1、- STD-BSI BS EN IS0 7822-ENGL L999 II Lb24bb9 0793827 BRITISH STANDARD Textile glass reinforced plastics - Determination of void content - Loss on ignition, mechanical disintegration and statis tical counting methods The European Standard EN IS0 7822:lW has the status of a British Standard ICs 83.12
2、0 74T II BS EN IS0 7822:1999 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STDmBSI BS EN IS0 7822-ENGL 1999 1b24bb9 0793828 beb = direction of the Sector Committee for Materiais and Chemicals, was published under the authority of the Standards Committee and comes into effect
3、 on 15 September 1999 Amd. No. 0 BSI 09-1999 BS EN IS0 7822:1999 Date Comments National foreword This British Standard is the English language version of EN IS0 78221999. It is identical with IS0 7822: 1990. Your attention is brought to the fact that PRY42 did not support the adoption of IS0 7822: 1
4、990 speciically noting that method B (by disintegration) is not used and is unlikely to be effective for composites. In its reply to CEN, PRY42 further stated its intention to submit to ISOITC61 a propsal for the revision of IS0 7822 1990. The UK participation in its preparation was entrusted to Tec
5、hnical Committee PRY42, Fibre reinforced thermosetting plastics and prepregs, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible internationaVEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests
6、informed; - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention is dram to the fact that CEN and CENELEC Standards normally include an anne
7、x which lists normative references to international publications with their corresponding European publications. The British Standards which implement international or European publications referred to in this document may be found in the BSI Stan b) a polishing machine; c) a mould for encasing the
8、section in transparent resin; d) an ultrasonic cleaning bath. 5 Preparation and number of test specimens 5.1 Methods A and B 5.1.1 The test specimens shall be representative of the composite to be examined. The quantity and form will depend on the pyknometer and the disintegration procedure used. Wh
9、en an air pyknometer is used, quantities of about 25 g or 12 o00 mm3, preferably in the form of strips about 38 mm long, about 10 mm wide and of the thickness of the composite, are needed for each determination. 5.1.2 From the composite to be examined, cut a series of at least five strips of appropr
10、iate size and mass. The pieces shall be clean and dry. 5.2 Method C 5.2.1 The specimens shall have the shape of a parallepiped 40 mm long and 10 mm wide, the thickness depending on the thickness of the structure from which the specimens have been cut, with a maximum value of 15 mm. The number of spe
11、cimens to be taken will depend on the number of sections needed and on the nature of the structure to be tested; each specimen can give several sections. 5.2.2 Prepare a total of at least five sections from among the specimens. The polishing operation and the encasing of the sections in cold-curing
12、resin shall be carried out in accordance with the procedures used in micrography. (See annex A.) 6 Atmosphere for conditioning and testing 6.1 Conditioning of the specimens The test specimens shall be conditioned in one of the standard atmospheres specified in IS0 291, for at least 16 h, unless othe
13、rwise stipulated. 6.2 Test atmosphere The specimens shall be tested in the standard atmosphere selected for conditioning (see 6.1). 7 Procedure 7.1 Method A 7.1.1 General Densities calculated from mass and volume measurements are acceptable if the specimens are smooth, uniform, and of such 2 - STD-B
14、SI BS EN IS0 7822-ENCL 1999 m lb24bb9 0793835 8Lb m EN IS0 7822:1999 I shape that the volume can be calculated accurately from the dimensions. being tested. To prevent loss of material, enclose the sample in the film material (4.2.5). Inspect the crushed material and, if necessary, crush it further
15、until a cmletelv disintmrated 7.1.2 Density of the composite 7.1.2.1 The volume of each specimen shall be not less than 2 cm4 Make dimensional measurements with the micrometer (4.1.1) at all edges (12 in all for a six-sided rectangular black). Use the averages for each dimension to calculate the vol
16、ume. 7.1.2.2 The tolerance on the precision of the micrometer measurements shall be fl pm. With maximum tolerance build-up on a small specimen, this could result in an error in the calculated volume of 0,6 %. For larger specimens, and with some measurements being in error on the plus side and some o
17、n the minus side, the error in the calculated volume ought not to exceed 0.2 %. 7.1.2.3 Calculate the density of each test specimen by dividing the mass by the volume; express the density in grams per cubic centimetre. 7.1.3 Density of the glass reinforcement material is obtained. After conditioning
18、, detekine the v b1 the number of fields for each section : area of the section area covered by the grid N3 = Care shall be taken to use the exact density. c) the number of sections n to be made: 7.1.4 Density of the resin Density measurements supplied by the resin manufacturer are acceptable if the
19、y are certified for each batch. 7.3.2 Measurement of the void content 7.1.5 Resin content of composite Count the total number N, of points of the grid that are superimposed on a void in the N2 fields of the n microscopic sections. Fields distributed over the same section shall not ovedap each other.
