The introduction of asymmetric heterocyclic units into poly(p-phenylene terephthalamide) and its effect on microstructure, interactions and properties

Luo, Longbo; Wang, Yazhe; Dai, Yu; Yao, Yuan; Meng, Chenbo; Cheng, Zheng; Wang, Xu; Li, Xiangyang

doi:10.1007/s10853-018-2580-1

Cited by 43 publications

(38 citation statements)

References 44 publications

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“…WAXD curves on the equatorial direction of modified PBIA fibers are shown in Figure . Content of crystalline, mesomorphic, and amorphous phase was calculated respectively . Content of different phases does not show obvious change after modification.…”

Section: Resultsmentioning

confidence: 99%

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Improving Interfacial and Compressive Properties of Aramid by Synchronously Grafting and Crosslinking

Dai

Feng

Meng

et al. 2019

Macro Materials & Eng

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Improving compressive strength of aramid and its adhesion to resin is of great significance for its application in reinforcing materials. In this study, a novel method for improving interfacial and compressive properties of aramid fiber is presented. α,α′‐Dichloro‐p‐xylene (DCX) is utilized as an external crosslinker to modify aramid fiber containing benzimidazole units during the post swelling process. Chloromethyl groups from DCX can react with benzimidazole moieties of the aramid fiber. The reaction can be regarded as crosslinking inside the fiber and grafting on the surface. By controlling the swelling effect of the solvent during modification, bulk crosslinking degree and surface grafting density can be adjusted. Therefore, intermolecular interaction and surface polarity of the aramid fiber can be improved simultaneously. After modification, the compressive strength of the fiber can be enhanced by nearly 100% and interfacial shear strength increases by 37%, while excellent mechanical properties are maintained. Therefore, comprehensive performance of aramid fiber can be improved significantly by synchronously crosslinking and grafting.

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Section: Resultsmentioning

confidence: 99%

“…All these methods can only enhance IFSS but do not have positive effect on compressive properties. Low compressive strength of aramid derives from weak interaction among polymer chains . Introduction of chemical crosslinking, which can enhance lateral interaction, is effective for improving compressive strength .…”

Section: Introductionmentioning

confidence: 99%

Improving Interfacial and Compressive Properties of Aramid by Synchronously Grafting and Crosslinking

Dai

Feng

Meng

et al. 2019

Macro Materials & Eng

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“…For these materials, tested at these conditions, the stress strain curves are not linear, but instead have a kink centered at around 2% strain [9,20,29], potentially due to the low crystallinity of the fibers [13,20,21,[29][30][31][32]. It is hypothesized that, at less than 2% strain, there is reorientation of the macromolecules, which upon unloading form structured blocks and new intermolecular bonds.…”

Section: Mechanical Properties Determinationmentioning

confidence: 99%

“…See Figs. 13, 14, 15, 16, 17 and Tables 2, 3 SN Applied Sciences (2020) 2:705 | https://doi.org/10.1007/s42452-020-2489-6 Table 5 Maximum likelihood estimated Weibull modulus scale parameter of directly-gripped specimens with shape parameter in parentheses, all scale parameters in GPa, and the numbers of specimens given in Table 2 Conditions 116 (20) 115 (22) 116 (25) 119 (27) 125 (22) 125 (18) 127 (20) 127 (18) 125 (20) 123 (22) Copolymer B 126 (15) 116 (24) 113 (15) 112 (14) 113 (16) 124 (22) 124 (15) 125 (15) 127 (24) 124 (12) 127 (19) 123 (13) Homopolymer 102 (21) 80 (15) 80 (24) 75 (16) 68 (11) 99 (29) 83 (15) 90 (19) 91 (25) 93 (20) 95 (8) 63 ( (24) 113 (28) 121 (20) 120 (23) 113 (19) 116 (19) 118 (19) Copolymer B 122 (15) 112 (8) 122 (26) 112 (16) 124 (26) 117…”

Section: Appendixmentioning

confidence: 99%

“…In this study, we examine three different fibers, all of which are commercially produced materials based on poly 5-amino-2-(p-aminophenyl)benzimidazole, or PBIA. Information on how PBIA copolymers are prepared has been previously published [2,20,21]. One homopolymer of this chemical structure and two random copolymers with different ratios of PBIA and PPTA linkages are studied herein [15].…”

Section: Introductionmentioning

confidence: 99%

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Effect of elevated temperature and humidity on fibers based on 5-amino-2-(p-aminophenyl) benzimidazole (PBIA)

et al. 2020

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Soft body armor is typically comprised of materials such as aramid. Recently, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and PPTA were introduced to the body armor marketplace. The long-term stability of these copolymer fibers have not been the subject of much research, however they may be sensitive to hydrolysis due to elevated humidity because they are condensation polymers. Efforts to evaluate the impact of environmental conditions on fiber strength is very important for the adoption of these materials in armor systems. Three PBIA-based fibers were selected for the study, and were aged at 25 °C, 75% RH; 43 °C, 41% RH; 55 °C, 60% RH; and 70 °C, 76% RH for up to 524 days. Molecular spectroscopy, scanning electron microscopy, and single fiber tensile testing were performed to characterize changes in their chemical structure, tensile strength, and failure strain as a function of exposure time to different conditions. The fibers were all found to have some reduction in strength at high humidity conditions, with an approximately 14% reduction for the copolymers and a 29% reduction for the homopolymer. Molecular spectroscopy revealed some changes which suggest that hydrolysis of the benzimidazole ring is occurring at these elevated temperatures, possibly explaining the observed change in strength.

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Holey Reduced Graphene Oxide Scaffolded Heterocyclic Aramid Fibers with Enhanced Mechanical Performance

Wen

Xiao

et al. 2022

Adv Funct Materials

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Poly(p‐phenylene‐benzimidazole‐terephthalamide) (PBIA) fibers, a kind of heterocyclic aramid fibers, possess extraordinary mechanical properties and advanced applications in aerospace, military protection, and other civilian areas. However, harsh application scenarios are putting forward even stringent requirements for the mechanical performances and environmental compatibility of PBIA fibers. Strengthening lateral interactions between polymer chains are approachable methods but ongoing challenges to obtain PBIA fibers with high‐performance. This work develops a novel holey reduced‐graphene‐oxide (HrGO)/PBIA composite fiber with a scaffolded structure, in which the HrGO plays a role of clamp to effectively band plentiful PBIA chains through the in‐plane holes. A small amount of HrGO (0.075 wt%) is able to improve the tensile strength and Young's modulus of HrGO/PBIA fibers by 11.5% and 8.3%, respectively. The small amount of well dispersed HrGO improves the crystallinity and serves as the topological constraint that enhances the lateral interaction of the PBIA chains, which is unveiled by the wide‐angle X‐ray scattering and the coarse‐grained molecular dynamics simulations. In addition, the favorable compatibility of HrGO/PBIA fibers in complex application scenarios is demonstrated by the dynamic and cyclic‐loading measurements.

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The introduction of asymmetric heterocyclic units into poly(p-phenylene terephthalamide) and its effect on microstructure, interactions and properties

Cited by 43 publications

References 44 publications

Improving Interfacial and Compressive Properties of Aramid by Synchronously Grafting and Crosslinking

Improving Interfacial and Compressive Properties of Aramid by Synchronously Grafting and Crosslinking

Effect of elevated temperature and humidity on fibers based on 5-amino-2-(p-aminophenyl) benzimidazole (PBIA)

Holey Reduced Graphene Oxide Scaffolded Heterocyclic Aramid Fibers with Enhanced Mechanical Performance

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