Dibutyl phthalate absorption

In addition to the fundamental property of particle si2e (and surface area), carbon black possesses a secondary characteristic of stmcture, best described as the tendency of individual particles to agglomerate or associate with one another. These two properties or characteristics of the carbon control the degree and nature of the reinforcing character of the black in mbber. The stmcture of the carbon black is deterrnined by dibutyl phthalate absorption and surface area is estimated by N2 absorption (Table 10). 

Besides the electrochemical performance, the selection of graphite additives depends on electrode processing aspects. Flaky graphite particles have a higher dibutyl phthalate absorption (DBPA) and, thus, require more polymer binder than isometric graphite particles to achieve a sufficiently high mechanical electrode stability, as shown in Table 7.1. 

BET SSA, Brunauer Emmett Teller specific surface area SSA, specific surface area DBPA, dibutyl phthalate absorption OAN, oil absorption number. 

Important physical characteristics for rubber blacks are, in addition to the average particle size, the DPB (dibutyl phthalate) absorption, which increases with increasing structure (agglomeration of primary particles), and the specific (nitrogen) surface area, which increases with decreasing particle size and increasing porosity of the primary particles, (see Table 5.7-7). 

ASTM D 2414-96. Carbon black - n-dibutyl phthalate absorption number. 

This interpretation is not without difficulty. Evidence based on thermal expansion and NMR (see Section IV) does not support the existence of a layer of this magnitude with essentially glass-like properties. However, the idea of a larger effective filler concentration is confirmed by other evidence. Medalia (5) found extrusion die swell data to follow an effective filler concentration which was governed by polymer volume occluded in the interstices of the primary structure aggregates. He calculated this effective filler concentration from electron micrographs and the dibutyl phthalate absorption, A, as... 

Practically, structure determination of fillers is obtained by a very simple and easy method dibutyl phthalate absorption (DBPA) (Creeden, 1997). This method consists of filling up the voids in and between aggregates with DBP, which is a viscous liquid. Historically, the DPB volume was determined by making a solid pellet of carbon black and DBP with a spoon. Now, this delicate measurement is made automatically with a couple-monitored Banbury, in which a well-known quantity of dry carbon black is placed. DBP is then added drop by drop, and the structure value is obtained when torque reaches a given value. 

The percolation threshold, cpc, is the fiUer loading level at which the polymer first becomes conductive, which is generally considered to be a value of about 10 S/cm. Comprehensive experimental and theoretical treatments describe and predict the shape of the percolation curve and the basic behaviors of composites as a function of both conductive filler and the host polymer characteristics (36-38). A very important concept is that the porous nature of the conductive carbon powders significantly affect its volume filling behavior. The typical inclusive stractural measurement for conductive carbon powder porosity is dibutyl phthalate absorption (DBF) according to ASTM 2314. The higher the DBF, the greater the volume of internal pores, which vary in size and shape. The crystalhnity of the polymer also reduces the percolation threshold, because conductive carbons do not reside in the crystalhtes but instead concentrate in the amorphous phase. Eq. (2) describes the percolation curve (39). 

Standard Test Method for Carbon Black-n-Dibutyl Phthalate Absorption Number. 

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