1、BRITISH STANDARDBS 2782-3: Method 323C: 1996ISO 6721-6: 1996Incorporating amendment no. 1Methods of testingPlastics Part 3: Mechanical properties g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3
2、g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Method 323C: Shear vibration Non-resonance methodICS 83.080BS 2782-3:Method 323C:1996of the Environment (Building Research Establishment)rtment of Trade and Industry (National Physical Laboratory)ectrical and Electronic Insulation Association (BEAMA Ltd.
3、)Committees responsible for this British StandardThCommittee reBrBrDepartment DepaElThis British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 September 1996 BSI
4、 2007The following BSI references relate to the work on this standard: Committee reference PRI/21 Draft for comment 94/341468 DCISBN 0 580 26066 6GAMBICA (BEAMA Ltd.)Institute of MaterialsMinistry of DefencePackaging and Industrial Films AssociationPIRA InternationalRAPRA Technology Ltd.Royal Societ
5、y of ChemistryAmendments issued since publicationAmd. No. Date Comments16995 30 March 2007 See national foreworde preparation of this British Standard was entrusted to Technical PRI/21, Testing of plastics, upon which the following bodies were presented:itish Apparel and Textile Confederationitish P
6、lastics FederationBS 2782-3:Method 323C:1996 BSI 2007National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 6721-6:1996, incorporating amendment 1:2007.ISO 6721-6 is one of a ten part series of ISO 6721 methods of determination of the dynamic mechanical prope
7、rties of rigid plastics. ISO 6721-1, implemented as BS EN ISO 6721-1 (dual numbered BS 2782-3:Method 342A), is an introductory section which includes the definitions and all aspects that are common to the individual test methods described in the subsequent versions.The start and finish of text intro
8、duced or altered by amendment is indicated in the text by tags !“. Tags indicating changes to ISO text carry the number of the ISO amendment. For example, text altered by ISO amendment 1 is indicated in the text by !“.The UK participation in its preparation was entrusted to Technical Committee PRI/2
9、1, Testing of plastics.A list of organizations represented on PRI/21 can be obtained on request to its secretary.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 Standard cannot confer
10、 immunity from legal obligations.iblankBS 2782-3:Method 323C:19961 ScopeThis part of ISO 6721 describes a forced, non-resonance method for determining the components of the shear complex modulus G*of polymers at frequencies typically in the range 0,01 Hz to 100 Hz. ! Higher-frequency measurements ca
11、n be made, but significant errors may be obtained in the dynamic properties measured (see 10.2.1 and 10.2.2).“ The method is suitable for measuring dynamic storage moduli in the range 0,1 MPa to 50 MPa. Although materials with moduli greater than 50 MPa may be studied, more accurate measurements of
12、their dynamic shear properties can be made using a torsional mode of deformation (see parts 2 and 7 of ISO 6721).This method is particularly suited to the measurement of loss factors greater than 0,1 and may therefore be conveniently used to study the variation of dynamic properties with temperature
13、 and frequency through most of the glass-rubber relaxation region (see ISO 6721-1:1994, subclause 9.4). The availability of data determined over wide ranges of both frequency and temperature enables master plots to be derived, using frequency/temperature shift procedures, which display dynamic prope
14、rties over an extended frequency range at different temperatures.2 Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 6721. At the time of publication, the editions indicated were valid. All standards are su
15、bject to revision, and parties to agreements based on this part of ISO 6721 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.ISO 6721-1:1994, Plast
16、ics Determination of dynamic mechanical properties Part 1: General principles.ISO 6721-2:1994, Plastics Determination of dynamic mechanical properties Part 2: Torsion-pendulum method.ISO 6721-7:1996, Plastics Determination of dynamic mechanical properties Part 7: Torsional vibration Non-resonance me
17、thod.3 DefinitionsSee ISO 6721-1:1994, clause 3.4 PrincipleA test-specimen assembly is subjected to a sinusoidal shear force or deformation at a frequency significantly below the fundamental shear resonance frequency (see 10.2.1). The amplitudes of the force and displacement cycles applied to the te
