GREEN CHEMISTRY
·
2021
·Vol. 23
·期 19
·7646-7658
·
IF 10.182
Hui-Jun Chen,Qi-Yao Bai,Mei-Chen Liu,Gang Wu,Yu-Zhong Wang
Aramid fiber products have been widely used in both civil and military fields. However, the improper disposal of waste aramid fiber products could result in potential environmental problems and waste of valuable resources. In comparison with mechanical recycling, recycling of aramid fibers into aramid nanofibers (ANFs) as a novel 1D building block for functional materials has better development prospects and has got greater attention. However, the time-consuming preparation cycle of the existing approaches is not conducive to rapid and large-scale production or an in situ study of the mechanism. Herein, based on the in situ size control of solid KOH, a proton donor-assisted deprotonation system for both Kevlar fibers and their various products, i.e. KOH(aq)/DMSO system, was developed to prepare ANFs with a well-defined and uniform structure. Through this novel deprotonation system, not only is the preparation time of 0.2 wt% ANFs greatly shortened to 26 min (a tenth of the time of the state-of-the-art technology) but also the production of ANFs with high concentration (4.0 wt%) and in large amounts (1500 mL) can be realized within several hours. Importantly, the deprotonation process of Kevlar fibers as well as the formation mechanism and structural restoration of ANFs were studied by in situ characterization methods. In addition, the controlled preparation of ANF aerogels with diverse microstructures was realized by the structural restoration of ANFs under different protic solvents and subsequent lyophilization, and the physical properties of ANF aerogels were investigated. Significantly, the various Kevlar products and ANF aerogels both can be rapidly and highly efficiently dissociated to ANFs, undoubtedly demonstrating the proof-of-concept for recycling of waste aramid products and closed-loop recycling of ANF-based materials. Therefore, this work not only offers a better understanding of the mechanism of both the deprotonation of aramid fibers and the restoration of ANFs, but also provides a highly feasible, highly efficient and cost-effective recycling strategy of waste aramid products and ANF-based materials.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2023
·Vol. 44
·期 9
·6083-6096
·
IF 5.2
Jingyi Nie,Jianfei Liao,Danni Wang,Meiyun Zhang,Zhaoqing Lu,Bin Yang
Aramid materials have been applied in many important civil and military fields. But a major drawback to aramid materials is the susceptibility to UV-induced damage. In this work, aramid nanofibers (ANFs) and ANF/nano-ZnO composites were used to protect aramid materials from UV-induced damage. ANF protective layer was created on the surface of aramid fibers, and the ANF-coated aramid fibers could be further prepared to aramid paper. Moreover, ANF/nano-ZnO composites were synthesized and used for stronger UV-blocking ability. ANFs provided effective protection to aramid material. The properties after UV exposure (about 9.3 years in the natural environment) were largely improved: ANFs improved the retention rate of strength by 17.96% for aramid fibers and by 16.93% for aramid paper. ANFs also showed synergistic effect with UV-absorbing inorganic nanoparticles. After UV exposure, the tensile strength of aramid paper with ANF/nano-ZnO composites was even higher than the initial value (121.55%), and the retention rate of strength was 2.43 times higher than the original aramid paper.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Bo Zhang,Tianze Lian,Xiaoming Shao,Ming Tian,Nanying Ning,Liqun Zhang,Wencai Wang
A novel method of constructing nanostructures on the surface of aramid fiber (AF) was demonstrated in this article. Through the π–π* interaction between the aramid nanofiber (ANF) and graphene (G), the G/ANF dispersion stably existed in water. In an alkaline solution of tannic acid (TA) and polyethyleneimine (PEI), a TA/PEI (TP) layer was deposited on the surface of AF to introduce functional groups. Then, the modified AF was impregnated with the G/ANF dispersion to construct surface nanostructures to enhance the interfacial adhesion between the fiber and rubber. The results showed that the H pull-out force of the AF and rubber after impregnating with G, ANF, and G/ANF was increased by 15.3, 21.5, and 84.7%, respectively, compared with the untreated AF. The Raman spectroscopy and SEM results show that there is a π–π* interaction between G and ANF, and the ANFs are firmly attached to the surface of G. The hybrid G/ANF nanofiller can form 3D nanostructures on the surface of AF to improve the mechanical interlocking and stress transfer between the fiber and the rubber matrix, thereby achieving excellent interfacial adhesion while maintaining the excellent mechanical properties of AF.
