475:
availability and low cost. In the experiment, two rubber bands are used to each suspend two small water bottles. One is suspended outdoors, protected from the sun and rain, and one indoors. A data recording sheet is placed behind the setup and taped to a wall. The user then marks the changes in the height of the water bottles as the natural rubber degrades from ozone pollution. Since both water bottles are nearly the same mass, the force on each rubber band is similar, and the spring constant of each rubber band is compared via ratio of the water bottle relative extensions on the rubber bands. Typically, the home experimenter sees relatively little damage to the indoor control compared to the outdoor setup. After a week or two, the home experimenters seal both rubber bands into a small plastic bag and mail them, along with their data sheets to the GORP researchers. Researchers examine loss of elasticity versus data and location. The GORP study was originally implemented during the SARS-CoV-2 pandemic as a means to test for reduced ozone pollution during the quarantine.
309:
30:
44:
1206:
1196:
332:). By cleaving the chain, the molecular weight drops rapidly and there comes a point when it has little strength whatsoever, and a crack forms. Further attack occurs in the freshly exposed crack surfaces and the crack grows steadily until it completes a circuit and the product separates or fails. In the case of a seal or a tube, failure occurs when the wall of the device is penetrated.
196:
231:
256:
344:
336:
210:
Ozone cracks form in products under tension, but the critical strain is very small. The cracks are always oriented at right angles to the strain axis, so will form around the circumference in a rubber tube bent over. Such cracks are very dangerous when they occur in fuel pipes because the cracks will
474:
Rubber bands have been used in at least one publicized home experiment to allow for global testing of ozone pollution. Titled GORP, for Global Ozone Rubber
Participant, users can see the effects of ozone pollution near their own homes or places of employment. Rubber bands were chosen due to their
467:
408:
On the other hand, the problem does recur in unprotected products such as rubber tubing and seals, where ozone attack is thought to be impossible. Unfortunately, traces of ozone can turn up in the most unexpected situations. Using ozone-resistant rubbers is another way of inhibiting cracking.
151:
is more resistant but still has a small number of double bonds in its chains, so attack is possible. Exposed surfaces are attacked first, the density of cracks varying with ozone gas concentration. The higher the concentration, the greater the number of cracks formed.
175:. Attack is less likely because double bonds form a very small proportion of the chains, and with the latter, the chlorination reduces the electron density in the double bonds, therefore lowering their propensity to react with ozone.
443:
with moving parts constructed from insulating materials. If those compressors feed pressurised air into a closed pneumatic system, then all seals in the system may be at risk from ozone cracking.
281:
fabrication line. The problem was solved by adding effective filters in the air line and by modifying the design to eliminate the very sharp corners. An ozone-resistant elastomer such as
320:, which then decomposes rapidly so that the double bond is cleaved. This is the critical step in chain breakage when polymers are attacked. The strength of polymers depends on the chain
248:
Ozone attack will occur at the most sensitive zones in a seal, especially sharp corners where the strain is greatest when the seal is flexing in use. The corners represent
95:, where ozone attack is considered unlikely. Only a trace amount of the gas is needed to initiate cracking, and so these items can also succumb to the problem.
420:
For high value equipment where loss of function can cause serious problems, low cost seals may be replaced at frequent intervals so as to preclude failure.
211:
grow from the outside exposed surfaces into the bore of the pipe, so fuel leakage and fire may follow. Seals are also susceptible to attack, such as
375:
peak. The spectrum at right shows the unaffected elastomer surface spectrum, with a relatively low oxygen peak compared with the sulfur peak.
1138:
234:
308:
277:, and once cracking had started, it continued as long as the gas was present. This particular failure led to loss of production on a
364:
405:
is a wax which bleeds to the surface and forms a protective layer, but other specialist chemicals are also widely used.
575:
1037:
633:
561:
363:. The net result is a high concentration of elemental oxygen on the crack surfaces, which can be detected using
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or VOCs, such as gasoline vapour present in the air of towns and cities, in a problem known as
401:
sidewalls, but are now seen rarely thanks to the use of these additives. A common and low cost
1072:
858:
803:
147:
units, but the proportion of acrylonitrile is usually lower than butadiene, so attack occurs.
971:
936:
252:, so the tension is at a maximum when the diaphragm of the seal is bent under air pressure.
916:
515:
485:
249:
8:
1240:
1042:
678:
650:
626:
535:
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gas is present, cracking will occur in the seals unless preventative measures are taken.
223:
seals are commonly used in pneumatic systems because of its oil resistance. However, if
1235:
1080:
911:
510:
455:
436:
424:
219:
controls, and if a crack penetrates the seal, all functions of the system can be lost.
