1、Designation: D 6854 03Standard Test Method forSilican-Dibutyl Phthalate Absorption Number1This standard is issued under the fixed designation D 6854; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of then-dibutyl phthalate (DBP) absorption number of silica.1.2 The values stated in SI units ar
3、e to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practice
4、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1799 Practice for Carbon BlackSampling PackagedShipments2D 1900 Practice for Carbon BlackSampling Bulk Ship-ments2D 2414 Test Method for Carbon BlackOil AbsorptionNumber23. Summary o
5、f Test Method3.1 In this test method, DBP is added by means of aconstant-rate buret to a sample of silica in the mixer chamberof an absorptometer. As the sample absorbs the DBP, themixture changes from a free-flowing state to one of a semi-plastic agglomeration, with an accompanying increase invisco
6、sity. This increased viscosity is transmitted to the torque-sensing system of the absorptometer. The test is stopped whena predetermined torque level has been reached. Preferably thetorque versus volume of DBP is recorded by a penwriter or bya data acquisition system allowing a reliable determinatio
7、n ofthe endpoint. The volume of DBP per unit mass of silica is theDBP absorption number.4. Significance and Use4.1 The DBP absorption number of a silica is related to theprocessing and vulcanizate properties of rubber compoundscontaining the silica.5. Apparatus35.1 Balance, analytical, with 0.001-g
8、sensitivity.5.2 Sieve, 500 m (U.S. standard No. 35), having a 200-mm(8 in.) diameter and 25 mm (1 in.) height.5.3 Bottom Receiver Pan.5.4 Oven, gravity-convection type, capable of temperatureregulation within 61C at 125C and temperature uniformitywithin 65C.5.5 Spatula, rubber, 100-mm.5.6 Absorptome
9、ter,4equipped with a constant-rate buret thatdelivers 4 6 0.024 cm3/min.5.7 Desiccator, with silica gel as desiccant.6. Reagents and Standards6.1 n-Dibutyl Phthalate,5having a density of 1.042 to 1.047mg/m3(g/cm3) at 25C.6.2 Silica, commercial grade with a nitrogen surface area of175 6 10 m2/g.7. Sa
10、mpling7.1 Samples shall be taken in accordance with PracticesD 1799 and D 1900.8. Calibration8.1 Absorptometer6 The absorptometer is composed ofcomponents that influence calibration: the dynamometer torquespring or the load cell, the torque-limit or the indicator setpoint, the oil damper (absorptome
11、ters Type E and Type H areequipped with electronic damping), and the mixer-measuringhead.7It is necessary that each of the components be in goodcondition or proper adjustment to achieve acceptable calibra-tion.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the dire
12、ct responsibility of Subcommittee D11.20 on Compounding Materialsand Procedures.Current edition approved Jan. 10, 2003. Published February 2003.2Annual Book of ASTM Standards, Vol 09.01.3All apparatus is to be operated and maintained in accordance with themanufacturers directions for optimum perform
13、ance.4Available from C. W. Brabender Instruments, Inc., 50 E. Wesley St., Hacken-sack, NJ 07606, website: , and HITEC Luxembourg, 5 ruede lEglise, L-1458 Luxembourg, website: www.hitec.lu.5Technical grade has turned out to be suitable for the test, provided that thedensity is in the specified range.
