Hydrogen bonding in poly

McKee MG, Elkins CL, Park T, Long TE. Influence of random branching on multiple hydrogen bonding in poly(alkyl methacrylate)s. Macromolecules 2005 38 6015-6023. 

Fig. 24. Effect of pH on the formation of intermac-romolecular complex through hydrogen bonds in poly-(methacrylic add) (PMAA)-poly(ethylene oxide) (PEO) syst n. (1) and (2) pH of the initial mixing solution = 5.5. (3) and (4) pH of the initial mixing solution = 5.9...

Fig. 27. Effect of hydrophobic interactions on the formation of intermacromolecular complex through hydrogen bonds in poly-(methacrylic acid) (PMAA)-po-ly(N-vinyl-2-pyrrolidone)...

Gupta, R.P. andR.C. Laible, "Study of Hydrogen Bonding in poly(vinyl alcohol) by a Nuclear Magnetic Resonance Method", JPolySciA3, 1965, p 3951. 

Cesteros, L. C., Isasi, J. R., and Katime, I. 1993. Hydrogen bonding in poly(4-vinylpyridine)/poly(vinyl acetate-co-vinyl alcohol) blends An infrared study. Macromolecules 26 7256-7262. 

Kaczmarczyk B, Sek D (1995), Hydrogen bonds in poly(ester amide)s and their model compounds . Polymer, 36 (26), 5019-5025. 

Based on the solution property of poly (DMAEMA-co-AAm) in response to temperature, the temperature dependence of equilibrium swelling of poly (DMAEMA-c6>-AAm) gel as a function of chemical composition was observed as shown in Figure 6. The transition temperature of copolymer gel between the shrunken and swollen state was shifted to the lower temperature with increases in AAm content in the gel network. This is attributed to the hydrogen bond in the copolymer gel network and its hydrophobic contribution to the LCST Copolymer II gel was selected as a model polymer network for permeation study because it showed the sharp swelling transition around 34°C. 

Freitas LDL, Jacobi MM, Goncalves G, Stadler R. Microphase separation induced by hydrogen bonding in a poly(l,4-butadiene)-f>tock-poly(l,4-isoprene) diblock copol3mier— an example of supramolecular organization via tandem interactions. Macromolecules 1998 31 3379-3382. 

Thirdly, PMMI starts thermally degrading at about 154 C to form an anhydride [65,74]. Thermal analysis showed that the onset temperatures for degradation of the complexes PMMI/PDMA, PMMI/PEOX and PEMl/PVPo was substantially higher than those of the corresponding poly(monoalkyl itaconates), and the difference was attributed to the fact that hydrogen bonds in the complexes need to be broken before anhydride formation takes place. 

From such a background, some kinds of polypeptide blend samples have been studied by solid state NMR.27,72 74 Especially, detailed information for four kinds of blend samples such as poly(L-alanine) (PLA)/poly(L-valine) (PLV), PLA/poly(L-isoleucine) (PLIL), poly(D-alanine) (PDA)/PLV and polyglycine (PG)/PLV blends, have been reported. Here, let us describe some reasons why PLA/PLV, PDA/PLV, PLA/PLIL and PG/PLV blends are interesting systems. PLA and PDA in the solid-state can take the a-helix and (3-sheet forms due to intra- and intermolecular HBs, respectively. PG in the solid-state can take the 3j-helix (PG-II) and (3-sheet (PG-I) forms due to intra- and intermolecular HBs, respectively. However, PLIL and PLV in the solid state can predominantly take the (3-sheet form as the stable conformation. For this reason, it is interesting to know whether an isolated a-helix or 3i-helix form polypeptide surrounded by a major polypeptide in the (3-sheet form can take the helical conformation, or not, due to the balance between intramolecular and intermolecular hydrogen bonds. In addition, we would like to know whether a polypeptide in the (3-sheet form surrounded by a major polypeptide in the a-helix or 3 -helix form can take the (3-sheet form. 

Polyacrylamides are chemically stable towards acids (TFA, hydrogen fluoride [163]), bases, and weak oxidants or reducing agents. Problems, which might be related to cleavage of the amide bonds in poly(7V,/V-dialkylacrylamidcs), were encountered upon treatment of such supports with sodium in liquid ammonia [169]. 

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