Hydrophilic/hydrophobic copolymers functionalized

In this linkages are covalent bonds. They are influenced by the chemical linkages and functional groups present in the gel networks. Hydrophilic polymers and hydrophilic-hydrophobic copolymers are examples of chemically crosslinked gels obtained by the polymerization of vinyl monomers in fhe presence of multifunctional crosslinkers. These crosslinkers are the crosslinking points within and between the polymeric chains allowing modification of the entire physicochemical properties of the gel systems... 

The synthesis of block copolymers by macromonotner RAFT polymeriza tion has been discussed in Section 9.5.2 and examples are provide in Table 9.9. RAFT polymerization with thioearbonylthio compounds has been used to make a wide variety of block copolymers and examples arc provided below in Tabic 9.28. The process of block formation is shown in Scheme 9.59. Of considerable interest is the ability to make hydrophilic-hydrophobic block copolymers directly with monomers such as AA, DMA, NIPAM and DMAEMA. Doubly hydrophilic blocks have also been prepared.476 638 The big advantage of RAFT polymerization is its tolerance of unprotected functionality. 

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). 

As described in Sec. 2, polymeric micelles that are formed through either hydrophilic-hydrophobic interaction of PEG-based block copolymers or electrostatic interaction of PE G-polycation block copolymers with negatively charged macromolecules have attracted considerable attention in the field of drug delivery and gene delivery systems, owing to their excellent biocompatibility, long blood circulation time, and nontoxicity. In this section, the preparation and the characterization of end-functionalized polymeric micelles... 

Polyacrylates as binders consist of copolymers of acrylate and methacrylate esters. Other unsaturated monomers (e.g., styrene and vinyltoluene) may also be incorporated, but usually to a lesser extent. Copolymers formed exclusively from acrylates and/or methacrylates are termed straight acrylics. The comonomers differ as regards the alcohol residues of the ester group, which also allow incorporation of additional functional groups. Choice of suitable monomers allows wide variation of the physical and chemical properties of the resulting polymer. Hydrophilicity, hydrophobic-ity, acid base properties as well as can be adjusted resins containing hydroxyl, amine, epoxy, or isocyanate groups can also be produced. 

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