Structure, morphology, and properties of PBZT and methyl pendant PBZT fibers

Mehta, Vinay R.; Kumar, Satish

doi:10.1002/(sici)1097-4628(19990718)73:3<305::aid-app1>3.0.co;2-8

Cited by 12 publications

(27 citation statements)

References 19 publications

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“…A similar phenomenon may also be playing a role in the reported decrease in tensile properties of analogous systems 222–225. The observation of a non‐fibrillar morphology226 in free annealed MePBZT fiber, can be interpreted as indication of inter‐ as well as intra‐fibrillar crosslinking; however, chain degradation has also been mentioned as a possible factor for this change in morphology227 as well as for the decrease in tensile strength. Comparatively, fibers tension heat‐treated at similar temperatures were found to not only retain their fibrillar nature, but developed a skin/core morphology.…”

Section: Chemical Modificationsmentioning

confidence: 88%

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

Hu¹,

Jenkins

Min

et al. 2003

Macro Materials & Eng

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174

105

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Synthesis, structure, and properties of rigid‐rod polymers with special emphasis on poly(p‐phenylene benzobisoxazole) (PBO) and poly(p‐phenylene benzobisthiazole) (PBZT) have been reviewed. Recent studies on chemical modifications and molecular simulations have also been given. After nearly 20 years of research and development, PBO fiber was commercialized in the late 1990s. However, due to processing difficulties, the concept of the so called molecular composites has not been successful. Development of the high compressive strength M5 and dihydroxy‐PBI fibers clearly suggest that there is potential for further developing properties of this class of materials. Opto‐electronic properties have also been reviewed.Synthesis of PBZT.magnified imageSynthesis of PBZT.

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Section: Chemical Modificationsmentioning

confidence: 88%

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

Hu¹,

Jenkins

Min

et al. 2003

Macro Materials & Eng

Self Cite

174

105

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“…The fiber compressive strength was determined using recoil and loop tests . The recoil test was conducted at 2.54 cm gage length, and a sharp scissor was used for cutting the fiber.…”

Section: Methodsmentioning

confidence: 99%

“…From these observations, recoil compression failure probability ( p ) was determined as follows

p = \frac{K}{K + N}

where K is the number of kinked halves, and N is the number of halves without kink. The recoil failure probability was plotted against the recoil stress to determine the stress level at which the recoil failure probability was 0.5 . This stress level is reported as the recoil compressive strength of the fiber.…”

Section: Methodsmentioning

confidence: 99%

“…Compressive strength was also measured using the elastica loop test . In theory, the ratio of the major to the minor axis of the loop ( L / D ) (Figure ) should be constant and equal to 1.34, as long as the fiber behaves elastically . As the loop was made smaller, the L / D ratio began to increase, as shown in Figure , and the kinks developed on the compression side of the loop.…”

Section: Methodsmentioning

confidence: 99%

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The Effect of Asymmetric Heterocyclic Units on the Microstructure and the Improvement of Mechanical Properties of Three Rigid‐Rod co‐PI Fibers

Luo

Wang

Zhang

et al. 2016

Macro Materials & Eng

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Three kinds of rigid-rod copolyimide (co-PI) fibers are prepared by wet-spinning of their precursor poly(amic acid)s, which are copolymerized from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), p-phenylenediamine (PDA), and the third asymmetric heterocyclic diamines, including 2-(4-aminophenyl)-5-aminobenzoxazole (BOA), 2-(4-aminophenyl)-5-aminobenzimidazole (PABZ), and 2,5-bis(4-aminophenyl)-pyrimidine (PRM), respectively. The asymmetry is increasing in the order PRM < BOA ≈ PABZ. The introduction of asymmetric heterocyclic units results in mesomorphic order structure and decreases the size of microvoid of PI fiber, which apparently improves the toughness of PI fiber and shows positive effects on mechanical properties. The tensile strength and initial modulus of co-PI fibers are in the ranges of 2.6-3.2 GPa and 91.8-133.5 GPa, respectively. The lowest asymmetry leads to the highest lateral order, crystal orientation, and initial modulus of BPDA/PDA/PRM co-PI. Moreover, the introduction of asymmetric heterocyclic units can effectively improve compressive properties. BPDA/PDA/PABZ co-PI fiber shows the highest loop strength and recoil compressive strength due to hydrogen bonding interactions. The highest orientation leads to the lowest transverse strength of BPDA/PDA/ PRM co-PI fibers, reducing the recoil compressive strength.

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“…By incorporating a thermally reactive cross-linking moiety fluorene into PBZT (267,268), iii. Cross-linking benzobisthiazole rigid-rod copolymers via labile methyl or dimethylephenoxy pendent groups (261,(269)(270)(271)(272)(273)(274)(275), or forming copolymers of tetramethylbiphenyl PBZT/PBZT (276,277), iv. Cross-linking PBO fibers with polyphenylene sulfide pendent groups (278), and v. Cross-linking PBZT by introducing benzocyclobutene (BCB) crosslinking moieties in PBZT backbone (264,270,(279)(280)(281)(282).…”

Section: Compressive Properties As Listed Inmentioning

confidence: 99%

Rigid‐Rod Polymers

Wang¹,

Jiang²,

Adams³

2011

Encyclopedia of Polymer Science and Technology

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Pursuing high strength and high modulus polymer fibers and novel electrooptical properties have motivated much research activity in rigid‐rod polymers in the past 40 years. In this review, we examine the synthesis, structures, and properties of rigid‐rod polymers with emphasis on polybenzobisoxazoles (PBO), polybenzobisthiazoles (PBZT) and polybenzimidazoles (PBI), beginning with their solution properties, especially lyotropic liquid crystallinity. High performance fibers spun from lyotropic liquid crystalline polyphosphoric acid (PPA) solution are described. The characterization of fiber properties including mechanical, thermal, electrical, and optical properties is summarized. PBO (Zylon) and PIPD (M5) fibers were successfully commercialized in high strength applications such as body armor, ropes, cables, and recreational equipment in the last 10 years, and we discuss the possible causes of rapid degradation of some PBO fibers. The concepts of molecular composites and nanocomposites provide new applications in antiballistic materials, fire protection, athletic equipment, cables, strings, ropes, cordage, sails, multilayer circuits, and catalyst supports. Recently, rigid‐rod polymer films have drawn attention in the electrooptical fields, especially for phosphoric acid (PA)‐doped PBI membranes (Celtec MEAs) in the applications of high temperature fuel cells. Computer simulation has been employed as a powerful tool to predict the properties of the rigid‐rod polymers.

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Structure, morphology, and properties of PBZT and methyl pendant PBZT fibers

Cited by 12 publications

References 19 publications

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

The Effect of Asymmetric Heterocyclic Units on the Microstructure and the Improvement of Mechanical Properties of Three Rigid‐Rod co‐PI Fibers

Rigid‐Rod Polymers

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