Measurement of Carbon Black Dispersion in Rubber by Surface Analysis

1978 ◽  
Vol 51 (4) ◽  
pp. 817-839 ◽  
Author(s):  
P. C. Vegvari ◽  
W. M. Hess ◽  
V. E. Chirico
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Carbon Black ◽  
Distinct Advantage ◽  
Dispersion Index ◽  
Programmable Calculator ◽  
Wide Range ◽  
Heat Buildup ◽  
Carbon Black Dispersion

Abstract A stylus-type surface roughness tester has been applied to the study of carbon black dispersion in a number of different rubber systems. The method is based on a freshly cut rubber surface which is tracked by the stylus to provide a roughness trace on a strip chart. Carbon black agglomerates deflect the cut path because of their higher hardness relative to the surrounding matrix. Thus, surface roughness diminishes at increasing levels of dispersion. A quantitative index of dispersion quality may be derived from the frequency and average height of the roughness peaks. The method offers a distinct advantage over previous methods in its ability to provide precise dispersion ratings over a very wide range of rubber processing levels from the masterbatch to the final product. The technique is applicable to the analysis of unvulcanized rubber compounds and could be utilized as a factory quality control procedure. Direct interfacing of the surface analyzer to a programmable calculator would provide quantitative dispersion ratings within five minutes of the receipt of a sample. Studies of varied carbon black dispersions in SBR and SBR/BR passenger tread formulations have confirmed the work of previous authors. Tensile strength, fatigue life, resilience, elongation, and extrusion shrinkage increased at higher dispersion levels, while Mooney viscosity, Shore hardness and heat buildup exhibited a progressive decrease. The properties of a 50/50 NR/BR truck tread formulation showed a more varied response to black dispersion. Tensile strength and resilience showed considerably less dispersion dependence than SBR and SBR/BR. However, the tensile response increases with increasing black fineness and decreasing structure, while resilience showed the opposite trend. Fatigue life and heat buildup showed the same trends observed for SBR and SBR/BR. However, NR/BR treadwear (radial tires) showed considerably less dependence on dispersion above the 70% level, in comparison to those other polymers (bias ply tires). NR/BR with N220 at a dispersion index of 68 gave treadwear resistance that was equivalent to the same compound at a dispersion index of 89. However, dispersion indices of 50 or lower caused severely depressed treadwear resistance for the different blacks that were tested. The milling of NR/BR masterbatches cooled overnight produced significantly higher dispersion levels in comparison to hot batches at the same total mixing energy. This procedure can be employed to optimize treadwear and other properties at lower levels of energy consumption.

Elastomer Blend Properties—Influence of Carbon Black Type and Location

1977 ◽  
Vol 50 (2) ◽  
pp. 301-326 ◽  
Author(s):  
W. M. Hess ◽  
V. E. Chirico
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Wide Distribution ◽  
Continuous Phase ◽  
Unit Size ◽  
Polymer Phase ◽  
Tear Strength ◽  
Lower Heat ◽  
Heat Buildup ◽  
Tear Resistance

Abstract Criteria for minimizing hysteresis in carbon-black-filled elastomer blends are: (1) large black unit size, wide distribution, and low structure; (2) higher black loading in the discrete polymer phase (large zones); and (3) polymer of lower hysteresis as the continuous phase (low black loading). Of the different strength properties that were evaluated, tear and fatigue resistance showed the greatest dependence on black location in NR-BR and NR-SBR blends. Both properties were markedly higher for NR-BR, with most of the black in the NR phase. In NR-SBR, tear strength was higher with high loadings of black in the SBR. Fatigue life showed a reverse pattern, but the variations were not as great in this system. Criteria for maximizing tear resistance are: (1) small black unit size, low structure; (2) higher loading of carbon black in the continuous polymer phase ; and (3) the polymer of higher strength as the continuous phase. There may also be optimum levels of polymer zone size and black size distribution which affect tear strength. Optimized performance in a 50:50 NR-BR radial truck tire tread stock was obtained with a wide-distribution N-375 (50:50 N-351-N-110 blend) black with 75% location in the NR phase. This black gave 5–6°C lower heat buildup, equivalent modulus, 35% higher tear strength, and almost double the fatigue life of a conventionally mixed N-220 at essentially equivalent tread wear resistance (−4%). Optimized performance in 50:50 NR-SBR was indicated for a wide-distribution N-231 type (50:50 blend of N-351-N-119) with 75% of the black in the SBR phase. In comparison to conventionally mixed N-234 and N-220, this black gave about 8–10°C lower heat buildup, about 15% lower modulus, and essentially equal tensile, tear, and fatigue properties. Alternatively, a standard N-231 type with 75% location in the NR phase showed about 5–6°C lower heat buildup, about 20% lower modulus, equivalent tensile strength, 60% higher tear resistance, and 75–120% higher fatigue life.

