Ageing test

Artificial ageing test methods simulate the behaviour of the cured adhesive in the bonded joint under environmental influences. The exposures are for example heat, cold, moisture, chemicals or UV-radiation and their combinations. Each ageing test method defines the duration of exposure, exposure temperature, type and concentration of chemicals and joint design. 

Numerous cyclic ageing tests are defined, such as for example VDA cyclic ageing test or P1210 cyclic ageing test. According to the experience of vehicle manufacturers and to the authors experience, the adhesion of elastic bonding 

In practice, a bead is appiied to the substrate and a sequence of ageing storage conditions is carried out, whereas after each storage test the bead is peeied off from the substrates (Fig. 22). With a gripper the bead is ciamped and peeied vertical to the horizontai iying substrate by cutting the peeled bead near to the substrate with a knife. 

Further, the adhesive is exposed for 1 day to heat at 80°C and up to 5000 h of UV-radiation. The requirements are that the peeling tests result in more than 75% cohesion failirre. 

Even if no values for peel strength are measured, this peeling test shows very sensitive adhesion or cohesion failure, which sometimes are the only criteria to be checked. Remember, the mechanical values of the adhesive can be determined by other methods. If cohesion failure occurs, the result is generally good. If there is an influence of humidity and temperature on the adhesion, this peeling test will usually show it. 

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Long-term heat-aging tests on Tefzel 280 are in progress. It is expected that its continuous-use temperature will be above 150°C. 

Use isothermal aging tests to monitor stability at desired drying temperature... 

Elevated drum Evaluate thermal stability parameters of material temperatures (isothermal aging tests, SADT, etc.) reaching Self, Keep drums away from source of heat Accelerating Decomposition store at required temperature Temperature (SADT). CCPS G-15 CCPS G-22 CCPS G-29 CCPS G-30... 

This is an alternative to the ageing test and is applicable for shunt capacitors of 1000 V and above. It is an in-house process test and is carried out on the capacitor elements before they are assembled into a capacitor unit to ascertain their dielectric stability against repeated overvoltages. For the test procedure refer to lEC 60871-2. 

Shunt power capacitors of the self healing type for a.c. systems having rated voltage up to and including 1000 V Ageing test, self-healing lest and destruction lest 13.341/1992 BS EN 60831-2/1996... 

A different variety of copolymer has been prepared by Gramain and Frere who treated 1,10-diaza-l 8-crown-6 with the bisglycidyl ether of bisphenol A. The reaction was conducted at reflux in a mixture of THF and methanol. The polymer, illustrated in Eq. (6.24) was formed 83% yield. The polymer was appparently quite stable, surviving aging tests conducted over a two-year period. 

The accelerated aging test should take into account the associated materials as well as the atmosphere that will be encountered in actual use, since they are also controlling factors. It is helpful to include materials of known performance against which to rate the new material, since this allows a check of controlling factors and further validates the extrapolation. Thus, existing data from long term tests may be of considerable value. 

Modeling. There is as yet no rapid simulated laboratory aging test for catalysts that is recognized as a good predictor of catalyst aging in the vehicle. 

Report 84 Rheology and its Role in Plastics Processing, P. Prentice, The Nottingham Trent University. Report 110 Long-Term and Accelerated Ageing Tests on Rubbers, R.P. Brown, M.J. Forrest and G. Soulagnet, Rapra Technology Ltd. 

The most common test used to study the oxidation resistance of mbber compounds involves the accelerated aging of tensile dumbbell samples in an oxygen-containing atmosphere. Brown et al. [22] recently reviewed long-term and accelerated aging test procedures. The ASTM practices (D 454 (09.01) D 865 (09.01) D 2000 (09.01, 09.02) D3137 (09.01) D 572 (09.01) D 3676 (09.02) D 380 (09.02)) for these tests clearly state that they are accelerated tests and should be used for relative comparisons of various compounds and that the tests may not correlate to actual long-term... 

Thomas, R. E. Gaines, B. G. "Methodology for Designing Accelerated Aging Tests for Predicting Life of Photovoltaic Arrays" Department of Energy/National Bureau of Standards Workshop on Stability of Thin Film Solar Cells and Materials, Washington, D.C., May 1-3, 1978. 

Many researchers have found that differences in film deposition techniques and deposition parameters profoundly influence the oxidation and stability of MO layers. For example, increases of Ar pressure and bias voltage, leading to more porous structures, result in easier oxidation and quicker changes in aging tests [168-172], Such films are particularly corrosion-prone. 

Prevedel B., Wohlgemuth L., et al. The C02SINK boreholes for geological C02-stor-age testing. 2009 Energy Procedia 1 2087-2094. 

These findings clearly illustrate how the results of so-called "accelerated-aging" tests can be affected by the high temperatures in ordinary xenon- and carbon-arc equipment and can, therefore, lead to erroneous conclusions regarding the photochemical behavior of materials at near-normal temperatures (23). 

M. Regert, S. Colinart, L. Degrand, O. Decavallas, Chemical alteration and use of beeswax through time accelerated ageing tests and analysis of archaeological samples from various environmental contexts, Archaeometry, 43, 549 569 (2001). 

Figure 7.2 Summary of the main chemical transformations undergone by beeswax during accelerated ageing tests. Reprinted from Archaeometry, 2001, 43, 549 569, Regert, Col inart, Degrand and Decavallas, with permission from Wiley Blackwell...

An electrically heated oven supplied with circulating kit, originally used in accelerated ageing tests. 

Firing experiments induced thermal transformations on the ochre-precipitates. From these experiments, hematite and a well crystalline arsenate resulted. This indicates that arsenic may be scavenged by an arsenic-rich compound, freshly formed during the initial stages of the water treatment. This is in agreement with the results obtained by Jia Demopoulos (2008), when performing aging tests on solids precipitated from As(V)-Fe(lll) solutions. 

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