Using Polymers in Vehicles

The persistence of polymers in the environments is useful for long term durability of structures such as buildings, vehicles, docks, boats and navigation aids. Unfortunately, when the polymers are unintentional byproducts of recreational or commercial activities, collateral wildlife loss may result from entanglement in packaging materials, lost nets, lines and ropes. These wildlife losses due to litter have received significant public visibility. The critical degradation to address this... 

Polyimide (PI) caps all other polymers in its temperature range of use (-200 to 260 °C in air short-time even up to 500 °C). Because of its high price, it is used in special cases only, such as space vehicles, nuclear reactors and some electronic parts. Newer developments, related to polyimide, are the polyether imides (e.g. Ultem ), polyester imides and polyamide imides (e.g. Torlon ), all with very good mechanical, thermal and electrical properties and self-extinguishing. 

Binders bind pigments to surfaces. They solidify by drying, cooling, or reacting to produce polymers. Acrylic paints use polymer resins as vehicles. They can be thinned with water, but dry readily. Drying agents aid in the evaporation of a vehicle or help paint mixtures to polymerize. 

Polyimides have also been the subject of many review compilations of papers and continue to be the focus of many conferences around the world [28-33]. Having various chemical forms, including isoimides, polyimides have found use in a vast array of applications that in some cases, due to their superior physical characteristics have displaced epoxies, for example, as matrix polymers in aerospace vehicles. 

For the processing of polymer dispersions in hydrocarbons, equipment constructed of Type 316 stainless steel is generally used. Where the vehicle is an alcohol such as methanol, or water containing traces of metallic chlorides, the use of equipment constructed of Monel or nickel is generally considered more suitable. Both of the centrifuges described above are available with any of these materials as parts in contact with the process material. 

Corn oil is used primarily in pharmaceutical formulations as a solvent for intramuscular injections or as a vehicle for topical preparations. Emulsions containing up to 67% corn oil are also used as oral nutritional supplements see also Section 18. When combined with surfactants and gel-forming polymers, it is used to formulate veterinary vaccines. 

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