scholarly journals Rubber-Filler Interactions in Polyisoprene Filled with In Situ Generated Silica: A Solid State NMR Study

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 822 ◽  
Author(s):  
Silvia Borsacchi ◽  
Umayal Sudhakaran ◽  
Lucia Calucci ◽  
Francesca Martini ◽  
Elisa Carignani ◽  
...  
Keyword(s):  
Solid State ◽  
Dynamic Properties ◽  
Sol Gel ◽  
Relaxation Times ◽  
Reaction Times ◽  
Rubber Matrix ◽  
Polymer Bulk ◽  
Nmr Study ◽  
Bound Rubber

In this paper we used high- and low-resolution solid state Nuclear Magnetic Resonance (NMR) techniques to investigate a series of polyisoprene samples filled with silica generated in situ from tetraethoxysilane by sol-gel process. In particular, 1H spin-lattice and spin-spin relaxation times allowed us to get insights into the dynamic properties of both the polymer bulk and the bound rubber, and to obtain a comparative estimate of the amount of bound rubber in samples prepared with different compositions and sol-gel reaction times. In all samples, three fractions with different mobility could be distinguished by 1H T2 and ascribed to loosely bound rubber, polymer bulk, and free chain ends. The amount of bound rubber was found to be dependent on sample preparation, and it resulted maximum in the sample showing the best dispersion of silica domains in the rubber matrix. The interpretation of the loosely bound rubber in terms of “glassy” behaviour was discussed, also on the basis of 1H T1 and T1ρ data.

Nmr Imaging of Silica-Silicone Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Leoncio Garrido ◽  
Jerome L. Ackerman ◽  
James E. Mark
Keyword(s):  
Imaging Techniques ◽  
Spin Echo ◽  
Sol Gel ◽  
Relaxation Times ◽  
Reaction Times ◽  
Silica Glasses ◽  
Spin Lattice ◽  
H Nmr ◽  
Hydrolysis Of

ABSTRACTPolydimethylsiloxane (PDMS) model networks reinforced by in situ precipitated SiO2, and polymer-modified silica glasses were obtained following the usual sol-gel methods. The conditions were chosen to increase the probability of observing inhomogeneities: (i) bulky samples, and (ii) limited reaction times. These composites were characterized by measuring bulk spin-lattice (T1) and spin-spin (T2) relaxation times and using 1H NMR two-dimensional Fourier transform (2DFT) spin echo imaging techniques. The T1 and T2 maps show clear and significant variations of NMR signal intensity throughout the sample due to nonuniform hydrolysis of the tetraethylorthosilicate (TEOS) in the specimens.

FUNCTIONALIZATION OF EPDM RUBBER TOWARD BETTER SILICA DISPERSION AND REINFORCEMENT

2018 ◽  
Vol 92 (2) ◽  
pp. 219-236 ◽  
Author(s):  
Naresh D. Bansod ◽  
Bharat P. Kapgate ◽  
Pradip K. Maji ◽  
Anasuya Bandyopadhyay ◽  
Chayan Das
Keyword(s):  
Maleic Anhydride ◽  
Sol Gel ◽  
Silica Content ◽  
Rubber Matrix ◽  
Epdm Rubber ◽  
In Situ Silica ◽  
Grafted Epdm ◽  
Composite Properties ◽  
Rubber Filler

ABSTRACT Functionalization of non-polar ethylene propylene diene monomer (EPDM) rubber by melt grafting of maleic anhydride (MA) and in situ incorporation of sol–gel derived silica in the MA grafted EPDM has been done to prepare EPDM/silica composites to use dual benefits of both the approaches, which results in adequate rubber–filler compatibility, good filler dispersion, and enhanced composite properties. Controlled growth of silica up to 25 parts per hundred rubber (phr) is carried out with the solution sol–gel process using tetraethoxysilane (TEOS) as a silica precursor. Mechanical and dynamical properties of the composites are found to improve consistently as silica content increases. Furthermore, treatment of maleic anhydride grafted EPDM by γ-aminopropyltrimethoxysilane (γ-APS) results in remarkable improvement in composite properties even at the same silica content. This is attributed to the generation of uniformly dispersed spherically shaped nanosilica throughout the rubber matrix as observed in a transmission electron microscopic (TEM) study. This contributes to enhanced crosslinking density and improved rubber–filler interaction. In fact, the reinforcement effect brought by in situ silica relative to unmodified in situ silica/EPDM composites is found to be much higher than that reported in recent work on EPDM/in situ silica composites even with higher silica loading. The mechanical, rheological, and dynamic mechanical behaviors of all the composites are evaluated and compared in detail.

