Surface-initiated anionic polymerization

Till now, only three reports on the preparation of polymer brushes by means of surface-initiated anionic polymerization on planar substrates with accounts on the morphology and special properties can be found. 

Surface-initiated anionic polymerization provides an alternative approach to polyolefin-functionalized CNTs that would have potential applications in the reinforcement of widely used polyolefins such as PE and PP. 

Figure 5.18 CNT surface-initiated anionic polymerization of styrene (top), and representative TEM images of PS-grafted MWCNTs with PS layer thickness up to 30 nm. ...

Jordan, R., Ulman, A., Kang, J. F., Rafailovich, M. H., and Sokolov, J. 1999. Surface-initiated anionic polymerization of styrene by means of self-assembled monolayers, lournal of the American Chemical Sodetu 121 1016-22. 

In an all-glass reactor, a SAM of 4, 4-bromo-mercaptobiphenyls on Au(lll) surfaces was converted to biphenyUithium moieties by treatment with seoBuIi to initiate anionic polymerization of styrene on gold substrates (Fig. 9.24). 

Potassium carboxylate groups introduced onto the surface of carbon fibers initiated anionic polymerization of epoxides (e.g., styrene oxide, epichlorohydrin, and glycidyl phenyl ethers) and cyclic acid anhydrides (e.g., maleic anhydride, succinic anhydride, and phthalic anhydride) in the presence of 18-crown-6 [41]. 

The halo-surface groups were readily converted to lithiated derivatives which allowed their use as macromolecular templates from which to initiate anionic polymerizations. A wide variety of surface functionalities were introduced by combining the lithiated monodendron with various electrophiles. 

It has been demonstrated that surface basic sites of PCPs successfully catalyze polymerization in the nanochannels. Thus, the pillared-layer complex [Cu2(pzdc)2bpy] acted as a host for spontaneous polymerization of substituted acetylenes in a specific manner (Fig. 5) [67]. In the case of acidic monosubstituted acetylenes, the basic oxygen atoms from carboxylate ligands in [Cu2(pzdc)2bpy] produced reactive acetylide species that subsequently initiated anionic polymerization in the nanochannel. Compared with a control experiment using a discrete model catalyst... 

Cyanoacrylate adhesives (Super-Glues) are materials which rapidly polymerize at room temperature. The standard monomer for a cyanoacrylate adhesive is ethyl 2-cyanoacrylate [7085-85-0], which readily undergoes anionic polymerization. Very rapid cure of these materials has made them widely used in the electronics industry for speaker magnet mounting, as weU as for wire tacking and other apphcations requiring rapid assembly. Anionic polymerization of a cyanoacrylate adhesive is normally initiated by water. Therefore, atmospheric humidity or the surface moisture content must be at a certain level for polymerization to take place. These adhesives are not cross-linked as are the surface-activated acryhcs. Rather, the cyanoacrylate material is a thermoplastic, and thus, the adhesives typically have poor temperature resistance. 

The mechanism of the anionic polymerization of styrenes and 1,3-dienes initiated by alkaU metals has been described in detail (3,20) as shown in equations 3—5 where Mt represents an alkaU metal and M is a monomer molecule. Initiation is a heterogeneous process occurring on the metal surface. The... 

The precipitated silica (J. Crosfield Sons) was heated in vacuo at 120° for 24h. before use. Two grades of surface areas 186 and 227 m g l (BET,N2), were used during this project. Random copolymers, poly(methyl methacrylates) and polystyrene PS I were prepared by radical polymerization block polymers and the other polystyrenes were made by anionic polymerization with either sodium naphthalene or sodium a methylstyrene tetramer as initiator. The polymer compositions and molecular weights are given in Table I. 

Surface-initiated Polymerization Using Living Anionic Polymerization... 

During the last 5 years, there have been several reports of multiblock copolymer brushes by the grafting-from method. The most common substrates are gold and silicon oxide layers but there have been reports of diblock brush formation on clay surfaces [37] and silicon-hydride surfaces [38]. Most of the newer reports have utilized ATRP [34,38-43] but there have been a couple of reports that utilized anionic polymerization [44, 45]. Zhao and co-workers [21,22] have used a combination of ATRP and nitroxide-mediated polymerization to prepare mixed poly(methyl methacrylate) (PMMA)Zpolystyrene (PS) brushes from a difunctional initiator. These Y-shaped brushes could be considered block copolymers that are surface immobilized at the block junction. 

Advincula R. Polymer Brushes by Anionic and Cationic Surface-Initiated Polymerization (SIP). Vol. 197, pp. 107-136. 

Keywords Anionic Cationic Initiator Nanoparticles Surface initiated polymerization... 

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