Aqueous Dispersion Medium Research Articles

Properties of a Dental Adhesive Containing Graphene and DOPA-Modified Graphene.

Graphene is a promising biomaterial. However, its dispersion in aqueous medium is challenging. This study aimed to modify graphene nanoparticles with L-dopa to improve the properties of experimental dental adhesives. Adhesives were formulated with 0% (control), 0.25%, 0.5%, and 0.75% of graphene, modified or not. Particle modification and dispersion were microscopically assessed. Degree of conversion was tested by Fourier-transform infrared spectroscopy. Flexural strength and modulus of elasticity were evaluated by a 3-point flexural test. Bond strength was tested by shear. To test water sorption/solubility, samples were weighed during hydration and dehydration. Antibacterial activity was tested by Streptococcus mutans colony-forming units quantification. Cytotoxicity on fibroblasts was evaluated through a dentin barrier test. The modification of graphene improved the particle dispersion. Control presented the highest degree of conversion, flexural strength, and bond strength. In degree of conversion, 0.25% of groups were similar to control. In bond strength, groups of graphene modified by L-dopa were similar to Control. The modulus of elasticity was similar between groups. Cytotoxicity and water sorption/solubility decreased as particles increased. Compared to graphene, less graphene modified by L-dopa was needed to promote antibacterial activity. By modifying graphene with L-dopa, the properties of graphene and, therefore, the adhesives incorporated by it were enhanced.

In silico-guided discovery and in vitro validation of novel sugar-tethered lysinated carbon nanotubes for targeted drug delivery of doxorubicin

ContextMultiwalled carbon nanotubes (MWCNTs) functionalized with lysine via 1,3-dipolar cycloaddition and conjugated to galactose or mannose are potential nanocarriers that can effectively bind to the lectin receptor in MDA-MB-231 or MCF-7 breast cancer cells. In this work, a method based on molecular dynamics (MD) simulation was used to predict the interaction of these functionalized MWCNTs with doxorubicin and obtain structural evidence that allows a better understanding of the drug loading and release process. The MD simulations showed that while doxorubicin only interacted with pristine MWCNTs through π-π stacking interactions, functionalized MWCNTs were also able to establish hydrogen bonds, suggesting that the functionalized groups improve doxorubicin loading. Moreover, the elevated adsorption levels observed for functionalized nanotubes further support this enhancement in loading efficiency. MD simulations also shed light on the intratumoral pH-specific release of doxorubicin from functionalized MWCNTs, which is induced by protonation of the daunosamine moiety. The simulations show that this change in protonation leads to a lower absorption of doxorubicin to the MWCNTs. The MD studies were then experimentally validated, where functionalized MWCNTs showed improved dispersion in aqueous medium compared to pristine MWCNTs and, in agreement with the computational predictions, increased drug loading capacity. Doxorubicin-loaded functionalized MWCNTs demonstrated specific release of doxorubicin in tumor microenvironment (pH = 5.0) with negligible release in the physiological pH (pH = 7.4). Furthermore, doxorubicin-free MWNCT nanoformulations exhibited insignificant cytotoxicity. The experimental studies yielded nearly identical results to the MD studies, underlining the usefulness of the method. Our functionalized MWCNTs represent promising non-toxic nanoplatforms with enhanced aqueous dispersibility and the potential for conjugation with ligands for targeted delivery of anti-cancer drugs to breast cancer cells.MethodsThe computational model of a pristine carbon nanotube was created with the buildCstruct 1.2 Python script. The lysinated functionalized groups were added with PyMOL and VMD. The carbon nanotubes and doxorubicin molecules were parameterized using the general AMBER force field, and RESP charges were determined using Gaussian 09. Molecular dynamics simulations were carried out with the AMBER 20 software package. Adsorption levels were calculated using the water-shell function of cpptraj. Cytotoxicity was evaluated via a MTT assay using MDA-MB-231 and MCF-7 breast cancer cells. Drug uptake of doxorubicin and doxorubicin-loaded MWCNTs was measured by fluorescence microscopy.

