JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Yuhao Yang,Zejun Pu,Jiachun Zhong,Chihan Meng,Qiuxia Peng,Dayang Yu,Pan Zheng
PA6T is one of the most typical high-temperature resistant polyamides, which is widely used in military, transportation and communication fields. As an engineering plastic, thermal stability is a very important point, although there are many studies on copolyamide PA6T, but the in-depth analysis of its heat resistance and thermal degradation process is rarely studied. Therefore, two copolyamides, PA6T/66 and PA6T/610, were synthesized by high temperature and high pressure solution polycondensation method, and their thermal degradation processes and kinetic mechanisms were analyzed in depth. Firstly, the structure and composition of both were characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance spectroscopy ( 1 H NMR). The results showed that copolyamide was synthesized successfully. Thermogravimetric analysis (TGA) and thermogravimetric infrared comprehensive analysis (TG-IR) were used to analyze the heat resistance and degradation products of the two copolyamides PA6T. The results of TGA showed that the initial decomposition temperature of the two copolyamides was about 400°C, and the temperature of PA6T/610 was slightly higher. TG-IR results showed that both copolyamides maintained good thermal stability before 350°C, without the generation of degradation products and their corresponding obvious characteristic absorption peaks. Thermal decomposition products increased significantly at about 400°C, and gradually became complete after 450°C. By comparing the Kissinger method, Flynn-Wall-Ozawa method (FWO), and Coats-Redfern method (CR), the thermal degradation activation energy and kinetic reaction mechanism of the two copolyamides were obtained.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Jianfei Xia,Lingling Ni,Chenxuan Sun,Ying Zheng,Junfeng Liu,Chengtao Yu,Wei Li,Jingdai Wang,Pengju Pan
Copolymerization of diacids and diamines can produce copolyamides with diversified physical properties. Due to the interplay between even–even and odd–even diamine-diacid units, the even–even/odd–even copolyamides can show much different crystal polymorphism and phase transition behavior from the typical (co)polyamides. Herein, we synthesized the novel even–even/odd–even copolyamides from nylon 5,6 and nylon 6,6 salts and investigated their crystallization kinetics, crystalline structure, and phase transition behavior. The copolyamides display the typical isodimorphic behavior, and the solution-crystallized copolyamides experience α–γ Brill transition upon heating. Intriguingly, the crystalline structure and phase transition of copolyamides are strongly influenced by the copolymer composition and initial crystallization temperature (Tc) upon cooling due to the possible change of H-bonding structure regularity induced by the incorporated comonomer units in the crystalline phase. The 66-unit-rich copolyamides initially form the γ phase and subsequently transform into the α phase during cooling, while the 56-unit-rich ones merely crystallize in the γ phase. For the copolyamide with pseudoeutectic composition, high and low Tc promote the generation of single γ phase of PA6,6 and double γ phases of PA5,6 and PA6,6, respectively. Upon cooling, the PA6,6-type γ phase always transforms into the α phase, while the PA5,6-type γ phase is maintained. This study has elucidated the synergetic effects of copolymer composition and Tc on the crystallization and phase transition of isodimorphic copolyamides.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
IRANIAN POLYMER JOURNAL
·
2024
·
IF 2.4
Yang Yuhao,Pu Zejun,Meng Chihan,Zhong Jiachun,Pang Jiahong,Yang Kaijie,Yue Mengjie,Wu Fang
