Tiêu chuẩn iso 02782 1 2016

© ISO 2016 Rubber, vulcanized or thermoplastic — Determination of permeability to gases — Part 1 Differential pressure methods Caoutchouc vulcanisé ou thermoplastique — Détermination de la perméabilit[.]

Rubber, vulcanized or

Part 1:

Ca utch uc v lca isé o the mo lastique — Déte mination de la

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F reword v

Introduction vi

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms and definitio s 2

4 Principle 2

5 Pres ur e sensor method 2

5.1 A pp r atus 2

5.2 Calbration 4

5.3 Tes gas 4

5.4 Tes pie es 5

5.4.1 Sha e an dimensions 5

5.4.2 Pr ep ration 5

5.4.3 Numbe of tes pie es 5

5.4.4 Measur ement of thicknes 5

5.4.5 Time inte v l betwe n forming an tes ing 5

5.5 Conditioning 5

5.6 Tes con itions 5

5.7 Gastr ansmis ion ar ea 5

5.8 Pr oc dure 6

5.9 Calculation an ex pr es ion of results 7

5.9.1 Gas tr ansmis ion rate 7

5.9.2 Gas pe mea i ty coeficient 8

5.9.3 Gas difusion coeficient 8

5.9.4 Gas solubi ty coeficient 8

6 Simplfied pres ure sensor metho 8

6.1 A pp r atus 8

6.1.1 Tes c l 9

6.1.2 Tes pie e sup ort

9 6.1.3 T wo pr es ur e sensors 9

6.1.4 Tes gas sup ly r ese v ir 9

6.1.5 Temperatur e sensor 9

6.2 Calbration 1

6.3 Tes gas 1

6.4 Tes pie es 1

6.4.1 Sha e an dimensions 1

6.4.2 Pr ep ration 1

6.4.3 Numbe of tes pie es 1

6.4.4 Measur ement of thicknes 1

6.4.5 Time inte v l betwe n forming an tes ing 1

6.5 Conditioning 1

6.6 Tes con itions 1

6.7 Gastr ansmis ion ar ea 1

6.8 Pr oc dure 1

6.9 Calculation an ex pr es ion of results 1

7 Gas-chromatog raphic method 11

7.1 A pp r atus 1

7.2 Calbration 1

7.3 Tes gas 1

7.4 Car ie gas 1

7.5 Tes pie es 1

7.5.2 Pr ep ration 1

7.5.3 Numbe of tes pie es 1

7.5.4 Measur ement of thick es 1

7.5.5 Time inte v l betwe n forming an tes ing 1

7.6 Conditioning 1

7.7 Tes con itions 1

7.8 Gastransmis ion ar ea 1

7.9 Calbr ation curve 1

7.1 Pr oc dur e 1

7.1 Calculation an ex pr es ion of result 14

7.1 1 Gas transmis ion rate 14

7.1 2 Gas pe mea i ty coeficient 1

8 Test r ep rt 15

A nne x A (normative) Calbration s hedule 17

ISO (he Int ernational Org nization for Stan ardization) is a worldwide fede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Standards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a l shed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www.iso.org dir ctives)

A tt ention is drawn t o the p s ibi ity that ome of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such pat ent right Detais of

any p t ent right identif ied d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www.iso.org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the meaning of ISO spe if ic t erms an ex r s ions r lat ed t o conformity

as es ment, as wel as information a out ISO’ s adhe enc t o the WTO principles in the Te h ical

Bar ie s t o Trade (TBT), se thefolowing URL:F or word — Sup lementary information

The committ ee r sp nsible for this document is ISO/TC 45, Ru be a d ru be produc ts , Subcommitt ee

SC 2, Tes tin a d a alys i s

This se ond edition canc ls an r plac s thef irs edition (ISO 2 8 -1:2 1 ), w hich has be n t ech icaly

r vised A new Clause on simplfied pr s ur sensor method has be n ad ed ( e Clause 6)

ISO 2 8 consis s of the folowing p rt , un e the g ene al title R ub e , v ulc ani zed or the mo las tic —

Dete min tio o pe mea i t y to g s es:

