Effect of hydrogen bonding and moisture cycling on the compressive performance of poly-pyridobisimidazole (M5) fiber

Leal, A. Andrés; Deitzel, Joseph M.; McKnight, Steven H.; Gillespie, John W.

doi:10.1016/j.polymer.2009.04.019

Cited by 29 publications

(16 citation statements)

References 18 publications

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“…As a result of the better lateral interactions between polymer chains, compressive strengths as high as 1.7 GPa were reported [41]. This polymer is rather expensive and the compressive properties appear to be sensitive to water, which reduces compressive performance over time [42]. The authors identify the upsetting of the intermolecular hydrogen bond formation as the reason for this effect.…”

Section: Structure and Properties Of P-aramid Fibersmentioning

confidence: 98%

Manufacturing and Properties of Aramid Reinforced Composites

Denchev¹,

Dencheva²

2012

Synthetic Polymer-Polymer Composites

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Section: Structure and Properties Of P-aramid Fibersmentioning

confidence: 98%

Manufacturing and Properties of Aramid Reinforced Composites

Denchev¹,

Dencheva²

2012

Synthetic Polymer-Polymer Composites

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“…This can be explained by the forming of hydrogen bonds between the adjacent chains due to the introduction of PIPD segments into the main chains. [23][24][25] As the mole ratio between PBO segments and PIPD segments decreases below 5/1, the tensile modulus of PBO-b-PIPD fibers begin to decrease obviously, and this can be attributed to more disordered packing of PBO-b-PIPD chains with higher content of PIPD segments, which can be confirmed by the WAXD patterns shown in Figure 6. As for PBO-b-PIPD (5/3) fibers, the degree of chaos in chain arrangement becomes severe, which shows the lowest tensile modulus, which is even lower than that of PBO fibers.…”

mentioning

confidence: 89%

Effect of hydration on the structures and properties of poly(p-phenylene benzobisoxazole)/poly(pyridobisimidazole) block copolymer fibers

Cao

Zhong

Guan

et al. 2012

High Performance Polymers

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A rigid-rod copolymer, poly(p-phenylene benzobisoxazole)-block-poly(pyridobisimidazole) (PBO-b-PIPD), was synthesized, and the effect of hydration on the structures and performance of the block copolymer fibers was evaluated. PBO and PBO-b-PIPD as-spun fibers (AS-fibers) were prepared by dry-jet wet spinning, and subsequent thermal treatment in a nitrogen atmosphere was performed. Fourier transform infrared and wide-angle X-ray diffraction were used to characterize the structures of the thermally treated fibers. Mechanical properties of both the AS-fibers and thermally treated fibers were tested, and scanning electronic microscopy was used to observe the fracture surfaces of the fibers from tensile testing. It has been revealed that heat treatment is an effective method to remove the absorbed water to improve the orderly arrangement of chains along the fiber direction, which resulted in enhancement of the tensile modulus of the block copolymer fibers.

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“…In contrast, Figure 6b shows how the polarization ratio obtained from the secondary amide C=O stretching vibration band located at 1638 cm -1 is directly proportional to the degree of draw ratio imparted to the CoPA fiber. This behavior can be ascribed to the fact that as the degree of molecular orientation in the fiber increases, the possibility that the secondary amine engages in intermolecular hydrogen bonding with neighboring chains is enhanced considerably [47,48], providing an energetic barrier for the ketone group to be realigned in the fiber direction, which in turn also promotes an : ratio > 1 for this vibrational band.…”

Section: Polarized Raman Spectroscopymentioning

confidence: 99%

Spectroscopic elucidation of structure-property relations in filaments melt-spun from amorphous polymers

Leal

Best

Rentsch

et al. 2017

European Polymer Journal

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Melt spinning and drawing of amorphous cyclo-olefin and co-polyamide polymeric materials were performed to develop mono-component continuous filaments. Raman spectroscopy was employed to assess the effect of a static bending deformation on the microstructure of the filaments. Spectra stemming from the fiber regions under tensile and compressive loading do not show any appreciable shift of their vibrational bands as a function of applied strain. The bent filaments manage to redistribute strains without any stretching or buckling of polymer chains associated with peak shifting in the Raman spectrum. The influence of fiber draw ratio on the degree of molecular ordering was demonstrated by means of polarized Raman spectroscopy. An increase in draw ratio leads to a variation of the polarization ratio for spectroscopic bands located along the polymer backbone. We observed a correlation between the polarization ratio of these vibrational bands and the macroscopic tensile modulus of the material.

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Effect of hydrogen bonding and moisture cycling on the compressive performance of poly-pyridobisimidazole (M5) fiber

Cited by 29 publications

References 18 publications

Manufacturing and Properties of Aramid Reinforced Composites

Manufacturing and Properties of Aramid Reinforced Composites

Effect of hydration on the structures and properties of poly(p-phenylene benzobisoxazole)/poly(pyridobisimidazole) block copolymer fibers

Spectroscopic elucidation of structure-property relations in filaments melt-spun from amorphous polymers

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