backbone. The macromonomer (grafting through) method can be employed using any known polymerization technique. Living polymerizations give special control over the molecular weight, molecular weight distribution, and chain-end functionalization. Applications Graft copolymers became widely studied due to their increased number of applications like in drug delivery vehicles, surfactants, water filtration, rheology modifiers, etc. It is their unique structures relative to other copolymers such as alternating, periodic, statistical, and block copolymers. Some common applications of graft copolymers include: Membranes for the separation of gases or liquids Hydrogels Drug deliverers Thermoplastic elastomers Compatibilizers for polymer blends Polymeric emulsifiers Impact resistant plastics High impact polystyrene High impact polystyrene (HIPS) was discovered by Charles F. Fryling in 1961. HIPS is a low cost, plastic material that is easy to fabricate and often used for low strength structural applications when impact resistance, machinability, and low cost are required. Its major applications include machined prototypes, low-strength structural components, housings, and covers. In order to produce the graft polymer, polybutadiene (rubber) or any similar elastomeric polymer is dissolved in styrene and polymerized. This reaction allows for two simultaneous polymerizations, that of styrene to polystyrene and that of the graft polymerization of styrene-rubber. During commercial use, it can be prepared by graft copolymerization with additional polymer to give the product specific characteristics. The advantages of HIPS includes: FDA compliant Good impact resistance Excellent machinability Good dimensional stability Easy to paint and glue Low cost Excellent aesthetic qualities New properties as a result of grafting By grafting polymers onto polymer backbones, the final grafted copolymers gain new properties from their parent polymers. Specifically, cellulose graft copolymers have various different applications that are dependent on the structure of the polymer grafted onto the cellulose. Some of the new properties that cellulose gains from different monomers grafted onto it include: Absorption of water Improved elasticity Hydrophilic/Hydrophobic character Ion-exchange Dye adsorption capabilities Heat Resistance Thermosensitivity pH sensitivity Antibacterial effect These properties give new application to the ungrafted cellulose polymers that include: Medical body fluid absorbent materials Enhanced moisture absorbing ability in fabrics Permselective membranes Stronger nucleating properties than ungrafted cellulose, and adsorption of hazardous contaminants like heavy metal ions or dyes from aqueous solutions by temperature swing adsorption Sensors and optical materials Reducing agents for various carbonyl compounds References Polymers