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458:. The ozone formed can drift many miles before it is destroyed by further reactions.
274:
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560:
Layer, R. W., & Lattimer, R. P. (1990). Protection of rubber against ozone.
68:
attack, and the characteristic form of attack of vulnerable rubbers is known as
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328:, the higher the chain length, the greater the mechanical strength (such as
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841:
836:
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371:. The spectrum at left shows the high oxygen peak compared with a constant
148:
76:, but is now rarely seen in those products owing to preventive measures.
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However, it does occur in many other safety-critical items such as
606:
Forensic
Polymer Engineering: Why polymer products fail in service
461:
301:
The reaction occurring between double bonds and ozone is known as
1090:
317:
215:
in air lines. Such seals are often critical for the operation of
180:
92:
88:
372:
356:
273:
The seal shown at left failed from traces of ozone at circa 1
688:
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73:
65:
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642:
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368:
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260:
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when one molecule of the gas reacts with the double bond:
343:
611:
335:
16:
Cracks in many different elastomers due to ozone attack
72:. The problem was formerly very common, especially in
351:
The carbonyl end groups which are formed are usually
1222:
397:. Ozone cracks were commonly seen in automobile
462:Use of rubber bands to test for ozone pollution
35:A vehicle tire showing signs of ozone cracking
627:
285:was also considered as a replacement for the
1139:European Tyre and Rim Technical Organisation
599:Forensic Materials Engineering: Case studies
103:Tiny traces of ozone in the air will attack
123:being most sensitive to degradation. Every
634:
620:
235:Environmental scanning electron microscope
131:, so every unit can be degraded by ozone.
597:Lewis, Peter Rhys, Reynolds, K, Gagg, C,
347:EDX spectrum of unaffected rubber surface
98:
608:, 2nd edition, Woodhead/Elsevier (2016).
465:
446:Ozone is also produced by the action of
342:
334:
316:The immediate result is formation of an
254:
229:
194:
389:The problem can be prevented by adding
60:Cracks can be formed in many different
1223:
470:Rubber band damaged by ozone pollution
615:
199:Macrophotograph of ozone cracking in
576:"Are you breathing ozone pollution?"
365:energy-dispersive X-ray spectroscopy
1182:Uniform Tire Quality Grading (UTQG)
190:
155:Ozone-resistant elastomers include
127:in the first three materials has a
13:
573:
439:can build up within machines like
417:are ozone resistant, for example.
312:A generalized scheme of ozonolysis
307:
14:
1277:
1205:
1204:
1194:
289:. The pictures were taken using
42:
28:
1038:Tire-pressure monitoring system
562:Rubber Chemistry and Technology
359:, which can oxidise further to
259:Close-up of ozone crack (using
244:formed at sharp corners in seal
567:
554:
521:Forensic materials engineering
1:
1028:Central Tire Inflation System
547:
423:Ozone gas is produced during
378:
367:in the environmental SEM, or
339:EDX spectrum of crack surface
296:
526:Forensic polymer engineering
7:
1149:Tire Science and Technology
669:Low rolling resistance tire
478:
203:(Nitrile Butadiene Rubber)
10:
1282:
452:volatile organic compounds
382:
187:are also ozone-resistant.
1190:
1157:
1129:
1071:
1003:
970:
857:
802:
649:
641:
541:Stress corrosion cracking
237:image of ozone cracks in
326:degree of polymerization
293:for maximum resolution.
990:Slip (vehicle dynamics)
947:Lateral Force Variation
897:Pacejka's Magic Formula
877:Cold inflation pressure
506:Electrostatic discharge
107:in rubber chains, with
1086:List of tire companies
957:Traction (engineering)
952:Radial Force Variation
471:
348:
340:
313:
270:
245:
207:
99:Susceptible elastomers
1261:Materials degradation
937:Tire load sensitivity
580:www.instructables.com
469:
393:to the rubber before
346:
338:
311:
258:
250:stress concentrations
233:
198:
917:Self aligning torque
516:Forensic engineering
486:Applied spectroscopy
1043:Tire-pressure gauge
679:Michelin PAX System
601:, CRC Press (2004).
536:Polymer degradation
1256:Forensic phenomena
1081:Tire manufacturing
912:Rolling resistance
604:Lewis, Peter Rhys
511:Forensic chemistry
472:
456:photochemical smog
437:Static electricity
425:electric discharge
349:
341:
314:
271:
246:
208:
49:Ozone cracking in
1266:Rubber properties
1246:Polymer chemistry
1218:
1217:
907:Relaxation length
784:Formula One tyres
564:, 63(3), 426-450.
