Extracting Dispersion from Roughness

2000 ◽  
Vol 661 ◽  
Author(s):  
Claude Tricot
Keyword(s):  
Carbon Black ◽  
Mathematical Analysis ◽  
Mixing Time ◽  
Small Scales ◽  
Scale Roughness

ABSTRACTA mathematical analysis of surfaces may help to understand how the carbon black is dispersed into polymer. Rubber samples are broken out, and the rupture interface is scanned with a prolometer. The roughness is detected at the micron scale. Roughness functions are dened, measuring the average oscillations of the surface. The roughness behaviour is “fractal” for small scales until around 10 microns, then become linear. A roughness ratio is defined, depending both on the scale and on the mixing time. There is evidence to suggest that the roughness ratio does not depend on the polymer, but only on the dispersion of the filler. A dispersion factor is derived, and results are shown on three diserent compounds.

Effect of Dispersion on Dynamic Properties of Filler-Loaded Rubbers

1966 ◽  
Vol 39 (2) ◽  
pp. 365-374 ◽  
Author(s):  
A. R. Payne
Keyword(s):  
Carbon Black ◽  
Phase Angle ◽  
Dynamic Viscosity ◽  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Mixing Time

Abstract Increased time of mixing carbon black-rubber vulcanizates reduces dynamic modulus and dynamic viscosity as well as phase angle at moderate amplitudes of oscillation. Changes in dynamic properties with mixing time are shown to be associated with dispersion of carbon black.

Influence of Morphology and Particle Size of Powdered Rubber on Mill Processing

1975 ◽  
Vol 48 (2) ◽  
pp. 254-262 ◽  
Author(s):  
P. L. Bleyie
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Granular Material ◽  
Specific Energy ◽  
Mixing Time ◽  
Considerable Effect ◽  
Area Increase ◽  
Surface Area Increase ◽  
Powdered Rubber ◽  
Carbon Black Dispersion

Abstract The powdered rubber method leads to a considerable shortening of mill mixing time and hence to a reduction of the specific energy required. While the transition from granular material to powder (from above 1 mm to below 1 mm particle size) has considerable effect both on mixing time and on specific energy, the effect of size reduction on specific energy for sizes below 1 mm is substantially smaller than expected from the surface area increase, probably, because a large part of the energy is used for carbon black dispersion. No effect of specific surface on specific energy and mixing time was found.

Latex Compounding of GR-S

1944 ◽  
Vol 17 (3) ◽  
pp. 711-718
Author(s):  
H. F. O'Connor ◽  
C. W. Sweitzer
Keyword(s):  
Carbon Black ◽  
Heat Resistance ◽  
High Temperatures ◽  
Room Temperature ◽  
Milling Time ◽  
Mixing Time ◽  
The Other ◽  
Stress Strain ◽  
Convenient Form ◽  
Latex Compounding

Abstract The more important findings in this study can be summarized as follows. (1) A satisfactory technique has been worked out for compounding GR-S in latex form, either with carbon alone or with carbon plus the other compounding ingredients. (2) Latex compounding of GR-S results in notable improvements in stress-strain properties. (3) Latex compounding of GR-S results in outstanding improvements in heat resistance properties, without any loss in rebound. (4) Latex compounding of GR-S results in lower modulus, higher elongation and higher subpermanent set. The increased set is significant, since it is accompanied by maintained rebound. Besides giving improved quality, latex compounding offers practical advantages and possibilities. These are listed below: (1) Latex compounding makes possible a reduction in the total milling time. This saving amounts to at least 10 per cent for carbon latex compounds and up to 50 per cent for complete latex compounds. The mixing time normally required in the Banbury is certainly not required. (2) Latex compounding makes possible cooler handling of the GR-S. Since the carbon is added to the latex at room temperature, no high temperatures are involved during its incorporation as in Banbury mixing. (3) Latex compounding makes possible cleaner handling of carbon, since it is added to the latex and is, therefore, mixed in the rubber before milling. If desired, the handling of carbon black could thus be transferred in toto to the polymer plants. This offers some interesting possibilities. (4) Latex compounding to the black crumb stage, followed by sheeting and baling, should provide a convenient and economical means for shipping black, particularly for transoceanic deliveries. There would also be important savings in containers. (5) The black latex crumb may provide a convenient form of compounded GR-S for extrusion and related operations.

