Copolymer networks

Resin bead polymer composition Either acrylic resins or, more generally, styrene (vinylbenzene, VB) are cross-linked with typically 4 to 20% divinylbenzene (DVB) in a copolymer network or matrix. 

Bifunctional initiators are sometimes needed e.g., for the synthesis of triblock copolymers, networks, or a,co-difunctional macromolecules. Whenever it is possible to carry out the polymerization in a polar solvent no major difficulty is involved, as bifunctional initiators covering a wide range of nucleophilicities are available (Table 2). 

Fig. 9. The effect of interpolymer complexation on the correlation length, , and the effective molecular weight between crosslinks, Mc, in P(MAA-g-EG) graft copolymer networks with permanent, chemical crosslinks ( ).

Mazurek, M. Silicone Copolymer Networks and Interpenetrating Networks. In Silicon-Containing Polymers. The Science and Technology of Their Synthesis and Applications-, Jones, R. G., Ando, W., Chojnowski, J., Eds. Kluwer Dordrecht, 2000 pp 113-137. 

Malberg S, Plikk P, Fiime-Wistrand A, Albertsson A-C (2010) Design of elastomeric homo-and copolymer networks of functional aliphatic polyester for use in biomedical applications. Chem Mater 22 3009-3014... 

Madsen, F. and Peas, N.A. (1999). Complexation graft copolymer networks swelling properties, calcium binding and proteolytic enzyme inhibition. Biomaterials, 20, 1701-1708. 

The second example used visible light absorption that increased the temperature locally within the thermosensitive gel [39]. The gel consisted of a covalently cross-linked copolymer network of N-isopropylacrylamide and chloro-phyllin, a combination of a thermo-sensitive gel and a chromophore. In the absence of light, the gel volume changed sharply but continuously as the temperature was varied. Upon illumination the transition temperature was lowered, and beyond a certain irradiation threshold the volume transition became discontinuous. The phase transition was presumably induced by local heating of polymer chains due to the absorption and subsequent thermal dissipation of light energy by the chromophore. The details will be discussed in a later section. 

Byme et al. [124] have shown the possibility of creating imprinted polymer ordered micropattems, of a variety of shapes and dimensions, on polymer and silicon substrates using iniferters and photopolymerization. They applied this approach to the recognition of D-glucose using copolymer networks containing poly(ethylene glycol) and functional monomers such as acrylic acid, 2-hydro-xyethyl methacrylate, and acrylamide. 

Lemieux, P., et al. 2000. Block and graft copolymers and NanoGel copolymer networks for DNA delivery into cell. J Drug Target 8 91. 

To use this method for the preparation of imprinted colloids, Whitcombe et al. applied it during the shell preparation. They synthesized a copolymer network shell consisting of poly(EGDMA-co-cholesteryl (4-vinyl)phenyl carbonate) using a variety of different seed particles to build the polymer core [26]. The seed particles used were 30-45 nm in diameter and the imprinted p(EGDMA-co-CVPC) shell resulted to a thickness of about 15 nm (Fig. 3). The specific BET surface area of the core-shell particles was typically 80 m2 g... 

In the next step, the cholesteryl ester entities copolymerized in the shell, were split by carbonate ester hydrolysis. The hydrolysis was carried out in sodium hydroxide in methanol. Thereby, an analogue of cholesterol, the target molecule for later recognition, was removed from the copolymer network. The particles were now ready for non-covalent binding of cholesterol. To quantify the binding behavior of colloidal MIPs, they were mixed with a cholesterol containing solution, separated from the liquid and the cholesterol concentration in the supernatant was quantified by HPLC. 

Resins from Solvent-Modified SDVB Copolymers. Millar et al. have made a systematic study of the modification of SDVB copolymer networks by carrying out the polymerization in presence of diluents. From such polymers ion-exchange materials have been prepared whose mechanical properties, exchange kinetics, and equilibria differ from those of corresponding materials prepared from SDVB copolymers obtained by conventional method. The diluent may be a solvent, nonsolvent or a poor solvent for the copolymer, and, depending on the nature of the diluent used, the properties of the products differ. 

O. Okay, Macroporous copolymer network. Progress in Polymer Science 25,711-779 (2000). 

Figure 12. Schematic of transition metal complex-based grafted copolymer network.

Oh KS, Oh JS, Choi HS, Bae YC (1998) Effect of crosslinking density on the swelling behavior of NIPA gel particles. Macromolecules 31 7328-7335 Okay O (2000) Macroporous copolymer networks. Prog Polym Sci 25 711-779 Okay O, Gundogan N (2002) Volume phase transition of polymer networks in polymeric solvents. Macromol Theory Simul 11 287-292... 

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