Semi-aromatic polyamides have excellent comprehensive properties and can effectively adjust thermodynamic properties through monomer composition and ratio to meet different application requirements. Therefore, in this study, two copolyamides (PA6T/66 and PA6T/610) were synthesized by one-pot method and their thermal and mechanical properties were subsequently analyzed and compared. Firstly, the chemical compositions and microstructures of the two copolyamides were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy ( 1 H NMR), wide-field X-ray diffraction (XRD) and polarized ophthalmic microscopy (POM), and the viscosities [η] of the specimens were tested. Secondly, the heat resistance of the two copolyamides was analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Subsequently, the mechanical strength of the two copolyamides was evaluated. The FTIR, NMR and XRD results show that the molecular structure and crystal morphology of the two copolyamides are highly similar, which may prove the success of the target products. The TG results show that the heat resistance of the two copolyamides is very good, with the extrapolated initial decomposition temperature above 430 °C, and PA6T/66 has better heat resistance. The DSC results show that PA6T/66 has a higher melting and glass transition temperature. The mechanical test results show that PA6T/66 has greater tensile and flexural strengths of 70 MPa and 110 MPa, respectively, while PA6T/610 has better impact toughness. The above comparative results can be extended to determine the differences in performance between long-chain and short-chain polyamides, which can provide a reference for future related research. Graphical abstract
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 2
·49678
·
IF 2.52
Jiabao Guo,Haijie Li,Bingfeng Xue,Donghui Zhu,Xiaomeng Zhang,Haitao Zhao,Xiaoguang Qiao,Zhe Cui,Peng Fu,Qingxiang Zhao,Xinchang Pang,Minying Liu
To fabricate the low-cost transparent polyamide with high heat resistance and good melt flowing property simultaneously is a huge challenge in many high-end fields due to the contradiction between these two properties. In order to balance this contradiction, in this paper, by using isophthalic acid (IPA, aromatic monomer), 4,4′-methylenebis(cyclohexylamine) (PACM, alicyclic monomer) as rigid stereoscopic monomers, 1,6-hexanediamine (HMD, aliphatic monomer) as the flexible monomer, a series of transparent poly(hexamethylene isophthalamide/poly(m-benzoyl4,4′-methylenebis(cyclohexylamine)) (PA6I/PACMI) with rigid and stereoscopic structure (corresponding to the large distance between adjacent molecular chains) were successfully synthesized. The results indicated that the newly synthesized PA6I/PACMI copolymer has an intrinsically amorphous structure and high optical transparency, which could reach as high as 90%. Furthermore, the highest glass transition temperature ( T g ) of the copolymer is over 153.9°C, at the same time, the copolymer also possesses excellent melt flowing property, which can be melt processed easily. Therefore, the newly synthesized copolymer has great advantages in many fields, and it can also shed light on the design and fabrication of high-performance materials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2021
·
IF 7.267
Chao Lin,Weipei Li,Yurong Yan,Hanhan Ke,Zhengyu Liu,Lingli Deng,Zhiming Qiu
A novel form-stable phase change material (FSPCM) based on ionic liquid/aluminum nitride/copolyamide composite were fabricated from electrospinning approach. The ionic liquid 1-hexadecyl-3-methylimidazolium bromide (IL) was chosen as phase change materials while nano aluminum nitride (AlN) and copolyamide 6/12 (CoPA) were chesen as additive and supporting matrix, respectively. The surface morphology and heat storage property had been systematically investigated by Scanning Electronic Microscopy (SEM) and Differential Scanning Calorimetry (DSC), respectively. Results showed that the diameter of the phase change fibers are 0.92–1.07 μm and was influenced by the IL and AlN content. With 57 wt% of IL and 5 wt% of AlN, the composite fiber achieved a fusion enthalpy of 86.4 J/g and the thermal conductivity was increased by 165.2% compared to that of IL/CoPA. Thermogravimetric Analysis (TGA) and thermal cycle test also indicated a good thermal stability and reusability of the composite fiber. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses indicated that new hydrogen bonds between IL and CoPA were formed in the composite and showed a significant effect on the thermal performance of the composite fibers. The electrospun composite fiber based on ionic liquids can be applied as form-stable phase change material in thermal energy storage and temperature regulation.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 9
·47132
·
IF 1.901
X. Qi,W. Wang,J. Zhang,C. Yan,Y. Zhu,F. Zhang
