Weather-Ometer

Quality Control and Testing. Control of inks is done by examining their color strength, hue, tack, rheology, drying rate, stabiHty, and product resistance. Elaborate control equipment and laboratory testing procedures are employed to test the finished inks. Weather-Ometers,... 

Fig. 5. Effect of uv exposure on nylon-6,6 yam tenacity and whiteness with and without copper salt and alkah haUde in polymer scoured 210-denier 34-filament yams exposed in Xenon-arc Ci65 Weather-Ometer using radiation intensity of 0.55 W/m at a wavelength of 340 nm. Exposure from 0 to 800...

In an attempt to accelerate testing, higher irradiances were employed in the Weather-Ometer . Reciprocity is a necessary condition for this acceleration to be... 

Figure 18.1 Effect of Weather-Ometer exposure (0.35W/m2/nm) for color of materials [2]. From Weathering of polyester and copolymer sheeting, presentation given by D. R. Fagerburg at the Atlas School for Natural and Accelerated Weathering (ASNAW) course, Miami, FL, May 1999, and reproduced with permission of Atlas Electric Devices Company...

Figure 18.2 Effect of Weather-Ometer reciprocity testing at high (0.70 W/m2/nm) and low (0.35 W/m2/nm) for color of Spectar copolymer and Spectar UV sheeting [7a]. From Fagerburg, D. R. and Donelson, M. E., Effect of water spray and irradiance level on changes in copolyester sheeting with xenon arc exposure, ANTEC 98 Conference Proceedings, Paper 808, Atlanta, GA, April 30, 1998, and reproduced with permission of the Society of Plastics Engineers...

The black panel temperature is measured with a thermocouple mounted on a flat black painted panel which is placed on the sample rack of the Weather-Ometer. As such, the temperature registered is meant to indicate a maximum temperature of the specimens under the same irradiation. 

Figure 4.124 shows two examples of the retention of tensile strength and elongation at break for a film exposed to the Weather-Ometer. 

LCPs are slightly altered by one year of outdoor exposure, with a light surface chalking, but after a 2000 h exposure in a Weather-Ometer, retention of mechanical properties is superior to 90%. 

The effect of ultraviolet (UV) light on aliphatic clear polyurethanes or aromatic polyurethanes that have had UV stabilizers added can be evaluated using Weather-Ometer . The tests are performed to ASTM D750 or to ISO 4665/3. 

All three modified celluloses, as well as the nonoxidized starting sample, were exposed to uv light for various periods of time using a Weather-Ometer. The light source in the Weather-Ometer was a xenon... 

Light Exposures. Silk fabric samples, 0.25 m x 0.17 m, were mounted in Atlas Electric Devices aluminum sample holders according to AATCC Test Method 16E-1982 (7). An Atlas Ci-35 Weather-Ometer xenon-arc was used on continuous light cycle. Exposures were conducted at an irradiance of 0.35 W/m2 measured at 340 nm and the irradiance was monitored and controlled automatically. Borosilicate inner and outer filters were used to simulate the solar spectrum. The relative humidity was maintained at 65% and the black panel temperature was 50°C. The actual fabric temperature during the irradiation was measured, using small thermocouples threaded into the fabric, and was found to be 35 C. Control samples for these tests were kept in the dark at 35°C and 65% RH for the same time period as the illuminated samples. 

Figure 22.6. Accelerated weather testing, (a) Xenon arc Fade-Ometer. (Courtesy of Atlas Electric Devices Company.) (b) Fluorescent lamp QUV accelerated weathering tester. (Courtesy of Q-Panel Company.) (c) Xenon arc Weather-Ometer. (Courtesy of Atlas Electric Devices Company.)...

To determine the stability of the resin color, samples were exposed to UV in an Atlas Xenon Arc Weather-ometer. Samples previously tested for dry shear strength and samples of the cured, neat resin were exposed for 100 and 200 hours in the weather-ometer. One hundred hours of exposure is approximately equivalent to 1 year of exposure to sunlight at the latitude of Chicago. The resin was the same color as the wood or lighter after both lengths of exposure. 

The persistence of outdoor mechanical integrity depends on the concentration of the ketone comonomer and its specific structure, e.g., the nature of Ri and R2. The time-to-embrittlement of Ecolyte PS and PE in our Weather-Ometer exposures are listed in Tables I and II. 

A 6000W xenon arc Atlas Weather-Ometer (] ) equipped with Corning No. 77 +0 horosilicate inner and outer filters was used as a laboratory light source because its emission spectrum is similar to that of sunlight, as illustrated in Fig. 1. The Weather-Ometer was operated with the lamp on continuously and the exposure chamber was maintained at a black panel temperature of ll+5 5°F and a relative humidity of 30 5. ... 

