Crack growth and abrasion resistance of carbon black-filled purified natural rubber vulcanizates

2003 ◽  
Vol 90 (7) ◽  
pp. 1793-1796 ◽  
Author(s):  
N. Rattanasom ◽  
O. Chaikumpollert
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth ◽  
Abrasion Resistance ◽  
Natural Rubber Vulcanizates

Effect of Crosslink Density on Cut Growth in Black-Filled Natural Rubber Vulcanizates

2002 ◽  
Vol 75 (5) ◽  
pp. 935-942 ◽  
Author(s):  
G. R. Hamed ◽  
N. Rattanasom
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth ◽  
Crosslink Density ◽  
Longitudinal Crack ◽  
Test Pieces ◽  
Filled Rubber ◽  
Longitudinal Cracks ◽  
Natural Rubber Vulcanizates ◽  
High Crosslink Density

Abstract Tensile strengths, σb, of gum and N115-filled natural rubber test pieces, with and without edge pre-cuts, have been determined. At low crosslink density, the regular (uncut) σb of filled and gum vulcanizates is similar. However, at high crosslink density, the gum NR becomes brittle, while the corresponding filled rubber remains strong and resistant to cut growth. It is proposed that the tightly linked gum does not strain-crystallize appreciably during stretching, but that its filled counterpart does. Carbon black appears capable of inducing crystallization in a network that alone remains amorphous during extension. Filled vulcanizates of various crosslink densities have similar normal tensile strengths ( ≈ 30 MPa), but strengths differ, sometimes more than twofold, if a pre-cut is present. Lightly crosslinked specimens containing a small cut have strengths that depend very weakly on cut size, c. Furthermore, these develop long longitudinal cracks from which catastrophic rupture initiates. With larger cuts, strength decreases more rapidly with increasing c, there is less longitudinal crack growth, and rupture initiates near the original cut tip. In contrast, the strength of a highly crosslinked vulcanizate is sensitive to small cuts and test pieces exhibit minimal longitudinal cracking before failure.

scholarly journals Utilization of chitin powder as a filler in natural rubber vulcanizates: In comparison with carbon black filler

2020 ◽  
Vol 11 (1) ◽  
pp. 43-51
Author(s):  
Wisdom Okechukwu Egbujuo ◽  
Placid Ikechukwu Anyanwu ◽  
Henry Chinedu Obasi
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
Filler Content ◽  
Chemical Extraction ◽  
Local Market ◽  
Roll Mill ◽  
Crab Shell Waste ◽  
Natural Rubber Vulcanizates

AbstractNatural rubber (NR) vulcanizates were prepared from natural rubber and chitin using a two-roll mill. The chitin was extracted from crab shell waste obtained from a local market in Oron, Akwa Ibom State, Nigeria using the chemical extraction method. The effects of the chitin at different contents (0–40 phr) on the mechanical properties of the NR/Chitin vulcanizates with carbon black as reference filler have been investigated. The tensile strength of the chitin filled natural rubber (NCH), and the carbon black filled natural rubber (NCB) vulcanizates were found to increase with an increase in filler content to reach optimum at 30 phr after which it decreased. The hardness, impact and abrasion resistance properties of the NCH and NCB vulcanizates increased as filler content increases. The tensile strength and abrasion resistance of the vulcanizates containing blends of varying percentages of carbon black to chitin (CBCH) increased as more carbon black (CB) is introduced while the hardness and impact strength increased with increase in chitin content. However, carbon black filled vulcanizates showed better property enhancement than the chitin filler.

scholarly journals Effects of chemically treated and carbonized spear grass fibre on the curing and mechanical properties of natural rubber vulcanizates

2021 ◽  
Vol 39 (4) ◽  
pp. 1142-1149
Author(s):  
A.C. Ezika ◽  
V.U. Okpechi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
Filler Loading ◽  
Carbonization Temperature ◽  
Compression Set ◽  
Chemically Treated ◽  
Natural Rubber Vulcanizates

