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The persistence of these compounds is due to the high resistance to oxidation, reduction, addition, elimination and electrophilic substitution. [6] The toxicological interactions of PCBs are affected by the number and position of the chlorine atoms, without ortho substitution are referred as coplanar and all others as non-coplanar. [ 5 ]
By definition, biodegradable materials are formed or organic compounds which can thus be broken down by living organisms, such as bacteria, fungi, or water molds, and reabsorbed by the natural environment. [13] Whether a material is biodegradable is determined by its chemical structure, not the origin of the material from which it is made. [14]
The polymerization can take place in a non-polar solvent (in which case the polymer forms as a slurry) or in neat trioxane (e.g. in an extruder). After polymerization, the acidic catalyst must be deactivated and the polymer stabilized by melt or solution hydrolysis to remove unstable end groups.
These compounds are also precursors to the commercially important non-ionic surfactants alkylphenol ethoxylates and nonylphenol ethoxylates, which are used in detergents, paints, pesticides, personal care products, and plastics.
A molecule may be nonpolar either when there is an equal sharing of electrons between the two atoms of a diatomic molecule or because of the symmetrical arrangement of polar bonds in a more complex molecule. For example, boron trifluoride (BF 3) has a trigonal planar arrangement of three polar bonds at 120°. This results in no overall dipole ...
This compound is moderately toxic to humans, whilst being highly toxic to aquatic organisms. Tetrabromodiphenyl ether (tetraBDE) and pentabromodiphenyl ether (pentaBDE) are industrial chemicals and the main components of commercial pentabromodiphenyl ether (pentaBDE). This pair of molecules have been detected in humans in all regions of the world.
A wide variety of non-biodegradable polymers have been used for orthopedic applications including silicone rubber, polyethylene, acrylic resins, polyurethane, polypropylene, and polymethylmethacrylate. The primary role of many of these polymers was to act as a biocompatible cement in the fixation of prostheses and in the replacement of joints.
Lipophobicity, also sometimes called lipophobia (from the Greek λιποφοβία from λίπος lipos "fat" and φόβος phobos "fear"), is a chemical property of chemical compounds which means "fat rejection", literally "fear of fat". Lipophobic compounds are those not soluble in lipids or other non-polar solvents. From the other point of ...