A series of novel aqueously soluble semi-aromatic (co)polyamides, poly[(ethylenedioxy)bis(ethylene) terephthalamide]- ran -poly[(ethylenedioxy)bis(ethylene) (2,5-dihydroxy-3,6-diallyl)terephthalamide] (CRPAOT-x), were prepared via the solid-state Claisen rearrangement reaction of poly[(ethylenedioxy)bis(ethylene) terephthalamide]- ran -poly[(ethylenedioxy)bis(ethylene) 2,5-bis(allyloxy)terephthalamide] (APAOT-x), where x (= 0, 13, 25, 50, 75, and 100) represents the molar fraction of allyloxy containing unit. APAOT-x was obtained through the interfacial copolymerization of terephthaloyl chloride, 2,5-bis(allyloxy)terephthaloyl chloride, and 2,2′-(ethylenedioxy)bis(ethylamine). The reaction conditions including reactant concentration, temperature, and solvent were optimized. The chemical structures of the target (co)polyamides and their precursors were characterized by proton nuclear magnetic resonance ( 1 H NMR) and Fourier transform infrared spectroscopies. The incorporation of hydrophilic (ethylenedioxy)bis(ethylene) units greatly improved the polymer solubility. CRPAOT-x dissolved not only in polar organic solvents such as dimethylformamide, dimethyl sulfoxide, and N-methyl pyrrolidone but also in ammonia water. Due to the presence of hydroxyl groups and oxygen-rich aliphatic units, CRPAOT-x showed excellent affinity toward epoxy resins. The microbond test indicated that the aramid fibers sized by these dual-functional polymers exhibited remarkably enhanced interfacial shear strength in epoxy matrices. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47132.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2016
·Vol. 55
·期 4
·690-698
·
IF 3.114
Wenbin Wang,Xiang Qi,Fei Zhang,Yingdan Zhu,Xinhua Wan
A series of novel semiaromatic (co)polyamides, poly(octylene terephthalamide)- ran -poly[octylene 2,5-bis(allyloxy)terephthalamide] (APA8T- x , x represents the molar fraction of allyloxy containing structure unit), were prepared via the interfacial polymerization of 1,8-diaminooctane, terephthaloyl chloride, and 2,5-bis(allyloxy)terephthaloyl chloride. The polymerization conditions were optimized in terms of the yields and the molecular weights of the resultant polymers. These polymers were converted to the target macromolecules, poly(octylene terephthalamide)- ran -poly[octylene (2,5-dihydroxy-3,6-diallyl)terephthalamide] (CRPA8T- x ), through solid state Claisen rearrangement reaction, as characterized by 1 H NMR and FT-IR spectroscopies. While APA8T- x was only soluble in very limited solvents, the solubility of CRPA8T- x in polar solvents improved remarkably, especially for those with high counit content. Due to the polarity of hydroxyl group, CRPA8T- x showed an improved hydrophilicity than APA8T- x . The treatment of aramid fibers with CRPA8T- x , as sizing agents, enhanced obviously their interfacial adhesion toward epoxy resin. The fibers sized with 0.5 wt% CRPA8T-75 solution in the mixture of 1,1,2,2-tetrachloroethane and phenol (40:60, w/w) exhibited a maximum increase of 60% in interfacial shear strength than the naked fibers. The easy preparation and the facility for the further modification through the dual functional substituents may greatly widen the application of semiaromatic polyamides. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 690–698
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 22
·e53903
·
IF 3
Rongli Zhu,Zejun Pu,Hongbo Hou,Xianyong Li,Xu Wang,Dayang Yu,Pan Zheng,Fang Wu,Jiachun Zhong
This work synthesized the pure poly (decamethylene terephthalamide) acid (PA10T) and a series of PA10T/10I through an efficient one-pot melt polymerization method. The structures, thermal behavior, crystallization performance, and mechanical properties of PA10T and PA10T/10I were investigated by FT-IR, DSC, TGA, POM, XRD, and mechanics performance testing, respectively. The thermal analysis demonstrates that the melting temperature of PA10T/10I gradually decreased with the increase of isophthalic acid (IPA) copolymerization proportions. Specifically, it was observed that, the T m1 of pure PA10T was 299.5°C, while the T m1 of PA10T/10I-4 with a linear downward trend was 284.7°C. And the introduction of IPA copolymerization has an obvious beneficial effect on the thermal stability of PA10T/10I ( T d,5 varied from 429.5 to 434.5°C) with a wider temperature range of processing, which could potentially be applied in high-temperature scenes. POM and XRD were used to characterize the crystallization behavior of all samples further. It was discovered that although adding IPA did not alter the crystal structure