Theoretical multiscale study on the properties, aqueous solution behavior and biological impact of zinc oxide nanoparticles

The aim of this theoretical study is to describe the relationship between the structure and the physicochemical properties of zinc oxide nanoparticles (ZnO NPs) and Mn doped ZnO NPs to assess their toxicological impact. In order to do so, a multiscale modelling approach is applied. Different nanoparticles, as well as the mechanism(s) of nanoparticle aggregation and growing, are characterized in terms of size and shape considering electronic, surface, structural and topological properties via quantum mechanics simulations. To evaluate the toxicology impact of ZnO NPs in human health safety and their possible environmental impact, classical molecular dynamics simulations were carried out to study the interaction between the nanomaterials and biological target systems: a set of selected human proteins and model plasma membranes. Likewise, the simulation of nanoparticles dispersion in aqueous media along with water adsorption on their surfaces was conducted.The mayor findings may be summarized as: (i) the ZnO NPs from 12 to 96 (ZnO) units are characterized and their interaction energies, HOMO-LUMO gaps, superficial areas and volumes are reported; (ii) the (ZnO)12 NP and Zn11MnO12 NP are further characterized via their topological properties, vibrational spectra, PDOS and non-covalent interactions; (iii) the doping with Mn atoms is favourable. The interaction energies, HOMO-LUMO orbitals and gaps, PDOS, atomic charges, superficial areas and volumes are reported for NPs doped with up to 5 Mn atoms; (iv) high water affinity for ZnO NPs is reported with both quantum and classical calculations, v) (ZnO)12 NPs do not penetrate the cell membrane and (vi) the affinity energy of both ZnO and Mn doped NPs for human proteins is moderate.The reported results provide in-depth whole-chain studies of zinc oxide nanoparticles, which have been successfully applied for different technologies.

Reply to the ‘Comment on “Lewis acid-surfactant complex catalyzed polymerization in aqueous dispersed media: cationic or radical polymerization?”’ by I. V. Vasilenko, F. Ganachaud and S. V. Kostjuk, Polym. Chem., 2024, 15, DOI: 10.1039/D3PY00661A

We respond to the comment of Vasilenko et al. on our work entitled “Lewis acid-surfactant complex catalyzed polymerization in aqueous dispersed media: cationic or radical polymerization?” (Polym. Chem., 2020, 11, 5757).

Lignin Nanoparticles as Charge Storage Centers in Organic Battery Electrodes

Lignin, the second most abundant biopolymer on Earth, has recently emerged as a promising redox-active material for organic batteries. Different types of lignin have been explored but inherent challenges have remained, i.e., the difficulties of processing kraft lignin and the low charge storage capacity retention of lignosulfonate due to its high water-solubility. In this work, we propose the use of an alternative candidate, lignin nanoparticles (LNPs), which are insoluble, but colloidally stable dispersions in aqueous media, which, can be easily processed using different manufacturing techniques. By combining LNPs with a conducting polymer (PEDOT:PSS), we have successfully prepared a composite that has a charge storage capacity of up to 42.5 mAh/g at a current density of 1 A/g, while its capacity retention shows a good improvement (70% after 1000 cycles) in comparison to the similar systems of lignosulfonate-based electrodes. The morphology and chemical structure of LNPs are tunable, therefore, the effects of particle sizes and the preparation methods of LNPs on the electrode performance were also studied. With the obtained results, this work suggests LNPs as promising materials for the preparation of green and low-cost lignin-based energy storage devices. Keywords: Lignin nanoparticles, Organic batteries, PEDOT:PSS, Electrochemistry.

