Ballistic fibers: A review of the thermal, ultraviolet and hydrolytic stability of the benzoxazole ring structure

Holmes, Gale A.; Rice, Kirk D.; Snyder, Chad R.

doi:10.1007/s10853-005-5597-1

Cited by 77 publications

(48 citation statements)

References 31 publications

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“…Past studies have shown that fibers based on the aramid moiety and azole moiety found in PBIA-co-PPTA2 fibers can be susceptible to acid-catalyzed hydrolysis [6,20,21]. Through the use of difference FTIR spectra, where the infrared spectra taken from the unconditioned sample are subtracted from the spectra of fibers which have been subjected to the water treatment, the evolution of changes in chemical structure can be evaluated [22][23][24][25].…”

Section: Spectroscopy -Ftir Resultsmentioning

confidence: 99%

“…Although the imidazole group has been shown to be more hydrolytically stable, due to resonance stabilization, than oxazole groups like those found in PBO [6], in neutral water, benzimidazole is at least half protonated [26,27]. The 2-imidazolinium ion that is formed has been shown to undergo hydroxide ion attack to form a tetrahedral addition intermediate that decomposes the imidazole ring to form an amide linkage and primary amine ( Figure 12) [28].…”

Section: Spectroscopy -Ftir Resultsmentioning

confidence: 99%

“…Research by Holmes et al [6,7] has shown that woven fabrics from SBA may be susceptible to hydrolytic damage and localized folding damage that can occur during use. To quantify this damage, fiber tows are harvested from the woven fabric.…”

Section: Introductionmentioning

confidence: 99%

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Testing and analyses of copolymer fibers based on 5-amino-2-(p-aminophenyl)-benzimidazole

et al. 2015

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Fibers containing 5-amino-2-(p-aminophenyl)benzimidazole are being considered for use as reinforcement in soft body armor applications. Past research in this laboratory has resulted in a suite of tests that have been used to detect degradation in other fibers and are now being applied to the fibers in question. Due to the architecture of the yarns in this study, two methods to extract single filaments for tensile testing were described and analyzed. A dry method resulted in fibers with surface damage, reflected in a high standard deviation in strength. A wet extraction method showed a reduction in surface damage and a lower standard deviation in strength. Fourier Transform Infrared analysis detected signs of hydrolysis in the fibers that were exposed to water. Although no noticeable loss in tensile strength was noted upon exposure, the possibility of hydrolysis in these fibers may indicate a need for further study.

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Section: Spectroscopy -Ftir Resultsmentioning

confidence: 99%

Section: Spectroscopy -Ftir Resultsmentioning

confidence: 99%

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Testing and analyses of copolymer fibers based on 5-amino-2-(p-aminophenyl)-benzimidazole

et al. 2015

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“…Gale A. Holmes and Chad R. Snyder I n a recent review [1] of the potential degradation mechanisms of the ballistic fiber poly (p-phenylene benzobisoxazole, i.e., PBO), ultraviolet (UV) radiation exposure, exposure to moisture, elevated temperature exposure, and mechanical folding have been identified as mechanisms that may compromise the structural integrity of the active ballistic fiber during use. Since answers related to the long-term durability of the armor are sought, any testing methodology must allow relevant degradation mechanisms to occur under field conditions and controlled exposure conditions without compromising the structural integrity of the armor.…”

Section: Safety and Reliabilitymentioning

confidence: 99%

Materials Science and Engineering Laboratory Polymers Division :

Amis¹,

Snyder²

2008

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“…However, PBO is known to be susceptible to ultraviolet light 4 and undergoes a self-sensitized photo-induced electron-transfer reaction. [5][6][7] The photostability of PBO is unsatisfactory.…”

Section: Introductionmentioning

confidence: 99%

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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Ballistic fibers: A review of the thermal, ultraviolet and hydrolytic stability of the benzoxazole ring structure

Cited by 77 publications

References 31 publications

Testing and analyses of copolymer fibers based on 5-amino-2-(p-aminophenyl)-benzimidazole

Testing and analyses of copolymer fibers based on 5-amino-2-(p-aminophenyl)-benzimidazole

Materials Science and Engineering Laboratory Polymers Division :

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

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