of PA10T, it dramatically reduced the size of crystalline grains and increased the number of crystal nuclei. In addition, the copolyamides possess excellent mechanical properties, and the tensile strength of PA10T/10I varied between 42.91 and 46.89 MPa, the bending strength varied between 76.69 and 85.83 MPa, and the izod impact strength varied between 25.41 and 29.82 kJ m −2 . Moreover, the influence of the IPA comonomer of copolyamides PA10T/10I on melting points, thermal stability, crystallization behavior, and mechanical characteristics was investigated. This work provides a reference for preparing biobased semi-aromatic copolyamides PA10T/10I with outstanding processing performance, excellent thermal characteristics, and adjustable mechanical properties.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 135
·期 31
·46531
·
IF 1.901
Guangji Zou,Pingli Wang,Wutong Feng,Zhonglai Ren,Junhui Ji
Poly(decamethylene terephthalamide) (PA10T), a bio-based high-performance semi-aromatic polyamide, has been commercialized in recent years. However, there still are some weaknesses restricting its application range, such as narrow melt processing window and low ductility. In this study, we chose dodecanedioic acid (a potential bio-based raw material) as the comonomer to prepare copolyamides [poly(decamethylene terephthalamide/decamethylene dodecanediamide), PA10T/1012] for solving these problems. The basic properties of these copolyamides were characterized by viscosity measurement, Fourier transform infrared spectrometer, proton nuclear magnetic resonance, wide-angle X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile measurement. Results show that, compared to PA10T, PA10T/1012 exhibits wider melt processing window and more outstanding elongation at break. Meanwhile, PA10T/1012 is still qualified for high temperature resistant material. Furthermore, T g , T d ,5% , T d ,10% , and T d ,max of PA10T/1012 show a linear dependence on 1012 content, which is helpful to design new bio-based copolyamides for meeting the needs of various occasions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46531.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Wutong Feng,Guangji Zou,Yue Ding,Tianhao Ai,Pingli Wang,Zhonglai Ren,Junhui Ji
A series of 10T/10X (X = 6, 8, 10, 12, 14, 16) copolyamides was synthesized, and the thermal and mechanical properties were investigated. The effects of the lengths of alkyl chains of diacids on their resultant properties were studied, and we found that the introduction of a small amount of aliphatic diacid hardly changed the lattice parameters of the copolyamides. The Tm and Tc values of the 10T/10X copolyamides decreased and had a zigzag oscillation behavior as the lengths of alkyl chains on the diacids increased. A density functional theory study showed that the observed behaviors were related to the change in hydrogen bond strength and the length mismatches of the diacids in the copolymer chains. The tensile strength decreased slightly, while the elongation at break increased significantly with an increase in the chain length of the aliphatic diacid; further, the notched impact strength decreased but was still higher than PA10T.
研究领域:
高分子科学
·
材料科学
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Kejian Yang,Qi Guo,Yanlin Liu,Jinping Ni,Zhaobin Tang,Xudong Chen
The long-ignored discoloration behavior of polyamide during polymerization has a significant impact on its properties and applications. Here, we innovatively analyzed the discoloration behavior of pentamethylenediamine-derived bio-based copolyamide (PA5T/56) and proposed a possible discoloration mechanism. Pentamethylenediamine performed cyclization reactions at high temperature to generate piperidine, which was then combined with terephthalic acid to form dipiperidine terephthalate. After being oxidized, dipiperidine terephthalate was converted to terephthalic acid bis(2-carbonyl substituted piperidine), which was believed to be responsible for the discoloration of polyamide during polymerization. Moreover, it was demonstrated that the discoloration behavior led to poor spinnability and dyeability of ultrafine polyamide fibers. This work will help to optimize the polymerization process of pentamethylenediamine-derived polyamide and expand its applications in high-performance fibers and other fields.
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）