Degradable Low-Density Polyethylene (LDPE) Films. Typical xenon arc embrittlement times for unstabilized low-density polyethylene are l600-2UOO hrs. The controls chosen for this research are listed in Table II the thin LDPE garment bag embrittled in 1820 hr and the EcoPlastics LDPE control became brittle after 2075 hr xenon irradiation. The thin garment bag was not brittle, as determined by a fold test, after 18 months outdoor exposure. The Dupont "Sclair" LDPE control listed in Table II was unusual since it had short embrittlement times of 1175 hr in the Weather-Ometer and 6.5 months outdoors. This film was used as a yardstick to measure the Degradable LDPE films since a Degradable Plastic should not last more than 6 months, perhaps less, outdoors and 1200 hr in the xenon arc Weather-Ometer. 

Ecoten LDPE embrittled in 2210 hrs in the Weather-Ometer and 11 months outdoors. This sample of Ecoten does not appear to be a satisfactory Degradable Plastic because of the high level of Ti02 added to the film. Clear Ecoten film without the titanium dioxide pigment was tested outdoors in Israel as agricultural mulch and found to embrittle in less than four months ( ). 

The Ecolyte LDPE films are numbered in relation to the concentration of photosensitive vinyl ketone comonomer present in the polymer ie. 1>>2>3. The Ecolyte 1 LDPE containing the most vinyl ketone comonomer was brittle in 820 hr in the Weather-Ometer and 2.5 months outdoors. The Ecolyte 2 was brittle in Il80 hr and the Ecolyte 3 required ll+65 hr while the EcoPlastics Ltd. LDPE control required 2075 hr xenon arc irradiation to reach embrittlement. This series of Ecolytes demonstrates the varied and controlled lifetimes that can be designed into Degradable Plastics by controlling concentration of the photosensitizer. 

Atlas Fade-Ometer and Weather-Ometer Bulletin 1300 Figure L Energy distribution, as a function of wavelenglth, of a hi pressure xenon arc lamp and noon summer sunUght (4)... 

Figure 2. IR and tensile changes PmPiPA photodegradation. Xenon arc Weather-Ometer stress-strain data 44 tex, 2 ply yam Nomex. A A> vacuum irradiated 0, air irradiated. Initial elmga-Hon at break, 30%, Initial tensile strength, 9,0 X 10" g cmr, IR data lOfi films, Trans, + IRS, x(dp = 0.55/ij.

Figure 4. IR and tensile changes PET photooxidation. 21/1 Mylar film, irradiated Xenon arc Weather-Ometer. Initial elongation at break, 190%. Initial tensile strength, 7.3 X 1(P g cm. dp = depth of penetration for IRS ir spectra.

Figure 5. IRS ir spectra of air irradiated PPiPA films. Ge reflection element, 45 incidence. Film surface directly irradiated for specified times with Xenon arc Weather-Ometer. Ge curve due to reflection element alone (8).

Figure 7. Surface changes during PP photooiadation electron micrographs. A, 24 hr irraduUion flm and irrcSUation conditions in Figure 2. B, llSp. PP monoifilameta, ftMy oriented. C, D—130fi PP monofilament, medium orientation. B and D—19S hr, C— 275 hr. Xenon arc Weather-Ometer.

Figure 8. Scanning electron micrographs of photoondized PmPiPA. lOOn film, 120 hr Xe arc Weather-Ometer irradiated on side X. Flexed as shown. Ri t, fracture surface left, section U 90° to fkxjdirectUm (23).

Five replicate specimens of western redcedar and their longitudinally end-matched controls were artificially weathered (xenon arc Weather-Ometer, approximately 24-h light and 4-h deionized water spray daily). The Weather-Ometer was shut down for about 1 h Monday through Friday in order to soak the specimens in dilute acid for 15 min. Six types of acid soaks were used nitric and sulfuric acids at pHs of 3.0, 3.5, and 4.0. I found similar results with both acids. Compared with the unsoaked controls, the 3.0 pH acid caused a 10% increase in erosion rate. At a pH of 3.5 the effect was a 4% increase due to the acid, and no effect was found at a pH of 4.0. 

Atlas Weather-Ometer described In reference 2. Samples were exposed 50 cm from a bare carbon arc (no filters) and with a 90 sector immediately preceedlng the water spray blocked off by a metal baffle to simulate night conditions. 

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