TECHNOLOGY FOCUS - POLYMERS - Preferred Conditions: The compressed fluid is at 100-10000 bar during the contacting step. The polymer in the colloidal system is contacted with the additive in the presence of the compressed fluid for 1 minute to 15 days. The compressed fluid is normally gaseous at atmospheric pressure and room temperature and has a density at the processing pressure of at least 0.01 g/cm3.Preferred Components: The colloidal system is aqueous or alcohol based. The polymer further comprises a colloidal stabilizer to stabilize suspension of the polymer in the colloidal system. The colloidal stabilizer includes sulfates, amines, carboxylates, or their mixtures. It can be poly(ethylene oxide), poly(N-vinyl pyrrolidone), poly(sodium 4-styrene sulfonate), poly(acrylic acid), poly(diallyldimethylammonium chloride), or their copolymers or mixtures. The polymer is in particulate form. The polymer particles are 10-500 microns in size. The polymer is polystyrene, poly(lactide-co-glycolide), poly(lactic acid), poly(glycolic acid), poly(caprolactone), polyanhydrides, cellulose, natural rubbers, polyisoprene, styrene-butadiene polymers, butyl rubbers, chloroprene polymers, polyamides, polyimides, polyesters, nitrile rubbers, polyacrylic polymers, vinyl chloride polymers, vinylidene chloride polymers, polycarbonate polymers, polyurethane polymers, polyacrylates, polymethacrylates, polyacetylenes, or copolymers or mixtures. The polymer is preferably polystyrene, poly(lactide-co-glycolide), or poly(caprolactone). The compressed fluid is carbon dioxide, ethylene, ethane, propane, nitrous oxide, monochlorotrifluoromethane, acetylene, phosphine, phosphonium chloride, methyl fluoride, methane, fluoroform, sulfur dioxide, or their mixtures. It is preferably carbon dioxide. The additive is bioactive chemicals, dyes, antioxidants, accelerators, accelerator activators, plasticizers, softeners, vulcanizing agents, extenders, tackifiers, monomers, polymerization initiators, ultraviolet (UV) stabilizers, UV sensitizers, electronic dopants, optical dopants, or their mixtures. It is a dye including azo dyes, cyanine dyes, phthalocyanine pigments, nitroso dyes, nitro dyes, triphenylmethane dyes, or their mixtures. The additive is an azobenzene dye, a bioactive agent, or progesterone. The surfactant is non-toxic to humans. The surfactant is sorbitan esters, sucrose esters, alkyl polyglycosides, alkyl oligosaccharides, polyoxyethylene-polypropylene block and graft copolymers, polyoxyethylene-polybutylene block and graft copolymers, perfluoropolyether ammonium carboxylate, sulfated fats and oils, sulfated monoglycerides, alkyl betaines, alkyl aminopropionates, alkyl iminodipropionates, alkyl imidazoline derivatives, alkyl pyridinium salts, alkyl trimethylammonium slats, alkyl ammonium salts, alkyl amines, alkyl phosphate salts, olefin sulfonates, alkylaryl sulfonates, sulfated alkanolamides, alkyl sulfate salts, or their mixtures. The surfactant is preferably perfluoropolyether ammonium carboxylate, polysorbate, or sodium oleate. It is poly(ethylene oxide)-b-poly(butylene oxide).Preferred Composition: The dye is present in 0.05-10 wt.% based on the total weight of dye and polymer. The surfactant is present in 0.001-10 wt.% based on the total wt. of the colloidal system.Preferred Process: The additive is combined with the compressed fluid prior to or after introduction of the compressed fluid into the colloidal system. The process further comprises introducing a surfactant into the colloidal system during emulsification. The contacting step is carried out at a temperature at least as low as the critical temperature of the compressed fluid and at a pressure that is at least 10% of the saturated vapor pressure of the compressed fluid. It is preferably carried out at a temperature above the critical temperature of the compressed fluid and at a pressure 0.5-5 times the critical temperature of the compressed fluid. The process further comprises venting the compressed fluid from the colloidal system after contacting the polymer with the additive, and removing liquid dispersion phase from the colloidal system to obtain a polymer product with at least a portion of the additive incorporated in it. The process is carried out as a batch or continuous process. The colloidal system is aqueous, the polymer is styrene grafted with poly(N-vinyl pyrrolidone), the compressed fluid is carbon dioxide, the additive is an azo dye or progesterone, and the process carried out at 310 bar and 25 degrees C for 24 hours further comprises adding a surfactant to assist in emulsification, and releasing the compressed fluid from the colloidal system. EXAMPLE - A milky colloidal suspension of polystyrene with surface grafted poly(N-vinyl pyrrolidone) was prepared by dispersing 0.3 g of dried particles into 10 ml deionized water by manual shaking. The colloidal system was transferred to a stainless steel variable volume view cell, and 0.05 g of Sudan Red 7B (RTM; azobenzene dye) was added. 0.095 g poly(ethylene oxide)-block-poly(butylene oxide) was used as a surfactant. The cell was sealed and 3.5 g carbon dioxide was introduced over 2 minutes. It was pressurized to 310 bar at 25 degrees C. After the emulsion was stirred vigorously for 24 hours at 310 bar and 25 degrees C, the compressed carbon dioxide was released over 1 hour. The remaining mixture was centrifuged for 1 hour at 7500 rpm. The liquid phase was decanted and the solid particles were re-suspended in 50 ml ethanol, centrifuged, and the liquid poured off. This ethanol washing step was repeated 4 times until only dye incorporated into the polymer remained. A red color was obtained and the dye was present in 0.17% based on total wt. of dye and polymer.