Effects of chemically treated and carbonized spear grass fibre on the curing and mechanical properties of natural rubber vulcanizates were carried out. Natural rubber (NR) was filled with carbonized (at carbonization temperatures of 400°C, 600°C and 800°C  respectively) and chemically treated (treatment with HCl and NaOH of 5% concentration) spear grass fillers respectively, at a filler loading of 30phr. The rubber compounding was carried out in a bambury mixer. The effect of carbonization temperature and chemical treatment of the filler on the mechanical properties (tensile strength, % elongation, hardness strength, abrasion resistance and compression set) and rheological properties (cure time, scorch time, maximum and minimum torque) were carried out on the  samples. The results of the mechanical properties of carbonized spear grass fibre (C-SGF) filled vulcanizates show that the optimum carbonization temperature for an improved tensile strength, % elongation, hardness, abrasion and compression set was obtained at 400°C. NaOH treated fibre filled vulcanizates showed better mechanical properties; with the highest abrasion resistance of 67.65%, while untreated and acidified fibre filled vulcanizates showed poor mechanical properties. Acidified (HCl) uncarbonized spear grass fibre (U-SGF) filled vulcanizate had the highest compression set of 48% against C-SGF filled vulcanzates and carbon black filled  vulcanizate, with carbon black filled vulcanizate having 47% as its compression set value. This reveals that at a carbonization temperature of 400°C, C-SGF appears to be a potential substitute filler for carbon black (CB). Keywords: Spear Grass Fibre, Natural Rubber, Chemical Treatments, Cure Characteristics, Mechanical Properties, Carbonization

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.

Effect of Vulcanization Additive on Cure Characteristics and Physical Properties of Silica Filled Epoxidised Natural Rubber Truck Tyre Tread Compound

2015 ◽  
Vol 1107 ◽  
pp. 113-118
Author(s):  
Ahmad Kifli Che Aziz ◽  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustafa Kamal
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Physical Properties ◽  
Abrasion Resistance ◽  
Butadiene Rubber ◽  
Cure Characteristics ◽  
Truck Tyre ◽  
Curing Systems

The challenges of using Epoxidised Natural Rubber (ENR) in truck tyre tread are to achieve good cure reversion resistant and physical properties especially on abrasion resistance towards long vulcanization time. The objectives of the project are to study the effects of vulcanization additive on cure characteristics and physical properties of silica filled ENR compound. In this work, a variation of curing systems were employed and a standard carbon black filled Natural Rubber/Butadiene Rubber (NR/BR) compound as a comparison. Greater reversion resistance and physical properties were observed with inclusion of vulcanization additive in the silica compound as compared to compound containing any. The abrasion resistance on the hand improved in spite of long vulcanisation time which commonly practices in truck tyre manufacturing.Keywords: ENR, silica, vulcanization additive, cure reversion, abrasion resistance

Modeling of Carbon Black Filled Natural Rubber Vulcanizates by the Standard Triboelastic Solid

1999 ◽  
Vol 72 (4) ◽  
pp. 673-683 ◽  
Author(s):  
V. A. Coveney ◽  
D. E. Johnson
Keyword(s):  
Mathematical Modeling ◽  
Carbon Black ◽  
Natural Rubber ◽  
Dynamic Behavior ◽  
Low Frequency ◽  
Specific Reference ◽  
Published Data ◽  
General Terms ◽  
Wide Range ◽  
Natural Rubber Vulcanizates

Abstract Mathematical modeling of the dynamic behavior of vulcanizates is reviewed with the emphasis on carbon black filled natural rubber (NR). The 3 constant standard triboelastic solid (STS) model and its behavior are described, in general terms and with specific reference to low frequency shear data for a wide range of filled NR vulcanizates. Good general agreement is found between model and experiment for the data obtained at strain amplitudes down to 0.01; there is also acceptably good correlation between carbon black loading and values of STS constants. For previously published data down to very low strain amplitudes (1×10−4), agreement is much less satisfactory.

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.

Stress Softening in Natural Rubber Vulcanizates. IV. Unfilled Vulcanizates

1967 ◽  
Vol 40 (3) ◽  
pp. 840-848 ◽  
Author(s):  
J. A. C. Harwood ◽  
A. R. Payne
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Molecular Networks ◽  
Mullins Effect ◽  
Total Recovery ◽  
Stress Softening ◽  
Affine Deformation ◽  
Nonaffine Deformation ◽  
Natural Rubber Vulcanizates ◽  
Random State

Abstract Stress softening (Mullins effect) in gum natural rubber vulcanizates is similar in magnitude to that in carbon black filled vulcanizates. The amount of stress softening is slightly greater in vulcanizates cured to produce predominantly polysulfide crosslinks than in those containing monosulfide or carbon to carbon crosslinks. The total recovery of stress softening in the vulcanizates containing monosulfide or carbon to carbon crosslinks suggests that the phenomenon is attributable to a quasiirreversible rearrangement of molecular networks due to localized non-affine deformation resulting from short chains reaching the limit of their extensibility. This nonaffine deformation results in a displacement of the network junctions from their initial random state.

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