1、BRITISH STANDARD BS 2782-7: Method 732F:1991 ISO 1628-6: 1990 Methods of testing Plastics Part 7: Rheological properties Method 732F: Determination of viscosity number of methyl methacrylate polymers IMPORTANT NOTE. Before reading this method it is essential to read BS2782-0, Introduction, issued se
2、parately.BS2782-7:Method 732F:1991 This British Standard, having been prepared under the directionof the Plastics and Rubber Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 28June1991 BSI 12-1999 The following BSI references relate to the w
3、ork on this standard: Committee reference PRM/21 Draft for comment 87/38634 DC ISBN 0 580 19774 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical Committee PRM/21, upon
4、which the following bodies were represented: British Plastics Federation British Steel Industry British Telecommunications plc British Textile Confederation Department of Trade and Industry (National Physical Laboratory) EEA (the Association of Electronics, Telecommunications and Business Equipment
5、Industries) Electrical and Electronic Insulation Association (BEAMA Ltd.) Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) GAMBICA (BEAMA Ltd.) Ministry of Defence Packaging and Industrial Films Association PIRA Plastic Industrial Containers Association Plastics and Rubber In
6、stitute RAPRA Technology Ltd. Standards Association of Australia Yarsley Technical Centre Ltd. Amendments issued since publication Amd. No. Date CommentsBS2782-7:Method 732F:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative referenc
7、es 1 3 Definitions and units 1 4 Principle 1 5 Measurements 1 6 Apparatus 1 7 Solvent and test solution 2 8 Temperature of measurement 2 9 Procedure 2 10 Expression of results 2 11 Test report 3 Annex A (normative) Calibration of the viscometer 4 Annex B (normative) Determination of the limiting vis
8、cosity number 5 Annex C (informative) Bibliography 5 Figure A.1 Kinetic energy correction as a function of the reciprocal of efflux time 5 Publication(s) referred to Inside back coverBS2782-7:Method 732F:1991 ii BSI 12-1999 National foreword This British Standard has been prepared under the directio
9、n of the Plastics and Rubber Standards Policy Committee and is identical with ISO1628-6:1990 “Plastics Determination of viscosity number and limiting viscosity number Part 6: Methyl methacrylate polymers”, published by the International Organization for Standardization (ISO). The Technical Committee
10、 has reviewed the provisions of ISO3105:1976 and ISO8257-1:1987, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. WARNING NOTE. This British Standard, which is identical with ISO1628-6, does not necessarily detail all the pre
11、cautions necessary to meet the requirements of the Health and Safety at Work etc. Act1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. A British Standard does not purport to include all the necessary provisions of a cont
12、ract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO 1628-1:1984 BS 2782 Methods of testing plastics Met
13、hod 732A:1991 Determination of viscosity number: general conditions (Identical) ISO 4793:1980 BS 1752:1983 Specification for laboratory sintered or fritted filters including porosity grading (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pa
14、ges1 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS2782-7:Method 732F:1991 BSI 12-1999 1 1 Scope This part of ISO1628 specifies the c
15、onditions to be used for the determination of the viscosity number of methyl methacrylate polymer moulding and extrusion materials in dilute solution. It applies to methyl methacrylate (MMA) homopolymers and copolymers, and mixtures of the two with a minimum of80%(m/m) of MMA and up to20%(m/m) of ot
16、her monomers, with and without additives, as defined in ISO8257-1. NOTEThe dilute-solution viscosity of polymers can be also expressed as a limiting viscosity number (seeAnnex B). 2 Normative references The following standards contain provisions which, through reference in this text, constitute prov
17、isions of this part of ISO1628. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO1628 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated
18、below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 1628-1:1984, Guidelines for the standardization of methods for the determination of viscosity number and limiting viscosity number of polymers in dilute solution Part 1: General conditions. ISO 3105:1976
19、, Glass capillary kinematic viscometers Specification and operating instructions. ISO 4793:1980, Laboratory sintered (fritted) filters Porosity grading, classification and designation. ISO 8257-1:1987, Plastics Poly(methyl methacrylate) (PMMA) moulding and extrusion materials Part1: Designation. 3 D
