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ofi – Sports Technology1
ISSS TM Vienna – Aging - Binder
ISSS Technical Meeting Vienna 2004
(Artificial) Aging of Synthetic TurfBy Konrad Binder
Consultant
ofi – Technologie & Innovation GmbH, Vienna
ofi – Sports Technology2
ISSS TM Vienna – Aging - Binder
Com parative Exam inations under D ifferent W eathering Conditions
Eduard PO HLELeopold KRANNER
1st European Weathering Symposium EWS – Prague 2003XXIII Colloquium of Danubian Countries on Natural and Artificial Ageing of Polymers
ofi – Sports Technology3
ISSS TM Vienna – Aging - Binder
Most relevant European Documents and Standardsconcerning Artificial Weathering
CEN/TC 217/WG6 N 560 (9th draft, 2002-12):Surfaces for Sports areas
Synthetic turf for Football, Hockey, Tennis and Multi-Sportsprimarily designed for outdoor use
Specification
CEN: prEN 14836: Synthetic surfaces for outdoor sports areas –Method of test – Artificial weathering
(EN) ISO 4892: Plastics - Methods of exposure to laboratory lightsources:
Parts 1- 4
ofi – Sports Technology4
ISSS TM Vienna – Aging - Binder
Content of prEN 14836 – Special Features and Aspects(based on recent German version)
Normative References (among others):(EN) ISO 4892:Plastics - Methods of exposure to laboratorylight SOURCES –
Part 1: General guidancePart 2: Xenon arc sources.Part 3: Fluorescent UV lamps – (no reference – just forgotten?)
Pinciple: Test pieces are exposed to artificialweathering... colour and selected physicalproperties are determined.Light source: UV-A 340 nm lampsExposure Chamber
Temperature and irradiation controlaccording to ISO 4892-1Spraying with water or wetting by ahumidity condensing mechanismaccording ISO 4892-2 and –3.
Exposure conditions (recommended)4 h dry UV exposure at a black-standard temp. of 55±3 °C2 h of condensation exposure, withoutradiation, black stand. temp. 45±3 °C(this cycle is not listed in ISO 4892-3)
Procedure: No obligatory time or otherconditions.Measuring / Expression of results
Colour changes according to ISO 7724and ISO 105-A02Physical properties (change in %):
MeasuresTensile strengthFrictionShock absorptionVertical (?) Deformation
ofi – Sports Technology5
ISSS TM Vienna – Aging - Binder
Discussion of prEN 14836 – Questions
Some of the main flaws should beeliminated, e.g.:
Simply by reference to EN ISO 4892-3Especially the irradiance on the face ofthe samples must be specified exactly.
Selection of properties for evaluationShould be left to the relevantspecification of the special sportssurface.This has been done already in thepaper N 560 specifying synthetic turf:
Tensile strength (of fibre).Colour fastness
Checking other properties (as acriterion) seems to be useless
Further open questions:Aging of rubber granulesAging of EPDM granulesHow can we achieve sufficientrepeatability of the results ?How can we find out the statisticaltolerances ?(which could be extremely high).
Finally once more the question:Can „perfect“ correlation to naturalweathering really be achieved by theUV-A lamps ?Or do we need the well-tried andapproved Xenon arc ?
ofi – Sports Technology6
ISSS TM Vienna – Aging - Binder
Outdoor and Artificial Aging of Polymers - Basics
Main agents of outdoor Aging:Sun light (short-wave UV)OxygenHeatWaterFrost-dewMechanical stress,abrasion
Main effects of aging onchemical structure
Oxidation(foto-, thermoxidation)Chain-break anddegradation
Change of material performanceLoss of elongation at breakLoss of tensile strength
→ brittleness→ increasing abrasion
Loss of colour
Change of sports performance:Long-term effect is a consequenceof many other factors as well.
ofi – Sports Technology7
ISSS TM Vienna – Aging - Binder
Search for test methods for Polyethylene and Polypropylene
These polymers are similar, both arepolyolefins.
Aging by weathering is a very complexchemical process and the polyolefinsare very senitive to degredation by UV,oxygen and high temperatures.
Therefore the polymers must have highquality and a high quality UV stabilizersystem (including effect of heat).
How can this quality be verified ?
By means of an effective and reliable testmethod taking into account the specialstructure of the relevant polymers !
