JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 45
·51348
·
IF 3.125
Junming Chen,Jinxuan He,Longquan Liu,Yongzhu He,Xiaobin Huang
Polymeric ablative materials (PAMs) are widely used in spacecraft currently for thermal insulation. However, it is challenging to find a single filler that can improve both ablative and mechanical properties of PAMs. In this study, a new type of hybrid cross-linked polyphosphazene microspheres (PHC) is added to ethylene propylene diene monomer (EPDM) composites as a filler for the first time and its influence on the ablation, mechanical, and thermal properties of EPDM is investigated. The results show that the addition of 3 phr PHC increases the ablation performance by about 10% and enhances the mechanical properties by 20% approximately. In addition, the ablation mechanism is studied in accordance with SEM, FTIR, and Raman spectroscopy. On the one hand, PHC has the effect of catalyzing carbonization, thus increasing the rate of residual carbon; on the other hand, PHC changes the morphology of the char layer, forming a cross-linked structure containing P─O─Si bonds on the surface. The findings regarding catalyzing carbonization and the special char layer structure could guide the design of ablative materials.
研究领域:
高分子材料
·
航天热防护
·
复合材料科学
·
材料化学
·
热力学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 7
·3111-3118
·
IF 3.069
Lulu Pan,Jianfeng Ban,Li Ren,Zuocai Zhang,Qingyuan Peng,Shaorong Lu
This paper aims at elucidating the influence of liquid crystals (LCs) on the properties of shape memory polymers. A novel series of liquid crystalline shape memory polyurethanes, named LC-SF-SMPUs were successfully prepared by chemically cross-linking polyester sisal fibre cellulose (PSF) with polycaprolactone (PCL) and 4,4′-di(6-hydroxyhexyloxy)biphenyl (BP6). The effect of BP6 on the morphology and properties has been carefully investigated. The results show that the cross-linking structures provided a stable network, high elasticity and good thermal stability to the LC-SF-SMPUs, and demonstrate that the obtained LC-SF-SMPUs not only maintained the LC property of BP6, but also enhanced the intrinsic crystallization of PCL. Thus, the LC-SF-SMPUs showed excellent multi-shape memory properties with two crystalline transition temperatures. In the triple-shape memory effect of LC-SF-SMPUs, the first step of strain recovery is associated with the melting transition of the soft segment crystals of the polyurethane matrix, and the second step of strain recovery results from the melting transition of the LC mesogen. The strain fixity improved with increasing BP6-content, due to the enhanced crystallinity. However, the total strain recovery decreased as a result of the lubrication of the BP6 chains. This work demonstrates a new combination of LC properties and multi-shape memory properties, which makes it ideal for many potential applications in new smart devices.
研究领域:
高分子材料
·
智能材料
·
功能高分子
·
形状记忆聚合物
·
生物基材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Miao Guo,Shuhao Wang,Kaifeng Gu,Xiaoxiao Song,Yong Zhou,Congjie Gao
Performance enhancement of the TFC membrane depends on the fine design of the functional layer. In this study, a gradient cross-linking strategy has been successfully applied to fabricate an ultra-thin gradient cross-linked PVA (GC-PVA) functional layer with the aid of surfactant on a polysulfone (PSF) support membrane. Such a strategy was accomplished by impregnating the crosslinker (Trimesic acid) on the porous support membrane prior to PVA coating. As confirmed by XPS and EDX studies, the GC-PVA membrane features a gradient cross-linked structure, where the bottom surface is densely cross-linked while the top is only slightly cross-linked. Overall, the lowest thickness achieved by the gradient-crosslinked ultrathin functional layer was 75.4 nm. This strategy significantly improved water flux compared with the conventional fully cross-linked PVA membranes while similar salt rejections can be maintained. In addition, the impact of key fabrication parameters, such as the concentration of PVA, surfactant, crosslinker, and the post-treatment temperature has been systematically studied. The optimized membrane had a significantly high water flux of 72.9 L m −2 h −1 at 0.2 MPa and showed rejection rates of 38.2% and 90.7% towards NaCl, Na 2 SO 4 aqueous solution (500 mg/L), respectively.