20、efinitions and units For the purposes of this part of ISO1628, the following definition applies, in addition to those in clause3 of ISO1628-1:1984. viscosity number, V.N. where V.N.is the viscosity number, in millilitres per gram; is the dynamic viscosity of the test solution, in millipascal seconds
21、; 0 is the dynamic viscosity of the solvent, in millipascal seconds; c is the concentration, in grams per millilitre, of polymer in the solution. NOTEIf the solvent and solution densities 0and are substantially equal, in equation (1) may be replaced by and 0by 0 , where and 0are the kinematic viscos
22、ities, in square millimetres per second, of the solution and the solvent, respectively (see clause10). 4 Principle Determination of the efflux time at25 C 0,05 C of a solvent and of a polymer solution, having a specified concentration, in that solvent. Calculation of the viscosity number and the lim
23、iting viscosity number from the above measurements and the known concentration of the solution. 5 Measurements The data needed to calculate the function defined in clause3 are obtained by means of a capillary tube viscometer, as explained in clause4 of ISO1628-1:1984. The efflux time of a liquid is
24、related to its viscosity by the Poiseuille-Hagenbach-Couette equation: where k is the viscometer constant, in square millimetres per second squared; t is the efflux time, in seconds; %t is the kinetic energy correction (Hagenbach correction), in seconds; is the density, in grams per cubic centimetre
25、, of the liquid; A is a kinetic energy correction parameter, as defined in ISO1628-1. NOTEThe kinetic energy correction %t becomes insignificant if it is less than0,2% of t. For Ubbelohde type OC apparatus, %t can be neglected if the efflux time t is greater than270s; for micro-Ubbelohde type MI app
26、aratus, %t can be neglected if t is greater than70s. 6 Apparatus (see also ISO 1628-1:1984, clause5) 6.1 Capillary viscometer: suspended-level Ubbelohde type OC apparatus with a capillary diameter of0,36mm and measuring bulb of volume2ml, in accordance with ISO3105, or micro-Ubbelohde type MI viscom
27、eter, with a capillary diameter of0,40mm and measuring bulb of volume0,75ml. Any viscometer listed in ISO3105 may be used, provided it gives results equivalent to those obtained with the specified viscometers, which shall be used in the event of a dispute. . . . (1) . . . (2)BS2782-7:Method 732F:199
28、1 2 BSI 12-1999 The calibration of the viscometer used shall be checked by the method specified inAnnex A. 6.2 Timing device, with an accuracy of0,1s for the Ubbelohde type OC viscometer and0,02s for the type MI viscometer. 6.3 Thermostatic bath, capable of being maintained at a temperature of25 C 0
29、,05 C. 6.4 One mark volumetric flask, of100ml capacity, fitted with a ground-glass stopper. 6.5 Balance, accurate to0,1mg. 6.6 Sintered-glass filter funnel, with a maximum pore diameter of404m (porosity grade P40 as defined in ISO4793). 6.7 Shaking machine 7 Solvent and test solution (see also ISO16
30、28-1:1984, clause 6) 7.1 Solvent Chloroform, recognized analytical grade, stabilized with less than1% (V/V) of ethanol, kept in a brown bottle and stored in the dark. 7.2 Sample It is important that the sample is representative of the material to be tested. 7.3 Test solution concentration The soluti
31、on concentration shall be2,6g of polymer per litre of solution. 7.4 Preparation of the test solution Weigh, to the nearest0,1mg, 0,26g 0,005g of the sample into the volumetric flask (6.4). Add50ml of chloroform (7.1) and dissolve the sample completely with shaking. Then make up to the mark with chlo
32、roform at20 C 1 C and shake once more briefly. With polymers containing viscosity-increasing additives requiring modifications to the solution preparation process, such modifications shall be agreed upon by the interested parties. For materials containing pigments and/or special additives, the quant
33、ity weighed into the volumetric flask shall be increased so that the test solution contains0,26g of MMA homopolymers and copolymers per100ml. 8 Temperature of measurement The temperature of measurement shall be25 C 0,05 C. 9 Procedure (see also 1628-1:1984, clause8) Using the sintered-glass filter (
34、6.6), introduce the chloroform solvent or the test solution directly into the tube of the viscometer. Determine the efflux times of the solvent and the test solution at25 C 0,05 C in three to five passages through the same viscometer. If the maximum difference between the efflux times exceeds0,2s fo
