ASTM_D_3364_-_99_2011.pdf

Designation:D336499(Reapproved 2011)Standard Test Method forFlow Rates for Poly(Vinyl Chloride)with MolecularStructural Implications1This standard is issued under the fixed designation D3364;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last 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 is an extension of Test Method D1238specific to the measurement of flow rates of poly(vinylchloride)(PVC)compounds while detecting and controllingvarious polymer instabilities associated with the flow rate.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.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 practices and determine the applica-bility of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD3835 Test Method for Determination of Properties ofPolymeric Materials by Means of a Capillary RheometerE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor definitions related to plastics,see Ter-minology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 See Test Method D3835,Sections 5.1,5.2,and 5.3.3.2.2 Flow is the reciprocal of the viscosity;therefore,theflow is defined as the volumetric displacement through acontrolled orifice and is expressed as shear rate over shearstress.NOTE2Since PVC obeys the power law function,the above relation-ship can be expressed as follows:(Viscosity)(Shear Rate)1N=(shear stress)in which the shear rate isexpressed as 4Q/R3and depends on the power law exponent N.Since Q is the volumetric flow rate in terms of cubic millimetres/secondand R is the radius of the die,it follows that the flow rate varies muchfaster than the viscosity as a result of N.This means that the flow is muchmore sensitive to change than the viscosity.For PVC,N varies from 0.1to 0.33.3.2.3 Flow rate by this test method is the rate in milligrams/minute at which polymer flows through a specific die(see Fig.1)with a total load on the ram of 20 kg at a temperature of175C.4.Summary of Test Method4.1 Conditions:4.1.1 In order to test a wide variation of flow rates coveringsemirigid as well as nonrigid PVC compounds,the followingstandard conditions are used:Temperature175C(347F)Total load on piston20 000 gApproximate pressure2758 kPa(400 psi)Charge2.15 0.05 gPlugged orifice with 120 entrance angle4.2 Basis Principles:4.2.1 The lower temperature(relative to 190C)is chosen tominimize thermal decomposition,maximize sensitivity of theflow rate to structural changes in the PVC compound,and toallow a wide latitude of useful conditions associated with theload on the piston.4.2.2 Modern extrusion plastometers have been redesignedto accommodate much higher loads.Current research formulti-weight testing has reached levels of 50 kg and these areparticularly good for rigid PVC.Previously,flow rates for rigidPVC were limited to 190C.Recent research has shown thatrigid PVC can be run at 150C and 50 kg loads.This weight iseffective for all semirigid PVC and even some nonrigidcompounds.For flow rates in excess of 10 g/10 min(10001This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Properties.Current edition approved Sept.1,2011.Published October 2011.Originallyapproved in 1974.Last previous edition approved in 2004 as D3364-99(2004).DOI:10.1520/D3364-99R11.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 mg/min),lower weights are used,for example,color concen-trates used in PVC extrusion may have flow rates in excess of100 g/10 min(10 000 mg/min)and will require a 5-kg load onthe piston.4.2.3 When the flow rates become very small as in the caseof the stiffest semirigid containing 25 parts of plasticizer(flowrates below 15 mg/min),it may be desirable to use the die(flatentry 8 mm(0.315 in.)long)in Test Method D1238.The flowis so slow that little rheological instability exists.By changingthe