研究领域:
材料科学
·
复合材料
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Nan Zhou,Long Xia,Naiyu Jiang,Yingze Li,Hanxiong Lyu,Hongyan Zhang,Xiaohu Zou,Wenbo Liu,Dongxing Zhang
The application of aramid fiber (AF)/polyetheretherketone (PEEK) composites is currently hindered by the inert surface and poor wettability of AF, resulting in weak interfacial adhesion and poor mechanical properties. Surface coating and the introduction of nanostructures have been proven to be effective approaches to address this problem. Herein, a simple hybrid sizing agent has been developed to modify the AF surface, consisting of soluble polyimide (PI) as a compatibilizer, carboxyl-functionalized carbon nanotubes (CNT-COOH) as a rigid unit, and aramid nanofibers (ANF) as a flexible component. The synergetic effects of PI and the multiscale flexible-rigid structure (CNT-COOH/ANF) contribute to the formation of chemical and physical bonds between AF and PEEK matrix, further improving the interfacial adhesion and stress transfer efficiency. Attributed to the enhanced wettability and roughness of AF, compared with unsized AF, the flexural strength (220.97 MPa), modulus (10.72 GPa), ILSS (13.36 MPa), and storage modulus (12.93 GPa) of the AF/PEEK composite increase by 132.60%, 99.00%, 182.97%, and 82.70% respectively. Additionally, the flexible-rigid nanonetwork facilitates the penetration of the PEEK resin into pore spaces. This simple and effective approach exhibits promising potential in enhancing the interfacial bonding of AF/PEEK composites.
研究领域:
材料科学
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Fengdong Teng,Na Li,Ying Yuan,Yutong Cao,Junrong Yu,Yan Wang,Zuming Hu
Poor interfacial bond strength and complex processing limit the widely use of para-aramid paper. Here, the meta-poly(p-phenylene terephthalamide) (MPPTA) was obtained by introducing poly(m-phenylene isophthalamide) (PMIA) segments into the PPTA rigid molecular chains via secondary polymerization. The rigid-soft molecular structure not only gives MPPTA excellent thermal stability, but also enables the MPPTA fibrids to bond to the PPTA chopped fibers by plastic deformation during hot pressing. The tensile strength of Precipitated-MPPTA-paper (P-MPPTA-p) was increased by 20.3 % compared to Precipitated-PMIA-paper (P-PMIA-p). And the interfacial bond strength of aramid paper can be further improved by combining MPPTA solution and PPTA nonwoven fabric through a simpler and more efficient solution casting method, which together with more moderate hot pressing conditions can lead to the tensile strength of aramid paper up to 109.1 MPa, as well as exhibiting higher resistance to tearing and heat aging. The present study provides a new idea for the efficient preparation of para-aramid paper with excellent comprehensive performance.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 4
·621
·
IF 4.329
Xiao Wang,Shi Li,Yuanyuan Tu,Jiwen Hu,Zhenzhu Huang,Shudong Lin,Xuefeng Gui