— Part 1: Dife entialpr s s ur meth ds

— Part 2 : Eq alpr s s ur meth d

The measur ment of the pe mea i ity of rub e t o g ses is imp rtant in the ev luation of compoun s for

prod ct such as inne tubes, tubeles -tyr l ne s, hoses, b lo ns and othe g s-containing prod ct ,

as wel asseals an dia hra ms The measur ment is also of theor tical imp rtanc in the s u y of the

charact eris ics of g s difusion an g s solubi ty in r lation t o p lyme s ructur

This p rt of ISO 2 8 pro oses thr e dife ent methods for the det ermination ofthe pe mea i ity t o

g ses of vulcaniz d or the mo las ic rub e un e a dife ential p rtial pr s ur , w hich ar

— pr s ur sensor method w hich alow s a complet e charact erization of a mat erial,

— simpl fied pr s ur sensor method w hich is a pro riat e w hen only the g s pe mea i ty coefficient

is ne ded (routine control, spe if ication ve ification, design, et c ), an

— g s-chromat ogra hic method

Rubber, vulcanized or ther moplastic — Determination of

Part 1:

WARNING 1 — Per o s using this part of ISO 27 2 sho ld be fami iar with normal laboratory

practice This part of ISO 2782 does not purport to addres al of the safety pro lems, if any,

as ociated with its use It is the respo sibi ity of the use to establsh appropriate safety and

he lth practices and to ensure compl ance with any national re ulatory conditions

WARNING 2 Certain procedures specified in this part of ISO 2782 might inv lve the use or

g eneration of substances, or the g eneratio of waste, that co ld constitute a local enviro mental

hazard Reference sho ld be made to ap ro riate documentation o safe handl ng and disposal

after use

This part of ISO 2 8 spe ifies thr e methods for the det ermination of the pe mea i ty t o g ses of

vulcaniz d or the mo las ic rub e un e a dife ential p rtial pr s ur

The thr e methods spe if ied ar as folows:

— pr s ur sensor method (using v cu m):for det ermining the g s transmis ion rat e, g s pe mea i ty

coefficient, g s difusion coefficient an g s solubi ity coefficient ;

— simplfied sensor method (using a pl ed pr s ure): for dete mining the g s pe mea i ity

coef icient only;

— g s-chromat ogra hic method: for det ermining the g s transmis ion rat e an g s pe mea i ty

coefficient

These methods a ply t o vulcaniz d an the mo las ic rub e s of hard es not les than 3 IRHD

( int ernational rub e hardnes degr es) an t o b th single g ses an mixtur s of g ses

2 Normati ve r eferences

The folowing document , in w hole or in p rt, ar normatively r fe enc d in this document an ar

in ispensa le for it a pl cation F or dat ed r fe enc s, only the edition cit ed a pl es F or u dat ed

r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment )a pl es

ISO 1 89 :2 1 , R ub e — Guide to the c albratio o tes t eq ipment

ISO 2 5 9:2 1 , Ru be — G ene al proc edur s fr pr p ring a d c onditioning tes piec es fr p ys ic al

tes meth d s

F or the purposes of this document, the fol owing t erms and def initions a ply

3.1

g s transmis ion rate

n mbe of moles of t es g s p s ing through a t es pie e pe u it ar a, pe u it time, with unit p

rtial-pr s ur dife enc betwe n the two sides ofthe t es pie e

3.2

g s perme bi ity coef icient

n mbe of moles of t es g s p s ing through a t es pie e of unit thick es , pe u it ar a, pe unit time,

with u it p rtial-pr s ur dife enc betwe n the two sides of the t es pie e

3.3

g s dif usion coef icient

q antity of t es g s p s ing, b difusion, through a t es pie e of unit thick es , pe u it ar a, pe u it

time, w he e the e is a unit g s conc ntration gradient ac os the t es pie e

3.4

g s solubiity coef icient

t es g s conc ntration inside a t es pie e divided b thep rtial pr s ur of the t es g s at the surfac of

the t es pie e

3.5

g s transmis ion curve

<pr s ur sensor method> curve, plott ed a ains time, of the pr s ur chang e on the low-pr s ur side

