scholarly journals FUNCTIONALIZATION OF THE SURFACE OF HYPERCROSSLINKED POLYSTYRENE FOR CATALYST SYNTHESIS

2021 ◽  
pp. 49-57
Author(s):  
Анастасия Алексеевна Дмитриева ◽  
Елена Олеговна Щипанская ◽  
Антонина Анатольевна Степачёва ◽  
Маргарита Александровна Монжаренко ◽  
Мария Евгеньевна Маркова ◽  
...  
Keyword(s):  
Functional Groups ◽  
Chemical Engineering ◽  
Hypercrosslinked Polystyrene ◽  
Catalyst Supports ◽  
Polymeric Matrices ◽  
Catalyst Synthesis ◽  
Silica Phase ◽  
Basic Properties ◽  
Hypercrosslinked Polymers ◽  
Modification Of The Surface

Нанесенные наноразмерные катализаторы широко используются в различных процессах химической технологии. При этом особые требования предъявляются к носителю, используемому при синтезе катализаторов. Сверхсшитые полимеры являются перспективными носителями, однако зачастую не имеют требуемых свойств (например, кислотности). Для придания дополнительных свойств возможно модифицировать поверхность полимеров различными веществами или функциональными группами. В данной работе проведено исследование способов модификации и веществ-предшественников кремнийсодержащей фазы для модификации поверхности сверхсшитого полистирола диоксидом кремния. The supported nano-scale catalysts are widely used in different fields of chemical engineering. For the catalysts, the certain requirements are specified fort the catalyst supports. Hypercrosslinked polymers seem to be the prospective materials for the catalyst synthesis. However, polymeric matrices often do not meet some standards for catalyst supports (i.e. polymers are inert materials and do not have the acidic or basic properties). To infuse the additional properties to polymers it is possible to modify its surface with different compounds or functional groups. In this work, the study of the ways for the modification of the surface of hypercrosslinked polystyrene and silica-phase precursors was carried out.

Multifunctional Nanocomposite Coatings

2000 ◽  
Vol 628 ◽  
Author(s):  
Corné H.A. Rentrop ◽  
Lawrence F. Batenburg ◽  
Roelant A. Van Dam ◽  
Marinus P. Hogerheide ◽  
Harry A. Meinema ◽  
...  
Keyword(s):  
Functional Groups ◽  
Organic Molecule ◽  
Barrier Properties ◽  
Polymer Processing ◽  
Nanocomposite Coatings ◽  
Bulk Materials ◽  
Polymeric Matrices ◽  
Molecular Dispersion ◽  
Clay Platelets ◽  
Processing Techniques

ABSTRACTMultifunctional nanocomposite coatings and bulk materials have been developed on the basis of a combination of purely organic, as well as hybrid organic-inorganic polymeric matrices and anisotropic synthetic and natural clays. The clays have been chemically modified in such a way that they became compatible to the polymeric matrices. Clay platelets may be separated by modification with an organic molecule that contains two or more charged functional groups. The cations or anions located between the clay sheets are exchanged with one of these organic functional groups, which results in the formation of clay platelets “coated” with charges, thereby causing a molecular dispersion. Depending on the nature of the organic molecule colored or colorless coatings and polymeric bulk materials, containing homogeneously dispersed separated clay platelets, have been obtained.While retaining the basic functional properties of the materials new and/or improved properties have been introduced. This concerns in particular improved barrier properties, such as a decreased permeability for oxygen and water, improved corrosion resistance and increased thermal stability.The composition of the wet coating systems is such that they can be properly applied and thermally or photo-chemically cured on various substrates such as glass, steel, aluminum and plastics. The bulk materials can be processed into final product shapes by conventional polymer processing techniques.

Electrical and mechanical properties enhancing of PMMA and PA6 by functionalized MWCNTs addition

MRS Advances ◽  
2018 ◽  
Vol 3 (62) ◽  
pp. 3715-3721 ◽  
Author(s):  
José J. Contreras-Navarrete ◽  
Jael M. Ambriz-Torres ◽  
Carmen J. Gutiérrez-García ◽  
Francisco G. Granados-Martínez ◽  
Diana L. García-Ruiz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Raman Spectroscopy ◽  
Functional Groups ◽  
Strong Interaction ◽  
Sem Images ◽  
Polymeric Matrices ◽  
Casting Solution ◽  
Functionalized Mwcnts

ABSTRACTPA6 and PMMA polymers with different MWCNTs addition (5, 7 and 9 wt %) were synthetized through casting solution, resulting in improvement properties in contrast to pristine polymers. SEM images showed the MWCNTs embedded into polymeric matrices. D, G and G´ bands of MWCNTs were confirmed by Raman spectroscopy and functional groups observed in both nanocomposites by FTIR demonstrated a strong interaction. A significant increasing in electrical conductivity and microhardness was observed in all the nanocomposites. Major microhardness values were obtained in MWCNTs/PA6 (50 HV) however the MWCNTs/PMMA nanocomposites showed the highest electrical conductivity value (6.4×10-4 S/cm).

