Hydrogen-bonded chain polymer

As the amount of acrylic acid in the polymer increases, the degree of hydrogen bonding between polymer chains also increases causing the cohesive strength to improve without the need for crosslinking. Very similar observations can be made for other polar monomers, such as acrylamide. 

The molecular structure of cellulose, unlike that of starch, allows for strong hydrogen bonding between polymer chains. This results in the formation of strong water-resistant fibers such as those found in cotton, which is 98% cellulose. Cotton actually has a tensile strength greater than that of steel. The major industrial source of cellulose is wood ( 50% cellulose). 

PCL-diol and diphenylmethane-i -diisocyanate (MDI), by R. delemar lipase were examined. These polyurethanes have both the hydrogen bonds among polymer chains and aromatic rings in the polymer molecules. R. delemar lipase could hydrolyze the polyurethanes though the rate of hydrolysis toward polyurethanes decreased as compared to that ward PCL-diol. The rate of hydrolysis decreased with decreasing the Mn of PCL-moiety of polyurethanes (Figure T). 

Shimizu LS. Perspectives on main-chain hydrogen bonded supramolecular polymers. Polym... 

Some unexpectedly complex liquid solid interactions have been detected and studied by ultrasonic impedance measurements (ultrasonic impedometry). Small amounts of water and alcohols have pronounced effects on the physical state of hydrophilic polymers specifically, the high frequency shear modulus and crystallinity index of a poly (vinyl alcohol) film increases with water content to a maximum before normal solution phenomena occur. These effects are attributed to the increased molecular order owing to water hydrogen bonded between polymer chains. The unusual effects of moisture on a novel poly(vinyl chloride)/plasticizer system and on hydrophilic polymers other than poly (vinyl alcohol) are also described. 

Polyglycine, H(-CO-CH2-NH)n-H, is the simplest polypeptide. It has two solid state structures. Form I consists of chains of polymer that are hydrogen-bonded into two-dimensional sheets. This form (including selectively deuterated isotopomers) has been studied by INS [53-55]. The spectra were interpreted similarly to those of N-methylacetamide. Reexamination of the spectra with periodic-DFT calculations is necessary. Acetanilide, C6H5-NH-C(=0)-CH3, forms hydrogen-bonded chains similar to N-methylacetamide and as such is a potential model for phenyl substituted peptides. However, the interest in acetanilide is that the... 

Water-induced plasticization of polymers by disruption of intermolecular hydrogen bonding between polymer chains that are generally considered to be hydrophobic is rather common. Moy and Karasz [30] show that the lowering of Tg for an epoxy-diamine resin is proportional to the amount of water in the system. 

By proper choice of either the isocyanate or the polyol, actual chemical cross-links can be introduced in either the hard or soft segments that may be beneficial to some properties. The effectiveness of these cross-links is offset by a disruption of the hydrogen bonding between polymer chains. Highly cross-linked polyurethanes are essentially amorphous in character exhibiting high modulus, hardness, and few elastomeric properties. Many adhesives fall into this category. 

Li SL, Xiao T, Xia W, et al. New hght on the ring—chain equilibrium of a hydrogen-bonded supramolecular polymer based on a photochromic dithienylethene unit and its energy-transfer properties as a storage material. Chem EurJ. 2011 17 10716-10723. 

Xiao T, Feng X, Ye S, et al. Highly controllable ring—chain equilibrium in quadruply hydrogen bonded supramolecular polymers. Macromolecules. 2012 45 9585-9594. 

Bertrand A, Lortie F, Bernard J (2012) Routes to hydrogen bonding chain-end functionalized polymers. Macromol Rapid Commun 33(24) 2062-2091... 

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