研究领域:
材料科学
·
膜分离技术
·
高分子化学
·
纳米功能材料
·
环境工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Chenyu Lin,Tianqi Yang,Haiyuan Zhang,Donghuang Wang,Wenkui Zhang,Yao Wang,Yang Xia,Hui Huang,Xinhui Xia,Yongping Gan,Xinping He,Xinyong Tao,Jun Zhang
Solid-state lithium metal batteries with high energy density and safety have gained increasing attention due to their potential applications. However, the practical use of solid electrolytes is hindered by several challenges. These include poor compatibility at the electrode–electrolyte interface, low ionic conductivity at room temperature, and fast capacity degradation. To address these issues, here we propose ternary strategies by in-situ cross-linked plastic crystal electrolyte (in-situ PCE) based on succinonitrile (SN). Through the in-situ polymerization of SN with polyacrylonitrile/poly(vinylidene difluoride) (PAN/PVDF) nanofibers separator, excellent mechanical strength and compatibility at the electrode–electrolyte interface are achieved. The cross-linked structure of thermally polymerized ethoxylated trimethylolpropane triacrylate (ETPTA) immobilizes the SN molecule, preventing its contact with the lithium metal and inhibiting irreversible side reactions. Additionally, a LiF-rich passivation layer is employed to further protect the SN at the electrolyte-lithium metal interface. The dual protection from ETPTA and LiF offers excellent stability to lithium. Hence, the in-situ PCE exhibits high ionic conductivity (0.79 mS cm −1 at 30 °C) and wide electrochemical window (4.56 V, vs Li + /Li). The cells exhibit excellent cycling stability and high-rate performance. LiFePO 4 //Li cells retain 96.6 % capacity after 1000 cycles at 10C rate. This study provides valuable insights into the development of high-performance solid-state electrolytes.
研究领域:
材料科学
·
电化学
·
能源存储
·
高分子化学
·
固态离子学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Xinming Du,Zhe Wang,Wenchang Liu,Jingmei Xu,Zhaoyu Chen,Chunmei Wang
A series of phenolphthalein-based poly (arylene ether ketone) (PEK) copolymer are synthesized to prepare anion exchange membranes (AEMs). The ion group 1-vinyl imidazole is introduced on the unit of phenolphthalein-based as a hydrophilic segment and cross-linking agent. The structure of resulting membranes was investigated by 1 H NMR and FT-IR. The well-defined microphase-separated structures were verified by TEM and SAXS profiles. The cross-linked membrane of ImPEK-0.4 exhibits high hydroxide conductivity (0.0836 S/cm, at 80 °C), excellent mechanical performance (69.6 MPa) and the maximum swelling ratio is only 7.95% at 80 °C. Furthermore, the excellent alkaline stability is demonstrated by immersing the prepared membrane in 1 M NaOH at 40 °C for 400 h. The ionic conductivity is still high to 0.0381 S/cm for ImPEK-0.4. These results indicate that combining phase separation architecture and crosslinking may possess potential applications for alkaline fuel cells (AFCs).
研究领域:
高分子材料科学
·
电化学能源材料
·
燃料电池技术
·
膜分离工程
·
聚合物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Shengyang Zhou,Yali Zhao,Jifu Zheng,Suobo Zhang
A novel polymer of intrinsic microporosity , acyl chloride-functionalized polymer of intrinsic microporosity (PIM-COCl), was obtained by hydrolysis under alkaline conditions and acylation in thionyl chloride of PIM-1. PIM-COCl is soluble in common organic solvents , and it is used for the first time for organic solvent nanofiltration (OSN). The acyl chloride groups in PIM-COCl can be further cross-linked with an amine-functionalized polyacrylonitrile (APAN) ultrafiltration membrane to form an interconnected layer, which shrinks pore size and provides better structural stability and selectivity. The PIM-COCl composite membranes exhibit high rejection and alcohol flux during OSN. Compared with the reported PIM OSN membranes , [email protected] exhibits higher rejection for crystal violet (408 g mol −1 , over 94%) in ethanol and several times higher alcohol flux. The membrane shows outstanding stability in ethanol for 14 days. PIM provides a microporous structure, while the interconnected layer maintains this structure in organic solvents via hydrogen bonding , electrostatic interactions and covalent cross-linking. Other PIMs can readily undergo acyl chloride functionalization, which provides them with high reactivity towards amine groups to form stable interconnected layers. This work offers new strategies for the design and preparation of high performance OSN membranes .
研究领域:
高分子材料科学
·
膜分离技术
·
纳米过滤
·
有机溶剂处理
·
功能化聚合物
·
化学稳定性
·
材料化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）