1、Designation: D 6854 03 (Reapproved 2008)Standard 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 las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 stat
3、ed in SI units are 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 an
4、d health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1799 Practice for Carbon BlackSampling PackagedShipmentsD 1900 Practice for Carbon BlackSampling Bulk Ship-mentsD 2414 Test Method for Carbon BlackOil AbsorptionNum
5、ber (OAN)3. Summary of 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 accompan
6、ying increase inviscosity. 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
7、reliable determination 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, anal
8、ytical, with 0.001-g 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,
9、100-mm.5.6 Absorptometer,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
10、of175 6 10 m2/g.7. Sampling7.1 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 o
11、il damper (absorptometers Type E and Type H are1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.20 on Compounding Materialsand Procedures.Current edition approved July 1, 2008. Published September 2008. Originallyapproved
12、 in 2003. Last previous edition approved in 2003 as D 6854 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website
13、.3All apparatus is to be operated and maintained in accordance with themanufacturers directions for optimum performance.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.
14、lu.5Technical grade has turned out to be suitable for the test, provided that thedensity is in the specified range.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 proce
15、dure.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.equipped 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-t
16、ion.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 (140 in.) or less than1.5 m (60 in.). Stainless s
17、teel 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 minimizethe bowl surface effects on calibration (see An
18、nex 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 samplededicated to internal reference.8.1.2 The max
19、imum 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 results. Use an internal silica sample witha nitrogen
20、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 absorptometer inconjunction with a penwriter or p
21、referably 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 installed, frequentlymonitor the instrument for any drift
22、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 sample through Sieve No.35 (500 m), using a brush in or
23、der 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 sample mass used for the test. This modificationhas to
24、 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 and complywith Note 4 while running the samples.N
25、OTE 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. Preferably, allow 5 min betweenthe end of one test and
26、 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 the waste receptacle.9.6 Verify the drive speed is s
27、et 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 has developed toactivate the torque-limit switch,
28、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. Stop the testwhen the torque maximum has been record
29、ed 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. Measure the distance on the x-axis from the star
30、tpoint 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, and the test result (incm3/100 g) will be reported
31、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 weighing 2 g of the sieved silica (see 9.1) into a dish tothe nearest 0.001 g. Place the dish into an oven set a
32、t 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 after drying, g.10.2 Calculate the DBP absorptio
33、n 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! 1007The rotor motor speed is 1.31 rad/s (125 r/min).8Replacement stainless steel bowls which have been found to be satisfactory areavailable from Titan Specialt
34、ies, 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, Inc. P.O. Box 2316,Pampa, TX 790662316.9DBP Data Acquisition
35、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.D 6854 03 (2008)2where:A = volume of DBP used, cm3, andB = mass of tested sample, g.11. Report
36、11.1 Report the 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 p
37、hthalate absorptionnumber; 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 resul
38、tin erroneous 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,espe
39、cially above 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
40、 the system.A1.3.3 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.
41、6 Simultaneously 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.
42、4.1 Calculate 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 60.05AST
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46、on Standards, 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).D 6854 03 (2008)3