Carbon—Silica Dual Phase Filler: Part IV. Surface Chemistry

1998 ◽  
Vol 71 (5) ◽  
pp. 1015-1027 ◽  
Author(s):  
Lawrence J. Murphy ◽  
Elena Khmelnitskaia ◽  
Meng-Jiao Wang ◽  
Khaled Mahmud
Keyword(s):  
Functional Groups ◽  
Gas Chromatography Mass Spectrometry ◽  
Dual Phase ◽  
Surface Functional Groups ◽  
Infrared Band ◽  
Silica Sample ◽  
Silica Phase ◽  
Surface Areas ◽  
Phase Surface ◽  
The Individual

Abstract A method for estimating the amount of functional groups on the carbon—silica dual phase fillers (CSDPF) available to react with organosilane coupling agents is reported. The method employs trimethylchlorosilane (TMCS) as an analytical probe, and involves equilibrating the samples with TMCS in toluene. The amount of TMCS that reacts with the surface functional groups is obtained by monitoring the concentration of reactants and products of the reaction by Gas Chromatography Mass Spectrometry. The amount of TMCS reacted with the fillers' surface functional groups is compared to the pH, and the active hydrogen content as measured by LiAlH4. Comparison of these measures with the CSDPF, carbon blacks and a fumed silica sample is provided. The dual phase fillers have a heterogeneous surface, containing both carbon and silica phases. Multipoint BET nitrogen surface area is used in combination with iodine number to estimate the individual carbon and silica phase surface areas. From this, the packing density of the trimethylsilyl group attached to the silica phase of the CSDPF surface was estimated and compared to silica. Silanols on these dual phase fillers were detected by infrared spectroscopy. The infrared band for silanols is located at 975 cm−1. The absorbance of this band is shown to correlate with TMCS uptake and diminish after reaction with TMCS, suggesting that silanols indeed are participating in the uptake of TMCS.

scholarly journals ВПЛИВ РОЗМІРУ ПОР ТА МОРФОЛОГІЇ МЕЗОПОРИСТОГО КРЕМНІЮ НА ВИВІЛЬНЕННЯ МЕТОПРОЛОЛУ ТАРТРАТУ

2022 ◽  
pp. 18-25
Author(s):  
HONGJUAN WANG ◽  
WEI HU ◽  
OLENA SALIY
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Mesoporous Silica ◽  
Silicon Dioxide ◽  
Functional Groups ◽  
Chemical Engineering ◽  
Hollow Spheres ◽  
Metoprolol Tartrate ◽  
Mesoporous Silicon ◽  
Mesoporous Silicon Dioxide

Purpose. Study pore size effect and morphology of mesoporous silica on metoprolol tartrate release.Methodology. A sample of hollow mesoporous silicon dioxide with amino-functional groups containing 12.7 wt. % metoprolol tartrate has been investigated as potential carriers for the controlled release of active substance. Studies of the release profiles of metoprolol tartrate were performed under the following conditions: dissolution medium was buffer solution with a pH of 7.4 (phosphate buffer); sampling time: from 0.5 h before 18 h. The metoprolol concentration in the liquid phase was evaluated by a UV-Vis spectrophotometer (Persee TU-190, Beijing, China) by use of quartz cuvettes with an optical path length of 1 cm at a maximum wavelength of 274 nm.Findings. In this work we have studied mesoporous silica as possible carrier to controlled release of metoprolol tartrate, a drug used in the treatment of some diseases of the cardiovascular system. The material for research was a sample of hollow mesoporous silicon dioxide with amino-functional groups 200–400 nm in size and 20–30 nm in shell thickness. A calibrated curve to determine the amount of metoprolol was constructed by determining the absorption dependence of the concentration of metoprolol in the range from 10 to 300 ppm. The same drug concentration was obtained as calculated from the drug release test formula, which concludes that the release of metoprolol is controlled.Originality. The controlled release of a sample of hollow spheres of mesoporous silicon dioxide filled with metoprolol tartrate was studied, which was synthesized by the School of Chemistry and Chemical Engineering, Qilu University of Technology, using a new technology, where hollow spheres of mesoporous silicon dioxide with amino groups were synthesized using CO2 gas bubbles as templates.Practical value. The metoprolol release amount could achieve a 50% release amounts within 1 hour and 90% within 5 hours, indicating that the synthesized mesoporous hollow sphere could achieve controlled drug release, and shows the potential of carriers with stimulus response and targeted therapy.