of the t es c l u ti g s transmis ion r aches a st eady s at e

Not e 1t o entry: A g s transmis ion curve is il ustrated in Figure 2

The ca ity of a t es c l , maintained at a cons ant t empe atur , is divided b a t es pie e int o a

high-pr s ur an a low-pr s ur side The high-pr s ur side of the c l is filed with the t es g s The

q antity of g s that difuses through the t es pie e t o the low-pr s ur side is det ermined b a pr s ur

sensor or b a g s chromat ogra h

In the pr s ur sensor method, the g s transmis ion rat e, g s pe mea i ity coeff icient, g s difusion

coefficient an g s solubi ity coeff icient ar measur d, prod cing an a e ag e v lue for a g s mixtur

In the simpl f ied pr s ur sensor method only the g s pe mea i ty coeff icient is measur d In the g

s-chromat ogra hic method, measur ment ar p s ible on t es g ses containing wat er v p ur, an it is

also p s ible t o analy se mixtur s of g sest o det ermine the comp nent

5.1 A pparatus

The a paratus consis s of the t es c l, pr s ur sensors, a t es g s sup ly r se v ir, a v cu m pump

an as ociat ed tubing an v lves An ex mple of a t es a paratus is shown in Figur 1

5.1.1 Test c el, consis ing of a low-pr es ur e side an a high-pres ur e side, such tha when a tes pie e

is mou ted in it , the gas tr ansmis ion ar ea is clear ly defined The high-pr es ur e side has an inlet p rt

to supply tes gas, an a pr es ur e sensor is con e ted to the low-pres ur e side to dete t the chang e in

pr es ure caused b the gas transmited thr ough the tes pie e The surfac s of the two halves of the c l

which make contact with the tes pie e shal be smo th an flat to pr event any leakag e of gas A seal such

as an O-ring ma y be used betwe n these ar eas an the tes pie e, in which case the gastransmis ion rate

of the seal shal be considerably lowe than that of the mate ial being tes ed so that it does not afe t the

r esult of the test The mate ial of the tes c l shal be u reactive w ith r egar d to the tes gas an shal

not a sor b the gas used T e diamete of the gas transmis ion ar ea shal be within the rang e 1 mm to

1 0 mm, depen ing on thegas tr ansmis ion rate ex pe ted

The c l shal be eq ip ed with a heating sy st em ca a le of raising the t empe atur t o 8 °C The

t empe atur ac uracy shal be ± °C for t empe atur s from 40 °C t o 8 °C

NOTE Ex mples of a he ting system are an electric he ting jacket an an oven designed t o hold the t est cel

an test g s su ply reservoir

5.1.2 Test piec e support, instaled on the low-pr es ure side of the tes c l in or de to pr event

deformation of the tes pie e d e to the pr es ure difer enc betwe n the high- an low-pr es ur e sides

A ny mate ial, such as fite p pe or wir e mesh, that does not afe t the r esult of the tes ma y be used

When using fite p pe , pa e such as that used in chemical analysis is r ecommen ed, of thick es

0,1 mm to 0,3 mm, depen ing on the depth of the low-pr es ure side of the c l

5.1.3 T wo pr es ure sensor s, the first , ca a le of r eading to within 5 Pa or bette , to measur e

the chang e in pres ur e on the low-pres ur e side of the tes c l A v cu m gaug e with no mer cury, an

ele tronic dia hrag m-type sensor or othe suita le sensor shal be used as this pr es ure sensor T e

se ond, ca a le of r eading to within 1% or bete , is used to measur e the pr es ure of the tes gas sup ly

r ese v ir

5.1.4 Test gas suppl y r eserv ir, for sup lying tes gas at a constant pr es ur e to the high-pr es ur e

side of the tes c l The v lume of the r ese v ir shal be suficient to ensur e that the pr es ur e dr op on

the high-pr es ur e side, d e to transmis ion of the tes gas thr oug h the tes pie e to the low-pr es ur e side

d ring the test , does not exc ed 1 % of the tes pr es ure

5.1.5 Vacuum p mp, ca a le of ev cuating the tes c l to a pr es ur e of 1 Pa or lowe

5.1.6 Temperature sensor, fited in the tes c l, for measuring the tes temperatur e, an ca a le of

r eading to within 0,1 °Cor bete

8 pres ur e gaug e for test g as su ply r eservoir 1 data-pr oces ing u it

9 pres ur e sensor for low-pres ur e side of test cel 1 diameter of gas tr ansmis ion ar ea

