1
|
Ling M, Yuan J, Song Z, Gao J, Cao M, Xie H. Mechanism in palladium-catalyzed dearomative allylic reactions of benzyl phosphates with allyl borates: Insights from DFT calculations. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.113030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
2
|
Ding X, Kong H, Qiao M, Hu Z, Yu M. Study on Crystallization Behaviors and Properties of F-III Fibers during Hot Drawing in Supercritical Carbon Dioxide. Polymers (Basel) 2019; 11:polym11050856. [PMID: 31083401 PMCID: PMC6572010 DOI: 10.3390/polym11050856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 12/03/2022] Open
Abstract
In order to obtain F-III fibers with high mechanical properties, pristine F-III fibers were hot drawn at the temperature of 250 °C, pressure of 14 MPa, tension of 6 g·d−1, and different times, which were 15 min, 30 min, 45 min, 60 min, 75 min, 90 min, and 105 min, respectively, in supercritical carbon dioxide (Sc-CO2) in this article. All the samples, including the pristine and treated F-III fibers, were characterized by a mechanical performance tester, wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and thermogravimetric analysis (TGA). The results showed that the thermal stability of F-III fibers was enhanced to some extent, and the tensile strength and modulus of F-III fibers had great changes as the extension of treatment time during hot drawing in Sc-CO2, although the treatment temperature was lower than the glass transition temperature (Tg) of F-III fibers. Accordingly, the phase fraction, orientation factor fc of the (110) crystal plane, fibril length lf, and misorientation angle Bφ of all the samples were also investigated. Fortunately, the hot drawing in Sc-CO2 was successfully applied to the preparation of F-III fibers with high mechanical properties.
Collapse
Affiliation(s)
- Xiaoma Ding
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Shanghai Key Laboratory of Lightweight Composite, Shanghai 201620, China.
| | - Haijuan Kong
- School of Materials Engineer, Shanghai University of Engineer Science, Shanghai 201620, China.
| | - Mengmeng Qiao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Shanghai Key Laboratory of Lightweight Composite, Shanghai 201620, China.
| | - Zhifeng Hu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Shanghai Key Laboratory of Lightweight Composite, Shanghai 201620, China.
| | - Muhuo Yu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Shanghai Key Laboratory of Lightweight Composite, Shanghai 201620, China.
| |
Collapse
|
3
|
Trexler MM, Hoffman C, Smith DA, Montalbano TJ, Yeager MP, Trigg D, Nimer S, Calderón‐Colón X, Peitsch C, Xia Z. Synthesis and mechanical properties of para‐aramid nanofibers. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24810] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Morgana M. Trexler
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | - Christopher Hoffman
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | - Douglas A. Smith
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | | | - Matthew P. Yeager
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | - Douglas Trigg
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | - Salahudin Nimer
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | | | - Christopher Peitsch
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| | - Zhiyong Xia
- Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland 20723
| |
Collapse
|
4
|
Yang X, Tu Q, Shen X, Zhu P, Li Y, Zhang S. A Novel Method for Deposition of Multi-Walled Carbon Nanotubes onto Poly(p-Phenylene Terephthalamide) Fibers to Enhance Interfacial Adhesion with Rubber Matrix. Polymers (Basel) 2019; 11:E374. [PMID: 30960358 PMCID: PMC6419155 DOI: 10.3390/polym11020374] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 11/16/2022] Open
Abstract
In order to enhance the interfacial adhesion of poly(p-phenylene terephthalamide) (PPTA) fibers to the rubber composites, a novel method to deposit multi-walled carbon nanotubes (MWCNTs) onto the surface of PPTA fibers has been proposed in this study. This chemical modification was performed through the introduction of epoxy groups by Friedel⁻Crafts alkylation on the PPTA fibers, the carboxylation of MWCNTs, and the ring-opening reaction between the epoxy groups and the carboxyl groups. The morphologies, chemical structures, and compositions of the surface of PPTA fibers were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly deposited onto the surface of PPTA fibers with the covalent bonds. The measurement of contact angles of the fibers with polar solvent and non-polar solvent indicated that the surface energy of deposited fibers significantly increased by 41.9% compared with the untreated fibers. An electronic tensile tester of single-filament and a universal testing machine were utilized to measure the strength change of the fibers after modification and the interfacial adhesion between the fibers and the rubber matrix, respectively. The results showed that the tensile strength had not been obviously reduced, and the pull-out force and peeling strength of the fibers to the rubber increased by 46.3% and 56.5%, respectively.
Collapse
Affiliation(s)
- Xuan Yang
- College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, China.
| | - Qunzhang Tu
- College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, China.
| | - Xinmin Shen
- College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, China.
| | - Pengxiao Zhu
- State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery, Xuzhou Construction Machinery Group, Xuzhou 221004, China.
| | - Yi Li
- State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery, Xuzhou Construction Machinery Group, Xuzhou 221004, China.
| | - Shuai Zhang
- College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, China.
| |
Collapse
|
5
|
Yu B, Ling M, Xie H. A DFT study on the mechanism and origins of the ligand-controlled regioselectivity of a palladium-catalyzed dearomatic reaction of 1-(chloromethyl)naphthalene with phenylacetonitrile. NEW J CHEM 2019. [DOI: 10.1039/c9nj05515k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
DFT calculations demonstrated that the bulky ligand tBuPPh2 generates para-substituted products, while the small ligand Me2PPh provides ortho-substituted products.