Hydrogenation of levulinic acid using Ru-containing catalysts based on hypercrosslinked polystyrene

2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Igor I. Protsenko ◽  
Linda Zh. Nikoshvili ◽  
Alexey V. Bykov ◽  
Valentina G. Matveeva ◽  
Alexandrina Sulman ◽  
...  
Keyword(s):  
Aqueous Medium ◽  
Functional Groups ◽  
Metal Content ◽  
Levulinic Acid ◽  
Hypercrosslinked Polystyrene ◽  
Polymeric Matrix ◽  
Amino Groups ◽  
High Yields

AbstractThis work is devoted to the investigation of the possibility of the use of Ru-containing catalysts on the basis of polymeric matrix of hypercrosslinked polystyrene (HPS) in the hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL). HPS-based Ru-containing catalysts were synthesized at variation of HPS type (MN100 bearing amino groups or MN270 without functional groups) and metal content. Catalyst 5%-Ru/MN100 was shown to compete with commercial 5%-Ru/C and to allow carrying out the hydrogenation of LA in aqueous medium with high yields of GVL (more than 99%).

scholarly journals Iron Catalyzed α-C-H Cyanation of Simple and Complex Tertiary Amines

2020 ◽  
Author(s):  
Ozgur YIlmaz ◽  
Cagatay Dengiz ◽  
Marion Emmert
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Functional Groups ◽  
Late Stage ◽  
Functional Group ◽  
Reaction Pathway ◽  
Catalyst System ◽  
Tertiary Amines ◽  
Reaction Conditions ◽  
Catalyst Synthesis

This manuscript details the development of a general and mild protocol for the α-C-H cyanation of tertiary amines as well as its application in late stage functionalization. Suitable substrates include tertiary aliphatic, benzylic, and aniline-type substrates as well as complex substrates. Functional groups tolerated under the reaction conditions include various heterocycles, as well as ketones, amides, olefins, and alkynes. This broad substrate scope is remarkable, as comparable reaction protocols for α-C-H cyanation frequently occur via free radical mechanisms, and are thus fundamentally limited in their functional group tolerance. In contrast, the presented catalyst system tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway. All components of the described system are readily available, allowing implementation of the presented methodology without the need for lengthy catalyst synthesis.

scholarly journals Iron Catalyzed α-C-H Cyanation of Simple and Complex Tertiary Amines

2020 ◽  
Author(s):  
Ozgur YIlmaz ◽  
Cagatay Dengiz ◽  
Marion Emmert
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Functional Groups ◽  
Late Stage ◽  
Functional Group ◽  
Reaction Pathway ◽  
Catalyst System ◽  
Tertiary Amines ◽  
Reaction Conditions ◽  
Catalyst Synthesis

This manuscript details the development of a general and mild protocol for the α-C-H cyanation of tertiary amines as well as its application in late stage functionalization. Suitable substrates include tertiary aliphatic, benzylic, and aniline-type substrates as well as complex substrates. Functional groups tolerated under the reaction conditions include various heterocycles, as well as ketones, amides, olefins, and alkynes. This broad substrate scope is remarkable, as comparable reaction protocols for α-C-H cyanation frequently occur via free radical mechanisms, and are thus fundamentally limited in their functional group tolerance. In contrast, the presented catalyst system tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway. All components of the described system are readily available, allowing implementation of the presented methodology without the need for lengthy catalyst synthesis.

scholarly journals Cyclodextrin-Grafted TiO2 Nanoparticles: Synthesis, Complexation Capacity, and Dispersion in Polymeric Matrices

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 642 ◽  
Author(s):  
Pablo Monreal-Pérez ◽  
José Isasi ◽  
Javier González-Benito ◽  
Dania Olmos ◽  
Gustavo González-Gaitano
Keyword(s):  
Polyethylene Oxide ◽  
Titanium Dioxide Nanoparticles ◽  
High Energy ◽  
Photo Degradation ◽  
Polymeric Matrices ◽  
Tio2 Nps ◽  
The Matrix ◽  
Energy Ball ◽  
Uv Visible ◽  
Modification Of The Surface

The modification of the surface of titanium dioxide nanoparticles (TiO2 NPs) by the incorporation of cyclodextrins (CDs), cyclic oligosaccharides with a hydrophobic cavity, can largely improve the functionality of TiO2 by lodging molecules of interest in the CD to act directly on the surface of the nanoparticles or for further release. With this aim, we have synthesized βCD-modified nanoparticles (βCDTiO2 NPs) by a two-step reaction that involves the incorporation of a spacer and then the linking of the macrocycle, and characterized them by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The capacity of the functionalized structures to trap model compounds (Rhodamine and 1-naphthol) has been compared to that of bare TiO2 NPs by fluorescence and Ultraviolet-visible (UV-visible) spectroscopy. The presence of the CDs on the surface of the TiO2 avoids the photo-degradation of the guest, which is of interest in order to combine the photocatalytic activity of TiO2, one of its most interesting features for practical purposes, with the delivery of compounds susceptible of being photo-degraded. The βCDTiO2 NPs have been dispersed in polymeric matrices of frequently used polymers, polyethylene (LDPE) and polyethylene oxide (PEO), by cryogenic high energy ball milling to produce nanocomposites in the form of films. The surface modification of the nanoparticles favors the homogenization of the filler in the matrix, while the nanoparticles, either in bare or functionalized form, do not seem to alter the crystallization properties of the polymer at least up to a 5% (w/w) load of filler.

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

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