1 test g as cylin er

NOTE Dia ram at right shows an e ploded view of the t est cel

Figure 1 — Example of apparatus for g s perme bi ity me surement (pres ure sensor metho )

5.2 Cal bration

The t es a p ratus shal be calbrat ed in ac ordanc with the sched le given in Annex A

5.3 Test gas

Use a single g s, such as nitrog en, o y g en or hydrog en, or a mixtur of g ses, such as air, lq ef ied

petroleum g s ( in g seous form) or co l g s The purity of a single g s or thepurity of each comp nent

in a g s mixtur shal be 9 ,5 % b volume or highe , u les othe wise a r ed betwe n the int er st ed

p rties, in w hich case a g s of lowe purity ma be used The t es g s shal not inclu e any impurity that

might afe t the measur ment

When using a g s mixtur , the purity of each comp nent shal be ve if ied in adv nc with a suita le

ins rument, such as a g s chromat ogra h

When using a t oxic an / r flamma le g s, al ne es ary pr cautions should be taken in it use an in it

r co e y or disp sal

5.4 Test piec es

5.4.1 Shape and dimensions

The t es pie es shal be of uniform sha e an ha e a thick es of mor than 0,1 mm but les than

2,2mm, u les othe wise a r ed between the int er st ed p rties The t es pie es shal be larg e enough

t o ext en ac os the ful width of the t es c l an t o be clamped betwe n the flat edg es of the two

halves of the t es c l ( e 5.1.1)

5.4.2 Pr eparatio

The t es pie es shal be cut out an pr p r d in ac ordanc with ISO 2 5 9 Any t es pie e containing

for ign matt er, air bub les, sc at ches or holes shal be discarded

5.4.3 Numbe of test piec es

Thr e or mor t es pie es shal be used ex cept w hen t es ing for q al ty control purp ses, in w hich case

the n mbe of t es pie es ma be r d c d

5.4.4 Me sur ement of thicknes

Measur the thick es of each t es pie e at f ive or mor p int , inclu ing the c ntr of the g s

transmis ion ar a, t o the near s 0,0 mm using method A spe ified in ISO 2 5 9:2 1 , an take the

arithmetic mean of the measur ment No single measur ment on a t es pie e shal deviat e b mor

than 1 % from the mean for that t es pie e, and the mean v lue for any one t es pie e shal not deviat e

b mor than 1 % from the mean v lue for al the t es pie es measur d

5.4.5 Time interval betwe n for ming and testing

The time int erv l betwe n forming an t es ing shal be in ac ordanc with ISO 2 5 9

Samples an t es pie es shal be st or d in ac ordanc with ISO 2 5 9 d ring the int erv l betwe n

forming an t es ing

5.5 Conditioning

The minimum time between forming an the commenc ment of con itioning of the tes pie es shal

be1 h

Unles othe wise r q ir d in the mat erial spe if ication or a r ed betwe n the int er st ed parties, the

mat erial shal be con itioned befor t es ing for 1 h t o 24 h at a s andard la orat ory t empe atur an

h midity spe if ied in ISO 2 5 9 When using a t es pie e that can be easi y afe t ed b mois ur , dry it

for mor than 48 h at the t es t empe atur in a desic at or containing a suita le drying ag ent, such as

an ydrous calcium chloride

5.6 Test c onditions

5.6.1 T e la oratory con itions shal be in ac or danc with ISO 2 5 9

5.6.2 T e tes shal be con ucted at the same tempe ature as was used to con ition the tes pie es

( se 5.5) The tes temperature shal be measured b means of the temperature sensor fited in the tes c l