Collapse
Affiliation(s)
- Binbin Yu
- School of Pharmaceutical and Materials Engineering
- Taizhou University
- Taizhou
- P. R. China
| | - Menghang Ling
- Department of Applied Chemistry
- Zhejiang Gongshang University
- Hangzhou 310018
- P. R. China
| | - Hujun Xie
- Department of Applied Chemistry
- Zhejiang Gongshang University
- Hangzhou 310018
- P. R. China
| |
Collapse
|
6
|
Li Z, Liu B, Kong H, Yu M, Qin M, Teng C. Layer-by-Layer Self-Assembly Strategy for Surface Modification of Aramid Fibers to Enhance Interfacial Adhesion to Epoxy Resin. Polymers (Basel) 2018; 10:E820. [PMID: 30960745 PMCID: PMC6403607 DOI: 10.3390/polym10080820] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 12/03/2022] Open
Abstract
In this work, the layer-by-layer self-assembly technology was used to modify aramid fibers (AFs) to improve the interfacial adhesion to epoxy matrix. By virtue of the facile layer-by-layer self-assembly technique, poly(l-3,4-Dihydroxyphenylalanine) (l-PDOPA) was successfully coated on the surface of AFs, leading to the formation of AFs with controllable layers (nL-AF). Then, a hydroxyl functionalized silane coupling agent (KH550) was grafted on the surface of l-PDOPA coated AFs. The properties such as microstructure and surface morphology of AFs before and after modification were characterized by FTIR, XPS and FE-SEM. The results confirmed that l-PDOPA and KH550 were successfully introduced into the surface of AFs by electrostatic adsorption. The interfacial properties of AFs reinforced epoxy resin composites before and after coating were characterized by interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and FE-SEM, and the results show that the interfacial adhesion properties of the modified fiber/epoxy resin composites were greatly improved.
Collapse
Affiliation(s)
- Zhaomin Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Accupath Medical (Jiaxing) Co., Ltd., Jiaxing 314000, China.
| | - Baihua Liu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Haijuan Kong
- School of Materials Engineer, Shanghai University of Engineer Science, Shanghai 201620, China.
| | - Muhuo Yu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Minglin Qin
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
- Accupath Medical (Jiaxing) Co., Ltd., Jiaxing 314000, China.
| | - Cuiqing Teng
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
| |
Collapse
|
7
|
Fabrication and characterization of differentiated aramid nanofibers and transparent films. APPLIED NANOSCIENCE 2018. [DOI: 10.1007/s13204-018-0722-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
8
|
Tang C, Li X, Li Z, Hao J. Interfacial Hydrogen Bonds and Their Influence Mechanism on Increasing the Thermal Stability of Nano-SiO₂-Modified Meta-Aramid Fibres. Polymers (Basel) 2017; 9:E504. [PMID: 30965805 PMCID: PMC6418657 DOI: 10.3390/polym9100504] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/09/2017] [Accepted: 10/09/2017] [Indexed: 11/22/2022] Open
Abstract
For further analysis of the effect of nano-doping on the properties of high polymers and research into the mechanism behind modified interfacial hydrogen bonds, a study on the formation probability of nano-SiO₂/meta-aramid fibre interfacial hydrogen bonds and the strengthening mechanism behind interfacial hydrogen bonds on the thermal stability of meta-aramid fibres using molecular dynamics is performed in this paper. First, the pure meta-aramid fibre and nano-SiO₂/meta-aramid fibre mixed models with nanoparticle radiuses of 3, 5, 7 and 9 Å (1 Å = 10-1 nm) are built, and then the optimization process and dynamics simulation of the models are conducted. The dynamics simulation results indicate that the number of hydrogen bonds increase due to the doping by nano-SiO₂ and that the number of interfacial hydrogen bonds increases with the nanoparticle radius. By analysing the hydrogen bond formation probability of all the atom pairs in the mixed model with pair correlation functions (PCFs), it can be observed that the hydrogen bond formation probability between the oxygen atom and hydrogen atom on the nanoparticle surface is the greatest. An effective way to increase the number of interfacial hydrogen bonds in nano-SiO₂ and meta-aramid fibres is to increase the number of hydrogen atoms on the nano-silica surface and oxygen atoms in the meta-aramid fibre. By using the radial distribution function (RDF), the conclusion can be further drawn that the hydrogen bond formation probability is at a maximum when the atomic distance is 2.7⁻2.8 Å; therefore, increasing the number of atoms within this range can significantly increase the formation probability of hydrogen bonds. According to the results of chain movement, the existence of interfacial hydrogen bonds effectively limits the free movement of the molecular chains of meta-aramid fibres and enhances the thermal stability of meta-aramid fibres. The existence of interfacial hydrogen bonds is one of the important reasons for formation of the stable interface structure between nanoparticles and meta-aramid fibres. In addition, a nanoparticle with a small radius improves the interfacial hydrogen bond energy density and interfacial interaction energy density, enhancing the stability of the mixed model interface.
Collapse
Affiliation(s)
- Chao Tang
- College of Engineering and Technology, Southwest University, Chongqing 400715, China.
- School of Electronics and Computer Science, University of Southampton, Southampton SO171BJ, UK.
| | - Xu Li
- College of Engineering and Technology, Southwest University, Chongqing 400715, China.
| | - Zhiwei Li
- College of Engineering and Technology, Southwest University, Chongqing 400715, China.
| | - Jian Hao
- Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China.
| |
Collapse
|