Polyacrylonitrile solubility parameter

Polymers containing long alkyl side chains are likely to have good resistance to water and alcohol since the solubility parameters of the polymer and solvents are quite different. Conversely, polar polymers, such as polyacrylonitrile, are predicted to show good resistance to attack by aliphatic hydrocarbons. By the same token, the longer alkyl chain acrylics are expected to be more soluble in aliphatic solvents since solubility parameter of the former polymers is more nearly equal to that of aliphatic hydrocarbons. These and related predictions of this theory have been experimentally verified innumerable times by coating chemists and formulators. 

In addition to polymer content additives, and temperature, the nature of the solvent can have a marked influence on the transport properties of the resulting membrane. Eirich et al9 discovered that regardless of the nature of the polymer, the highest porosity membranes were made from casting solutions utilizing solvents with high solubility parameters. Eirich investigated cellulose acetate, polystyrene, polyvinyl chloride, polyvinylidene difluoride, polycarbonate, polymethyl methacrylate, polyacrylonitrile, and polyacrylonitrile/polyvinyl... 

Most polymers are not miscible and those having closely similar solubility parameter values are likely to be compatible. Two incompatible polymers can be compatibihzed by the presence of a third component, which results in a good improvement in the physical and mechanical properties of the blend. The effect of the polyacrylonitrile compatibilizer, on the miscibility and properties of NBR/SBR blends, has been studied by Darwish et al. (2005). 

Solubility parameter (SP, 8) n. The square root of the cohesive energy density of a polymer, solvent, or adhesive. For solvents, SP equals the square root of the heat of vaporization per unit volume (J/cm )°. Values for polymers (which do not vaporize) are found by indirect methods. If the solubility parameters of a polymer and solvent differ by 3 (J/cm )° or less, the polymer will probably dissolve in the solvent differ by (J/cm )° or less, the polymer will probably dissolve in the solvent. SPs for organic solvents range from 13 for neopentane to 30 methanol for polymers, from 13 for polytetrafluoroethylene to 32 for Polyacrylonitrile. Wypych G (ed) (2001) Handbook of solvents. Chemtec Publishing, New York. Barton AFM (1983) Handbook of solubility parameters and other cohesion parameters. CRC Press, Boca Raton, FT. Brandrup J, Immergut EH, Elias HG (eds) (1975) Polymer handbook. Interscience Publishers Inc., New York. 

The solubility parameter is an indication of polarity nonpolar polymers, such as polyethylene, have a low value (7.9), while more polar materials, such as polyacrylonitrile, have higher values (15.4). Solubility of a polymer is most likely when the solubility parameter of the polymer and the solubility parameter of the solvent vary by less than 0.5. Dissimilar materials can be solvent bonded as long as the solubility parameters of both materials match that of the solvent. Solubility of either the same or dissimilar thermoplastics is not assured, however, and prior testing of the solvent is recommended.[ ][ ]... 

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