18、st-specimen assembly and the phase angle between these cycles are measured. The storage and loss components of the shear complex modulus and the loss factor are calculated using equations given in clause 10 of this part of ISO 6721.5 Apparatus5.1 Loading assemblyThe requirements for the loading asse
19、mbly are that it shall permit measurements of the amplitudes of, and phase angle between, the force and displacement cycles for a test-specimen assembly subjected to a sinusoidal shear force or deformation. Various designs of apparatus are possible: a suitable version is shown schematically in Figur
20、e 1. The shear test-specimen assembly consists of two identical specimens S of the polymer bonded to metal end-pieces P1and P2. A sinusoidal force is generated by the vibrator V and applied to the two outer end-pieces P1of the test-specimen assembly through the clamping device C1of the shear load st
21、age. The amplitude and frequency of the vibrator table displacement are variable and monitored by the transducer D. The test-specimen assembly is held at its centre P2by a fixed clamp C2, and thus each specimen S of the polymer is subjected to simple shear deformations of equal magnitude. The sinuso
22、idal force applied in deforming the test-specimen assembly is monitored by a force transducer F connected to C2. The members between the clamps C1and V, and between C2and F, shall be much stiffer than the test-specimen assembly and shall have a low thermal conductance if the test-specimen assembly i
23、s to be enclosed in a temperature-controlled cabinet.NOTE 1 While each member of the loading assembly may have a much higher stiffness than the test-specimen assembly, the presence of clamped or bolted connections can significantly increase the apparatus compliance. It may then be necessary to apply
24、 a compliance correction as described in section 10.2.3. BSI 2007 1BS 2782-3:Method 323C:1996A clamping arrangement may be used in which a single specimen of the polymer is subjected to a simple shear deformation, but precautions shall then be taken to ensure that any torque in the loading assembly
25、resulting from the application of load to the specimen does not influence the measurements of the dynamic shear force and displacement. Measurements of the deformation of the specimen may also be made by locating the displacement transducer so as to measure the relative displacement of the two parts
26、 C1and C2of the load stage. The magnitude of the correction for the compliance of the loading assembly will then become small or negligible (see 10.2.3).5.1.1 Load stageThe shear load stage shall be capable of gripping the test-specimen assembly with sufficient force to prevent any relative movement
27、 between the metal blocks P of the test-specimen assembly and the load stage clamps, and to maintain the force at low temperatures. Any misalignment of the load stage with respect to the force transducer will produce a lateral component of the force applied to the transducer during loading of the te
28、st-specimen assembly. The alignment of the loading assembly and test-specimen assembly shall be such that any lateral component recorded by the transducer is less than 1 % of the applied longitudinal force.5.1.2 TransducersThe term transducer in this part of ISO 6721 refers to any device capable of
29、measuring the applied force or displacement, or the ratio of these quantities, as a function of time. The calibration of the transducers shall be traceable to national standards for the measurement of force and length. The calibration shall be accurate to 2 % of the minimum force and displacement cy
30、cle amplitudes applied to the test-specimen assembly for the purpose of determining dynamic properties.5.2 Electronic data-processing equipmentData-processing equipment shall be capable of recording the force and displacement cycle amplitudes to an accuracy of 1 %, the phase angle between the force
31、and displacement cycles to an accuracy of 0,1 and the frequency to an accuracy of 10 %.5.3 Temperature measurement and controlSee ISO 6721-1:1994, subclauses 5.3 and 5.5.5.4 Devices for measuring test specimen dimensionsSee ISO 6721-1:1994, subclause 5.6.6 Test assemblySee ISO 6721-1:1994, clause 6.
