Interaction of trimethylchlorosilane with silanol groups silica surface in the presence of amines

1993 ◽  
Vol 50 (1-2) ◽  
pp. 305-310
Author(s):  
E. M. Pakhlov ◽  
V. M. Gun'ko ◽  
E. F. Voronin
Keyword(s):  
Silica Surface ◽  
Silanol Groups

scholarly journals Peculiarities of Chemisorption of Dimethyl Carbonate on Silica Surface

2016 ◽  
Vol 17 (1) ◽  
pp. 88-92
Author(s):  
I.S. Protsak ◽  
E.M. Pakhlov ◽  
V.A. Tertykh
Keyword(s):  
Ir Spectroscopy ◽  
Fumed Silica ◽  
Dimethyl Carbonate ◽  
Silica Surface ◽  
Chemical Interaction ◽  
Spectroscopy Method ◽  
Silanol Groups

This paper presents the results of studies of dimethyl carbonate interaction with sites of the fumed silica surface. The investigations were performed in a vacuum quartz cuvette using IR spectroscopy method. Chemical interaction of dimethyl carbonate with sites of the dehydrated silica surface was shown to occur at temperature of 200 °C and higher, chemisorption processes take place involving both structural silanol groups and siloxane bridges on the surface.

Modelling the surface of amorphous dehydroxylated silica: the influence of the potential on the nature and density of defects

2018 ◽  
Vol 42 (2) ◽  
pp. 1356-1367 ◽  
Author(s):  
Stéphanie Halbert ◽  
Simona Ispas ◽  
Christophe Raynaud ◽  
Odile Eisenstein
Keyword(s):  
Molecular Dynamics ◽  
Silica Surface ◽  
Silanol Groups

The nature and density of defects on the amorphous dehydroxylated silica surface are studied by molecular dynamics for information on the silanol groups of pretreated silica.

scholarly journals Clean chlorination of silica surfaces by a single-site substitution approach

2018 ◽  
Vol 47 (12) ◽  
pp. 4301-4306 ◽  
Author(s):  
Niladri Maity ◽  
Samir Barman ◽  
Edy Abou-Hamad ◽  
Valerio D'Elia ◽  
Jean-Marie Basset
Keyword(s):  
Silica Surface ◽  
Single Site ◽  
Silanol Groups ◽  
Silica Surfaces ◽  
Selective Chlorination ◽  
Hydrogen Bonded

Unveiling a clean, selective chlorination method for the quantitative substitution of well-defined non-hydrogen bonded silanol groups of the silica surface.

Reinforcement of Silicone Rubber by Particulate Silica

1975 ◽  
Vol 48 (4) ◽  
pp. 558-576 ◽  
Author(s):  
B. B. Boonstra ◽  
H. Cochrane ◽  
E. M. Dánnenberg
Keyword(s):  
Silicone Rubber ◽  
Silica Surface ◽  
Specific Interaction ◽  
Interaction Coefficient ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Silanol Groups ◽  
Compression Set ◽  
Surface Hydroxyl Groups ◽  
Bound Rubber

Abstract The interaction between fumed silica and silicone elastomer after various treatments of the silica surface has been investigated. The effect of the treatments was determined by measuring bound rubber, an interaction coefficient by means of the oscillating disk rheometer, the mechanical properties of the vulcanizates, the morphology of the silica aggregates, and the use of an hydroxyl-terminated silicone rubber. The results indicated that the interaction is much more intensive than in carbon black-hydrocarbon rubber systems. This is demonstrated by much higher bound rubber values (by a factor of 2–3) and a higher interaction coefficient. It is shown that the major effect on this interaction coefficient is the specific interaction by hydrogen bonding, between silica surface silanol groups and the polydimethylsiloxane chain. In this bonding the isolated hydroxyl groups should play the major part. Partial inactivation of these isolated silanol groups leads to improved strength but lower modulus. Maximum inactivation of the surface hydroxyl groups leads to soft compounds with lower tensile strengths and moduli, as well as very low bound rubber. Replacement of surface hydroxyl groups by vinyldimethylsilyl groups did not have the expected activating effect. Apparently the attached vinyldimethylsilyl groups do not form crosslinks with the elastomer chains, so that the overall result of the presence of these groups on the silica surface is a weakening of the interaction with the silicone rubber chains, although to a lesser degree than in the case of trimethylsilyl groups. The interaction between filler surface and polysiloxane can be maximizedby the use of a hydroxyl-terminated elastomer. The terminal groups will react with the silica surface so strongly that the particles act as crosslinks after proper heat treatment and a crosslinked polymer is obtained with a tensile strength of the same level as a peroxide-crosslinked vulcanizate but with higher compression set. At the temperature of the compression set test (175°C) the bonds apparently rearrange so that the permanent deformation is practically 100%. Quantitative data have been presented which prove that breakdown of silica aggregates does occur during mixing in silicone rubber on a two-roll mill.

SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS CONTAINING BIO-BASED PROCESS OILS. I: ASPECTS OF MIXING SEQUENCE AND EPOXIDE CONTENT

2019 ◽  
Vol 93 (2) ◽  
pp. 360-377
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Rate Constant ◽  
Silica Surface ◽  
Early Stage ◽  
Shielding Effect ◽  
Cure Reaction ◽  
Silanol Groups ◽  
Rubber Compounds ◽  
Tan Δ ◽  
Flocculation Rate

ABSTRACT A bio-based process oil for rubber compounds is one of the compounding ingredients to be used toward an eco-friendly and more sustainable rubber technology. This work investigates epoxidized palm oil (EPO) as an alternative for petroleum-based process oil in silica-reinforced natural rubber (NR) tire tread compounds. The effect of different incorporating steps of EPO on the properties of the rubber compounds is first studied, taking into account that the polar functional groups in the oil molecules may interact with the silanol groups on the silica surface. The properties of silica-reinforced NR compounds with EPO oil are compared with that of reference mixes with treated distillate aromatic extract (TDAE) and without oil. The compounds with EPO show a lower viscosity, filler–filler interaction, and flocculation rate constant but higher cure reaction rate constants compared with the compound with TDAE. The results indicate that the epoxide groups in EPO interact with the silanol groups on the silica surface, promoting a greater shielding effect on the polar surface and thus better silica dispersion and less interference with the vulcanization reaction. The different incorporating steps of EPO show no significant effect on the viscosity, filler–filler interaction, or flocculation rate constant but clearly affect the extent of crosslinking, as indicated by the cure torque difference. The presence of EPO in an early stage of the mixing together with the first half addition of silica and silane results in the lowest cure torque difference, modulus, and tensile strength (i.e., the highest tan δ at 60 °C), which indicates a possible obstruction for the interaction between the silanol groups and silane coupling agent by the EPO molecules. Comparing EPO with different epoxide contents in the range of 1–3 mol%, the increase in epoxide content gives similar Payne effects but enhances the cure reaction, resulting in improved tensile properties and tan δ at 60 °C. The results clearly prove that EPO can be used as a TDAE alternative.

Investigations into the Silica/Silane Reaction System

1997 ◽  
Vol 70 (4) ◽  
pp. 608-623 ◽  
Author(s):  
Udo Goerl ◽  
Andrea Hunsche ◽  
Arndt Mueller ◽  
H. G. Koban
Keyword(s):  
Silica Surface ◽  
Reaction System ◽  
Rolling Resistance ◽  
Kinetic Studies ◽  
Reaction Model ◽  
Secondary Reaction ◽  
Primary Reaction ◽  
Silanol Groups ◽  
Precipitated Silica ◽  
Low Concentrations

Abstract Silica in combination with organosilanes (e.g. [bis(3-triethoxysilylpropyl)tetrasulfane] = TESPT) has recently become more important in tire applications. Their use in tire treads leads to an improvement in rolling resistance and wet traction. The requirements for the attainment of these properties are, that the triethoxysilyl groups of TESPT react with the silanol groups on the silica surface during compounding, and the polymer active groups react with the polymer during cure. The reaction of precipitated silica with this silane was investigated. The influence of various parameters on the reaction type and the reaction kinetics was considered. The results of the investigation obtained using 29Si-CP/MAS solid state NMR spectroscopy agree well with a horizontal reaction model in which a single siloxane bond is first formed with the silica surface (primary reaction). It is followed by condensation reactions between silanol groups of silane molecules which are already bound to the silica surface (secondary reaction). The kinetic studies data show a clear difference between the fast primary reaction and the slow secondary reaction. Both reactions become more rapid in acidic and alkaline pH ranges. The primary reaction accelerates up to a particular H2O content after which the rate remains constant. The secondary reaction keeps on accelerating with rising H2O content. Modification with different silane concentrations showed a higher rate constant at low concentrations.

