Biomod/2014/UANL/Jesus

From OpenWetWare

Jump to: navigation, search

Chemical Resistance of Polycarbonate Sheets

The mechanism of chemical attack on polycarbonate sheets differs significantly from the mechanism of corrosion of metals.
Corrosion of metals results in a gradual loss of surface material as a result of electrolytic action by the relevant chemicals.
In the cases where chemical attack on polycarbonate sheet occurs, all or a portion of a range of effects can be observed.
Ethylene choride, chloroform, tetrachloroethane, m-cresol, pyridine and other chemicals can cause partial dissolution of
polycarbonate. Swelling agents include benzene, chlorobenzene, tetralin, acetone, ethyl acetate, acetonitrile and carbon
tetrachloride. Additional effects include color change and/or whitening. These effects may not always lead to product
failure, especially for non-loaded sheets. Nevertheless, the level of measured mechanical properties will be reduced.
The most critical effect of chemical attack is stress cracking or crazing, which may range in size from being visible to the
naked eye to being only observable under a microscope. Stress cracks will always result in sheet failure which will eminate
from areas of greatest stress (screws, fixings, bends, etc.)
Polycarbonate sheets are generally not recommended for use with acetone, ketones, ethers, and aromatic and chlorinated
hydrocarbons in addition to aqueous or alcoholic alkaline solutions, ammonia gas and its solutions and amines.
Polycarbonate is resistant to mineral acids, many organic acids, oxidizing and reducing agents, neutral and acid salt solutions,
many greases, waxes and oils, saturated, aliphatic and cycloaliphatic hydrocarbons and alcohols, with the exception of
methyl alcohol. The resistance of polycarbonate to water may be described as good up to approximately 60°C. At higher
temperatures, degradation occurs, the extent of which depends on time and temperature. Polycarbonate should therefore
not be exposed for long periods of time to hot water. However, brief contact with hot water has no effect. For example,
polycarbonate tableware can be washed over 1000 times in a dishwashing machine with no adverse effects being observed.

Physicochemical properties


Enzyme Some inhibitors KM value mM pH optimum pH range Temperature optimum Temperature range
Urease
Canavalia ensiformis
(2-[[(2-[[2-(hydroxy-kappaO)ethyl]amino-kappaN]ethyl)
imino-kappaN]methyl]-4-nitrophenolato-kappaO)
(methoxymethanolato-kappaO)zinc

(2-[[(2-[[2-(hydroxy-kappaO)ethyl]amino-kappaN]ethyl)
imino-kappaN]methyl]-4-nitrophenolato-kappaO)
(nitrato-kappaO)copper


(2E)-3-(1,3-benzodioxol-5-yl)-1-(2-hydroxyphenyl)
prop-2-en-1-one
2.7 5.5 5.5-7 25 NR
Catalase
Bos taurus
2-mercaptoethanol, 3-amino-1H-1,2,4-triazole, dinitrosyl iron complex,  Glutaraldehyde,  hydroxylamine,  NaCN 28.6 7 6-7.5 25 25-35
Uricase
Arthrobacter globiformis
8-Azaxanthine, Cu2+, 0.075 8.5-9.5 6-9.5 30 25-40

References
Polycarbonate membranes Enzymes proerties

Personal tools