Solution Masterbatching Studies

1966 ◽  
Vol 39 (3) ◽  
pp. 553-566 ◽  
Author(s):  
C. E. Scott ◽  
F. J. Eckert
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Dynamic Modulus ◽  
Polymer Adhesion ◽  
Electron Microscope Analysis ◽  
Carbon Gel ◽  
Conventional Manner ◽  
Mixed Stock ◽  
Carbon Black Dispersion ◽  
Better Than

Abstract Hydrosolution masterbatching (HSMB) imparts excellent dispersion and improved pigment-to-polymer adhesion to carbon and oil masterbatches of poly-butadiene, SBR and blends of these rubbers. Tire tests show HSMB stocks to resist wear slightly better than like stocks mixed in a conventional manner. The HSMB process can be used to produce fully compounded vulcanizable tread stocks in which the stock is discharged continuously from a drying extruder. The dispersion and adhesion advantages of HSMB stocks are also noted in complete masterbatches. HSMB oil, black, and polymer masterbatches usually have higher viscosity, tensile strength, hardness, and dynamic modulus but lower resilience and reduced scorch safety, in comparison with conventionally mixed stock. Carbon black dispersion as revealed by light and electron microscope analysis is excellent. Experiments characterizing carbon gel and development of carbon black dispersion on HSMB stocks (vacuum dried), indicate the total effective molecular contact between elastomer and pigment to be increased, so that, in effect, surface area is increased.

scholarly journals Influence of Infill Patterns Generated by CAD and FDM 3D Printer on Surface Roughness and Tensile Strength Properties

2021 ◽  
Vol 11 (16) ◽  
pp. 7272
Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin ◽  
Ahmad Serjouei ◽  
Ali Zolfagharian ◽  
Saghi Hatami ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Strength Analysis ◽  
Element Analysis ◽  
Fused Deposition ◽  
Dog Bone ◽  
Wide Range

Fused deposition modeling (FDM) is a capable technology based on a wide range of parameters. The goal of this study is to make a comparison between infill pattern and infill density generated by computer-aided design (CAD) and FDM. Grid, triangle, zigzag, and concentric patterns with various densities following the same structure of the FDM machine were designed by CAD software (CATIA V5®). Polylactic acid (PLA) material was assigned for both procedures. Surface roughness (SR) and tensile strength analysis were conducted to examine their effects on dog-bone samples. Also, a finite element analysis (FEA) was done on CAD specimens to find out the differences between printing and simulation processes. Results illustrated that CAD specimens had a better surface texture compared to the FDM machine while tensile tests showed patterns generated by FDM were stronger in terms of strength and stiffness. In this study, samples with concentric patterns had the lowest average SR (Ra) while zigzag was the worst with the value of 6.27 µm. Also, the highest strength was obtained for concentric and grid samples in both CAD and FDM procedures. These techniques can be useful in producing highly complex sandwich structures, bone scaffolds, and various combined patterns to achieve an optimal condition.

scholarly journals Improving the surface quality and mechanical properties of selective laser sintered PA2200 components by the vibratory surface finishing process

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Hamaid M. Khan ◽  
Tolga B. Sirin ◽  
Gurkan Tarakci ◽  
Mustafa E. Bulduk ◽  
Mert Coskun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Microstructural Analysis ◽  
Surface Hardness ◽  
Physical And Mechanical Properties ◽  
Surface Finishing ◽  
Finishing Process ◽  
Wide Range

Abstract This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials. Graphic abstract

Biaxial Fatigue Testing Of Vulcanizates

1961 ◽  
Vol 34 (2) ◽  
pp. 506-526 ◽  
Author(s):  
S. D. Gehman ◽  
P. Rohall ◽  
D. I. Livingston
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Natural Rubber ◽  
Fatigue Testing ◽  
Fatigue Tests ◽  
Biaxial Fatigue ◽  
Wide Range ◽  
Different Types ◽  
Extreme Probability ◽  
General Service

Abstract Extensive fatigue tests of vulcanizates of natural rubber and SBR were carried out using a cycle of alternate stretching in two perpendicular directions. It is shown that the data can be best handled statistically by assuming a lognormal distribution or by the use of extreme probability techniques. Illustrative results are given to compare the fatigue life of different types of SBR ; to show the value of the method for studying the effects of processing variations on fatigue life ; to determine the effect of various loadings of different types of carbon black; and to evaluate the effectiveness of anitoxidants and antiozonants. Exploratory tests using ozone instead of pinholes to initiate the failure eliminated the wide range in fatigue life between natural rubber and SBR, and in this respect gave a result which is more consistent with general service experience. This type of biaxial fatigue testing has many areas of usefulness for developing good endurance qualities in vulcanizates.

