scholarly journals Structure of carbon black-elastomer composites by small-angle neutron scattering and the method of contrast variation

1997 ◽  
Author(s):  
Rex P. Hjelm ◽  
Wesley Wampler ◽  
Michel Gerspacher
Keyword(s):  
Carbon Black ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation ◽  
Elastomer Composites

scholarly journals Variation of Solvent Scattering-Length Density in Small-Angle Neutron Scattering as a Means of Determining Structure of Composite Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
Rex P. Hjelm ◽  
Wesley Wampler ◽  
Michel Gerspacher
Keyword(s):  
Composite Materials ◽  
Carbon Black ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Length ◽  
Contrast Variation ◽  
Length Scales ◽  
Excluded Volume Effects ◽  
Component Form

ABSTRACTAs part of our work on the structure of composite materials we have been exploring the use of small-angle neutron scattering using the method of contrast variation to dissect the component form, structure and distribution. This approach has resulted in a new look at very old problemreinforcement of elastomers by carbon black.Using this approach we studied an experimental high surface area (HSA) carbon black and a gel of "HSA-bound" rubber in cyclohexane/deuterocyclohexane mixtures. HSA in cyclohexane is found to be short rodlike particle aggregates. The aggregates have a shell-core structure with a high density graphitic outer shell and an inner core of lower density amorphous carbon. The core is continuous throughout the carbon black aggregate, making the aggregate a stiff, integral unit. Contrast variation of swollen composite gels shows that there are two length scales in the gel structure. Above 10 Å, scattering from carbon black predominates, and below 10 Å the scattering is from both carbon black and the elastomer. The HSA in the composite is completely embedded in polyisoprene. An estimate of the carbon black structure factor shows strong exclusion of neighboring aggregates, probably from excluded volume effects. The surface structure of the carbon black is unaltered by the interactions with elastomer and appears smooth over length scales above about 10 Å. These results show that contrast variation can provide information on composite structure that is not available by other means. This information relates to the reinforcement mechanism of elastomers by carbon blacks.

scholarly journals The microstructure and morphology of carbon black: A study using small angle neutron scattering and contrast variation

1994 ◽  
Vol 9 (12) ◽  
pp. 3210-3222 ◽  
Author(s):  
Rex P. Hjelm ◽  
Wesley A. Wampler ◽  
Philip A. Seeger ◽  
Michel Gerspacher
Keyword(s):  
Carbon Black ◽  
Neutron Scattering ◽  
Internal Structure ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
High Surface ◽  
High Surface Area ◽  
Major Axis ◽  
Contrast Variation ◽  
The Core

This is a study of the form and structure of particles and particle aggregates of an experimental high surface area carbon black (HSA) using small-angle neutron scattering and the method of contrast variation. Contrast variation was effected by studying suspensions of the carbon black in cyclohexane containing different fractions of deuterocyclohexane. We find that the approximately 29 nm diameter USA particles are arranged as small, linear aggregates with an average aggregation number between 4 and 6. The structure averaged over the particle population is best represented by a prolate ellipsoid of revolution with semiaxes 14.5 and 76.4 nm. The surface of the aggregates appears smooth over length scales larger than 1 nm, which places an upper limit on the surface roughness observed by other methods. The internal structure of the aggregates is described by a shell-core model, with the shell density being consistent with a graphitic structure and the core being of lower density, more like amorphous carbon. Some fraction of the core volume (0.1 to 0.2) is taken up by voids that are not accessible to the solvent. An estimate of the shell thickness gives 1 to 2 nm along the ellipsoid minor axis and 6 to 10 nm along the major axis. The particles of the aggregate appear to be fused so that the less dense amorphous core is continuous through the inner parts of the aggregate. The information that can be obtained on the internal structure using contrast variation is limited by heterogeneity in the chemical composition of carbon black aggregates.

STRUCTURE ANALYSES OF SWOLLEN RUBBER–CARBON BLACK SYSTEMS BY USING CONTRAST VARIATION SMALL-ANGLE NEUTRON SCATTERING

2012 ◽  
Vol 85 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Mikihito Takenaka ◽  
Shotaro Nishitsuji ◽  
Naoya Amino ◽  
Yasuhiro Ishikawa ◽  
Daisuke Yamaguchi ◽  
...  
Keyword(s):  
Carbon Black ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Adsorption Layer ◽  
Scattering Length ◽  
Scattering Function ◽  
Characteristic Parameters ◽  
Contrast Variation ◽  
Polymer Layers

Abstract In a previous study [Takenaka et al., Macromolecules 42, 308 (2009)], we have investigated the polymer layers absorbed on silica (Si) particles in rubber–Si systems with the contrast variation small-angle neutron scattering (SANS) method. We have investigated the polymer layers absorbed on carbon black (CB) particles in rubber–CB systems with contrast variation SANS method. The scattering intensities of specimens swollen by the solvents having various scattering length densities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer–polymer correlation SPP(q), the scattering function for CB–CB correlation SCC(q), and the scattering function for polymer–CB correlation SPC(q). The analyses of SCC(q) explored the structures of the aggregates formed by CB particles. The analyses of SPC(q) and SCC(q) clarified the existence of dense polymer layers around CB aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, and the volume fractions of polymer layers and matrix. We found that the adsorption layer around CB aggregates is thicker than that around Si aggregates in rubber–Si systems.

