Advances in Hair Styling 424 VP has also been copolymerized with vinyl imidazole and its derivatives. An example of an advanced styling polymer in this case is VP/methacrylamide/vinyl imidazole copolymer, which is claimed to have good setting properties under high humid conditions, low tack, and still preserve clarity in polyacrylate type thickeners.10 The structure is illustrated in Figure 3. Besides using VP as a basis to create advanced styling polymers, monomers from other chemical families have been used. These consist of acrylates, maleic anhydride, polyurethane, and natural based polymers and their derivatives. They can be categorized into their respective chemical classes in order to help in organization and selection for specific applications. Polymer synergies: Polymer modification strategy is guided by the blending of different monomers to achieve a particular benefit or benefits. As mentioned above, stiffness, high hold in humid conditions, mechanical durability, and gel clarity are important attributes. Also popular, based on consumer trends, are volume/ body, shine, curl management, fiber alignment, and anti-frizz effects. If a particular polymer with a blend of monomers cannot achieve a multi-benefit effect then the formulator usually resorts to physically blending polymers together to achieve an additive effect, where one polymer can supplement another to overcome deficiencies. Consequently there are many styling products on the market where PVP is still used as the primary fixative resin but in combination Figure 3. Structure of VP/Methacrylamide/Vinyl Imadazole Copolymer