Copolymers hydrophilic-hydrophobic grafts

Emulsion polymerization has become an important process for the production of a large number of industrial polymers in the form of polymer colloids or latexes. They are the base of adhesives, paints and especially of waterborne coatings. An interest has been developed in recent years in emulsion polymerization systems in which the classical low molecular weight surfactaints are replaced by polymeric surfactants, either hydrophilic-hydrophobic block and graft copolymers (1-4) or functionalized oligomers (5). 

Uchida T, Serizawa T, Ise H, et al. (2001). Graft copolymer having hydrophobic backbone and hydrophilic branches. 33. Interaction of hepatocytes and polystyrene nanospheres having lactose-immobilized hydrophilic polymers on their surfaces. Biomacromol. 2 1343-1346. 

Siloxane amphiphilic copolymers are a class of silicone surfactants consisting of a methylated siloxane hydrophobe attached to one or more polar chains such as poly(oxyalkylene). The blocks in the copolymer can be arranged in a linear fashion (as in A-B-type block copolymer) or, as in graft copolymers, one type of blocks can be attached (usually randomly) to a linear, backbone chain of the other type of blocks. Siloxane amphiphiUc copolymers are of special interest since their hydrophile-hydrophobe balance can be easily tailored by changing the length of the corresponding blocks [26-28]. 

Fliwatari, K., Serizawa, T., Seto, F., Kishida, A., Muraoka, Y., Akashi, M. Graft copolymers having hydrophobic backbone and hydrophilic branches XXXIV. Fabrication and control of honeycomb structure prepared from amphiphilic graft copol5Tners. Polym J 33, 669-675 (2001)... 

ATRP is probably the most utilized CRP technique for the synthesis of graft copolymers via the grafting through process. ATRP has been used by a number of groups to polymerize or copolymerize hydrophilic monomers or maaomonomers, including co-methacryloyloxy-PEO maaomonomers. Many efforts have been devoted over the years to design copolymers characterized by a hydrophobic backbone (PS, PMMA) and... 

Hydrophilic/hydrophobic force balance of polymers may be varied by incorporation of a hydrophilic polymer in a bulk of a hydrophobic polymer (grafting of a hydrophilic monomer would be such a case). Also different block copolymers and polymer alloys are prepared with the aim to ensure the desired properties of the polymer. All these procedures alter the nature of the polymer, changing the magnitude of its long and short range forces. 

Figure 7.1 Typical structures of hydrophilic-hydrophobic block and graft copolymers. A hydrophilic block B hydrophobic block.

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