Journal of Spectroscopy
·
2013
·
IF 0
Dandan Sun,Jiang Li,Qinghua Pan,Chaowei Hao,Guoqiao Lai
PA6/LiCl composites were synthesized by in situ anionic polymerization based on the interaction between the inorganic salts and PA6. Sodium hydroxide as initiator and N-acetylcaprolactam as activator were used in the preparation of PA6/LiCl composites with variety of LiCl content. X-ray diffraction (XRD) and differential scanning calorimeter (DSC) testing results showed that both of degree of crystallinity and melting temperature of the composites were decreased under the influence of LiCl. And the γ crystal phase proportion increased with increasing the LiCl content to appropriate amount.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
MACROMOLECULES
·
2022
·
IF 6.057
Yuanyuan Dou,Nan Tian,Zhenbo Ning,Ni Jiang,Zhihua Gan
Polyesteramides have attracted much attention due to their intriguing properties. However, the synthesis of di- or triblock polyesteramides based on polyamide 6 (PA6) remains challenging owing to their harsh reaction conditions. In this work, we introduced a new strategy to synthesize poly(ε-caprolactone)-block-PA6-block-poly(ε-caprolactone) (PCL-b-PA6-b-PCL) in a mild way. A series of well-designed copolymers were characterized by gel permeation chromatography, 1H, DOSY, and 13C NMR, and their crystallization and melting behavior, degradation rate, and compatibilization effect on PA6/PCL blends were found to be strongly composition dependent. Interestingly, the copolymers exhibited diverse spherulite morphologies, including curving stems and banded spherulites, which also correlated with the different relative content of PA6. Besides, PA6 nanodomains could act as physical cross-linking points to improve the tensile strength and Young’s modulus of PCL. This work fills the synthesis gap of well-defined PA6-based triblock polyesteramides, providing new materials for material modification and elucidation of some basic scientific questions.
研究领域:
高分子科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 13
·e55150
·
IF 2.7
Yongjun Wang,Yintao Guo,Shuimi Zhong,Qisong Lin,Feng Gao,Wenxing Chen,Wangyang Lu
The preparation process from waste fibers to regenerated fibers is an environmental significance work. In this work, liquid chromatography/time-of-flight mass spectrometry, advanced polymer chromatography/multi-angle laser-light-scattering/refractive index detector, and two-dimensional wide-angle X-ray diffractometry were employed to characterize the polycaprolactam(PA6) fibers above oligomers composition and content, molecular weight and distribution, crystallization and orientation, and analyzing the changes in mechanical properties. The total content of oligomers in physical and chemical regenerated PA6 fiber is 2.084 wt% and 1.812 wt%, individually, which is higher than that in waste PA6 fiber. And the oligomer content of C1–C4 (cyclic monomer, cyclic dimer, cyclic trimer, and cyclic tetramer) in the regenerated PA6 fiber is higher than that of waste PA6 fiber. The regenerated PA6 fiber sample contains more low-molecular-weight substances, making it easier to form crystal nuclei and crystallize. During the dyeing process of the regenerated PA6 fiber, the γ crystal transformed into α crystal. The tensile strength of physical and chemical regenerated PA6 fiber is lower than that of waste PA6 fiber. And after dyeing, the oligomers content of regenerated PA6 fiber is significantly decreased, especially in C1–C4 oligomer. However, the crystalliniy and orientation of regenerated PA6 fibers were improved, which also leads to the fracture strength increased by about 20% compared to undyed fibers.