Influence of Residual Silanol Groups on Solvent and Ion Distribution at a Chemically Modified Silica Surface

2009 ◽  
Vol 113 (21) ◽  
pp. 9230-9238 ◽  
Author(s):  
Sergey M. Melnikov ◽  
Alexandra Höltzel ◽  
Andreas Seidel-Morgenstern ◽  
Ulrich Tallarek
Keyword(s):  
Silica Surface ◽  
Ion Distribution ◽  
Modified Silica ◽  
Silanol Groups ◽  
Chemically Modified ◽  
Chemically Modified Silica ◽  
Residual Silanol Groups

scholarly journals Spectroscopic study on peculiarities of fumed silica hydridesilylation with triethoxysilane under fluidized bed conditions

2021 ◽  
Vol 12 (4) ◽  
pp. 314-325
Author(s):  
P. O. Kuzema ◽  
◽  
A. V. Korobeinyk ◽  
V. A. Tertykh ◽  
◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Surface Area ◽  
Fumed Silica ◽  
Silica Surface ◽  
High Surface ◽  
Space Filling ◽  
Silica Sample ◽  
Widespread Application ◽  
Silanol Groups ◽  
Heating Mode

Fumed silica has found widespread application in industry due to variety of fascinating properties. Owing to its specific manufacturing process, it consists of finely dispersed particles and is featured with large specific surface area covered by profoundly reactive silanol groups which are available for chemical grafting. Spherical shape of fumed silica particles and lacking porosity provides a space-filling structure. These characteristics implement the fume silica’s utilization as high-surface-area carriers for various catalysts, i.e. metallic nanometer-sized particles, organic moieties, etc. Currently a great attention is called to on-surface grafting to improve the silica-based carrier. Most of research is carried out in area of liquid phase chemistry involving an abundance of expensive and often toxic solvents while the space-filling properties of silica are favoring reactions in fluidized bed conditions. In current research fumed silica (A-300) was a subject for hydridesilylation with triethoxysilane under fluidized bed conditions. In all synthesis reported in current research the insignificant amount of solvent (1.00 wt. % of the amount used in typical wet-chemical modifications method) was spent for the silica surface silylation. While the mass ratio of silica/TES was kept constant, other conditions, i.e. solvent/catalyst presence, surface pretreatment, additional treatment with water, and the fluidized bed heating mode have been varied. FTIR spectroscopy revealed the interaction between groups of triethoxysilane and silica surface silanol groups and demonstrated the effect of modification conditions on the density of the hydridesilyl groups coverage. The results of FTIR spectroscopic studies have confirmed the presence of grafted silicon hydride groups on the surface of modified silica, as well as the presence of ethoxy and/or silanol groups – either intact or formed due to hydrolysis of the ethoxy groups. Titrimetric and spectrophotometric analysis was performed to estimate the concentration of grafted SiH groups (in all samples prepared under fluidized bed conditions their concentration ranged within about 0.28–0.55 mmol/g as dependent on the reaction conditions). Other important aspects of fluidization such as the presence of solvent and/or hydrolyzing agent, bed heating mode and the effect of the silica sample thermal pre-treatment are also discussed.

scholarly journals Quantum chemical study on the interaction of arginine with silica surface

2021 ◽  
Vol 12 (4) ◽  
pp. 358-364
Author(s):  
A. A. Kravchenko ◽  
◽  
E. M. Demianenko ◽  
A. G. Grebenyuk ◽  
M. I. Terets ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Oxygen Atom ◽  
Silica Surface ◽  
Silanol Group ◽  
Basis Set ◽  
Carboxyl Group ◽  
Amino Group ◽  
Silanol Groups ◽  
Guanidine Group

The structure and energy characteristics of structures formed during arginine adsorption on silica surface from aqueous solution were studied by the density functional theory (B3LYP) method using a valence-split basis set 6-31++G(d,p) within the continuous solvent model (PCM) and supermolecular approximation. The equilibrium structural and energy parameters of the protonated arginine molecule in the gas phase dependent on the location of the hydrogen atom are considered including those of two possible zwitterions. The structure of the arginine ion Н2А+, which is formed when a proton attaches to a molecule or zwitterion of a given amino acid, has been elucidated. To determine the deprotonation constant of the carboxyl group in an acidic medium, the complexes of the arginine molecule (AH32+) in the state with undissociated and deprotonated carboxyl groups are considered. The simulation of the acid medium was performed by taking into account the interaction with two hydrated HCl ion pairs, which provided the protonation of the a-amino group and the nitrogen atom of amino group within the guanidine group. In the study on the interaction of an arginine molecule with silica surface in an aqueous medium, complexes containing a Si8O12(OH)7O– ion with a deprotonated silanol group, six water molecules, and an arginine molecule with a deprotonated carboxyl group were considered. It has been found that the arginine molecule is most likely to be adsorbed on slica surface with formation of hydrogen bonds between the hydrogen atoms of the a-amino group and the oxygen atom of the deprotonated silanol group. In this case, the formation of a hydrogen bond between the oxygen atom of the carboxyl group and the hydrogen atom of the neighboring silanol group is possible. Slightly less likely is adsorption of arginine molecules due to interaction of the guanidine group with silanol groups of the surface. According to the calculated data, the adsorption of the zwitterionic form of the arginine molecule from the aqueous solution is equally likely to occur due to interaction of silanol groups of silica surface with both the carboxyl group and the guanidine group.

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

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