OPTICAL FIBER TECHNOLOGY
·
2013
·Vol. 20
·期 1
·28-31
·
IF 1.187
Jiao-Yang Li,Xu-Guang Huang,Wei Xu,Dong-Rui Xiao,Ze-Bing Zhong
A biocompatible fiber-optic pH sensor based on Fresnel reflection technique and a sensing coating is presented. Sodium alginate and polyethylenimine are alternatively deposited on the sensing fiber end to form the sensing coating via a layer-by-layer electrostatic self-assembly technique. An optical switch is added to the measurement system for the convenience of fast calibration. A linear, monotonic and fast response in a large pH range (from pH 5.87 to pH 10.55) is obtained with the resolution of 0.01 pH unit. The sensitivity of the pH sensor is 0.018 R.I.U/pH. It is not influenced by fluctuations of light source.
研究领域:
生物医学工程
·
传感技术
·
分子生物学
·
转化医学
·
生物材料
✓ 已验证
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Peng Wei,Dong Huang,Chen Luo,Yang Sui,Xi Li,Qingkun Liu,Bensheng Zhu,Chuanbo Cong,Qiong Zhou,Xiaoyu Meng
Due to its uncomplicated manufacturing procedure for large-scale industrialization and adaptable conductivity, the competitive proton exchange membrane (PEM) matrix employed is sulfonated poly (ether ether ketone). However, the conflict between the strong proton conductivity and high stability of SPEEK-based PEM constantly upsets the equilibrium; the primary chain of SPEEK will conduct more protons if additional sulfonic acid is introduced, but it also causes a high swelling ratio and lowers stability. To tackle this challenging issue, we coupled the high intrinsic proton conductivity of phosphotungstic acid (HPW) and the excellent stability of polyimide (PI) nanofibers in a single PEM. In particular, sandwich-structure hybrid membranes (PI/SPEEK + HPW) were created to reduce HPW loss under operational conditions, further improving stability. Consequently, the swelling ratio and conductivity of the premium sandwich-structure PI/SPEEK + HPW-20 were 29% and 223.4 mS cm −1 under 60 °C and 100% RH, their respective values were 8% larger than those of SPEEK. Its proton conductivity reached 170.9 mS cm −1 during 13 days of exposure under 60 °C and 100% RH, which would be 30% better than that of SPEEK over the same treatment. Protons in these membranes were transported through Grotthus and vehicle mechanism, and the establishment of an acid-rich layer at the surface among PI nanofiber with HPW/SPEEK, which was confirmed by FTIR, XPS , and TEM , is responsible for these superior performances. From our point of view, our findings might encourage more studies into the creation of high-performance PEM.
研究领域:
材料科学
·
高分子化学
·
能源材料
·
电化学
·
膜科学与技术
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2016
·Vol. 23
·期 4
·2539-2548
·
IF 3.195
He Hui,Hou Xunan,Ma Beibei,Zhuang Linzhou,Li Chuanfa,He Shihong,Chen Shuixia
Viscose fiber was oxidized with sodium periodate to prepare a reactive dialdehyde viscose fiber (DAVF) containing abundant aldehyde groups. A solid amine adsorbent (DAVF-PEI) with high amino density for CO 2 capture was then prepared by modifying DAVF with polyethylenimine (PEI). Response surface methodology (RSM) based on a three-level, three-factorial design was used to optimize the synthesis conditions of DAVF, in which multiple linear regression equations of aldehyde content and fiber mass loss degree were constructed. The well-designed DAVF was then employed as a support to graft with PEI via Schiff base reaction to prepare a solid amine fiber (DAVF-PEI) for CO 2 adsorption. The experimental results verified that DAVF-PEI possessed good thermo-stability and high CO 2 adsorption capacity (4.11 mmol/g). DAVF-PEI also showed promising regeneration performance, which could maintain almost the same adsorption capacity for CO 2 after ten adsorption and desorption recycles.
研究领域:
材料化学
·
环境科学
·
高分子科学
·
化学工程
·
吸附分离
·
碳捕集技术
✓ 已验证
DOI
高影响因子
TETRAHEDRON
·
2019
·Vol. 75
·期 31
·4174-4179
·
IF 2.379
Yingying Zuo,Feng Xiong,Jing Zhao
Organic sulfur compounds have broad applications in biology, medicine and material sciences and intensive efforts have been devoted to developing mild and general C–S bond-forming methods. However, a mild, transition-metal-free, direct C–H bond functionalization method remains elusive. Here, we report the use of an internal oxidant-directing strategy to achieve this goal. The cascade reactions described here show excellent chemoselectivity and a wide substrate scope for both oxyamines and sulfenylation reagents. This study enlarges the synthesis toolbox for preparing structurally diverse sulfilimines under mild conditions.
