyl-1-vinylimidazolium Bromide using ultrasonic irradiation. This way promoted high dispersion polymerization using a water-soluble free radical initiator namely 4,4'-Azobis (4-cyanopentanoic acid) and free of dispersant. The ionic liquid monomer was prepared via quaternization of 1-vinylimidazole with octyl bromide also promoted by ultrasound. The polymerization rates were compared with a conventional heating method and appeared to be higher in the case of the ultrasound method within a short reaction time. The structural/morphological features and thermal properties of the obtained products were determined by different analytical techniques such as (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electronic microscopy (SEM, TEM), Fourier transform infrared spectroscopy (FTIR) and NMR Spectroscopy (¹H and ¹³C NMR). The morphology and the thermal behavior of the obtained poly(ionic liquid) were investigated and discussed. The results indicated that self-assembled nanospherical particles of 30-80 nm in diameter were obtained through the ultrasound method, while on the other hand; worm-like/cylindrical agglomerated nanoparticles with irregular sizes 50-300 nm in diameter were obtained via the classical heating method.

A versatile strategy for mechanically durable nanocomposite cryogels based on cationic (alkyl)methacrylates and hydrophilic bentonite via freezing (cryo)polymerization

A simple strategy for the preparation of organic-inorganic (alkyl)methacrylate-based nanocomposite gels was established. The preparation procedure was based on free-radical copolymerization of cationic monomer N,N-dimethylaminoethyl methacrylate (DMAEMA) in the presence of a low amount of ionic comonomer 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), nanoclay bentonite (BENT) and diethyleneglycol dimethacrylate (DEGDMA) as a chemical crosslinker. The parameters of equilibrium volume swelling, initial swelling rate, diffusional exponent, and early- and late-time diffusion coefficients were evaluated from the swelling measurements in salt solutions. PDMAEMA retained its own characteristics regardless of the amounts of ionic comonomer AMPS and nanoclay bentonite. The prepared nanocomposite cryogels/hydrogels were found to be pH and temperature-responsive. The elastic moduli and compressibility of the nanocomposite NC/BENTm-Cgels were much higher than those of NC/BENTm-Hgels. The effective crosslink density distribution of the nanocomposite NC/BENTm-Hgels was evaluated from the elastic moduli data of the as-prepared state and the degree of crosslinking was described by a quadratic polynomial as a function of the clay concentration. At high clay content, the nanocomposite NC/BENTm gels exhibited a lower swelling degree, and thus a higher crosslinking density than the clay-free gels. Both NC/BENTm Hgels and Cgels exhibited obvious pH and temperature double sensitiveness; the equilibrium degree of swelling decreased as the solution's pH or the swelling temperature increased. The power law exponent values obtained from dynamic swelling in aqueous Na2SO4 solution indicated that the sorption mechanism of both the nanocomposite NC/BENTm-Hgel and NC/BENTm-Cgel samples was Fickian controlled. Overall, this study successfully establishes the thermodynamic relations between the physico-mechanical behavior and characteristic network parameters of (alkyl)methacrylate-based nanocomposite gels prepared at various BENT concentrations.

A Review of the Synthesis and Applications of Polymer–Nanoclay Composites

Recent advancements in material technologies have promoted the development of various preparation strategies and applications of novel polymer–nanoclay composites. Innovative synthesis pathways have resulted in novel polymer–nanoclay composites with improved properties, which have been successfully incorporated in diverse fields such as aerospace, automobile, construction, petroleum, biomedical and wastewater treatment. These composites are recognized as promising advanced materials due to their superior properties, such as enhanced density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic properties. The primary focus of this review is to deliver an up-to-date overview of polymer–nanoclay composites along with their synthesis routes and applications. The discussion highlights potential future directions for this emerging field of research.