14、6Mechanical absorptometers (type A or type B) can be used for the test;however, they are no longer commercially available. Refer to the instructions of thesupplier for calibration procedure.7The rotor motor speed is 1.31 rad/s (125 r/min).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
15、C700, West Conshohocken, PA 19428-2959, United States.NOTE 1Stainless steel mixing chambers8have been found satisfac-tory for this test when they are manufactured to a roughness average (Ra)of 2.5 6 0.4 m (100 6 15 in.) based upon eight measurements. Nosingle measurement should be greater than 3.6 m
16、 (140 in.) or less than1.5 m (60 in.). Stainless steel bowls purchased with an absorptometerhave been pre-polished for 16 h to minimize bowl surface changesaffecting calibration during their initial use. It is recommended that newreplacement stainless steel bowls should also be pre-polished to minim
17、izethe bowl surface effects on calibration (see Annex A1).8.1.1 The torque indicator is the primary component used tocorrect calibration. The load cell tension is adjusted by varyingthe alarm shut-off set point. Proper adjustment on the torqueindicator should provide repeatable values for a silica s
18、amplededicated to internal reference.8.1.2 The maximum torque span is set at 10 000 mNm(10 000 units) torque value. The torque-limit alarm is initiallyset at 5000 mNm (5000 units), but for testing silicas it will benecessary to adjust this setting to a lower value in order toobtain reproducible resu
19、lts. Use an internal silica sample witha nitrogen surface area of 175 6 10 m2/g to set the torque limitalarm which should correspond to approximately 70 % of themaximum torque developed during the test. After calibration,this setting should not be changed.NOTE 2It is generally recommended to use the
20、 absorptometer inconjunction with a penwriter or preferably with a data acquisition system(see 9.9 for further details).8.1.3 All digital signals are preset at 3 s damping for thetorque sensing system.8.1.4 Properly maintain the surface finish of the mixingchamber. If a new mixer chamber is installe
21、d, frequentlymonitor the instrument for any drift in calibration.8.2 Constant-Rate Buret:8.2.1 The delivery rate of the buret is to be 4 cm3/min. SeeAnnex A1 for detailed instructions on the procedure forcalibration check of the constant-rate buret.9. Procedure9.1 Pass a suitable amount of the sampl
22、e through Sieve No.35 (500 m), using a brush in order to deglomerate largerparticles. Use2gofthesieved material to test the moisturecontent (see 9.2).9.2 Weigh 12.5 g of the sample to the nearest 0.01 g.NOTE 3For silicas with an extraordinary high pour density it may benecessary to increase the samp
23、le mass used for the test. This modificationhas to be mentioned in the test report.9.3 It is recommended that a testing temperature of 23 65C be maintained, as measured by a thermocouple in themixing bowl. If a temperature controllable mixing bowl is notavailable, keep the bowl temperature below 30C
24、 and complywith Note 4 while running the samples.NOTE 4If the absorptometer has remained idle for more than 15 minand a temperature controllable bowl is not being used, a 10-min warm-upsample must be run before beginning a test. It is important that the mixerchamber temperature be kept uniform. Pref
25、erably, allow 5 min betweenthe end of one test and the start of another.9.4 Transfer the sample to the absorptometer mixer chamberand replace the cover.9.5 Place a waste receptacle under the delivery tube. Makesure that the tube is free of air bubbles by delivering approxi-mately 1 cm3of DBP into th
26、e waste receptacle.9.6 Verify the drive speed is set to 1.31 rad/s (125 r/min).9.7 Position the buret delivery tube over the hole in themixer chamber cover, and set the buret digital counter to zero.9.8 Activate the “start” buttons simultaneously. The appa-ratus will operate until sufficient torque
27、has developed toactivate the torque-limit switch, which will halt the absorptom-eter and buret.9.9 Record the volume of DBP used as indicated by theburet digital counter.NOTE 5If a penwriter is used to record the torque curve, deactivatethe automatic cut-off by setting the torque limit to 10 000. St