Ultra-Small-Angle Neutron Scattering Study of Colloidal Alloys. 1. Contrast Variation Experiments for Mixtures of Hydrogenated and Deuterated Polystyrene Latices in H2O/D2O

Langmuir ◽  
1999 ◽  
Vol 15 (2) ◽  
pp. 293-296 ◽  
Author(s):  
Hideki Matsuoka ◽  
Takashi Ikeda ◽  
Hitoshi Yamaoka ◽  
Mitsuhiro Hashimoto ◽  
Toshio Takahashi ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation ◽  
Scattering Study ◽  
Neutron Scattering Study

Mechanically Interlocked Structure of Polyrotaxane Investigated by Contrast Variation Small-Angle Neutron Scattering

2009 ◽  
Vol 42 (16) ◽  
pp. 6327-6329 ◽  
Author(s):  
Koichi Mayumi ◽  
Hitoshi Endo ◽  
Noboru Osaka ◽  
Hideaki Yokoyama ◽  
Michihiro Nagao ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation

Small angle neutron scattering experiments on nanostructured matter using contrast variation

1997 ◽  
Vol 9 (1-8) ◽  
pp. 327-330
Author(s):  
S. Janßen ◽  
J. Wagner ◽  
H. Natter ◽  
J. Prewo ◽  
R. Rupp ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation

Structure of Nanocomposite Hydrogel Investigated by Means of Contrast Variation Small-Angle Neutron Scattering

2008 ◽  
Vol 41 (14) ◽  
pp. 5406-5411 ◽  
Author(s):  
Hitoshi Endo ◽  
Sho Miyazaki ◽  
Kazutoshi Haraguchi ◽  
Mitsuhiro Shibayama
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nanocomposite Hydrogel ◽  
Contrast Variation

scholarly journals Amphiphilic Comb Polymers as New Additives in Bicontinuous Microemulsions

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2410
Author(s):  
Debasish Saha ◽  
Karthik R. Peddireddy ◽  
Jürgen Allgaier ◽  
Wei Zhang ◽  
Simona Maccarrone ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Amphiphilic Polymers ◽  
Side Chain ◽  
Side Chains ◽  
Contrast Variation ◽  
Dna Complexes ◽  
Comb Polymers ◽  
Polymer Architectures

It has been shown that the thermodynamics of bicontinuous microemulsions can be tailored via the addition of various different amphiphilic polymers. In this manuscript, we now focus on comb-type polymers consisting of hydrophobic backbones and hydrophilic side chains. The distinct philicity of the backbone and side chains leads to a well-defined segregation into the oil and water domains respectively, as confirmed by contrast variation small-angle neutron scattering experiments. This polymer–microemulsion structure leads to well-described conformational entropies of the polymer fragments (backbone and side chains) that exert pressure on the membrane, which influences the thermodynamics of the overall microemulsion. In the context of the different polymer architectures that have been studied by our group with regards to their phase diagrams and small-angle neutron scattering, the microemulsion thermodynamics of comb polymers can be described in terms of a superposition of the backbone and side chain fragments. The denser or longer the side chain, the stronger the grafting and the more visible the brush effect of the side chains becomes. Possible applications of the comb polymers as switchable additives are discussed. Finally, a balanced philicity of polymers also motivates transmembrane migration in biological systems of the polymers themselves or of polymer–DNA complexes.

scholarly journals Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites

2016 ◽  
Vol 49 (6) ◽  
pp. 2036-2045 ◽  
Author(s):  
Yohei Noda ◽  
Satoshi Koizumi ◽  
Tomomi Masui ◽  
Ryo Mashita ◽  
Hiroyuki Kishimoto ◽  
...  
Keyword(s):  
Form Factor ◽  
Binary Mixture ◽  
Neutron Scattering ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Ternary Mixture ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Scattering Function ◽  
Contrast Variation

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (PH). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping itsqdependence forPH= −35% orPH= 40%, respectively. Theqbehaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at lowq(∼0.01 Å−1) varied as a quadratic function ofPHand indicated a minimum value atPH= 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at highq(∼0.3 Å−1) decreased with increasingPH, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), theqbehaviour of SANS was varied by changingPH. AtPH= −35%, the scattering maxima originating from the form factor of SP prevailed, whereas atPH= 29% andPH= 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according toq−3.6, which is consistent with the results for the SBR/CP mixture.

Sign in / Sign up

Export Citation Format

Share Document