ISO 15825 pdf download – Rubber compounding ingredients —Carbon black- Determination ofaggregate size distribution by disccentrifuge photosedimentometry

ISO 15825 pdf download – Rubber compounding ingredients —Carbon black- Determination ofaggregate size distribution by disccentrifuge photosedimentometry.
x-value of the point on the mass distribution curve at which 50 % by mass of the test sample is larger and 50% by mass of the test sample Is smaller
Note I to entry: it represents the median value of the distribution.
Note 2 to entrr in the software of the Brookhaven disc centrifuge the median Stokes diameter is reported as d50. Note 3 to entry: I)so is used for reporting purposes only.
32.4
mode
value at which the most frequent diameter occurrence Is observed, which Is portrayed as a peak in the distribution curve
Note 1 to entry: In some cases, there may be more than one mode indicated Note 2 to entry: is used for reporting purposes only.
3.2.5
lower quartile
x-value of the point on the mass distribution curve at which 75% of the sample is larger, and 25% smaller
3.2.6
upper quartile
x’value olthe point on the mass distribution curve at whIch 75% of the sample is smaller, and 25% larger
3.2.7
quartile ratio
ratio of upper quartile to lower quartile
Note ito entry: In the software or the Brookhaven disc centrifuge the quartile ratio is reported as d75/d2S”
3.2.8
D-50
width of the plot of the mass distribution measured at the half•maximum point of the mode, which Is a measure of the breadth of the aggregate size distribution
Note ito entry: in the software ol the Brookhaven disc centrifuge iSV 541 is reported as FWKM (lull width at half maximum).
4 Significance and use
Disc centrifuge photosedimentometry produces a rapid mass-differential aggregate size distribution, by continuously measuring the solution turbidity as a Function olcentrifugatlon time. In order to obtain a true mass distribution, a light scattering correction shall be applied.
An example of a mass distribution curve is given in Annex A.
11 Initiation of procedure
11.1 Set the rotational speed. In general, 8 000 r/min to 11 000 r/min for reinforcing grades and4 000 r/min to 6 500 r/min for semi-reinforcing grades is suitable.Prior to the test, a 30 min warm-upphase at the chosen speed is necessary. Make sure that the spin fluid used in 11.3 is at room temperature.Keep the air filter of the test instrument clean at all time so that a temperature rise at the rotating disccell during testing is avoided.
NOTE Effective air ventilation can be achieved by keeping the ventilation window of the instrument open.11.2 Inject 1,0 cm3 of ethanol (6.2) and start the centrifuge.
11.3 Inject carefully 15 cm3 of the spin fluid (6.5) to underlay the ethanol.
11.4 Inject 0,1 cm3 of dodecane (6.4) on top of the gradient layer to reduce evaporative cooling.11.5Allow stabilization of spin fluid, typically for 3 min.
11.6 Set turbidity to zero on the DCP photodetector, if required.This step may be optional, dependingon the instrument used in the procedure.
The use of “cut” and “boost” controls is not recommended since it leads to poor reproducibility of thetest results.
11.7 Inject 0,25 cm3 of the test sample, prepared as in Clause 9, into the spinning disc, and immediatelystart the computer for data acquisition.For injecting the test sample, it is recommended to use a syringewith a needle having an inner diameter of 1,19 mm (16 gauge).
11.8 Read the temperature of the chamber measured by the integrated thermocouple.
11.9 Inspect the disc for hydrodynamic instability or streaming which may be seen as vortices of sampleoriginating from the dark band of layered carbon black, spiralling towards the outer boundary of thespin fluid.A normal run will produce a smooth, diffuse, circular band of carbon black moving outwardtowards the perimeter of the disc.
11.10 Continue to run until the turbidity has returned close to the baseline, then stop the run. If thebaseline condition is not reached within 1 h, repeat the test with an increased rotational speed. If thebaseline condition is not reached within 1 h even though maximum rotational speed (11 000 rpm) isapplied, continue the test until the turbidity has returned close to the baseline.
11.11 Read the temperature of the chamber. If different from the initial value, use the average of thestarting and ending temperatures for calculation.The temperature difference shall not exceed 4 °℃.
11.12The acquired data will be automatically stored.For calculation of the results,use a light-scatteringcorrection. Refer to the user’s manual to find how to activate this feature.