研究领域:
材料科学
·
环境科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 37
·e55936
·
IF 2.7
Guang-Zhao Li,Hao Yu,Hongwei Zhang,Rui Han,Pan He,Jiaxuan Cao,Qian Lu,Gen Liu,Gang Chen,Wenyan Wang,Weicai Wan,Yujun Wei,Shuai Zhang
This work investigated the composites (PA6/BF) made of basalt fiber (BF) and nylon 6. To improve the interfacial bonding between the fibers and the polymer matrix, and to enhance the thermal and mechanical properties of the composites, polyhedral oligosilsesquioxanes (POSS) with epoxide groups was introduced to modify the surface of BFs using the slurry coating method. It is revealed that the mechanical properties of the composites increased and then decreased with increasing POSS coating. The composite PA6/BF-POSS3 with BFs modified with a POSS solution of 3.0 wt% showed the best properties. The tensile strength of PA6/BF-POSS3 was 130.8 MPa, 26.4% higher than that of the PA6/BF and 126.3% higher than that of neat PA6. In addition, PA6/BF-POSS3 exhibited a 5% weight loss temperature of 417.7, 35.6°C higher than that of PA6/BF. The chemical bonding formed between the amide and epoxide groups, and the hydrogen bonding formed between the amide groups and hydroxyl groups were believed to be the main reasons for the improved interfacial interaction and improved properties.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2022
·Vol. 62
·期 4
·1052-1060
·
IF 2.573
Wentong Gao,Baoyin Yu,Shuhang Li,Shao Chen,Yuhong Zhu,Bo Zhang,Yilei Zhang,Hong Cai,Bing Han
SEBS-based thermoplastic elastomers modified by PA6 with maleic anhydride grafted copolymer (SEBS-g-MAH or PP-g-MAH) as the compatibilizer were prepared, and the effects of compatibilizer and PA6 on the mechanical and surface properties of blends were investigated in detail. The dosage ratio of SEBS-g-MAH to PA6 at 3:5 is an optimal combination for improving mechanical properties. The maleic anhydride of SEBS-g-MAH can react with the terminal amine of PA6 to form the SEBS-g-PA6 graft copolymer as a bridge at the phase interface. With the increase of PA6, a typical sea-island structure gradually appears in the matrix, and when PA6 is 15 phr, the tensile strength and ultimate elongation both reach the maximum of 18.58 MPa and 1097%, and the corresponding wear rate is only 54.4% of that before modification. Furthermore, the addition of PA6 also significantly reduced the contact angle of the blends to below 90°, transforming the hydrophobic surface into a hydrophilic surface. These outcomes provide an effective strategy for reinforcing and modifying the surface properties of thermoplastic elastomers and benefit the development of SEBS in industrial applications.
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
·
2022
·Vol. 140
·期 8
·e53536
·
IF 3.057
Wengui Wang,Fan Wang,Heng Li,Yaochi Liu
To improve the flame retardancy of PA6/PA66 copolymer, a phosphorus-nitrogen flame retardant DDP-M was successfully synthesized via melt condensation reaction between 2-[(5-oxo-6H-phosphanthridin-5-yl)methyl]butanedioic acid (DDP) and melamine (Mel). Its structure, product composition, and thermal stability were characterized by FTIR, nuclear magnetic resonance spectroscopy (NMR), matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and thermogravimetric analysis (TGA). The results suggested that DDP-M was a hybrid flame retardant. A series of flame-retardant PA6/PA66 composites were prepared by melt extrusion. Their thermal stability and flame retardancy were assessed by differential scanning calorimetry (DSC), TGA, limiting oxygen index (LOI), and vertical burning test (UL-94). The combustion behavior demonstrated that DDP-M can effectively improve flame retardancy, achieving 32% of LOI value and UL-94 V-0 rating with only 9 wt.% addition. No melt dripping was accomplished by adding 12% DDP-M. The high dose (15%) harmed the flame-retardant properties. The results of pyrolysis gaseous productions analysis and residual carbon analysis revealed the flame-retardant mechanism of DDP-M was a synergistic effect of melamine inducing gaseous phase flame retardancy and highly condensed P-N char layers inducing condensed phase flame retardancy. The composites retained good mechanical properties due to the good dispersibility and compatibility between polyamide and DDP-M.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Benjamin Tawiah,Sana Ullah,Zhixing Cheng,Mohammad Z. Rahman,Yang Ming,Daming Chen,Chanchal K. Kundu,Wei Cai,Anthony C. Yuen,Bin Yu,Zheng Guangping,Bekeshev Amirbek,Bin Fei
