Extents of hydrogen bonding in polyamides and polyurethanes

Trifan, Daniel S.; Terenzi, J. F.

doi:10.1002/pol.1958.1202811727

Cited by 157 publications

(49 citation statements)

References 5 publications

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“…Assignments of IR absorption bands used in this work are consistent with the work of Seymour et al [27] and other investigators of segmented polyurethane elastomers and model compounds [15,[28][29][30]. It is well known [12,27,[31][32][33][34][35][36] that the urethane NH group forms hydrogen bonds with the C = O group of the urethane linkages as well as the soft segment oxygen atoms in both polyester and polyether polyurethanes. Especially in polyether urethanes, analysis of the IR spectra allows estimation of the distribution of hydrogen bonding between the urethane NH and these various proton acceptors and thus infrared spectroscopy becomes valuable in probing the morphology of segmented polyurethanes.…”

Section: A Infrared Analysis Of Polyether Polyurethanessupporting

confidence: 80%

Segmental orientation studies of polyether polyurethane block copolymers with different hard segment lengths and distributions

Lin

Hwang

Tsay

et al. 1985

Colloid & Polymer Sci

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Abstract:The orientation behavior of two series of segmented polyether polyurethanes containing different hard segment length distributions has been studied as a function of the average hard segment length which was varied from one to five methylene bis (p-phenyl isocyanate) (MDI) units. The orientation behavior of the soft segments, isolated hard segments, and of hard segments aggregated in hard domains was determined from the dichroic behavior of representative infrared bands. As the hard segment length increases, a transition in orientation behavior is observed which corresponds to a change in sample morphology.The effects of annealing and hard segment length distribution were also studied and were shown to affect the orientation response through their influence on sample morphology. Orientation hysteresis studies were performed to probe the mechanism of the transverse orientation and orientation inversion which occurred in polyurethanes with the longer, more crystallizable hard segment lengths.

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Section: A Infrared Analysis Of Polyether Polyurethanessupporting

confidence: 80%

Segmental orientation studies of polyether polyurethane block copolymers with different hard segment lengths and distributions

Lin

Hwang

Tsay

et al. 1985

Colloid & Polymer Sci

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“…Therefore, L 1 and L 2 represent the period structure in the neat PA66 and its nanocomposites. The ability to form H-bonds between the NH group and the CO group is the determining factor for the crystal structures in PA66 [46]. Bunn and Garner reported that the chains in the α structure of PA66 were in the fully extended planar zig-zag conformation and parallel to the c-axle direction [38].…”

Section: Resultsmentioning

confidence: 99%

The Influence of Epitaxial Crystallization on the Mechanical Properties of Polyamide 66/Reduced Graphene Oxide Nanocomposite Injection Bar

Chi

Yao

et al. 2017

Crystals

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Polyamide 66 (PA66) was chosen as the representative of hydrophilic polymers, to investigate the influence of epitaxial crystals in semi-crystalline polymers/reduced graphene oxide nanocomposite injection-molding bars. A differential scanning calorimeter was used, and the two-dimensional wide-angle X-ray diffraction technique, as well as the two-dimensional small angle X-ray scattering technique, were used to research the crystallization behavior in PA66/RGO nanocomposites. The results indicated that RGO was an effective nucleation agent for PA66. The presence of RGO could enhance the orientation degree of the PA66 crystals and did not influence the crystal structure of the PA66. The non-epitaxial crystals and the epitaxial crystals existed in PA66/RGO nanocomposites. The size of epitaxial crystals was much greater than that of the non-epitaxial crystals. Tensile test results showed that the presence of fewer epitaxial crystals can improve the mechanical properties of a polymer.

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“…The dissociation energy for the CO-HN hydrogen bond is known to be 8 kcal mol-1 . 32 The reported activation energy of rotation is 8 kcal mol-1 for the CC bond, and 14 kcal mol-1 for the CONH bond in polypeptides. 33 The activation energy for carrier transport associated with the rotation of the amide group may not be less than the sum of the dissociation and rotation energies, about 20 kcal mol- 1 The other mechanism of carrier transport is proton hopping through the chain of hydrogen bonds.…”

Section: Discussionmentioning

confidence: 99%

Electrical Conduction of Polypeptides as Related to Molecular Structure

Hirota

1982

Polym J

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ABSTRACT:The temperature dependence of electric conductivity, the frequency and temperature dependence of the dielectric constant, and the hydrogen-deuterium exchange reaction of the amide group were studied for solid poly(y-methyl L-glutamate), poly(y-benzyl L-glutamate), and poly(fJ-benzyl L-aspartate). A linear relation was found between the activation energy for conductivity and the reciprocal of the static dielectric constant, and was interpreted in terms of the carrier generation process. The conductivity at the glass-like transition temperature was about 3 x 10-18 ohm -1 em -1 . The generation of protons from the amide groups was concluded to be a source of the charge carriers in solid polypeptides.

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Extents of hydrogen bonding in polyamides and polyurethanes

Cited by 157 publications

References 5 publications

Segmental orientation studies of polyether polyurethane block copolymers with different hard segment lengths and distributions

Segmental orientation studies of polyether polyurethane block copolymers with different hard segment lengths and distributions

The Influence of Epitaxial Crystallization on the Mechanical Properties of Polyamide 66/Reduced Graphene Oxide Nanocomposite Injection Bar

Electrical Conduction of Polypeptides as Related to Molecular Structure

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