1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 828:2013Adhesives - Wettability - Determination by measurement of contact angle and surface free energy of solid surfaceBS EN 828:2013 BRITISH STANDARDNational forewordThis
2、 British Standard is the UK implementation of EN 828:2013. It supersedes BS EN 828:1998 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/52, Adhesives.A list of organizations represented on this committee can be obtained on request to its secretary.
3、This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013ISBN 978 0 580 72245 5 ICS 83.180 Compliance with a British Standard cannot confe
4、r immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2013.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 828:2013EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 828 January 20
5、13 ICS 83.180 Supersedes EN 828:1997English Version Adhesives - Wettability - Determination by measurement of contact angle and surface free energy of solid surface Adhsifs - Mouillabilit - Dtermination par mesurage de langle de contact et de lnergie superficielle libre de la surface solide Klebstof
6、fe - Benetzbarkeit - Bestimmung durch Messung des Kontaktwinkels und der freien Oberflchenenergie fester Oberflchen This European Standard was approved by CEN on 24 November 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
7、 European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official ve
8、rsions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austri
9、a, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
10、 Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Memb
11、ers. Ref. No. EN 828:2013: EBS EN 828:2013EN 828:2013 (E) 2 Contents Page Foreword . 3 1 Scope 4 2 Normative references . 4 3 Terms and definitions 4 4 Principle 6 5 Test equipment . 6 6 Measuring conditions 7 7 Procedure . 8 8 Expression of results . 9 9 Test report 9 Bibliography 11 BS EN 828:2013
12、EN 828:2013 (E) 3 Foreword This document (EN 828:2013) has been prepared by Technical Committee CEN/TC 193 “Adhesives”, the secretariat of which is held by AENOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at
13、 the latest by July 2013, and conflicting national standards shall be withdrawn at the latest by July 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or al
14、l such patent rights. This document supersedes EN 828:1997. Safety Statement People applying this document, the user shall be familiar with normal laboratory practice. This standard does not purport to address all the safety problems, if any, associated with its use. It is the responsibility of the
15、user to establish safety and health practices and to ensure their compliance with the provisions of any regulatory conditions. Environmental Statement It is understood that some of the material permitted in this standard may have a negative environmental impact. As technological advantages lead to a
16、cceptable alternatives for these materials, they will be eliminated from this standard as far as possible. At the end of the test, the user of the standard should take care to carry out appropriate disposal of waste, according to local regulations. According to the CEN/CENELEC Internal Regulations,
17、the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lat
18、via, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 828:2013EN 828:2013 (E) 4 1 Scope This European Standard specifies a method for the determination of the surface free energy of a so
19、lid surface by measuring the contact angle of a liquid wetting the solid surface. It allows the prediction of the ability of a particular adhesive to wet a particular adherend. It can be used to characterise surfaces intended for pre-treatment, coating or bonding. NOTE 1 In order to determine the su
20、rface free energy, the method of measuring the static contact angle is used in combination with a statistical interpretation. NOTE 2 The measurement results are influenced by mechanical surface roughness and chemical homogeneity. 2 Normative references The following documents, in whole or in part, a
21、re normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 923:2005+A1:2008, Adhesives Terms and definitions 3
22、 Terms and definitions For the purposes of this document, the terms and definitions given in EN 923:2005+A1:2008 and the following apply. 3.1 triple point point where the solid, the liquid and the gas phases coincide with each other Note 1 to entry: The triple point can be identified in the silhouet
23、te of a liquid drop situated on a test piece, at the intersection of the drops contour line with the test piece surface. 3.2 baseline in the case of plane test pieces, a straight line going through the two triple points 3.3 contact angle angle to the baseline, formed by a tangent to the drop contour
24、 going through one of the triple points (see Figure 1) BS EN 828:2013EN 828:2013 (E) 5 Key 1 solid body surface 2 liquid drop Lsurface tension (= surface energy) of the liquid in equilibrium with the gas phase Ssurface free energy of the solid body surface SLinterfacial energy of the solid body surf
25、ace in contact with the liquid contact angle Figure 1 Wettability 3.4 wettability a liquid coming into contact with a solid surface exhibits a typical drop shape. The characteristic of the drop is the angle formed by the tangent to the contour at the triple point (wetting point) (Figure 1). A contac
26、t angle = 0 indicates a surface that is completely wetted 3.5 contour analysis image analysis procedure consisting in capturing the silhouette of a liquid drop on a surface by optical methods and calculating the contour profile of that silhouette 3.6 surface free energy of a solid Senergy measure (e
27、xpressed in mN/m) which characterises the wettability of a solid material by a liquid that is based on the adsorption theory. The forces present in the state of equilibrium are described by Youngs formula: S= SL+ L cos (1) The Young-Dupr formula defines the work of adhesion obtained during wetting:
28、Wad= L+ L cos = L (1 + cos ) (2) The position of the thermodynamic equilibrium resulting in the formation of the static contact angle depends on both the pressure and the temperature conditions. When carrying out the measurement, standard conditions should be maintained. Since the interfacial energy
