Hydrofluorocarbon solvents, polymer

Polymer Synthesis using Hydrofluorocarbon Solvents Synthesis of Cross-Linked Polymer Microspheres by Dispersion Polymerization in R134a... 

Hydrocarbon aerosol hair sprays contain an alcohol-hydrocarbon solvent-propellant system, a synthetic polymeric resin, a base to neutralize the resin if it is a carboxylic acid-containing resin, plasticizer(s), fragrance, and, in some cases, surfactant(s) to improve the spreading characteristics of the polymer. Most of the new low-VOC aerosol hairsprays contain alcohol-water as the solvent system and dimethyl ether as the propellant. Together the alcohol-dimethyl ether content must be below 55% (54.5%). For cost considerations, dimethyl ether is the propellant of choice, although Hydrofluorocarbon 152-A is exempt as a VOC and provides acceptable, but expensive formulations with previously used resins [54]. In Europe and other parts of the world, there are no VOC limits, and hydrocarbon-alcohol systems with virtually no water are widely used. 

The production of many solvents traditionally used to clean for oxygen service is being phased out. The cost of these solvents and their disposal is rapidly increasing as a result. However, many new solvents are being developed specifically for cleaning and are becoming commercially available. These include terpenes, aliphatic hydrocarbons, alcohols, esters, hydro-chlorofluorocarbons, hydrofluorocarbons, and silicone-based solvents. Solvents must be tested for material compatibility, particularly with regard to any polymer components in the equipment to be cleaned. 

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