Carbon black tests

Pinmixers used for pelleting carbon black. Test results with a furnace oil carbon black. Reproduced from ref. [11]. 

A carbon black test sample is obtained by mixing carbon black and zinc oxide with epoxidized soybean oil. The mixture is milled in a mechanical muller with frequent scraping. The specimen is prepared by film drawdown, roller spreader or by the glass slide method. Reflectometer readings are obtained. The result is a comparison of the tint strength of standard with the test sample expressed in tint... 

Excellent protection is afforded by a range of carbon blacks for the weatherability of PP. Although the average particle size of the carbon blacks tested, as measured by electron microscopy, varied from 16 to 38 pm, at a concentration of 2%, none of the PP showed a significant fall-off in MW after 6,000 sunshine hours exposed under tropical conditions at Curasao. For the small-particle-size carbon black, a reduction in concentration to 0.5% gave similar results (see Figure 18.57). 

In addition, there are 23 other ASTM Standard Test Methods dedicated strictly to carbon black testing for the rubber industry. These standard methods are ... 

ASTM Standards on Carbon Black, American Society for Testing and Materials, Philadelphia, Pa., 1991. 

Stmcture is usually measured by a void volume test such as the absorption of dibutyl phthalate (DBPA) (15), or by bulk density measurements of the carbon black under compression. In order to eliminate the effects of pelletizing conditions the DBPA test has been modified to use a sample that has been precompressed at a pressure of 165 MPa (24,000 psi) and then broken up four successive times (24M4) (16). This procedure causes some aggregate breakdown and is claimed to more closely approximate the actual breakdown that occurs duting mbber mixing. 

There are many other test methods used to characterize carbon blacks for quaHty control and specification purposes. Table 5 Hsts some of these methods which, with a few exceptions, have been adopted by ASTM. 

Table 5. Special Analytical Test Methods for Carbon Black...

These problems can be dealt with by usiag artificial test cloths impregnated with various approximations of natural soils such as vacuum cleaner dust, dirt from air conditioner filters, clays, carbon black, fatty acids, dirty motor oil, and artificial sebum, either alone or ia combination (37,94—98). The soils are appHed by sprayiag, immersion, or padding. If the soils are carefully appHed, reproducible results can be obtained. Soil test cloths can be of great help ia detergency studies, when used with an understanding of their limitations. 

Examples of artificially soiled test pieces used to test the performance of amylases include cocoa /milk/sugar, cocoa/sugar/potato starch, cocoa /milk/sugar/potato starch, and starch/carbon black, all on cotton or polyester/cotton. 

The effect of synthesis gas composition on conversion, catalyst life, carbon black formation, etc. was determined in numerous tests. Characteristic variables in the synthesis gas composition are the H2/CO ratio, residual C02 content, and content of trace components in the form of higher hydrocarbons and catalyst poisons. 

In all tests, there was no sign of carbon black formation. Pressure drop over the reactor remained constant during the whole operating period, and there was no accumulation of free carbon on the catalyst. Analysis of the discharged catalyst for free carbon revealed that the carbon content was lower than the amount of carbon added to the catalyst as a pelletizing aid. 

Recent advances in the application of ultrafine talc for enhanced mechanical and thermal properties have been studied [12]. A particularly important use is of finely divided filler in TPO as a flame-retardant additive. In a representative formulation, 37 parts of E-plastomer, Ml 2.0, density 0.92, 60 parts of amorphous EPR, and 4 parts of fine carbon black were dry blended, kneaded at 180°C, pelletized, and press molded into test pieces, which showed oxygen index 32 versus 31 in the absence of a filler. The oxygen index is a measure of flame retardancy. 

In order to test this concept a series of compounds was prepared in a 5 L Shaw Intermix (rubber internal mixer, Mark IV, Kl) with EPDM (Keltan 720 ex-DSM elastomers an amorphous EPDM containing 4.5 wt% of dicyclopentadiene and having a Mooney viscosity ML(1 +4) 125°C of 64 MU 100 phr), N550 carbon black (50 phr), diisododecyl phthalate (10 phr), stearic acid (2 phr), and l,3-bis(tert-butylperoxy-isopropyl)benzene (Perkadox 14/40 MB ex Akzo Nobel 40% active material 6 or 10 phr). A polar co-agent (15 phr) was admixed to the masterbatch on an open mill and compounds were cured for 20 min at 180°C in a rheometer (MDR2000, Alpha Technologies). The maximum torque difference obtained in the rheometer experiments was used as a measure of... 

Carbon black may serve as a low-cost additive for controlling the gas migration in cement slurries [303]. It is intended as a suitable substitute for polymer latex and silica fume and has been tested in field applications [304,1256]. The concentration of carbon black varies from 2 to 20 parts, based on the weight of the dry cement [1220]. The particle size varies from 10 to 200 nm. A surfactant is necessary for dispersion, for example, formaldehyde-condensed naphthalene sulfonate or sulfonated cumarone or indene resins. 

Table 2.4) or proprietary test methods. Forrest [38] has listed 94 international rubber analysis standards (ISO) and 20 ISO standards in preparation referring to latices, carbon-black-filled compositions, raw and compounded rubbers. 

Table 2.7 lists techniques used to characterise carbon-blacks. Analysis of CB in rubber vulcanisates requires recovery of CB by digestion of the matrix followed by filtration, or by nonoxidative pyrolysis. Dispersion of CB within rubber products is usually assessed by the Cabot dispersion test, or by means of TEM. Kruse [46] has reviewed rubber microscopy, including the determination of the microstructure of CB in rubber compounds and vulcanisates and their qualitative and quantitative determination. Analysis of free CB features measurements of (i) particulate and aggregate size (SEM, TEM, XRD, AFM, STM) (ii) total surface area according to the BET method (ISO 4652), iodine adsorption (ISO 1304) or cetyltrimethylammonium bromide (CTAB) adsorption (ASTM D 3765) and (iii) external surface area, according to the dibutylphthalate (DBP) test (ASTM D 2414). TGA is an excellent technique for the quantification of CB in rubbers. However, it is very limited in being able to distinguish the different types of... 

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