32、6.1 Shape and dimensionsA suitable design for the shear test-specimen assembly is shown in Figure 2. Here the metal end-pieces P are cylindrical, but any cross-sectional shape is suitable as long as the end-pieces can be clamped rigidly in the shear load stage. The dimensions of the end-pieces and t
33、he polymer specimens S shall be chosen such that the deformation of the end-pieces under an applied load is negligible in comparison with that of the specimens. For a polymer whose shear modulus is less than 100 MPa, this will mean that the thickness of the end-pieces may be comparable with the thic
34、kness L of the specimens.The cross-sectional shape of the polymer specimens in the plane of their bonded faces is not critical, although a rectangular section is recommended in order to simplify the application of a term representing the contribution to the specimen deformation from bending see equa
35、tion (1) in 10.2. The specimens may then be conveniently cut from a sheet of the polymer and bonded to the end-pieces to construct the shear test-specimen assembly. The dimensions of each polymer specimen shall not vary by more than 3 % of the mean value. This dimension shall be sufficiently large t
36、o allow adequate accuracy to be achieved in the determination of dynamic strain and hence dynamic moduli see equation (1) in 10.2. In addition, it is recommended that the dimension h of the polymer in the direction of the applied load should be greater than 4L in order to make the correction for ben
37、ding negligible.NOTE 2 A variation in dynamic properties may be observed between specimens of different thickness prepared by injection moulding owing to differences which may be present in the structure of the polymer in each specimen.6.2 Preparation of polymer specimensSee ISO 6721-1:1994, subclau
38、se 6.2.7 Number of test assembliesSee ISO 6721-1:1994, clause 7, reading “test-specimen assemblies” for “test specimens”.8 ConditioningSee ISO 6721-1:1994, clause 8.9 Procedure2 BSI 20079.1 Test atmosphereSee ISO 6721-1:1994, subclause 9.1.BS 2782-3:Method 323C:19969.2 Measuring the cross-section of
39、 the polymer specimenSee ISO 6721-1:1994, subclause 9.2.9.3 Clamping the test assemblyMount the test-specimen assembly in the load stage using a clamping force that is sufficient to prevent relative movement between each clamp and the associated end-piece under all test conditions.9.4 Varying the te
40、mperatureSee ISO 6721-1:1994, subclause 9.4.9.5 Performing the testApply to the shear test-specimen assembly a dynamic force which yields force and displacement signal amplitudes which can be measured by the transducers to the accuracy specified in 5.1.2.NOTE 3 If the shear strain exceeds the limit
41、for linear behaviour, then the derived dynamic properties will depend on the magnitude of the applied strain. This limit varies with the composition of the polymer and the temperature, and is typically in the region of 0,2 % for glassy plastics, !but the effect is evident at very low dynamic strains
42、 in carbon-particle-filled rubbers. The dynamic strain range for linear behaviour can be explored by varying the dynamic displacement amplitude at a constant frequency and recording any change in dynamic stiffness with strain amplitude. A low frequency should be used for this purpose to minimize any
43、 temperature increase caused by mechanical loss. If non-linear behaviour is detected in the strain range of interest, the dynamic strain limit shall be recorded in the test report.“Record the amplitudes of, the phase difference between and the frequencies of the force and displacement signals, as we
44、ll as the temperature of the test. Where measurements are to be made over ranges of frequency and temperature, it is recommended that the lowest temperature be selected first and measurements made with increasing frequency, keeping the temperature constant. The frequency range is then repeated at th
45、e next higher temperature (see ISO 6721-1:1994, subclause 9.4).For those test conditions under which the polymer exhibits medium or high loss (for example in the glass-rubber transition region), the energy dissipated by the polymer may raise its temperature sufficiently to give a significant change
46、in dynamic properties. Any temperature rise will increase rapidly with increasing strain amplitude and frequency. If the data-processing electronics is capable of analysing the transducer outputs within the first few cycles, then the influence of any temperature rise will be minimized. Subsequent me
47、asurements will then change with time as the specimen temperature continues to rise, and such 10 Expression of results10.1 SymbolsNOTE 4 The magnitude of k will give an estimate of the A bonded area, in square metres, of the specimensf measurement frequency, in hertzfFresonance frequency, in hertz,
48、of the force transducerfsresonance frequency, in hertz, of the test-specimen assemblyG9a,G9 apparent and corrected shear storage modulus, in pascalsG0 shear loss modulus, in pascalsh mean of the specimen heights, in metres, in the direction of the applied loadka, k measured and corrected magnitude,
49、in newtons per metre, of the complex stiffness of the test-specimen assemblykFstiffness of the force transducer, in newtons per metrekmeasured stiffness, in newtons per metre, of a metal bar whose cross-sectional dimensions are the same as those of the end-pieces of the shear test-specimen assembly (see note 4). This bar shall be at least 100 times stiffer than the stiffest polymer specimen to be tested.L mean of dimension, in metres, of each polymer specimen between bonded facesmFmass, in kilograms, of that part of the loading assembly between the force tr