Surface active polyesters based on N-substituted glutamic acid as promising materials for biomedical applications

In the present work, N-substituted glutamic acid, polyethylene and polypropylene glycols have been used to design biocompatible copolyesters via Steglich reactions. Due to the presence of alternating hydrophilic and hydrophobic blocks in their structures, these copolyesters are able to form self-stabilized nanoparticle dispersions in aqueous media. The lipophilic core of these nanoparticles can solubilize poorly water-soluble compounds and release them into a model of lipids in a human body. Moreover, the obtained copolyesters possess no cytotoxic effects over a wide concentration range. Thus, we conclude that obtained copolyesters show significant promise for further development as drug delivery systems.

Research Design of the Release of Amizon, Decametoxine, and Chlorhexidine from the Composition of Dental Medicinal Films

Introduction: The treatment of most diseases in dentistry is related to the local application of antiseptic drugs that regulate the microbiocenosis in the oral cavity. The study of pharmacodynamic and kinetic parameters of the release of active pharmaceutical ingredients (APIs) from the dosage form (DF) is an important task. In this study, we tried to evaluate the release of APIs from developed dental medicinal films (DMF) produced on a polymeric basis. Methods: To confirm the antimicrobial activity of the three developed DMF with amizon, decamethoxine and chlorhexidine digluconate, a statistical analysis and mathematical processing of the research results were carried out. Results: Statistical processing made it possible to organize the results of our earlier studies, in which the concentrations of three APIs (amizon, decamethoxine, and chlorhexidine digluconate) were determined during their diffusion from the polymer base of the DMF to the aqueous dispersion medium (0.9% sodium chloride solution). Due to performed statistical calculations, regarding the reliability of APIs release, it was determined that the time duration of complete release of the three active substances from the polymer base was different, which will ultimately affect the duration of the pharmacological effect of the APIs in the patient's body. Conclusion: In the manufacture of DMF on a polymeric base of hydrophilic type, it is necessary to take into account the release time of each API, according to the composition of the polymeric coatings.

Polymeric Surfactants Bearing Divalent Carboxy Pendants for Stable Color Dispersions with High Redispersibility

Inkjet printing of ink requires dyes or pigments insoluble in water but uniformly dispersing as fine particles for a long period. In addition, redispersibility after solidification by solvent vaporization around the jetting heads is also important for performance. In this study, thus, a series of amphiphilic copolymers were prepared for a dispersant of inkjet using reversible addition fragmentation chain-transfer copolymerization of styrene (St), benzyl acrylate (BnA), and phenoxyethyl acrylate (PEA) as a hydrophobic monomer with acrylic acid (AA) and itaconic acid (IA) as a hydrophilic monomer. To understand the fundamental properties and potentials as a polymer dispersant, the surface parameters and rheology of the copolymers and their color dispersions in aqueous media were investigated. The aqueous solutions were typical Newtonian fluids, whereas the color dispersions were non-Newtonian fluids with shear-thinning properties and yield values ranging from 0.57 to 1.04 Pa. Although the surface parameters, such as surface tension (γ), molecular occupied area (Amin), and zeta potential (ζ), did not show clear correlation with polymer structures, their behaviors as a dispersant were significantly different. The color dispersants containing the copolymer of St or BnA as a hydrophobic monomer and IA and AMPS as hydrophilic monomers exhibited sufficient redispersion both for yellow and cyan inks, even after the aging test at 60 °C for 5 days, whereas other copolymers did not exhibit such superior performances. In addition, the color dispersions of the copolymer of St, IA, and AMPS (St-IA-AMPS) showed lower viscosity and yield value and became closer to Newtonian fluid compared with that of St, AA, and AMPS (St-AA-AMPS). Thus, St-IA-AMPS provided good redispersibility and avoided sedimentation. These results suggest that the most suitable dispersant for inkjet inks among the polymers investigated was the copolymer of St, IA, and AMPS.