In Situ Silica Nanoparticle Formation in a Rubber Matrix Monitored via Real-Time SAXS and Solid-State NMR Spectroscopy

2014 ◽  
Vol 47 (15) ◽  
pp. 5174-5185 ◽  
Author(s):  
Elena Miloskovska ◽  
Michael Ryan Hansen ◽  
Cornelius Friedrich ◽  
Denka Hristova-Bogaerds ◽  
Martin van Duin ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Real Time ◽  
Solid State Nmr ◽  
Silica Nanoparticle ◽  
Rubber Matrix ◽  
Nanoparticle Formation ◽  
Solid State Nmr Spectroscopy ◽  
In Situ Silica

In situ solid-state NMR study of methanol-to-gasoline chemistry in zeolite HZSM-5

1992 ◽  
Vol 96 (19) ◽  
pp. 7740-7746 ◽  
Author(s):  
Eric J. Munson ◽  
Ali A. Kheir ◽  
Noel D. Lazo ◽  
James F. Haw
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Study ◽  
Methanol To Gasoline

scholarly journals `NMR Crystallization': in-situ NMR techniques for time-resolved monitoring of crystallization processes

2017 ◽  
Vol 73 (3) ◽  
pp. 137-148 ◽  
Author(s):  
Kenneth D. M. Harris ◽  
Colan E. Hughes ◽  
P. Andrew Williams ◽  
Gregory R. Edwards-Gau
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Solid Phase ◽  
Dynamic Properties ◽  
Time Resolved ◽  
Nmr Techniques ◽  
Versatile Technique ◽  
Crystallization From Solution ◽  
In Situ Nmr

Solid-state NMR spectroscopy is a well-established and versatile technique for studying the structural and dynamic properties of solids, and there is considerable potential to exploit the power and versatility of solid-state NMR for in-situ studies of chemical processes. However, a number of technical challenges are associated with adapting this technique for in-situ studies, depending on the process of interest. Recently, an in-situ solid-state NMR strategy for monitoring the evolution of crystallization processes has been developed and has proven to be a promising approach for identifying the sequence of distinct solid forms present as a function of time during crystallization from solution, and for the discovery of new polymorphs. The latest development of this technique, called `CLASSIC' NMR, allows the simultaneous measurement of both liquid-state and solid-state NMR spectra as a function of time, thus yielding complementary information on the evolution of both the liquid phase and the solid phase during crystallization from solution. This article gives an overview of the range of NMR strategies that are currently available for in-situ studies of crystallization processes, with examples of applications that highlight the potential of these strategies to deepen our understanding of crystallization phenomena.

A Solid State Multinuclear Magnetic Resonance Study of the Sol-Gel Process using Polysilicate Precursors

1986 ◽  
Vol 73 ◽  
Author(s):  
W. G. Klemperer ◽  
V. V. Mainz ◽  
D. M. Millar
Keyword(s):  
Solid State ◽  
Magnetic Resonance ◽  
Sol Gel ◽  
Building Blocks ◽  
Magnetic Resonance Study ◽  
Solvent Content ◽  
Molecular Building Blocks ◽  
Nmr Study ◽  
Sol Gel Process ◽  
Nmr Techniques

ABSTRACTA solid state multinuclear NMR study of the sol-gel process was performed using the molecular building blocks tetramethoxysilane, hexamethoxydisiloxane, octamethoxytrisiloxane and octamethoxyoctasilsesquioxane as precursor monomers. Water content, solvent content, and hydrolysis/condensation processes were monitored using 17O, 13C, and 29Si FT, FTMAS and CPMAS NMR techniques.

Understanding the Solid-State Phase Transitions of dl-Norleucine: An in Situ DSC, Microscopy, and Solid-State NMR Study

2015 ◽  
Vol 15 (10) ◽  
pp. 5157-5167 ◽  
Author(s):  
M. M. H. Smets ◽  
S. J. T. Brugman ◽  
E. R. H. van Eck ◽  
J. A. van den Ende ◽  
H. Meekes ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Solid State ◽  
Solid State Nmr ◽  
Nmr Study
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