20、 Determine the resin content of the composite in accordance with IS0 1172. The loss on ignition in that method is the resin content of the sample expressed as a percentage by mass. 7.2 Method 6 8 Expression of results Determine the volume VI of the test strips, using the pyknometer (4.2.21, and thei
21、r mass rnl, using the balance (4.2.3). Then piace the strips breadthwise between the platens of a press or in a closed die (see 4.2.1) and crush them. If the composite contains a matrix material too ductile to be disinte- grated at room temperature, place the test strips in the deep- freezing unit (
22、4.2.4) for a few minutes, cooling them with solid carbon dioxide or liquid nitrogen, depending on the material 8.1 Method A Calculate the void content (pv, expressed as a percentage by mass, using the formula 100 (Bc - emc) Pv = QC 3 STD-BSI BS EN IS0 7822-ENGL 1999 E Lb24bb9 079383b 752 E EN IS0 78
23、22:1999 where pm is the measured density, in grams per cubic centi- metre, of the composite; where N1 is the total number of void points counted; P is the total number of points examined. Q is the theoretical density, in grams per cubic centi- metre, of the composite; 9 Precision 100 wr W Bc = z+Pr
24、wf being the textile glass fibre content, expressed as a percentage by mass, of the composite; wr being the resin content, expressed as a percentage by mass, of the composite; Bf being the density, in grams per cubic centimetre, of the texule glass fibre; Q being the densir/; in grams per cubic cent
25、imetre, of the resin. 8.2 Method B Calculate the void content cpv , expressed as a percentage by volume, using the formula cpV = loo (1 - 2) where Q is the density, expressed in grams per cubic centimetre, of the composite to the nearest 0,001 g/cm3, given by the equation ml 1 = v, p2 is the density
26、, expressed in grams per cubic centimetre, of the disintegrated material to the nearest 0,001 g/cm3, given by the equation m2 2 = v, 8.3 Method C Calculate the void content cpv , expressed as a percentage by volume, using the formula Ni cpv = p The precision of this test method is not known because
27、inter- laboratory data are not available. This method may not be suitable for use in specifications or in the case of disputed results as long as these data are not available. 10 Test report The test report shall include the following particulars : a) a reference to this International Standard and t
28、he method used (A, B or Cl; b) an identification and description of the material tested; cl a description of the sampling; d) the number of determinations; el the results of each individual determination and the average void content as a percentage by volume; f) any additional observations; g) the f
29、ollowing additional information, depending on the method used: 11 Method A - the density of each of the specimens, - the percentage content by mass and the theoretical density of the resin and the textile glass fibre reinforcement; 2) Method 6 - the type of pyknometer used, - a description of the me
30、thod of freezing, if used; 31 Method C - the number of sections made and their positions in the test specimens, - the measurement parameters e, and P. 4 STD-BSI BS EN IS0 7822-ENGL 1999 1111 Lb24bb9 0793837 699 E EN IS0 7822:1999 M 4 O 2A O 28 3 1 o 2c The apparatus has two identical chambers, each
31、con- taining a piston. Originally, the pressure p1 is atmospheric pressure. 28 With the chambers closed, piston A is moved from pos- ition 1 to position 2; in order to equalize pressures (differential manometer M = O), piston B must be moved the same distance, .e. from position 1 to position 2. 2c S
32、ample of volume V, is insetted in chamber B. Same starting conditions as 2.4. Figure 2 - Principle of the gas-comparison pyknometer for measurement of the true volume of materials with open pores 5 - STD*BSI BS EN IS0 7822-ENGL 1999 Lb24bb9 0793838 525 E EN IS0 7822:1999 n 4 O 20 O dl 2E1 M LJ O 1 2
33、D With the chambers closed, piston A is moved from 1 to 2; due to V, when piston B is moved from 1 to 2, the pressures are not equalized. Pressure p3 in chamber B will be higher than p2. Pz PlV, P2Vx P3 P2 2E The pressures are equalized - either keeping p2 constant, .e. by moving piston B to positio
34、n 3 at a distance from position 2 proportional to V, (ee 2E1); - or keeping p3 constant, .e. by introducing into chamber A a calibrated volume equivalent to V,; the displacement 2 is proportional to V, (see 2E2). Typically, the sample volume is about 20 cm3. The precision attainable with the availab
35、le instruments varies from 0,001 cm3 to 0.05 cm3. A = ChamberA B = Chamer B M = Manometer p = Pressure Y = Volume O = Equilibrium position 1 = Position 1 of the piston 2 = Position 2 of the piston 3 = Position 3 of the piston d, = Piston displacement x = Unknown d2 = Calibrated volume displacement F
36、igure 2 (concludedl 6 STD.BS1 BS EN IS0 7822-ENGL 1999 Lb24bb 0393839 4bL EN IS0 7822:1999 60 50 8 4o Q t 30 20 10 10 100 1000 10 O00 Total number of points P Figure 3 - Measurement error versus the total number of points for different void content 7 STDOBSI BS EN IS0 7822-ENGL 1999 m IIb24bb9 03938
37、40 II83 m Time Grain 3 min 400 (35 Cim) EN IS0 7822:1999 Remark Copious watering Annex A (informative) 15 min Polishing the sections 12-H alumina (A1,O.J The alumina is used slightly diluted, with an almost pasty consistency. The general conditions for the polishing of the sedons are the following :
38、 Speed : 200 rpm Force : about 5 N (500 gfl (for 0 25 mm sections) I 5 min I 800 i22 pmi I copious watering I These conditions may be varied, depending on the type of reinforced plastic, in order to remove all the scratches from the face being polished. a EN IS0 7822:1999 Annex ZA (normative) Normat
39、ive references to international publications with their relevant European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed her
40、eafter. For dated references, subsequent amendments to or revisions of any of these publications appiy to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. PublicationYaat IS0 291 1997 IS0 1
41、172 1996 Plastics - Standard atmospheres for conditioning and testing Textile-glass-reinforced plastics - Prepregs, moulding compounds and laminates - Determination of the textile-glass and mineral-filler content - Calcination methods EN IS0 291 1997 EN IS0 1172 1998 BS EN IS0 7822:1999 BSI 389 Chis
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