Weathering and Aging

The aging of polymers causes changes in their physical and chemical properties, often to the point of material failure. Anti-corrosion coatings, resin based composites for wind turbines, parts of cars, trains or airplanes and many consumer products demand high long life stability. For this reason the examination of long-term stability and service life time prediction for polymers in exterior applications is highly important.

We offer examination methods for simulated weathering, for climatic storage and thermal aging.

For the simulated weathering in the laboratory, Xenon arc Weather-Ometer of the type Ci4000, Xenotest Alpha+ and Suntest XLS+ from Atlas Material Testing Technology are available. UV-Testing can be performed by a UV-Tester from QLab. We carry out standardized tests as well as tests with weathering cycles according to customer specifications. As long test durations cause high costs and delay developments, shorter testing procedures have long been of great interest to the industry. This can be achieved by tailor-made weathering cycles and conclusive early detection methods, which we develop and provide to our customers.

We offer weathering tests according to following standards:

WoM Ci4000

  • AATCC TM16-1998, AATCC TM16-2004, AATCC TM169
  • ASTM C1442, ASTM D2565, ASTM D3424, ASTM D4303, ASTM D4355, ASTM D4459, ASTM D4798, ASTM D5071, ASTM D6551, ASTM D6695, ASTM D904, ASTM E1596, ASTM G151, ASTM G155, ASTM D7869-13
  • FLTM BI 160-01
  • GME 60292
  • GMW 14162, GMW 3414
  • DIN EN ISO 105-B02, DIN EN ISO 105-B04, DIN EN ISO 105-B06, DIN EN ISO 105-B10, DIN ISO 12040, ISO DIN 3917, DIN EN ISO 4892-1, DIN EN ISO 4892-2
  • JASO M346
  • MIL-STD 810F, MIL-STD 810G
  • PV 1303, PV 3929
  • SAE J2412, SAE J2527
  • VDA 621-429, VDA 621-430, VDA 75202
  • VW PV 3930

Xenotest Alpha (Testing small series)

  • AATCC TM16-2004, AATCC TM16.3, AATCC TM169
  • ASTM D6695, ASTM G151, ASTM G155
  • GME 60292
  • GMW 3414
  • IEC 60068-2-5
  • DIN EN ISO 105-B02, DIN EN ISO 105-B04, DIN EN ISO 105-B06, DIN EN ISO 105-B10, DIN ISO 12040, DIN EN ISO 16474-2, ISO DIN 3917, DIN EN ISO 4892-1, DIN EN ISO 4892-2
  • JASO M346
  • M&S C9, M&S C9A
  • MIL-STD 810F
  • SAE J2019, SAE J2212
  • VDA 75202
  • VW PV 1303, VW PV 3929, VW PV 3930

Suntest XLS+ (mit Suncool-Option)

  • ASTM D3424, ASTM D5071, ASTM D6695, ASTM G151, ASTM G155
  • ICH Guideline G5C
  • ISO 10977, DIN EN ISO 11431, ISO 11979-5, ISO 4049, DIN EN ISO 4892-1, ISO 4892-2, ISO 7491

QUV-Bewitterungstester

  • AATCC TM186
  • ASTM C1257, ASTM C1442, ASTM C1501, ASTM C1519, ASTM C732, ASTM C734, ASTM C793, ASTM D1148, ASTM D1670, ASTM D3424, ASTM D3451, ASTM D4101, ASTM D4329, ASTM D4434, ASTM D4587, ASTM D4674, ASTM D4799, ASTM D4811, ASTM D5208, ASTM D5894, ASTM D6577, ASTM D750, ASTM D882, ASTM D904, ASTM D925, ASTM E3006, ASTM F1164, ASTM F1945, ASTM G151, ASTM G154
  • EN 13523-10 (DIN)
  • GM 9125P, IEC 61215, IEC 61345
  • DIN EN ISO 11507, DIN EN ISO 29664, DIN EN ISO 4892-1, DIN EN ISO 4892-3
  • SAE J2020

 

The air-conditioned storage of parts, test specimens and unprocessed materials is an essential requirement for reproducible testing.

© Weiss Umwelttechnik GmbH

Following climate test chambers from WEISS Umwelttechnik are available for climate testing:

  • WK 600
  • WK 11-180

Climate testing is carried out at relative humidities (RH) between 10 %RH to 95 %RH and at temperatures between 10 °C and 95 °C. Thermal ageing can be carried out in a range from -40°C to 180°C.

Standardized conditioning, for example, is followed through after:

  • DIN EN ISO 291
  • DIN EN ISO 1110

Testing for thermal aging, temperature-humidity cycling and resistance to humidity are also carried out accourding to standardized procedures.

For accompanying tests, a variety of physical and chemical characterization methods are available. Among these are testing methods according to industry standards, such as:

  • Cross cut tests
    Cutting distance 1mm, 2mm, 3mm (0-250µm)
    ISO2409:2007, ASTM D3002 / D3359
  • Color- and gloss measurements (Instruments: spectro-guide sphere gloss, BYK-Gardner GmbH)
    Color: ASTM D 2244, E 308, E 1164, DIN 5033, 5036, 6174, DIN EN ISO 11664, ISO 7724
    Gloss: ASTM D 523, D 2457, DIN 67530, ISO 2813, 7668
  • Transparency  (Instrument: Haze-Gard plus, BYK-Gardner GmbH)
    ASTM D 1003, ISO 13468

Monitoring of Ageing and Degradation (german)

For aging polymers, a wide variety of interplaying physical and chemical processes take place. For the prediction of service life time, these processes must be known, understood and implemented in models.

In the division Plastics at Fraunhofer LBF, appropriate measurement and testing techniques to comprehend polymer aging and the associated expertise are available. For example: ultrasonic measurement techniques and NMR-sensors were integrated in weathering devices, which allows to follow the in-situ changes of the material properties and to optimize the weathering cycles. Non-destructive examination of weathered polymer coatings is conducted with scanning acoustic microscopy. Structural elucidation with imaging and scattering techniques, dynamic mechanical analysis or differential scanning calorimetry complement these specialized testing methods. To grasp the changes of chemical properties, methods such as the determination of molar mass and optical spectroscopy are used.

By increasing the radiation intensity during artifical weathering, material properties can change faster and damage can occur after shorter weathering periods. This enables faster and more cost-effective weathering tests.

If the radiation intensity is intensified, it must be ensured that the material properties essential for the product change proportionally with the UV‑dose. By weathering plastic products with different radiation intensities – e. g. with 60 W/m², 120 W/m² and 180 W/m² - the proportionality between UV‑dose and changes in properties can be tested.

The upper figure shows schematically the decrease of a material property – for example gloss or tensile strenght – for arbitrarily chosen different radiation intensities. In this example, the material property changes intensity-dependently with the duration of weathering. The figure below shows the material property as a function of the radiation dose, which is calculated from the product of intensity and time. It becomes clear that the property changes uniformly with the radiation dose, independent of intensity.

If it is proven that the change in properties depends only on the radiation dose (and not on the radiation intensity), the radiation intensity can be increased and thus the duration of weathering is reduced. However, it is recommended that comparative experiments are carried out using standard-compliant weathering and outdoor weathering. If mechanisms other than photodegradation, such as hydrolysis, thermal or thermo-oxidative ageing or stress cracking due to shrinkage or swelling dominate the ageing behaviour of the plastic, an intensification of the radiation intensity does not allow reliable weathering results to be expected. A realistic acceleration can then only be achieved by a more complex approach to optimizing weathering cycles.

Investigations into the meaningful intensification of radiation can be carried out at Fraunhofer LBF for specific plastics and coatings.