1、BRITISH STANDARD BS ISO 17744:2004 Plastics Determination of specific volume as a function of temperature and pressure (p T diagram) Piston apparatus method ICS 83.080.01 BS ISO 17744:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 8 Dec
2、ember 2004 BSI 8 December 2004 ISBN 0 580 45006 6 National foreword This British Standard reproduces verbatim ISO 17744:2004 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics, which has the responsi
3、bility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Sta
4、ndards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standa
5、rd does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European
6、 developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 18, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the do
7、cument was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 17744:2004(E)NINRETOITALAN ADNATSDR OSI 14477 tide tsriFino -400251-11 Plastics Determination of specific volume as a function of temperature and pressure (pvT diagram) Piston apparatus method Pla
8、stiques Dtermination du volume spcifique en fonction de la temprature et de la pression (diagramme pvT) Mthode utilisant un appareil piston Referecne unbmer OSI 44771:002)E(4 OSI 4002INTERNATIONAL STANDARD ISO 17744 First edition 2004-11-15 scitsalP eteDtanimroifo n pscifice voula sa em ufncoitn fo
9、etrepma erutadn ( erusserpTvp idmarga) siP ton arappatem suthdo salPtiuqse D retmanitoiv ud nouls emcpifieuq f necnooitn de la pmetrrutae d tee la rpsesi( nodirgaaemm Tvp) tMedoh tulisitna nu rappaeil p istno BSISO17744:2004 ii BSISO17744:2004 iiiContents Page Foreword iv Introduction v 1 Scope 1 2
10、Normative references . 1 3 Terms and definitions. 2 4 Principle . 3 5 Apparatus. 4 6 Equipment calibration 7 7 Test sample . 8 8 Procedure. 8 9 Expression of results 10 10 Precision 10 11 Test report 10 Annex A (normative) Sources of error when specific volume is measured as a function of temperatur
11、e and pressure 12 Annex B (informative) Examples of pvT diagrams. 14 Bibliography . 18 BSISO17744:2004iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is norm
12、ally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in t
13、he work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare
14、 International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some
15、 of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17744 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical- chemical properties. BSISO17744:2004 vIntroduction T
16、he characterization of changes in volume of plastics, as a function of temperature and pressure, is necessary for the purpose of simulation studies and for optimizing polymer processing. These thermophysical data may be used as they are or modelled in the form of suitable mathematical laws (see Refe
17、rences 7 to 12 in the Bibliography). In injection moulding, during the packing phase, most of the flow results from solidification. During solidification, if the plastic is semi-crystalline, the shrinkage is primarily due to crystallization. pvT data are used to model the volumetric shrinkage, which
18、 is translated into dimensional changes in the moulding. It should be pointed out that, while all the techniques described hereafter are equivalent in their ability to characterize the melt state pvT behaviour, the isobaric cooling measurement is the only one which allows characterization of both th
19、e supercooling behaviour and the pressure dependency of the transition. A list of references related to this International Standard is given in the Bibliography. BSISO17744:2004blankINTENRATIONAL TSANDADR IS:44771 O4002(E)1Plastics Determination of specific volume as a function of temperature and pr
20、essure (pvT diagram) Piston apparatus method 1 Scope This International Standard describes procedures for determining the specific volume of plastics as a function of temperature and pressure in both the molten and solid states. The standard specifies the use of a piston-equipped apparatus in which
21、the test sample, held in a measurement cell, is pressurized by means of the piston. Measurements under conditions of constant pressure or constant temperature can be made. In the constant-pressure mode, the maximum heating and cooling rates permissible are restricted to 5 C/min. NOTE Higher heating
22、and cooling rates can be used, but data will then have to be corrected for thermal gradients 13 . For the acquisition of data needed for processing design, it is recommended that the isobaric cooling method be used (see ISO 17282). The result of this measurement cannot be used directly for injection
23、-moulding simulation. By using these procedures, it is possible to obtain: pvT diagrams that represent the relationship which exists between pressure, specific volume and temperature for a given material; compressibility and volumetric thermal-expansion coefficients; information on first-order and g
24、lass transitions as a function of temperature and pressure. Although thermoplastic polymers are currently tested down to room temperature using these procedures, it is emphasized that, at temperatures lower than T g , the difficulty in achieving a true hydrostatic state is a source of uncertainty on
25、 the specific volume measurement. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) a
26、pplies. ISO 1183 (all parts), Plastics Methods for determining the density of non-cellular plastics ISO 4287, Geometrical Product Specifications (GPS) Surface texture: Profile method Terms, definitions and surface texture parameters ISO 6507-1, Metallic materials Vickers hardness test Part 1: Test m
27、ethod ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system BSISO17744:20042 ISO 17282, Plastics Guide to the acquisition and presentation of design data NF T 51-561, Pla
28、stiques Dtermination de la masse volumique en fonction de la temprature Mthode par immersion 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 specific volume v volume per unit mass of a material at a given temperature T and pressure p NOTE Spe
29、cific volume is expressed in cm 3 /g. 3.2 density mass per unit volume of a material at a given temperature T and pressure p NOTE Density is expressed in g/cm 3 . 3.3 preheating time interval between the end of the cylinder-filling operation at the test temperature and the beginning of the measuring