研究领域:
有机化学
·
合成化学
·
药物化学
·
生物医学材料
·
分子生物学
✓ 已验证
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2019
·
IF 6.864
Chao Liu,Yufei Dong,Yang Lin,Hongxia Yan,Wenbo Zhang,Yan Bao,Jianzhong Ma
In order to simultaneously improve the dispersibility of graphene in the bismaleimide (BMI) resin and the interfacial interaction between them, the polytriazine@RGO nanocomposite (PTZ@RGO) with terminal amine was obtained by the method of one-step precipitation polymerization. The PTZ@RGO hybrid nanocomposite was then chosen as filler to improve the mechanical and tribological properties of BMI resin. Through effective surface modification, the compatibility and interface strength between graphene and BMI matrix were significantly improved, leading to the flexural strength , impact strength , anti-friction, wear resistance and thermal stability of PTZ@RGO/BMI composites were significantly improved as compared to those of neat BMI resin and RGO/BMI composites. The other properties including hardness and thermal properties of composites were all improved with increasing amount of PTZ@RGO fillers. These high performance BMI composites have a great potential for application in aerospace, mechanical engineering and other automobile brake devices.
研究领域:
材料科学
·
高分子复合材料
·
表面工程
·
摩擦学
·
航空航天材料
✓ 已验证
DOI
高影响因子
TETRAHEDRON-ASYMMETRY
·
2010
·
IF 2.625
Zhen-Wei Zhang,Gui Lu,Miao-Miao Chen,Ning Lin,Yong-Bo Li,Tamio Hayashi,Albert S.C. Chan
The first asymmetric Mannich-type reaction of methyl isocyanoacetate with N -sulfonylimines catalyzed by cinchona alkaloid derivatives yielded 2-imidazolines with high diastereoselectivities and good enantioselectivities (up to >99:1 dr and 70% ee). This reaction provided a convenient route to access various substituted 2-imidazoline-4-carboxylates and related α,β-diamino acids in high enantiomeric purities.
研究领域:
有机化学
·
药物化学
·
不对称合成
·
催化化学
·
生物有机化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Ruihan Wang,Nanxi Dong,Guofeng Tian,Gang Liu,Bo Zhou,Shengli Qi,Dezhen Wu
In order to allow polyimide (PI) to resist the erosion of atomic oxygen (AO) in Low Earth Orbit to extend the life of the aircraft, an in-situ precursor network approach was proposed to manufacture the inorganic gradient microstructure across the organic/inorganic transition interface and simplify the process, which create a three-tier microstructure film and lead the dense SiO 2 protective layer firmly grasps the PI film. Benefiting from the integrated structure, SiO 2 -coated PI film shows remarkable surface and interface state after 3000 times mechanical bending, which able to delay the initial AO corrosion caused by the defect of the protective layer, resistance to AO reported as AO erosion yield of 2.39 × 10 −26 cm 3 O atom −1 under 7 × 10 21 O atoms cm −2 AO fluence. This work proposes a novel approach for the fabrication of high-performance and AO resistant PI to enable the aircraft to complete more efficient and highly integrated flight missions and shows great potential in the general preparation of organic-inorganic interface.
研究领域:
高分子材料科学
·
航天材料工程
·
表面与界面化学
·
空间环境效应
·
功能涂层技术
✓ 已验证
DOI
高影响因子
POLYMER TESTING
·
2022
·
IF 4.931
Yang-he Mo,Hui Wang,Shao-hua Jin,Ke-lin Peng,Zi-ming Yang,Pu-wang Li,Yu Chen
Fast curing hydrogels are highly valuable in the skin care industry. Multi-arm polyethylene glycol (PEG) is a commonly used crosslinking agent for the preparation of fast curing hydrogels. However, the hydrogel preparation using multi-arm PEG crosslinking agents usually requires the end group modifications of reactants, which makes the preparation process complicated and produces hydrogels with low curing rates. In the present study, a fast in situ curing hydrogel, 4-arm-PEG-succinimidyl carbonate/carboxymethyl chitosan (PEG-SC/CMCS), was prepared using 4-arm-PEG-SC as the crosslinking agent and carboxymethyl chitosan (CMCS), a derivative of natural polysaccharide with excellent comprehensive properties, as the framework without any end groups modified. The structure and properties of the prepared hydrogel were characterized by FTIR, XRD, SEM, rheology and swelling kinetics. The effects of reaction conditions on the structure and properties of hydrogel were investigated. The PEG-SC/CMCS hydrogel exhibited pH-sensitive swelling behaviors. Its application potential in skin care products is demonstrated with its excellent sustained-release performance of Vitamin C, a model drug for skin treatment, and high adsorption capacity of heavy metal ions that are easily deposited on skin surface. Our work has provided a new strategy for building multifunctional gel materials for skin care and offered a PEG-SC/CMCS hydrogel with great application potentials.
研究领域:
生物材料
·
高分子化学
·
药剂学
·
皮肤科学
·
组织工程
·
药物递送系统
·
环境毒理学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）