New Methods for Estimating Dispersibility of Carbon Blacks in Rubber

1980 ◽  
Vol 53 (1) ◽  
pp. 48-65 ◽  
Author(s):  
Jay Jansen ◽  
Gerard Kraus
Keyword(s):  
Carbon Black ◽  
Mixing Time ◽  
Experimental Methods ◽  
The Other ◽  
Test Results ◽  
Rate Of Development ◽  
New Methods ◽  
Roll Mill ◽  
Dilute Suspension ◽  
Dispersion Test

Abstract Two convenient experimental methods are described for ascertaining dispersibility characteristics of carbon black. Both are based on the rate of development of optical density with dispersion or mixing time in a dilute suspension. One procedure uses polybutadiene medium and a roll mill to effect dispersion, the other chloroform and ultrasonic agitation. Correlations with conventional dispersion test results based on photomicrography are good. Advantages are precision and objectivity, not available to the same degree in photomicrograph evaluations.

Thermoplastic-Guayule Rubber Blends—Compositions and Mechanical Properties

1982 ◽  
Vol 55 (5) ◽  
pp. 1328-1340 ◽  
Author(s):  
L. F. Ramos-DeValle ◽  
R. R. Ramírez
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Carbon Black ◽  
Tensile Properties ◽  
Mixing Time ◽  
Cross Linking ◽  
Rubber Blends ◽  
Dominant Phase

Abstract An experimental study of the mixing and final mechanical properties of blends of guayule rubber with polyolefins was carried out. It was found that (1) variation in total mixing time during blend preparation produced only minor differences in maximum tensile properties; (2) tensile properties of the blends approach those of the plastic at GR concentrations of 50% and lower, those of the rubber at GR concentrations of 70% and higher; (3) tensile properties of partially crosslinked blends improve if the addition of DCP is effected after partial mixing of the pure homopolymers; (4) the partial cross-linking of the blend exerts a strong beneficial influence on the mechanical properties; (5) the addition of carbon black exerts little influence on the mechanical properties of the blend. It can be suggested that, at 60% GR, both polymers (GR and HDPE) show the same tendency to form the continuous or dominant phase. Above 60%, the rubber tends to be the dominant phase, and below 60% the plastic tends to be the dominant phase. The mechanical properties of partially crosslinked GR-HDPE blends are comparable with those of similar commercially available products. This suggests a further alternative in the commercialization of natural guayule rubber, namely, thermoplastic rubbers.

scholarly journals Recycling and Reusing Polyethylene Waste as Antistatic and Electromagnetic Interference Shielding Materials

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mostafizur Rahaman ◽  
Ibrahim Abdullah Al Ghufais ◽  
Govindasami Periyasami ◽  
Ali Aldalbahi
Keyword(s):  
Thermal Stability ◽  
Dielectric Properties ◽  
Carbon Black ◽  
Electromagnetic Interference ◽  
Mixing Time ◽  
Waste Product ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Emi Shielding ◽  
Scanning Calorimetry

The aim of this work is to manage the waste product based on polyethylene (PE) films by recycling and reusing it as antistatic material for electronic packaging and electromagnetic interference (EMI) shielding material for protecting electronic equipment from interference of EM radiation. To achieve this, a conductive carbon black has been mixed with the PE waste at different weight percent values by ultrasonication via a solution mixing process. Mixing time for sonication was determined by ultraviolet-visible (UV-VIS) spectra. A differential scanning calorimetry (DSC) study showed that the low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are immiscible in their blend composition. The tensile properties of PE have reduced substantially after reprocessing. However, the addition of carbon black has improved its strength up to a certain loading. The electrical percolation threshold values, calculated using the classical power law and sigmoidal Boltzmann model, were obtained at 3.5 and 2.8 wt% loading of carbon black, respectively. The conductivity result revealed that 1-2 wt% carbon-loaded composites can be used as antistatic material. The composites, having carbon loading above 4 wt%, can be effective materials for EMI shielding application. The 10 wt% carbon-loaded composite exhibits EMI SE value 33 dB which means there is approximately 99.93% protection of EM radiation at the sample thickness of 1.0 mm. Moreover, FTIR analysis, thermal stability, AC conductivity, dielectric properties, permeability, and current-voltage characteristics are also discussed in detail. There is a substantial increment in thermal stability, and dielectric properties are observed with the addition carbon black loading within the polymer matrix.