5.7 Gas transmis ion area

The g s transmis ion ar a A shal be calculat ed from the int ernal diamet er of the t es c l or, if a sealng

ring is used, from the int ernal diamet er of the seal ng ring

5.8 Proc edure

5.8.1 Fit a suita le tes pie e sup ort (4 in Fig ure 1) on the low-pr es ure side of the tes c l

5.8.2 A pply v cu m g r ease lg htly an u iformly to the flat edg es of the two halves of the tes c l

which wil make contact with the tes pie e an mou t the tes pie e in the lowe part of thec l, w ithout

any wrinklng or sag g ing

5.8.3 Plac a sealng ring (if used) on the tes pie e, folowed b the up e p rt of the c l Clamp the

two halves of the c l tog ethe w ith u iform pr es ure so that the tes pie e is completely sealed in plac

5.8.4 When making measurement at a temperatur e othe than a s andar d la oratory temperatur e,

bring the tes c l to the tes temperature

5.8.5 Close v lve 1 (1 in Fig ur e 1), v lve 2 (1 ) and v lve 3 (14), and o en v lve 4 (1 ) Start the

v cu m pump an then o en v lve 2 (1 ) A ir wil be ev cuated firs fr om the low-pres ur e side of

the tes c l, folowed b the high-pres ur e side, so that the tes pie e fit snugly agains the tes pie e

supp rt C ntin e u ti ev cuation is complete Sinc it is ne es ary to r emo e al a sor bed gas, alow

suficient ev cuation time for a tes pie e of low gas transmis ion rate to be thoroughly degas ed

NOTE T e evacuation time req ired wil difer for diferent ty es of sample an diferent con itioning

A q antitative comparison b tween diferent ty es of sample can b made by f ixing the e haustion time For

samples with a low g s transmis ion rate, evacuating overnight is a common practice Note that, with some ty es

of sample, long er evacuation times might remove the more re dily vaporized components from the t est piece

5.8.6 Sh t v lve 2 (1 )an v lve 4 (1 ) to maintain the pr es ure on b th the low-pr es ur e side an the

high-pr es ure side at 1 Pa or les Sto the v cu m pump

5.8.7 If the pr es ur e on the low-pres ur e side rises, r epeat s eps 5.8.2 to 5.8.6, as there is a p s ibi ty

of gas leakag e or gas being a sor bed b the tes pie e

5.8.8 Intr od c the tes gas into the high-pr es ure side b o ening v lve 1 (12), shutting of the gas

supply when the pres ur e (as measur ed b the pres ur e gaug e, 8 in Fig ur e 1) has reached the tes

pres ur e Re or d the pr es ur e on the high-pr es ur e side p

h

an the temperature Twhen the pr es ur e on

the low-pres ur e side starts incr easing d eto the pe meation of the tes gas fr om the high-pr es ure side

to the low-pres ur e side

5.8.9 Dra w the gas transmis ion cur ve b ploting the pres ure on the low-pres ure side agains time

C ntin e taking measurement u ti a cons ant rate of gas transmis ion has be n reached, as in icated b

a s raight lne ( se Fig ure 2) A gas transmis ion cur ve ploted b automatic recording ma y also be used

5.8.10 Dete mine the slo e of the straig ht-lne p rtion of thecurve (dp dt, se Fig ur e 2) The slo e ma y

also be dete mined automaticaly b the r ecorde

5.8.11 When dete mining the gas difusion coeficient , extrap late the s raight part of the gas

tr ansmis ion curve b ck to thex-ax is and dete mine the dela y time θ ( e Fig ur e 2)

Key

t time (s)

p pr es ure (Pa)

1 ste d -state reg ion

2 non-ste d -state r eg ion

Figure 2 — Gas transmis io curve

5.9 Calculation and ex pres ion ofresults

5.9.1 Gas transmis ion rate

The g s transmis ion rat e isdet ermined from F ormula (1):

GTR

d

dc

h

=

×V

is the pr s ur of thet es g s on the high-pr s ur side of the t es c l (Pa);

A is the g s transmis ion ar a (m

2

);

dp dt is the pr s ur chang e on the low-pr s ur side of the t es c l pe u it time (Pa s);

R is the g s cons ant [ 8,3 m

3

·Pa/(K·mol)]

Ex r s the g s transmis ion rat e asthe arithmetic mean of the r sult o tained for al the t es pie es