Carbon Black Dispersion Measurement in Rubber Vulcanizates via Interferometric Microscopy

2004 ◽  
Vol 77 (4) ◽  
pp. 691-710 ◽  
Author(s):  
Archie P. Smith ◽  
Toni L. Aybar ◽  
Ricky W. Magee ◽  
Charles R. Herd
Keyword(s):  
Carbon Black ◽  
Three Dimensional ◽  
Dispersion Index ◽  
Complete Understanding ◽  
Additional Information ◽  
Rubber Compounds ◽  
Varying Dispersion ◽  
Light Beams ◽  
Cut Surface ◽  
Carbon Black Dispersion

Abstract A new method for characterizing the carbon black dispersion in rubber compounds is introduced. This technique is based on interferometric microscopy (IFM) and utilizes the interference fringes between in-phase light beams reflected from the rubber sample and a smooth reference surface to measure the three-dimensional surface topography. The peaks and valleys present on the fresh-cut surface are representative of the carbon black agglomerates and are used to characterize the dispersion. A series of samples with different base rubbers and varying dispersion levels were created and characterized by both light microscopy and IFM. These results were used to generate a universal dispersion index based on the IFM data that correlates well with the LM dispersion index values. In addition, three-dimensional peak statistics were obtained from the IFM data and used to provide additional information about the carbon black agglomerate distribution. This data can be used for a more complete understanding of the compound behavior as a function of the carbon black dispersion and agglomerate distribution.

Effect of Cis-Trans Ratio on the Physical Properties of 1,4 Polybutadienes

1957 ◽  
Vol 30 (4) ◽  
pp. 1118-1141 ◽  
Author(s):  
J. N. Short ◽  
V. Thornton ◽  
G. Kraus
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Physical Properties ◽  
Low Temperatures ◽  
Elevated Temperatures ◽  
Trans Content ◽  
Wide Range ◽  
Brittle Point ◽  
Low Sulfur ◽  
In Cis

Abstract The physical properties of vulcanized 1,4 polybutadienes, prepared by heterogeneous catalysis and ranging from 95 per cent cis to nearly 100 per cent trans configuration, were investigated in gum and tread formulations. Comparisons were made at equal effective (physical) degree of crosslinking for both gum- and carbon black-reinforced stocks and for black stocks at equal 300 per cent modulus. In general, as polybutadienes require less sulfur for adequate vulcanization than trans polybutadienes. Vulcanizates of all 1,4 polybutadienes exceeding 15 per cent in cis content are completely rubbery at ordinary temperatures. Polybutadiene of 93 per cent trans content yields tough, leathery, crystalline vulcanizates at 80° F, which become rubbery at moderately elevated temperatures. Without exception the important physical properties change little between 25 and 80 per cent cis content. At both ends of this range the tensile strength of both gum and black stocks rises as a consequence of increasing chain regularity. However, in gum tensile strength not even the highest cis polybutadienes are equivalent to natural or synthetic cis-polyisoprenes. Black stocks of very good tensile strength with elongations ranging from 500 to 700 per cent are obtained with both cis- and trans-polybutadienes. At the crosslinking level for optimum tensile strength, modulus increases with trans content. The cis-polybutadienes have excellent resilience and low hysteresis and maintain their resilience to temperatures as low as −40° F. The latter is true even of the highest as polymers which crystallize at these temperatures. The tendency to crystallize rapidly at low temperatures disappears between 87 and 82 per cent cis content so that polymers of moderately high cis unsaturation have exceptional low-temperature characteristics. These polymers remain completely rubbery down to their brittle point (ca. −85° C). The excellent resilience of cis-polybutadiene is particularly apparent in carbon black-reinforced stocks. Because of the inherently low modulus of these stocks and their low sulfur requirement, these may be vulcanized to rather high degrees of crosslinking. This results in further improvements in resilience and heat build-up with only moderate sacrifices in tensile strength and ultimate elongation. Vulcanizates of 70 to 80 per cent trans-polybutadienes exhibit evidence of crystallinity over a wide range of temperatures and are probably not completely melted at room temperature. Although their resilience is less than that of the high cis-polybutadienes, it is still somewhat better than that of SBR, particularly at low temperatures. The 1,4 polybutadienes are more resistant to oxidative scission than emulsion polybutadiene or SBR and are greatly superior to natural rubber in this respect. The dominant effect in the aging of 1,4 polybutadienes is crosslinking. Because of their low sulfur requirements the cis polybutadienes offer a particular advantage in aging resistance. None of the polybutadienes exhibits ozone resistance comparable to Hevea.

