Poly N-alkylacrylamides

Poly(ethylene oxide) (PEO) has been employed frequently as a water-soluble catalyst support [9]. Further water-soluble polymers investigated include other linear polymers such as poly(acrylic acid) [10], poly(N-alkylacrylamide)s [11], and copolymers of maleic anhydride and methylvinylether [12], as well as dendritic materials such as poly(ethyleneimin) [10a, c] or PEO derivatives of polyaryl ethers [13]. The term dendritic refers to a highly branched, tree-like structure and includes perfectly branched dendrimers as well as statistically branched, hyperbranched macromolecules. 

Polyethylene oxide) and poly(N-alkylacrylamide)s are known to undergo a temperature-dependent phase change whereupon they separate from an aqueous phase at increased temperatures [14]. This inverse temperature dependence, i.e., the occurrence of a lower critical solution temperature, can be related to an entropi-cally favorable decrease in hydrogen bonding between water and the polymer with increasing temperature. In order to exploit this physical property for catalyst recovery, Bergbreiter et al. attached phosphines covalently to commercially available PEO or PEO-b-PPO-b-PEO block copolymers [Schemes 1 and 2 PPO = polypropylene oxide)] [9a],... 

Maeda Y, Nakamura T, Ikeda I (2001) Changes in the hydration states of poly (N-alkylacrylamide) s during their phase transitions in water observed by FTIR spectroscopy. Macromolecules 34 1391... 

Various thermoresponsive PNIPAM derivatives were also obtained by radical or ionic polymerization, in which most polymerizations were non-hving systems except for a few examples [63,204], including poly(N-alkylacrylamide)s (49) [12,13,63], poly(2-isopropyl-2-oxazoline) (50) [204], poly(N-vinyhsobutylamide) (51) [205], optically active poly(methacrylamide)... 

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