Luminescent Eu3+ doped SrF2 nanoparticles for fluorescent detection of fertilizers

Luminescent Eu3+-doped SrF2 nanoparticles were synthesized using microwave-assisted synthesis. Their surfaces were modified either by polyethylene glycol or mercaptopropionic acid to enhance their dispersibility in aqueous media and colloidal formation. X-ray diffraction analysis confirmed single-phase cubic structure in both types of hydrophilic-modified Sr0.9Eu0.1F2 luminescent powders. The average crystallite size of nanoparticles is found to be ∼13 nm. Scanning electron microscopy of the representative PEG2000-modified sample revealed that particles form agglomerates composed of densely packed nanoparticles. The microstructure at a local level was investigated by transmission electron microscopy showing the presence of sphere-like nanoparticles with an average particle size of 12.5 nm and 14 nm for PEG-modified and MPA-modified Sr0.9Eu0.1F2, respectively. Both PEG2000 and MPA-modified Sr0.9Eu0.1F2 water dispersions show strong red Eu3+ emission under 405 nm excitation that is quenched in the presence of the primary NP fertilizer, ammonium dihydrogen phosphate, NH4H2PO4. The limit of detection was calculated to be ∼19 mM for both hydrophilic-modified Sr0.9Eu0.1F2 luminescent nanoparticles.

Darifenacin Self-assembled Liquid Crystal Cubic Nanoparticles: a Sustained Release Approach for an Overnight Control of Overactive Bladder

The current study is regarding the development and characterization of Darifenacin-loaded self-assembled liquid crystal cubic nanoparticles (LCCN). An anhydrous approach was used for the preparation of these cubic nanoparticles using a hydrotropic agent (propylene glycol), with minimal energy input. Upon dispersion in aqueous medium, the system was successfully transformed to cubosomal nanoparticles counterpart as depicted by transmission electron micrographs. A Box-Behnken design was used to optimize formulation variables, namely A: amount of GMO, B: amount of Pluronic F127, C: amount of PG, and D: amount of HPMC. The design has generated 29 formulae which were tested regarding drug content uniformity, dispersibility in water, particle size, zeta potential, polydispersity index, and in vitro release behavior. The numerical optimization algorithms have generated an optimized formula with high desirability ≈ 1. The optimized formula displayed small particle size, good homogeneity, and zeta potential along with controlled in vitro release profile and ex vivo permeation through rabbit intestine. Thus, self-assembled LCCN might offer an alternative anhydrous approach for the preparation of cubosomal nanoparticles with controlled release profile for a possibly better control of overactive bladder syndrome which tremendously affect the overall life quality.Graphical

Composite hydrogels with host–guest interaction using cellulose nanocrystal as supramolecular filler

The functional nanocomposite hydrogels are of great interest in the research field of materials science because of their improved mechanical performances and their ability to be used in a wider range of applications. Herein, the supramolecular composite hydrogels were developed and studied using a cellulose nanocrystal (CNC) as bio-based filler. The hydrogels were designed by introducing supramolecular bonding between host β-cyclodextrin (β-CD) and guest adamantane (Ad) groups at the interface between the highly dispersed CNC and the polymer matrix. For this purpose, the CNC surface was successfully modified with Ad to act not only as a reinforcing filler in the polymer network but also as a supramolecular cross-linker with the β-CD-modified polymer. Importantly, CNC exhibited the ability of preserving their good dispersibility in aqueous media, even after modification with the hydrophobic Ad group, owing to electrostatic repulsion among negative charges incorporated onto CNC surface. Furthermore, the modification of CNC with Ad contributed to the greater interfacial compatibility between the filler and the matrix. The present study therefore highlights that the toughness of a hydrogel can be improved by the incorporation of supramolecular bonding as reversible bonding at the filler/matrix interface, which sacrificially depletes the mechanical energy upon deformation of the gels.

Persistent Luminescence Zn2GeO4:Mn2+ Nanoparticles Functionalized with Polyacrylic Acid: One-Pot Synthesis and Biosensing Applications.