Study on the effect of virgin and recycled chloroprene rubber (vCR and rCR) on the properties of natural rubber/chloroprene rubber (NR/CR) blends

2013 ◽  
Vol 33 (9) ◽  
pp. 803-811 ◽  
Author(s):  
Siti Z. Salleh ◽  
Hanafi Ismail ◽  
Zulkifli Ahmad
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Carbon Black ◽  
Natural Rubber ◽  
Maximum Torque ◽  
Elongation At Break ◽  
Constant Content ◽  
Cure Time ◽  
Chloroprene Rubber ◽  
Minimum Torque

Abstract The effects of various ratios of virgin chloroprene rubber (vCR) and recycled chloroprene rubber (rCR) with a constant content of carbon black (CB) on the properties of natural rubber/chloroprene rubber NR/CR blends were studied. The minimum torque (ML), maximum torque (MH), scorch time, and cure time increased with the addition of both CRs and the effects of rCR were more pronounced than vCR on these properties. The tensile strength and fatigue life of the NR/vCR blends increased with an addition of vCR up to 25 phr and then decreased with a higher vCR. However, NR/rCR blends reflected otherwise for both properties. The elongation at break and swelling percentage of NR/CR blends decreased with the addition of both vCR and rCR.

Autoradiographic Technique with Carbon14 in Rubber

1952 ◽  
Vol 25 (2) ◽  
pp. 291-302
Author(s):  
A. D. Kirshenbaum ◽  
C. W. Hoffman ◽  
A. V. Grosse
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Strength Data ◽  
Autoradiographic Technique ◽  
Carbon Black Dispersion

Abstract The autoradiograph technique making use of carbon14 is useful in studying the carbon black distribution in rubber. It is superior to the photomicrographic technique in studying carbon black dispersion in rubber. Autoradiographs of different carbon black-rubber mixes (tensile strengths varying from 300 to 3300 pounds per square inch) showed visible variations in the carbon black distribution which closely agree with the tensile strength data, whereas photomicrographs of the same mixes showed no differences among the various mixes. The autoradiographic technique is also useful in tracking down carbon black agglomeration in rubber.

scholarly journals Effect Surface Roughness on Fatigue Crack Propagation Behaviour of Fibre Metal Laminates (FMLs)

2019 ◽  
Vol 16 (2) ◽  
pp. 6588-6604
Author(s):  
A. Purnowidodo ◽  
S. Sofyan Arief ◽  
F. Hilmi Iman
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Shear Strength ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Fibre Orientation ◽  
Interface Shear ◽  
Fibre Metal Laminates ◽  
Fibre Metal ◽  
Effect Of Surface

In the present study, the effect of surface roughness of the metal lamina at the interface of fibre metal laminates (FMLs) on the crack propagation behaviours was investigated for different fibre orientation. The FMLs was made by combining the aluminium and the carbon fibre-epoxy composite lamina. The increasing of the aluminium surface roughness at the interface causes the tensile strength to increase for every fibre orientation. The highest tensile strength is 282 and 367 MPa., respectively for fibre orientation 0°/90° and -45°/45° when the surface roughness is 2.89 mm. The increasing surface roughness causes the development of the delamination taking place at the interface is more difficult, and it leads to the shear strength at the interface to increase. Because of this, the tensile strength increases. However, the lifetime is not only influenced by the interface shear strength but also the stress concentration just in front of the crack tip as well as the surface roughness itself leading to the crack to be initiated from the rougher surface. The longest fatigue life is 180 000 cycles in the case of the fibre orientation 0°/90° with the surface roughness of 1.78 mm, and in the case of fibre orientation of -45°/+45° the longest fatigue life is 420 000 cycles when the surface roughness is 0.33 mm. The results of the study show that the surface roughness affects the tensile strength and crack propagation behaviour.

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