Structural Characterization of Filled Vulcanizates Part 1. Determination of the Concentration of Chemical Crosslinks in Natural Rubber Vulcanizates Containing High Abrasion Furnace Black

1967 ◽  
Vol 40 (3) ◽  
pp. 866-882 ◽  
Author(s):  
M. Porter
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Volume Fraction ◽  
Exponential Relationship ◽  
Furnace Black ◽  
Simple Linear Relationship ◽  
Chemical Crosslinks ◽  
Natural Rubber Vulcanizates

Abstract The degree to which HAF black restricts the swelling of natural rubber vulcanizates in n-decane has been determined using a vulcanizing system in which the stoichiometry of crosslinking is unaffected by the carbon black. The dependence of the degree of restriction, as measured by the ratio of the volume fractions of rubber in the filled and unfilled vulcanizates swollen to equilibrium, on the concentration of carbon black follows an exponential relationship previously proposed by Lorenz and Parks. This is found to be equivalent to a simple linear relationship between the apparent and actual crosslink concentrations: napparent/nactual=1+Kϕ, where K is a constant characteristic of the filler and φ is its volume fraction in the vulcanizate. The relation has been used to determine actual crosslink concentrations in filled natural rubber vulcanizates. HAF black is found to cause increases of up to 25 per cent in the yield of polymer to polymer crosslinks in conventional sulfur vulcanizing systems, accompanied by changes in rate of cure and of crosslink reversion. All these are small compared with the effect of the filler on many physical properties.

Internal Field Emission in Carbon Black-Loaded Natural Rubber Vulcanizates

1964 ◽  
Vol 37 (2) ◽  
pp. 348-354 ◽  
Author(s):  
L. K. H. van Beek ◽  
B. I. C. F. van Pul
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Field Emission ◽  
Electron Micrographs ◽  
Internal Field ◽  
Emission Characteristics ◽  
Furnace Black ◽  
Three Samples ◽  
Insulating Gap ◽  
Natural Rubber Vulcanizates

Abstract The nonohmic behavior of carbon black-loaded natural rubber vulcanizates was studied. Three samples contained high-abrasion furnace black (HAF) in good, moderate, and poor dispersion. Another sample contained a good dispersion of medium thermal black (MT). The nonohmic behavior of the poor HAF dispersion and that of the MT dispersion could be interpreted as due to internal field emission across insulating gap widths of 2 and 2.5 µ. The existence of such gaps was confirmed by electron micrographs. No clear evidence of internal field emission could be obtained for the good and moderate HAF dispersions where, according to electron micrographs, the gaps are much narrower. There is some indication that the degree of dispersion can be correlated with field emission characteristics.

PREPARATION AND CHARACTERIZATION OF BROMINATED NATURAL RUBBER APPLIED IN SILICA-FILLED NATURAL RUBBER VULCANIZATES

2016 ◽  
Vol 89 (3) ◽  
pp. 406-418 ◽  
Author(s):  
Nuchanart Onchoy ◽  
Pranee Phinyocheep
Keyword(s):  
Natural Rubber ◽  
Bromine Atom ◽  
Proton Nuclear Magnetic Resonance ◽  
Strong Emission ◽  
X Ray ◽  
Rubber Compounds ◽  
Silica Filler ◽  
Natural Rubber Vulcanizates

ABSTRACT Functionalization of NR with a bromine atom was developed and explored for its application in a silica-reinforced NR system. Two possible pathways were investigated: the direct addition of a bromine atom using N-bromosuccinimide (NBS) with FeCl2 as a catalyst in the latex phase (NR–Br); and an indirect method using a ring opening of epoxidized natural rubber (ENR) with 2-bromopropionic acid (ENR–Br). The chemical structure, including determination of the bromine contents, was analyzed with proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. The occurrence of bromine in NR–Br was confirmed using scanning electron microscopy with energy dispersive x-ray spectroscopy. Strong emission peaks for Br Kα at 1.5 eV was evidenced. Moreover, glass transition temperature of modified NRs increased after bromination. Two types of brominated NR, that is, NR–Br and ENR–Br containing 2 and 4 mol% of bromine function, respectively, were used in a range of 1–5 phr in the silica-reinforced NR system with silica loading of 10 and 30 phr. Both cure and mechanical properties of the rubber compounds were investigated. The incorporation of the bromine function in NR of both ENR–Br and NR–Br enhanced the cure reactivity of the NR–silica vulcanization system. The modified NRs may have a role as a coupling agent between the NR and the silica filler.

Internal Field Emission in Carbon Black-Loaded Natural Rubber Vulcanizates

1963 ◽  
Vol 36 (3) ◽  
pp. 740-746 ◽  
Author(s):  
L. K. H. van Beek ◽  
B. I. C. F. van Pul
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Field Emission ◽  
Electron Micrographs ◽  
Internal Field ◽  
Emission Characteristics ◽  
Furnace Black ◽  
Three Samples ◽  
Insulating Gap ◽  
Natural Rubber Vulcanizates

Abstract The nonohmic behavior of carbon black-loaded natural rubber vulcanizates was studied. Three samples contained high-abrasion furnace black (HAF) in good, moderate, and poor dispersion. Another sample contained a good dispersion of medium thermal black (MT). The nonohmic behavior of the poor HAF dispersion and that of the MT dispersion could be interpreted as due to internal field emission across insulating gap widths of 2 and 2.5 µ. The existence of such gaps was confirmed by electron micrographs. No clear evidence of internal field emission could be obtained for the good and moderate HAF dispersions where, according to electron micrographs, the gaps are much narrower. There is some indication that the degree of dispersion can be correlated with field emission characteristics.

Swelling and Network (Crosslink) Density of Carbon Black-Filled Natural Rubber Vulcanizates

1962 ◽  
Vol 35 (2) ◽  
pp. 274-283 ◽  
Author(s):  
H. Westlinning ◽  
G. Butenuth
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Mean Value ◽  
Network Density ◽  
Low Density ◽  
Additional Measurement ◽  
Degree Of Swelling ◽  
Natural Rubber Vulcanizates

Abstract The method cited by W. Kuhn and coworkers for the determination of network densities on the basis of a thermal analysis of swollen samples has been applied to unfilled and carbon black-filled natural rubber vulcanizates. The results with unfilled rubber on the basis of the new method are in the expected correlation with the measurements of the degree of swelling and the modulus of elasticity. From the results with carbon black-filled samples it is probable that an inhomogeneously crosslinked system is formed under the influence of the filler. It is concluded that there are regions of high network density adjacent to regions of low density. Consequently, the degree of swelling, referred solely to the rubber portion, is to be considered a mean value in the case of filled vulcanizates from which the network density cannot be deduced without additional measurement.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

Preparation and Characterization of Natural Rubber Composites Comprising Conductive Carbon Black/Magnetite Hybrid Fillers Obtained by Impregnation Technology

2016 ◽  
Vol 55 (13) ◽  
pp. 1344-1356
Author(s):  
Ahmed A. Al-Ghamdi ◽  
Omar A. Al-Hartomy ◽  
Falleh R. Al-Solamy ◽  
Nikolay Dishovsky ◽  
Diana Zaimova ◽  
...  
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Rubber Composites ◽  
Conductive Carbon Black ◽  
Hybrid Fillers ◽  
Natural Rubber Composites
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