Zinc germanate doped with Mn2+ (Zn2GeO4:Mn2+) is known to be a persistent luminescence green phosphor with potential applications in biosensing and bioimaging. Such applications demand nanoparticulated phosphors with a uniform shape and size, good dispersibility in aqueous media, high chemical stability, and surface-functionalization. These characteristics could be major bottlenecks and hence limit their practical applications. This work describes a one-pot, microwave-assisted hydrothermal method to synthesize highly uniform Zn2GeO4:Mn2+ nanoparticles (NPs) using polyacrylic acid (PAA) as an additive. A thorough characterization of the NPs showed that the PAA molecules were essential to realizing uniform NPs as they were responsible for the ordered aggregation of their building blocks. In addition, PAA remained attached to the NPs surface, which conferred high colloidal stability to the NPs through electrostatic and steric interactions, and provided carboxylate groups that can act as anchor sites for the eventual conjugation of biomolecules to the surface. In addition, it was demonstrated that the as-synthesized NPs were chemically stable for, at least, 1 week in phosphate buffer saline (pH range = 6.0-7.4). The luminescence properties of Zn2GeO4 NPs doped with different contents of Mn2+ (0.25-3.00 mol %) were evaluated to find the optimum doping level for the highest photoluminescence (2.50% Mn) and the longest persistent luminescence (0.50% Mn). The NPs with the best persistent luminescence properties were photostable for at least 1 week. Finally, taking advantage of such properties and the presence of surface carboxylate groups, the Zn2GeO4:0.50%Mn2+ sample was successfully used to develop a persistent luminescence-based sandwich immunoassay for the autofluorescence-free detection of interleukin-6 in undiluted human serum and undiluted human plasma samples. This study demonstrates that our persistent Mn-doped Zn2GeO4 nanophosphors are ideal candidates for biosensing applications.

A Zn(II) coordination polymer as a dual sensor for ppb level detection of antibiotics and organo-toxins in a green solvent

Herein, we describe the synthesis of a new fluorescent d10 coordination polymer, [Zn2(CFDA)2(BPEP)]n·nDMF (CP-1) under solvothermal reaction condition using zinc metal ion. In CP-1, Zn(II) ion along with CFDA and BPED ligand forms a 2-fold self-interpenetrated 3D coordination polymers. This CP-1 is characterized by the single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), infrared spectra, optical microscope image and thermogravimetric analysis and the framework is found to maintain its structural stability in different solvents. The framework (CP-1) detected antibiotics (NFT (nitrofurantoin) and NZF (nitrofurazone)) and organo-toxin trinitrophenol in aqueous dispersed medium. Apart from the fast responsive (10 s), the detection limit for them was found at ppb level. The detection of these organo-aromatics were also comprehended by the colorimetric response through solid, solution and low cost paper strip technique i.e., triple mode recognition capability. The probe is re-usable without changing in its sensing efficiency and in addition, it has been applied for the detection of these analytes in the real field specimens (soil, river water, human urine and commercial tablet). The sensing ability is established by in-depth experimental analysis and the life time measurement where mechanism such as photo induced electron transfer (PET), fluorescence resonance energy transfer (FRET), inner filter effect (IFE) was recognized. The presence of guest interaction sites on the linker backbone in CP-1 induces diverse supramolecular interaction with the targeted analytes results to bring them in proximity for the occurrence of these sensing mechanism. The Stern-Volmer quenching constant values of CP-1 for the targeted analytes are admirable and the low detection limit (LOD) values for NFT, NZF and TNP are found to be 34.54, 67.79 and 43.93 ppb respectively. Further, the DFT theory is carried out in details to justify the sensing mechanism.

Zirconium Phosphate Assisted Phosphoric Acid Co-Catalyzed Hydrolysis of Lignocellulose for Enhanced Extraction of Nanocellulose.