30、 operation 3.4 pre-compression pressure p 0pressure applied during the pre-heating phase to achieve compaction of the sample 3.5 retention time interval between the end of the cylinder-filling operation and the end of the measuring operation 3.6 volumetric thermal-expansion coefficient v v= (1/v dv/
31、dT) p(with p constant) where dv/dT is deduced from the slope of the tangent to the v = f(T) curve taken at a point on the curve; may be a function of pressure and temperature. NOTE The volumetric thermal-expansion coefficient is expressed in C 1 . 3.7 volumetric compressibility coefficient v v= (1/v
32、 dv/dp) T(with T constant) where dv/dp is deduced from the slope of the tangent to the v = f(p) curve taken at a point on the curve; BSISO17744:2004 3 vmay be a function of pressure and temperature. NOTE The volumetric compressibility coefficient is expressed in Pa 1 . 3.8 isobaric measurement proce
33、dure in which the pressure is maintained constant during a test, the temperature being modified continuously or stepwise by heating or cooling in a predefined manner 3.9 isothermal measurement procedure in which the temperature is maintained constant during a test, the pressure being modified by eit
34、her increasing or decreasing its value in a predefined manner 4 Principle The pvT behaviour of a plastic material describes the specific volume as a function of temperature and pressure. The method described here consists of measuring, under given temperature and pressure conditions, the volume of a
35、 test sample, the mass of which is known and constant. The test sample is placed in a cylindrical measurement cell which is closed at one end by a moveable piston and sealed at the other end. The test sample is heated or cooled down in the cell and pressure is applied via the piston. Changes in the
36、specific volume are determined from the movement of the piston. There are two measurement procedures: at a constant pressure (isobaric measurement); at a constant temperature (isothermal measurement). The choice between an increasing or a decreasing temperature profile for isobaric testing (or incre
37、asing or decreasing pressure for isothermal measurement) may have a significant effect on the results. It is important to specify the appropriate increasing or decreasing profile as well as the rate of change of the parameter. When the temperature, the pressure (or applied force), the mass of the te
38、st sample, the cross-sectional area of the cell and the length of the test sample (derived from the piston position) are known, the pvT data can be obtained in absolute terms. Schematic curves are shown in Figure 1. BSISO17744:20044 Key X temperature (C) Y specific volume (cm 3 /g) 1 melting or crys
39、tallization zone 2 semi-crystalline polymer 3 amorphous polymer 4 glass transition temperature Figure 1 Specific volume of semi-crystalline and amorphous polymers at a given pressure (isobaric mode) (the association of several such curves obtained at different pressures gives the pvT diagram) 5 Appa
40、ratus 5.1 General The apparatus (see Figure 2) includes a cylinder (called a measurement cell), the bottom of which is closed, and a temperature-regulating device. Pressure is exerted on the test sample contained in the cylinder by means of a piston. BSISO17744:2004 5Key 1 piston of known radius, r
41、8 heating/cooling device 2 piston displacement, l 9 pressure, p 3 test sample 10 AD/DA converter 4 measurement cell of known diameter 11 displacement measurement 5 seals 12 temperature, T 6 springs (optional) 13 computer 7 end closure 14 printer Figure 2 Schematic diagram of a typical apparatus BSIS
42、O17744:20046 5.2 Measurement cell The cylindrical measurement cell shall be as smooth as possible on the inside surface, i.e. free of any visible scratches or defects. It shall have an inside diameter between 5 mm and 12 mm, constant to within 0,01 mm along its whole length. It shall be made of a ma
43、terial which is resistant to wear and corrosion up to the maximum temperature produced by the heating device. It may include an opening at the side or in the base into which a pressure sensor can be inserted. It shall be manufactured using a method that produces an inside surface with a Vickers hard
44、ness of at least 800 HV 30 (see ISO 6507-1) and a roughness Ra of less than 0,25 m (arithmetical mean deviation) (see ISO 4287). 5.3 Piston The piston shall be fitted with a seal made of a material which is inert to the test sample and suitable for use at the test temperature. The hardness of the pi
45、ston shall be less than that of the cylinder, without, however, being less than 375 HV 30 (see ISO 6507-1). The piston shall be designed so that there is minimum friction between it and the cylinder wall. NOTE 1 A suitable seal will minimize the likelihood of leaks during the test. NOTE 2 Examples o
46、f suitable seal materials are polytetrafluoroethylene up to 280 C and polyimide for higher temperatures. 5.4 Temperature-regulating device The temperature-regulating device shall be designed so that: for isothermal measurements, the temperature can be controlled so that the maximum allowable tempera
47、ture differences given in Table 1 are not exceeded during the test; for isobaric measurements, the heating or cooling rate can be controlled at a value between 1 C/min and 20 C/min (see 8.2.1.1). NOTE In the cooling mode, it is necessary to check that the pre-set minimum temperature is compatible wi
48、th the cooling rate used, taking into account the available cooling power of the cooling device used. 5.5 Test temperature measuring device The test temperature is measured with a sensor (platinum resistance thermometer or thermocouple), the end of which shall be in contact either with the molten ma
49、terial or, should that not be possible, with the metal inner wall of the cell at a point adjacent to the test sample, preferably mid-way along its length. A heat-conducting fluid may be used in the thermometer well to improve conduction. 5.6 Device for measuring the distance travelled by the piston This device shall be capable of determining the position of the piston with an accuracy