117:styrene-butadiene
1273:
1208:
1207:
1200:Outline of tires
1198:
1013:Tire maintenance
962:Treadwear rating
872:Circle of forces
794:Continental tire
734:Orange oil tires
724:Mud-terrain tire
704:All-terrain tire
636:
629:
622:
613:
612:
590:
589:
587:
586:
571:
565:
558:
496:Corona discharge
433:corona discharge
361:carboxylic acids
330:tensile strength
322:molecular weight
191:Form of cracking
161:fluoroelastomers
46:
32:
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1125:
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999:
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942:Tire uniformity
902:Pneumatic trail
892:Ground pressure
887:Cornering force
853:
827:Siping (rubber)
798:
769:Motorcycle tyre
645:
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594:
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572:
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559:
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387:
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299:
213:diaphragm seals
193:
177:Silicone rubber
169:polychloroprene
101:
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1159:Identification
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1127:
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1123:
1121:Ozone cracking
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1103:
1101:Tire recycling
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927:Steering ratio
924:
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847:Schrader valve
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739:Whitewall tire
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574:Wofsey, Mike.
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383:Main article:
380:
377:
298:
295:
287:Nitrile rubber
279:semi-conductor
268:diaphragm seal
242:diaphragm seal
221:Nitrile rubber
205:diaphragm seal
192:
189:
133:Nitrile rubber
121:nitrile rubber
109:natural rubber
100:
97:
70:ozone cracking
51:natural rubber
48:
41:
40:
39:
34:
27:
26:
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22:Ozone Cracking
21:
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15:
9:
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1131:Organizations
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1024:
1021:
1019:
1018:Tire rotation
1016:
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1002:
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988:
986:
985:Groove wander
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882:Contact patch
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867:Camber thrust
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744:Aircraft tire
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674:Run-flat tire
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659:Tubeless tire
657:
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438:
435:for example.
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395:vulcanization
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186:
185:polyurethanes
182:
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171:rubbers like
170:
166:
162:
158:
153:
150:
146:
145:acrylonitrile
142:
138:
134:
130:
126:
122:
118:
114:
113:polybutadiene
110:
106:
96:
94:
90:
86:
82:
77:
75:
71:
67:
63:
52:
45:
31:
1144:Tire Society
1120:
1058:Tire changer
1053:Bead breaker
1023:Bicycle pump
932:Tire balance
842:Presta valve
837:Dunlop valve
779:Racing slick
774:Tractor tire
759:Tubular tire
754:Bicycle tire
684:Airless tire
605:
598:
583:. Retrieved
579:
569:
556:
473:
445:
422:
419:
415:butyl rubber
407:
391:antiozonants
388:
350:
315:
300:
272:
247:
209:
154:
149:Butyl rubber
105:double bonds
102:
78:
69:
59:
1172:Plus sizing
1096:Waste tires
1048:Direct TPMS
1033:Tire mousse
1005:Maintenance
980:Aquaplaning
749:Tundra tire
729:Paddle tire
714:Knobby tire
664:Radial tire
491:Brittleness
441:compressors
411:EPDM rubber
403:antiozonant
385:antiozonant
129:double bond
125:repeat unit
119:rubber and
83:and rubber
1241:Elastomers
1225:Categories
1177:Tire label
1073:Life cycle
995:Tramlining
922:Slip angle
859:Attributes
832:Valve stem
804:Components
789:Spare tire
719:Large tire
585:2020-04-24
548:References
531:Ozonolysis
379:Prevention
303:ozonolysis
297:Ozonolysis
87:, such as
81:fuel lines
62:elastomers
1236:Corrosion
1167:Tire code
1116:Flat tire
1106:Tire fire
1063:Tire iron
972:Behaviors
764:Lego tire
699:Snow tire
694:Rain tyre
501:Corrosion
353:aldehydes
217:pneumatic
141:butadiene
137:copolymer
1231:Polymers
1210:Category
817:Beadlock
709:Bar grip
479:See also
448:sunlight
429:sparking
173:Neoprene
1111:Blowout
1091:Retread
357:ketones
318:ozonide
181:Hypalon
93:O-rings
89:gaskets
373:sulfur
53:tubing
1251:Tires
822:Tread
689:Tweel
651:Types
643:Tires
283:Viton
263:) in
225:ozone
165:Viton
163:like
135:is a
85:seals
74:tires
66:ozone
812:Bead
413:and
399:tire
369:ESEM
291:ESEM
261:ESEM
183:and
167:and
157:EPDM
143:and
91:and
450:on
431:or
427:by
355:or
324:or
275:ppm
265:NBR
239:NBR
201:NBR
139:of
64:by
1227::
578:.
179:,
159:,
115:,
111:,
635:e
628:t
621:v
588:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