Polyamide 6 (PA6) is a widely used engineering polymer with excellent mechanical and thermal properties. However, its inherent flammability, low thermal conductivity, and limited understanding of its nanomechanical and ferroelectric properties limit its engineering applications in high-performance composites. Herein, we fabricate a multi-functional PA6 composite with excellent flame retardancy, enhanced thermal conductivity, and improved ferroelectric response using Microporous Transition Metal Phosphides (MTMP). An optimal 3 wt% MTMP loading resulted in 83 % and 87 % improvement in the fire performance index and the flame retardancy index, respectively. Furthermore, a 30 % reduction in fire growth rate, a 67 % improvement in the smoke-to-heat release ratio, a 35.8 % increase in the LOI value, and a V-0 rating was achieved due to the enhanced radical quenching and condensed phase mechanism of MTMP. The thermal conductivity improved by ∼205 % and the maximum polarization of the composite reached 1.53 μC-cm −2 at 200 Kv/cm. The average permittivity increased to 83.8 with an approximate capacitance of 14.8 pF at the least resistance of ∼1.63 GΩ due to the enhanced ferroelectric response resulting from the charge storage and field-induced phase switching effects of MTMP. A significant improvement in nanoindentation hardness and Young's modulus was obtained with a 129 % improvement in the bulk material tensile strength due to the physically restrictive topological polymer chain interlock mechanism. This study offers an important perspective on the development of multi-functional polymer composites with potential applications in the energy, electronics, aerospace, and automotive sectors.
研究领域:
材料科学
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高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 20
·2946
·
IF 4.7
Lin Wang,Yuyang Li,Chenyang Yan,Xiangmei Li,Jiyu He,Rongjie Yang
In order to mitigate the release of toxic phosphine from aluminum hypophosphite in twin-screw processing, montmorillonite–melamine cyanurate was prepared by three methods: (1) mechanical intercalation, (2) water intercalation and (3) in situ intercalation. The sheet spacing of montmorillonite was increased from 1.140 nm to 1.141 nm, 1.208 nm and 1.217 nm for these three methods, respectively, and scanning electron microscope (SEM) and transmission electron microscopy (TEM) proved that melamine cyanurate was successfully inserted into the montmorillonite sheets. The montmorillonite–melamine cyanurate from in situ intercalation can best inhibit the release of PH3from aluminum hypophosphite, and the peaks of phosphine, mean values of phosphine and integral of phosphine were reduced by 81.9%, 72.1% and 72.2%, respectively. The mode of action of montmorillonite–melamine cyanuric inhibition of the emission of phosphine from aluminum hypophosphite can be attributed to the physical absorption of montmorillonite and the chemical bonding of melamine cyanurate. In addition, in situ intercalation can slightly improve flame retardancy, attributed to incomplete exfoliation of montmorillonite sheets.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBON
·
2024
·
IF 10.5
Xin Li,Haiyan Li,Zhike Li,Hongxin Luo,Nanqi Shi,Jiaying Jin,Changqing Yu
Enhancing the tribological characteristics of polyamide 6 (PA6) represents an effective strategy for extending the service life of self-lubricating PA6 composites. In this investigation, hollow mesoporous carbon spheres (HMCs) with an average diameter of 10 μm were synthesized using the template method, and the crucial factors influencing HMCs preparation were thoroughly examined. Successful synthesis of polyalphaolefin oil-containing microcapsules (PAO40@HMCs) was achieved, utilizing HMCs as microcontainers and PAO40 lubricant as the core material. The self-lubricating PAO40@HMCs microcapsules exhibited a notable oil content of 76.0 wt%. The tribological properties of the prepared self-lubricating PA6 composites were significantly better than those of pure PA6. When the content of PAO40@HMCs microcapsules in the composite reached 7 wt%, the coefficient of friction (COF) for the PA6 composite decreased by 87.9% (from 0.420 to 0.051), and the wear loss was reduced by 80% (from 0.115 to 0.023 g/0.5h). Through an analysis of the morphology and transfer film of the wear surface and friction pair, it was evident that microcapsules played a pivotal role in enhancing the self-lubricating properties of PA6 composites.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 14
