Poly weathering tests

AB-type polycondensations, 330 AB-type polymers, 135 Accelerated weathering tests, 245 Acceptor-catalytic polyesterification, 75 4-Acetoxy benzoic acid, poly esterification of, 74... 

Prevention of Soil Crusting. Acid-based fertilizers such as Unocal s N/Furic (a mixture of urea with sulfuric acid), acidic polymers such as FMC s Spersal (a poly(maleic acid) derivative originally developed to treat boiler scale) (58), the anionic polyacrylamides described previously, as weU as lower molecular weight analogues such as Cytec s Aerotil L Soil Conditioner, have all been used successfully in at least some circumstances to prevent the formation of soil cmsts. It is difficult to prove benefits in the laboratory, and field tests may give variable results depending on local weather conditions. 

We surveyed and screened a number of candidate glazing matmals (5,6), which include a varirty of polyesters, fluoropolymers, and polycarbonates (PC), as well as acryhc, polyetherinride, poly ylene (PE), polystyrene, and polyvinyl chloride. Bas on accelerated screaiing tests, we find that fluoropolymers and acrylic arc UV weatherable, and all other materials tested lose transmittance and yellow. However, fluoropolymers are relatively expensive and realistically would be limited to use as thin-film glazings. Acryhc tends to be too brittle and exhibits thomal sag as a glazing candidate for solar collector apphcations. 

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