The high mechanical strength, large specific surface area, favorable biocompatibility, and degradability of nanocellulose (CNC) enable it to be a potential alternative to petroleum-based materials. However, the traditional preparation of CNCs requires a large amount of strong acid, which poses a serious challenge to equipment maintenance, waste liquid recycling, and economics. In this study, a solid and easily recoverable zirconium phosphate (ZrP) was used to assist in the phosphoric acid co-catalyzed hydrolysis of lignocellulose for extracting CNCs. Due to the presence of acidic phosphate groups, ZrP has a strong active center with a high catalytic activity. With the assistance of ZrP, the amount of phosphoric acid used in the reaction is significantly reduced, improving the equipment's durability and economic efficiency. The effects of the process conditions investigated were the phosphate acid concentration, reaction temperature, and reaction time on the yield of CNCs. The Box-Behnken design (BBD) method from the response surface methodology (RSM) was applied to investigate and optimize the preparation conditions. The optimized pre-treatment conditions were 49.27% phosphoric acid concentration, 65.38 °C reaction temperature, and 5 h reaction time with a maximal cellulose yield (48.33%). The obtained CNCs show a granular shape with a length of 40~50 nm and a diameter of 20~30 nm, while its high zeta potential (-24.5 mV) make CNCs present a stable dispersion in aqueous media. Moreover, CNCs have a high crystallinity of 78.70% within the crystal type of cellulose Ⅰ. As such, this study may pioneer the horizon for developing a green method for the efficient preparation of CNC, and it is of great significance for CNCs practical production process.

Recent advances in radical polymerization of bio-based monomers in aqueous dispersed media

Vegetable oils and lipids, terpenes, lignin derivatives, carbohydrates, and proteins are used as biomass feedstock to prepare new bio-based monomers for radical polymerization in aqueous dispersed media, producing bio-based latexes.

Preparation of Small Unilamellar Vesicle Liposomes Using Detergent Dialysis Method.

Small unilamellar liposomes are commonly used as model biomembranes and carriers for drug and gene delivery. Although methods which employ mechanical forces or organic solvents can be used to reduce the liposome size and the number of lipid bilayers, they are not suitable options when the purpose is to incorporate biologically active proteins into lipid bilayers or to encapsulate nucleic acid into liposomes. Detergent dialysis is a simple and inexpensive procedure to produce homogeneous small unilamellar vesicles (SUVs). Lipids are solubilized by detergent at a concentration much higher than its critical micellar concentration (CMC) in an aqueous dispersion medium. Free monomer detergent molecules in the dispersion medium are removed during dialysis, while the supramolecular detergent-lipid mixed micelles (MMs) are kept inside the dialysis tubing, leading to dissociation of detergent molecules from MMs. SUVs are formed after the micelle to vesicle transition (MVT).

Clay-Catalyzed Ozonation of Organic Pollutants in Water and Toxicity on Lemna minor: Effects of Molecular Structure and Interactions

The use of clays as adsorbents and catalysts in the ozonation of organic pollutants (Atrazine, bis-Phenol A, Diazinon, and Diclofenac sodium) allowed simulating their natural oxidative degradation in clay soils and to evaluate the ecotoxicity of mixtures partially oxidized on the species Lemna minor, a biodiversity representative of plants in the aquatic environment. Kinetic data showed that the adsorption of organic pollutants on clay particles obeys the pseudo-second-order model, while the adsorption isotherms satisfactorily fit the Langmuir model. Adsorption reduces the dispersion of the organic pollutant in the environment and prolongs its persistence and its natural degradation probability. Measurements of the Zeta potential and particle size as a function of pH demonstrate that the catalytic activity of clay depends on its cation, its silica/alumina ratio, and therefore on its permanent and temporary ion exchange capacities. These factors seem to govern its delamination and dispersion in aqueous media, its hydrophilic-hydrophobic character, and its porosity. Tests conducted on Lemna minor in contact with ozonation mixtures revealed that the toxicity could be due to pH decrease and to the toxicity of the intermediates yielded. Ecotoxicity would depend on the structure of the organic molecules, the chemical composition of the clay surface and ozonation time, which determines the oxidation progress. These results are of great importance for further research because they allow concluding that the negative impact of the persistence of an organic molecule in clay-containing media depends on the type and composition of the very clay mineral.

