Effect of plasticizers on other properties

Several essential properties of plasticized materials, which were not discussed yet, can be influenced by the type and the amoimt of plasticizers in various polymers. The following properties are influenced permeation of gases, liquids, ions and dmgs, staining, fogging, sorption of water, hydrophobic/hydrophilic properties, dissolution, foaming, and shrink-agg 294-321 -pjjg available on these subjects are discussed below. 

Increase of DOS in PVC and polyurethane membranes by factor 2 increased apparent diffusion coefficient of NO in PVC by factor 7 and in polyurethane by factor 2. Addi- 

Plasticizers may also change properties of a polymer surface from l drophobic to hydrophilic which affects permeability of Itydrophilic penetrants. Decreased hydropho-bidty is recpiired for PVC material to increase its receptivity of water-based coatings. Combinations of plasticizers and metal salts were used to induce hydrophilic properties. ° Rubber print rolls also require to have hydrophilic properties to hold film of water-based ink and this was achieved by use of a special plasticizer. Increase in hpophillicity of plasticizer causes linear increase in water penetration coefficient and water flux across membranes obtained from PVC plasticized with various plasticizers. Compatibility of a polymer and a plasticizer was found to affect staining resistance. Compatible plasticizers were less likely to dissolve stains and help them to penetrate into material. 

Membrane swelling sorption characteristics depend on plasticization The most common plasticizers used in dental tissue conditioners are dibutyl phthalate and butyl phthalyl butyl glycolate. Acetyl-tri-n-butyl citrate was found suitable for tissue conditioner where it performs functions of slow drag release and it is more biologically similar than other plasticizers in use.  

Cell morphology of foamed PVC depends on concentration of a plasticizer, surface treatment of filler and foaming time and temperature. High concentrations of plasticizers produced poly disperse cell structure. Polyester plasticizer blends are useful for production of heat-shrinkable film. Plasticizer migration from geomembranes causes membrane shrinkage.  

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