28、op the testwhen the torque maximum has been recorded unequivocally. Mark on thecurve the DBP volume corresponding to the maximum torque andmeasure the height (in mm or in.) of the maximum. At the left side of themaximum, identify the point corresponding to a height of 70 % of themaximum of the curve
29、. Measure the distance on the x-axis from the startpoint to this point and convert the value to volume of DBP as follows:Volume DBP = delivery rate of buret distance / speed of penwriterNOTE 6If a data acquisition system9is used, the absorptometer willstop after having recorded the torque maximum, a
30、nd the test result (incm3/100 g) will be reported automatically.9.10 Dismantle the mixer chamber and clean the mixingblades and chamber with a rubber spatula and reassemble.9.11 Determine the amount of moisture in the silica undertest by weighing2gofthesieved silica (see 9.1) into a dish tothe neare
31、st 0.001 g. Place the dish into an oven set at 105C,leave it inside for 2 h, cool in a desiccator and weigh to thenearest 0.001 g.10. Calculation10.1 Calculate the moisture content as follows:Moisture, % 5 100 m02 m! / m0(1)where:m0= mass of the silica before drying, g, andm = mass of the silica aft
32、er drying, g.10.2 Calculate the DBP absorption number of the sample tothe nearest 0.1 10-5m3/kg (cm3/100 g) as follows:DBP absorption number, 1025m3/kg 5 (2)A / B 100 / 100 2 Moisture! 100where:A = volume of DBP used, cm3, andB = mass of tested sample, g.8Replacement stainless steel bowls which have
33、 been found to be satisfactory areavailable from Titan Specialties, Inc., P.O. Box 2316, Pampa, TX 79066-2316, andC. W. Brabender Instruments, Inc., 50 E. Wesley St., S. Hackensack, NJ 07606,website: , HITEC Luxembourg, 5 rue de lEglise, L-1458Luxembourg, website: www.hitec.lu, and Titan Specialties
34、, Inc. P.O. Box 2316,Pampa, TX 790662316.9DBP Data Acquisition Systems are available from C.W. Brabender Instru-ments, Inc., 50 E. Wesley St., S. Hackensack, NJ 07606, website: www.cwbra-, and HITEC Luxembourg, 5 rue de lEglise, L-1458 Luxembourg,website: www.hitec.lu.D685403211. Report11.1 Report t
35、he following information:11.1.1 Proper identification of the sample,11.1.2 Sample mass, if different than shown in 9.4, and11.1.3 The result obtained from the individual determina-tion is reported to the nearest 0.1 10-5m3/kg (cm3/100 g).12. Keywords12.1 n-dibutyl phthalate; n-dibutyl phthalate abso
36、rptionnumber; silicaANNEX(Mandatory Information)A1. CALIBRATION CHECK OF CONSTANT-RATE BURETA1.1 ScopeA1.1.1 The constant-rate buret is an integral part of theabsorption measuring system. Failure of the buret to deliver thedeliver the specified amount of reagent to the silica will resultin erroneous
37、 absorption readings. This annex provides amethod for checking the delivery rate of the constant-rateburet. One of the reasons for the incorrect absorption values(caused by incorrect reagent delivery by the automatic buret) isentrapped air in the plastic tubing or the delivery tube,especially above
38、the nozzle. This trouble source should bechecked first.A1.2 ApparatusA1.2.1 Stopwatch.A1.2.2 Beaker, 150-cm3.A1.3 ProcedureA1.3.1 Ensure that all seals and tubing are in good condi-tion.A1.3.2 Fill the buret and delivery tubes with n-dibutylphthalate. Ensure that all air is removed from the system.A
39、1.3.3 With the buret completely full, set the stopcock tothe delivery position. Run the buret on “deliver” until aconstant flow is obtained from the delivery tube.A1.3.4 Stop the buret and set the digital counter to zero.A1.3.5 Position a tared 150-cm3beaker under the deliverytube.A1.3.6 Simultaneou
40、sly start the buret and stopwatch.A1.3.7 After 2 min, stop the buret and record the digitalcounter reading.A1.3.8 Weigh and record the amount of reagent delivered.A1.3.9 Refill the buret.A1.3.10 Repeat A1.3.3-A1.3.9, changing the delivery timein A1.3.7 to 4 and 8 min.A1.4 CalculationA1.4.1 Calculate
41、 the volume of DBP from the deliveredmass and density as follows:Delivery, cm35 mass delivered / DBP density (A1.1)A1.5 Acceptable ResultsA1.5.1 The calculated delivery should be within the follow-ing limits of the digital counter reading:Time, min Tolerance, cm32 60.054 60.058 60.05ASTM Internation
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45、 at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6854033