The pH-responsive membrane is a new wastewater treatment technology developed in recent years. In this paper, a novel film with intelligent pH-responsiveness was first prepared by blending functional gates comprised of hydrolyzed aramid nanofibers (HANFs) into aramid nanofiber (ANF) membranes via a vacuum filtration method. Those as-prepared membranes exhibited dual pH-responsive characteristics, which were featured with a negative pH-responsiveness in an acidic environment and a positive pH-responsiveness in basic media. These dual pH-responsive membranes also exhibited a high tensile strength which could still reach 55.74 MPa (even when the HANFs content was as high as 50 wt%), a high decomposition temperature at ~363 °C, and good solvent resistance. The membranes described herein may be promising candidates for a myriad of applications, such as the controlled release of drugs, sensors, sewage treatment, etc.Keywords:aramid nanofiber;hydrolyzed aramid nanofiber;vacuum filtration;dual pH-responsive characteristic;high strength
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 39
·51011
·
IF 3.125
Bo Zhang,Xiaoming Shao,Tianze Liang,Wencai Wang,Ming Tian,Nanying Ning,Liqun Zhang
In order to improve the interfacial adhesion between aramid fiber (AF) and rubber matrix, a simple and facile method of aramid nanofiber (ANF) coating is demonstrated in this article. Tannic acid (TA) and polyethyleneimine (PEI) are polymerized in an alkaline solution to form a thin TA/PEI (TP) layer that is deposited on the surface of AF to introduce functional groups such as hydroxyl and amino groups. Then, the ANF coating is utilized to construct nanostructures on the surface of AF to improve the interfacial adhesion between the fiber and the rubber. Through hydrogen bonding and/or π-π stacking between the TP layer and the ANF, the ANF coating is firmly attached to the surface of AF. Compared with the untreated fiber, the interfacial adhesion of AF coated with ANF after 1, 3, 5, 7, 9 deposition cycles is increased by 27.8%, 29.1%, 31.5%, 43.1%, and 30.3%, and the mechanical properties of the fibers remain almost unchanged. This method shows its advantages of simple, facile, and time-effective, which is of great significance for industrial applications.
研究领域:
材料科学
·
表面工程
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Wenwen Wu,Xianhui Dong,Na Li,Yan Wang,Junrong Yu,Zuming Hu
Waste heterocyclic aramid fiber (HAF) retains the same or similar properties as the original fiber. It will be a waste of resources if these waste HAFs cannot be handled sensibly and efficiently. Based on the above background, in this paper, discarded HAFs are recycled for the preparation of heterocyclic aramid nanofiber aerogel membrane (HANFAM) at greatly reduced cost. The strategy started from the chemical exfoliation of discarded HAFs, which were converted into HANFAM through the bladed coating followed by the freeze-drying techniques. The prepared HANFAMs have tunable and ultra-low dielectric constants and low dielectric loss, with the dielectric constant range of 1.31–1.47 and the dielectric loss range of 0.0026–0.0073 at 1 MHz, which are much lower than other reported aerogel materials. Therefore, it can be used as an important substrate to secure high-speed circuit transmission in integrated electronic devices. In addition, the obtained HANFAMs exhibit a high initial thermal decomposition temperature of 514 °C and a low thermal conductivity of 28.87–40.73 mW/(m·K). This work provides a new perspective on the fabrication of HANFAMs with ultra-low dielectric and excellent thermal insulation based on upcycled waste HAFs.