29、 and the surface energy are based on interactive forces between atoms or molecules, it is necessary to take polarity into consideration when assessing the wettability. Examples for polar interactions are as follows: dipole-dipole interactions; hydrogen bridge bonds; acid-base interactions. BS EN 828
30、:2013EN 828:2013 (E) 6 The non-polar (disperse) interactions are commonly described as London interactions. In accordance with 1 and 2, the interfacial energy SLbetween a solid body (S for “solid“) and a liquid (L for “liquid“) is the sum of the surface tensions of the two phases (S+ L), reduced by
31、the disperse and the polar interactions at the phase border. These interactions are described as the doubled sum of the geometric mean values of the disperse (DLDS ) and the polar (PLPS ) tension components of the individual phases: SL= S+ L 2 ( DDSL+ PPsL) (3) Substitution SLfrom the Youngs formula
32、 (1) and rearrangement of formula (3) to the general form of a straight line y = mx + b (4) leads to the following formula: ( )1 cos2mbxy+= + PLL PDSSDDLL(5) The square of the slope is the polar proportion of the solid body surface energyPS , the square of the ordinate intercept b is the disperse pr
33、oportionDS . The sum of the two proportions is the total surface free energy of the solid body S. 4 Principle Ten drops each of at least three and up to eight known, different liquids are dosed onto a plane test piece surface. For each drop, the left and the right contact angles are measured. From t
34、he averaged contact angles of each liquid combined with its surface tension and its polar and disperse proportions, the surface free energy of the solid body is calculated, subdivided into the polar and the disperse proportions. Preferably, the liquids used should exhibit different polar and dispers
35、e proportions of the interfacial tension. Recommended liquids and their characteristic interfacial tensions are listed in Table 1. The drop volumes suitable for the measurement depend on the type of the liquid and should be adjusted such that the negative influence of gravity on the contact angle is
36、 kept to a minimum. 5 Test equipment 5.1 Solid surface to be assessed, substrate with pre-treated or untreated surface. 5.2 Contact-angle measuring system, any contact-angle measuring device, preferably systems comprising digital image acquisition and image analysis to comply with the current state
37、of the art. Figure 2 gives an example of a schematic representation of a contact-angle measuring system. BS EN 828:2013EN 828:2013 (E) 7 Table 1 Recommended test liquids Designation of the test liquid Surface tension mN/m Disperse proportion mN/m Polar proportion mN/m Literature (Author) Water 72,80
38、 21,80 51,00 See 3 Diiodomethane 50,80 50,80 0,00 See 3 Ethylene glycol 47,70 30,90 16,80 See 3 Glycerol 63,40 37,00 26,40 See 3 Hexadecane 27,60 27,60 0,00 See 3 -Bromine naphthalene 44,60 44,60 0,00 See 3 Benzyl alcohol 38,90 29,00 9,90 See 4 Decalin 30,60 30,60 0,00 See 3 Key 1 lighting 2 sample
39、carrier 3 dosage 4 optical system 5 screen Figure 2 Contact-angle measuring system 5.3 Reagents, at least three and up to eight of the test liquids recommended in Table 1. WARNING These reagents are chemicals carefully follow the safety advice on the labels and in the safety data sheets. 5.4 Micropi
40、pette (or suitable syringes for micro-dosing) which can be fastened above the sample carrier or the surface to be tested, respectively, by means of an appropriate holder. 6 Measuring conditions Constant measuring conditions in accordance with the thermodynamic state function (temperature and pressur
41、e) shall be maintained. BS EN 828:2013EN 828:2013 (E) 8 7 Procedure 7.1 The contact-angle measuring device shall be adjusted horizontally by means of the level. 7.2 The contact-angle measuring device, the lighting and the image acquisition and analysis system are switched on. The image display is ad
42、justed to be sufficient with regard to brightness and contrast (the manufacturers information should be taken into consideration). The light source of the contact-angle measuring device shall be calibrated to obtain optimum contrast and grey scale value in the image of a drop and of a surface. The d
43、osing needle is moved to the upper edge of the image and the zoom of the contact-angle measuring device is set in a way that the contour width of the located drop covers two thirds of the width of the image. Afterwards the drop image shall be focussed. 7.3 The dosing system is filled with one of the
44、 selected liquids. It shall be ensured that any contaminations during filling are avoided. 7.4 A plane sample of the surface to be measured is placed on the sample carrier. The sample carrier shall be adjusted such that the sample surface is located in the lower half of the image and in a horizontal
45、 position. 7.5 The dosing needle is positioned approximately 1 mm above the sample surface. The drop shall be dosed such that its volume is between 2 l and 6 l, depending on the liquid selected. Recommended drop volumes are given in Table 2, depending on the liquid selected. Table 2 Recommended drop
46、 volumes Liquid Drop volume l Water 26 Diiodomethane 23 Ethylene glycol 26 Glycerol 26 Hexadecane 26 -Bromine naphthalene 26 Benzyl alcohol 26 Decalin 26 7.6 One drop of the test liquid is dosed onto the surface. In doing so, the drop volumes given in Table 2 and the dosing rate of 100 l/min shall n
47、ot be exceeded. 7.7 The baseline shall be adjusted such that it intersects the triple points of the drop. In order to facilitate locating the triple points, a top-view angle of maximally 2 may be set. The maximum deviation of the baseline from the horizontal (slope) shall not exceed 0,1. 7.8 The mea
48、surement shall be started immediately (max. 15 s) after the completion of dosing. Over the contact period, no reaction and no mutual material conversion between the test liquid and the surface to be measured shall take place. As an example, it is recommended to carry out one measurement every second
49、 over a period of 20 s. BS EN 828:2013EN 828:2013 (E) 9 7.9 Depending on how the individual liquid drops behave on different solid body surfaces, different algorithms shall be applied for the accurate determination of the contact angle (e.g. equation of a circle for contact angles 120). 7.10 Repeat sub-clauses 7.3 to 7.9 for a total ten drops of each liquid. In order to get sufficient information concerning the homogeneity of a sample, the measure