·7620-7628
·
IF 3.049
Shuo Fan,Ruchao Yuan,Dequn Wu,Xueli Wang,Jianyong Yu,Faxue Li
A facile route of ‘copolymerization/blending’ was proposed to fabricate silicon/nitrogen synergistically reinforced flame-retardant PA6 nanocomposites with simultaneously improved anti-dripping and mechanical properties. Firstly, a persistently inherent flame-retardant PA6 (FR-PA6), with 1,3-bis(3-aminopropyl)tetramethyl disiloxane (MSDS), was synthesized via controllable amidation and a polycondensation reaction. Melamine cyanurate (MCA) nanoparticles as a ‘gas phase’ synergistic agent were then added into FR-PA6 to further improve its flame retardancy. The primarily obtained FR-PA6 could be extinguished after a few melt droplets dropped as ignited, and passed the V-2 rating with enhanced mechanical properties, while PA6 had no rating (NR). The prepared FR-PA6/MCA nanocomposites could attain a limiting oxygen index (LOI) value of 32.7%, and passed the V-0 level with only 1 melting droplet with similar mechanical properties to PA6. Accordingly, the special ‘condensed-gas phase’ synergistic flame-retardant mechanism of FR-PA6/MCA nanocomposites was proposed through studying the residues and pyrolysis volatiles. This work provided a facile route as a model for developing functional PA6 for diverse engineering applications.
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
JOURNAL OF POLYMER ENGINEERING
·
2018
·Vol. 39
·期 1
·16-24
·
IF 0.778
Xiaochao Liu,Dengwang Lai,Yuejun Liu,Pu Shi,Wenzhi Wang,Jinghua Tan,Long Mao,Jun Yang
In this study, PA6-66/γ-aminopropyltriethoxysilane-modified clay nanocomposites were prepared by in situ polymerization. It was found that the γ-aminopropyltriethoxysilane was chemically grafted onto clay successfully, and the covalent bond was formed between the clay and polymer chains. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) results indicated that intercalated and exfoliated nanocomposites were obtained. The PA6-66 nanocomposites exhibited improved mechanical performance compared to that of neat PA6-66. Most importantly, the PA6-66 nanocomposites showed significantly improved toughness. In comparison with neat PA6-66, the rupture stress and elongation at the break of the nanocomposite with only 0.5 wt% clay increased 91.9% and 91.8%, respectively. The excellent toughness of PA6-66 nanocomposites should be mainly ascribed to the combined effects of strong polymer-clay interaction, the intercalated-exfoliated structures of clay, refined crystalline, formation of γ-form crystals, and decreased crystallinity of PA6-66.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Jiahe Lin,Chongyi Chi,Yuxia Zhang,Jianrong Lin,Qinhui Chen
The interfacial interaction determines the morphology of polymer blends and affects their properties. Herein, snowman-like SiO2@polystyrene (PS) Janus particles (JPs) were synthesized by the phase separation method, and the JPs modified by epoxysilane (EJPs) were used as compatibilizers on PS/PA6 blends. The morphology transformation of PS/PA6 blends and the migration process of EJPs in blends with different processing times were studied. With prolonged processing time, EJPs migrate to the phase interface gradually. PS/PA6 blends with EJPs undergo a similar morphology transformation of sea island, cocontinuous, and sea island to that without EJPs. However, EJPs play refining and fibrotic roles on the dispersed phase, which increases the continuity of PA6. As a result, a continuous PA6 skeleton can be obtained by etching the PS phase from PS/PA6 blends (60/40/1.0) mixed for 5 min. The PA6 skeleton perfused with reduced graphene oxide (rGO) shows electrical conductivity. Moreover, PA6/rGO composites show perfect solar vapor generation properties due to the capillary action of microchannels and the photothermal conversion property of rGO. The water evaporation rate reaches 1.84 kg/m2 h under 1 sun irradiation in the presence of PA6/rGO9 composites, which is 4.7 times more than pure water. The phase separation method is one of the promising industrialization methods for Janus preparation, and PA6/rGO9 composites are expected to be used for solar water evaporators.
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
危险品化学品经营许可证（带存储）