35、r a Ubbelohde type OC viscometer or0,03s for a type MI viscometer, repeat the test with the same test solution after cleaning the viscometer with the solvent and drying it. The above procedure may be suitably modified if a viscometer other than the Ubbelohde as described in ISO3105 is used. 10 Expre
36、ssion of results (see also ISO1628-1:1984, clause 9) Calculate the viscosity number V.N., expressed in millilitres per gram, by means of the following equation (this equation is in accordance with ISO1628-1, but includes the kinetic energy correction, which is necessary in order to obtain accurate r
37、esults with the viscometer sizes specified): where is the viscosity of the test solution; 0 is the viscosity of the solvent; t is the arithmetic mean of the values obtained for the efflux time, in seconds, of the test solution; t 0 is the arithmetic mean of the values obtained for the efflux time, i
38、n seconds, of the solvent; c is the concentration, expressed in grams per millilitre, of the test solution; %t is the kinetic energy correction for t (seeAnnex A); %t 0 is the kinetic energy correction for t 0(seeAnnex A). . . . (3)BS2782-7:Method 732F:1991 BSI 12-1999 3 The equation for the viscosi
39、ty number given in ISO1628-1: may be used to give results of similar accuracy if a viscometer with a smaller capillary diameter is used so that the kinetic energy correction is less than0,2% of the efflux time. 11 Test report See ISO1628-1:1984, clause 10. . . . (4) V.N. tt 0 tc 0 - =BS2782-7:Method
40、 732F:1991 4 BSI 12-1999 Annex A (normative) Calibration of the viscometer A.1 Experience has shown that the required high accuracy of the viscosity number determination of MMA homopolymer and copolymer solutions cannot always be achieved with commercially available Ubbelohde viscometers because of
41、minor irregularities in the capillary. It is therefore advisable to check the accuracy of the viscometer by means of calibrating liquids whose kinematic viscosity1 is known. A.2 Viscometer constant k Using n-undecane of recognized analytical grade at25 C, make three to five passages with the same vi
42、scometer and determine the mean efflux time t in accordance with ISO3105:1976, clause 5. Calculate the viscometer constant k from the equation: where for n-undecane at25 C is1,4675mm 2 /s. NOTEThe density of n-undecane at25 C is0,7365g/ml. A.3 Kinetic energy corrections %t 0and %t The energy correct
43、ion can be neglected if it is less than0,2% of the efflux time. The Ubbelohde type OC viscometer complies with this requirement if the efflux time is greater than270s (ASTM viscometer). The micro-Ubbelohde type MI viscometer complies if the efflux time is greater than70s. If the efflux time is less
44、than specified above, a kinetic energy correction shall be made for the viscometer, using the following low-viscosity liquids as standards: Measure the efflux time of each standard liquid in three to five passages and determine the kinetic energy correction %t sifor each liquid using the equation wh
45、ere t si is the efflux time, in seconds, of the ith standard liquid; i is the kinematic viscosity, in square millimetres per second, of the ith standard liquid; k is the viscometer constant, in square millimetres per second squared. Linear interpolation, using the following equations, between the tw
46、o efflux times t s1and t s2for the standard liquids i=1and i=2 (seeFigure A.1) gives the kinematic energy correction %t 0for the efflux time t 0of the solvent (chloroform): . . . (A.1) 1. Dichloromethane (recognized analytical grade) 25 C= 0,314 2 mm 2 /s 25 C= 1,316 3 g/ml 2. Trichloroethylene (rec
47、ognized analytical grade) 25 C= 0,369 3 mm 2 /s 25 C= 1,455 5 g/ml 3. Tetrachloroethylene (recognized analytical grade) 25 C= 0,525 7 mm 2 /s 25 C= 1,614 4 g/ml . . . (A.2) k t - = %t si t si i k - = . . . (A.3) . . . (A.4)BS2782-7:Method 732F:1991 BSI 12-1999 5 In the same manner, linear interpolat
48、ion, using the following equations, between t s2and t s3gives %t for the efflux time t of the test solution: Annex B (normative) Determination of the limiting viscosity number The limiting viscosity number for methyl methacrylate polymer solutions may be calculated, in millilitres per gram, from val
49、ues obtained at a single concentration by use of the following equation2: where is the dynamic viscosity, in millipascal seconds, of the solution; 0 is the dynamic viscosity, in millipascal seconds, of the solvent; c is the concentration of polymer, in grams per millilitre of solution. Annex C (informative) Bibliography 1 BAUER, H., and MEERLENDER, G., Precise viscosity measurements of Newtonian liquids with 1mm 2 /s for the selection