A novel polymeric nanocomposite based on TiO2 NPs containing β-cyclodextrin membrane for ultratrace naked-eye detection of Pb and Cd ions

A unique, selective, and sensitive colorimetric nanosensor for the naked-eye detection and adsorption of Pb(II) and Cd(II) in aqueous media has been synthesized based on the organic–inorganic hybrid. Acrylamide (AM) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) as hydrophilic monomers, functionalized β-cyclodextrin (f-β-CD) as host-guest complex formation agent, and vinyl-dithizone (f-DTZ) as an efficient ligand were used. The β-CD with a hydrophobic interior and hydrophilic exterior can form a host-guest inclusion complex with a ligand that enhances nanosensors’ dispersion in aqueous media. The immediate color change of the sensor has been observed from gray to pink and blue for Pb(II) and Cd(II) with a wide linear range of [(1 ppb- 40 ppb)] and [(1 ppb- 60 ppb)], respectively. This study also considered the adsorption qualities of these heavy metals under various factors, including pH, time length, and initial ion concentration. The maximum adsorption capacity of Cd(II) via polymeric nanocomposite was 166 mg·g−1 at optimum condition. The experimental info has been investigated using the Langmuir and Freundlich isotherms and the pseudo-first-order and pseudo-second-order kinetic models.

Amphiphilic Cellulose Nanocrystals for Aqueous Processing of Thermoplastics.

Conventional composite formulation of cellulose nanocrystals (CNCs) with thermoplastics involves melt compounding or in situ polymerisation. In this rather unconventional approach, polypropylene (PP) microparticles were finely suspended and stabilized, at varying weight loadings, in aqueous suspensions of amphiphilic CNCs to enable adsorption of the nanoparticles onto the thermoplastic. In order to achieve these suspensions, CNCs were modified with either octyl or hexadecyl groups. These modifications imparted hydrophobic properties to the CNCs, hence increasing interfacial adhesion to the PP microparticles. The modification, however, also retained the sulfate half ester groups that ensured dispersibility in aqueous media. The CNCs were evidently coated on the PP microparticles as revealed by confocal microscope imaging and had no detrimental effect on the melt properties of the PP-based composites. The approach is demonstrated to increase the Young's moduli of CNC-thermoplastic composites prepared in optimum suspension loadings of 0.5 wt. % octyl-modified and 0.1 wt % hexadecyl-modified CNCs. This procedure can be extended to other thermoplastics as the ability to aqueously process these composites is a major step forward in the drive for more sustainable manufacturing.

Palladium Decorated, Amine Functionalized Ni-, Cd- and Co-Ferrite Nanospheres as Novel and Effective Catalysts for 2,4-Dinitrotoluene Hydrogenation.

2,4-diaminotoluene (TDA) is one of the most important polyurethane precursors produced in large quantities by the hydrogenation of 2,4-dinitrotoluene using catalysts. Any improvement during the catalysis reaction is therefore of significant importance. Separation of the catalysts by filtration is cumbersome and causes catalyst loss. To solve this problem, we have developed magnetizable, amine functionalized ferrite supported palladium catalysts. Cobalt ferrite (CoFe2O4-NH2), nickel ferrite (NiFe2O4-NH2), and cadmium ferrite (CdFe2O4-NH2) magnetic catalyst supports were produced by a simple coprecipitation/sonochemical method. The nanospheres formed contain only magnetic (spinel) phases and show catalytic activity even without noble metals (palladium, platinum, rhodium, etc.) during the hydrogenation of 2,4-dinitrotoluene, 63% (n/n) conversion is also possible. By decorating the supports with palladium, almost 100% TDA selectivity and yield were ensured by using Pd/CoFe2O4-NH2 and Pd/NiFe2O4-NH2 catalysts. These catalysts possess highly favorable properties for industrial applications, such as easy separation from the reaction medium without loss by means of a magnetic field, enhanced reusability, and good dispersibility in aqueous medium. Contrary to non-functionalized supports, no significant leaching of precious metals could be detected even after four cycles.