研究领域:
材料科学
·
环境科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 21
·7588
·
IF 4.927
Ge Ma,Qianshu Wang,Jun Ye,Lifan He,Longhai Guo,Xiaoyu Li,Teng Qiu,Xinlin Tuo
The comprehensive balance of the mechanical, interfacial, and environmental requirements of waterborne polyurethane (WPU) has proved challenging, but crucial in the specific application as the binder for high-performance polymer fiber composites. In this work, a multi-step chain extension (MCE) method was demonstrated using three kinds of small extenders and one kind of macro-chain extender (CE) for different chain extension steps. One dihydroxyl blocked small molecular urea (1,3-dimethylolurea, DMU) was applied as one of the CEs and, through the hybrid macrodiol/diamine systems of polyether, polyester, and polysiloxane, the WPU was developed by the step-by-step optimization on each chain extending reaction via the characterization on the H-bonding association, microphase separation, and mechanical properties. The best performance was achieved when the ratio of polyether/polyester was controlled at 6:4, while 2% of DMU and 1% of polysiloxane diamine was incorporated in the third and fourth chain extension steps, respectively. Under the condition, the WPU exhibited not only excellent tensile strength of 30 MPa, elongation of break of about 1300%, and hydrophobicity indicated by the water contact angle of 98°, but also effective interfacial adhesion topara-aramid fabrics. The peeling strength of the joint based on the polysiloxane incorporated WPU after four steps of chain extension was 430% higher than that prepared through only two steps of chain extension. Moreover, about 44% of the peeling strength was sustained after the joint had been boiling for 40 min in water, suggesting the potential application for high-performance fabric composites.Keywords:waterborne polyurethane;chain extension;binder;para-aramid
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Huimin He,Yanran Li,Hongzhen Liu,Yoonseob Kim,Aixin Yan,Lizhi Xu
Recent research on conductive hydrogels has revealed their potential for building advanced soft bioelectronic devices. Their mechanical flexibility, water content, and porosity approach those of biological tissues, providing a compliant interface between the human body and electronic hardware. Conductive hydrogels could be utilized in many soft tools such as neural electrodes, tactile interfaces, soft actuators, and other electroactive devices. However, most of the available conductive hydrogels exhibit weak mechanical properties, which hinders their application in durable biointegrated systems. Here, we report aramid nanofiber-based hydrogels providing a combination of high elasticity, strength, and electrical conductivity. Highly branched aramid nanofibers (ANFs) provide a robust three-dimensional (3D) framework resembling those in load-bearing soft tissues. When interlaced with poly(vinyl alcohol) (PVA) and cross-linked with both noncovalent and covalent interactions, the nanofiber composites exhibit a high water content of ∼76.4 wt %, strength of ∼7.5 MPa, ductility of ∼407%, and shape recovery of ∼99.5% under cyclic tensile stress of 0.3 MPa. Mobile ions impart a conductivity of ∼2 S/m to the hydrogels, enabling large-strain sensors with stable operation. In addition, the embedded silver nanoparticles afford broad-spectrum antimicrobial activities, which is favorable for medical devices. The versatility of aramid nanofiber-based composites suggests their further possibilities for functionalization and scalable fabrication toward sophisticated bioelectronic systems.
研究领域:
生物医学工程
·
材料科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2021
·
IF 4.43
Yadi Liu,Sheng Zhou,Ning Zhao,Jian Xu,Zhihao Shen,Xing-He Fan,Qi-Feng Zhou
A series of aramids containing hydroxyl side group (NOM-OH c , where c is the molar fraction of hydroxyl substitution in the polymer, and c = 0, 10, 20, 40, 60, 80, 100) were synthesized by direct high-temperature polycondensation . The synthesis employed a facile process. The monomer , 4,4'-(terephthaloylbis(azanediyl))bis(2-hydroxybenzoic acid), was prepared simply via an esterification reaction. The chemical structures of the soluble aramids were confirmed by 1 H NMR. And the molecular weight and mass dispersity of the aramids were obtained by size exclusion chromatography , instead of the traditional intrinsic viscosity method. The use of unsymmetrical monomers and the introduction of hydroxyl side group into the aramid structure decrease the conjugation of the polymer main chain, and thus the resulting aramid has excellent solubility in relatively polar solvents , such as N -methy-2-pyrrolidone, dimethylsulfoxide , N , N -dimethylacetamide, and N , N -dimethylformamide. As a result, the molding processability of the aramids and their composites is greatly improved. For example, films can be made by solution spinning and casting. The films have good mechanical strength , with tensile strength , tensile modulus , and elongation at break in the range of 68–95 MPa, 2.65–3.12 GPa, and 5–10%. The thermal resistance of the aramids is still quite good, with 5% weight loss temperatures in nitrogen and in air in the range of 360–430 °C.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MACROMOLECULAR MATERIALS AND ENGINEERING
·
2019
·Vol. 304
·期 6
·1900044
·
IF 3.038
Yu Dai,Jiabao Feng,Chenbo Meng,Longbo Luo,Jiaqiang Qin,Xiangyang Liu
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.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）