.
ofi – Sports Technology8
ISSS TM Vienna – Aging - Binder
Ultraviolet and Visible Part of Sunlight
Wavelength [nm]
Spec
tral
irra
dian
ce
Visible light
UV-area
ofi – Sports Technology9
ISSS TM Vienna – Aging - Binder
Spectral Irradiance of Xenon Arc Lamps
- Sunlight - Filtered Xenon arc irradiance
Spec
tral
irra
dian
ce [W
/m²/n
m]
Wavelength [nm]
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ISSS TM Vienna – Aging - Binder
Spectral Irradiance of Fluorescent UV-Lamps S
pect
ral i
rrad
ianc
e [W
/m²/n
m]
Wavelength [nm]
Sunlight
UVA-340
UVB-313
ofi – Sports Technology11
ISSS TM Vienna – Aging - Binder
Principle of UV-Weathering Device
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ISSS TM Vienna – Aging - Binder
Effects of Brittleness Caused by Outdoor Weathering
PE-HD slab: 9 years exposed in vienna
PP-Films withdifferentstabilizers.
Exposed 450days in Vienna.
Start: Summer
Results oftensile strengthtests
stress
strain
ofi – Sports Technology13
ISSS TM Vienna – Aging - Binder
Artificial Aging of PP-Fibres in QUV-ChamberIST - Kolitzus
Direct exposure of separated fibres showed damage – as on site
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ISSS TM Vienna – Aging - Binder
Artificial Weathering of Polypropylen Materials:Change of Tensile Strength
05
1015202530354045
0 285 570 850
Duration of radiant exposure [h]
Tens
ile s
treng
th [M
Pa]
Xenon arc lamps,material 1Fluorescent lamps,material 1Xenon arc lamps,material 2Fluorescent lamps,material 2Xenon arc lamps,material 3Fluorescent lamps,material 3Xenon arc lamps,material 4Fluorescent lamps,material 4
ofi – Sports Technology15
ISSS TM Vienna – Aging - Binder
Artificial Weathering of Polypropylen Materials:Change of Elongation at Break
05
1015202530354045
0 285 570 850
Duration of radiant exposure [h]
Tens
ile s
train
at b
reak
[%]
Xenon arc lamps,material 2Fluorescent lamps,material 2Xenon arc lamps,material 3Fluorescent lamps,material 3Xenon arc lamps,material 4Fluorescent lamps,material 4
ofi – Sports Technology16
ISSS TM Vienna – Aging - Binder
Artificial Weathering of Synthetic Turf:Austrian Test Method
Preparing of fibres for tensile test specimens(if necessary glued between acrylic clamps)
Artificial aging (7500 MJ/m²) according toDIN 53 387 (ISO 4892-2)(EN ISO 4892-3 ?)
Tensile strength tests according to EN 13864Requirements for elongation at break and strength:
Retained values ≥ 50 % (of initial values)(Colour fastness: ≥ 3 grey scale)
ofi – Sports Technology17
ISSS TM Vienna – Aging - Binder
PTFE
Requirements for the testmethod concerned:
High acceleration byartificial weatheringGood correlation tooutdoor weatheringGood quantifiable resultsof damages by artificialweatheringCost effectiveness
PE-HD Space filling model
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ISSS TM Vienna – Aging - Binder
Weathering Chamber Fitted w/ Xenon Arc Lamps
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ISSS TM Vienna – Aging - Binder
Which light source for artificial weathering ?
The main problem is a goodbalance of A and B. The „heart“ ofevery weathering device is the„artificial sun“ - most successfulexamples:
Xenon arc *)UV fluorescent lamp *)Carbon arc lampMetal halide emitter.
For plastics, there is sufficientexperience with these two *) lightsources only.
.
PA-6.6 Space filling model
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ISSS TM Vienna – Aging - Binder
Labosport – internal study for tropic islands
CalorimetryStudy Nr.AppearanceForce (N) Losses (%) Melting heat (°C)
1 Fibrillée 53.2 -27.6 -0.32 Fibrillée 42.0 -32.7 -0.93 Fibrillée 26.3 -25.6 0.04 Fibrillée 34.1 -29.4 -0.86 Fibrillée 26.6 -24.3 -0.29b Fibrillée 7.3 -17.3 -0.4
9a Monofil 6.0 -43.9 -0.9
5 Monofil 13.8 -58.1 -2.77 Monofil 11.1 -57.1 -2.88 Monofil 13.9 -72.6 -4.510 Monofil 16.4 -75.8 -4.2
Fibers after ageing (UV B lamps) 2 500 hoursForce at break in N (after ageing)losses related to the force before ageingMelting point : difference between the temperature after and before ageing
Polyeth
ylen
Tensile strength
Copolymer
Good correlation between the results on site (8 month) and artificial aging