Relationship between Molecular Structure and Mixing Mechanism

1987 ◽  
Vol 60 (1) ◽  
pp. 14-24 ◽  
Author(s):  
S. Shiga
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Carbon Black ◽  
Mixing Time ◽  
Molecular Size ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Strong Linear Correlation ◽  
Black Surface ◽  
The Relationship

Abstract The relationship between the molecular weight, the bound rubber, and the PI value was studied for EPR, of which the molecular structure was measured with GPC-LALLS. A strong linear correlation is found between the bound rubber and the PI value. The Meissner theorem, modified to express a severer dependence of the bound rubber on the molecular weight than the original theorem expects and the use of a molecular size instead of the molecular weight, can explain the relationship between the molecular weight and the bound rubber, accordingly the PI value. They indicate not only the dependence of mixing processability on polymer adsorption, but also strongly suggest the mechanism of carbon black dispersion that aggregates are scraped out from the surface of agglomerates as illustrated by the onion model. A pulsed NMR was used to measure the spin-spin relaxation time T2 of EPR in rubber compounds of different mixing time to study the rubber phase structure and its time change. It can be imagined from the T2-time curves that till tmin, polymer molecules are rapidly bound on the carbon black surface to become thick gradually, while adsorbed segments per a molecule increase with time. After tmin, gradual rearrangement of molecules on the surface and the biphasic structure of the bound rubber may proceed. The whole thickness of the bound rubber increases gradually even after tmin. The resistance against the dispersion of carbon black seems to be strengthened with mixing time.

A New Method to Prepare Carbon Fiber/Carbon Black Reinforced Concrete and its Properties

2010 ◽  
Vol 168-170 ◽  
pp. 1077-1081
Author(s):  
Zheng Tao Hou ◽  
Ming Qing Sun ◽  
Bin Li ◽  
Xie Dong Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Carbon Black ◽  
Water Solution ◽  
Mixing Time ◽  
Fiber Reinforced Concrete ◽  
New Method ◽  
Curing Period

A new method is proposed to prepare carbon fiber reinforced concrete (CFRC) and carbon fiber (CF)/carbon black (CB) reinforced concrete in this paper. First, CF is dispersed in 0.4% carboxymethylcellulose sodium (CMC) water solution. Then, resolvable carbon fiber surfacing mat (RCFCM) is manufactured and cut into small patches. Finally, these patches are mixed with cement, sand, gravel, CB and water. During mixing, RCFCM patches are broken up once they meet with water. So, CF is dispersed into concrete. Results show that this method is feasible. CF/CB reinforced concrete possesses low resistivity (<100 Ω•cm), high compressive strength (≥35 MPa) and low contents of CF (0.3 Vol.%) and CB (0.6 Vol.%), so it can be used as a kind of conductive concrete for melting snow and deicing applications on highways. Both the mixing time and the curing period can affect the electrical and mechanical properties of CF/CB reinforced concrete.

Mixing time influence on fatigue crack growth in a carbon black-filled natural rubber vulcanizate

2019 ◽  
Vol 36 (2) ◽  
pp. 115-130
Author(s):  
Harini Sridharan ◽  
Jagannath Chanda ◽  
Prasenjit Ghosh ◽  
Rabindra Mukhopadhyay
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Carbon Black ◽  
Crack Growth ◽  
Mixing Time ◽  
Processing Parameters ◽  
Rubber Matrix ◽  
Mixing Times ◽  
Bound Rubber ◽  
The Difference

Various processing parameters affect the dispersion of carbon black (CB) in a rubber matrix, of which mixing time plays a major role. The physical properties of a green compound namely bound rubber and Mooney viscosity along with mechanical and fatigue crack growth (FCG) are affected by the dispersion of filler particles. To determine the effect of mastication on dispersion, the mixing time was varied from 120 s to 600 s where it was gauged that an optimum range of mixing times display better dispersion. The difference in dispersion between the green and the cured compounds was also stark due to the flocculation mechanism. Longer mixing times do not show much decrease in agglomerate size on curing, that is, approximately 2%, whereas shorter time has led to a decrease of 20%. The FCG properties were studied using a tear and fatigue analyser, where the FCG rate displays a similar trend with the dispersion of CB.

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