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Xu X.,Key Laboratory for Ultrafine Materials of Ministry of Education | Liu J.,Key Laboratory for Ultrafine Materials of Ministry of Education | Chen P.,Key Laboratory for Ultrafine Materials of Ministry of Education | Wei D.,Key Laboratory for Ultrafine Materials of Ministry of Education | Guan Y.,Key Laboratory for Ultrafine Materials of Ministry of Education
Journal of Applied Polymer Science | Year: 2016

The thermal aging behavior of poly(3,3,3-trifluoropropyl)methylsiloxane was investigated by thermal gravimetric analysis and isothermal aging tests, and the results indicated the degradation mechanism II, oxidation scission of the side groups, played a more important role when the temperature was below 350°C. The addition of ceria had significantly improved the thermal stability of fluorosilicone rubber (FSR) by inhibiting the oxidation scission. Moreover, two types of ceria including laminar-structure ceria (LS-CeO2) and nanoparticle ceria (N-CeO2) were prepared and surface was modified by KH570 and characterized by scanning electron microscopy, transmission electron microscope, and X-ray diffractometer. FSR incorporated with modified LS-CeO2 and N-CeO2 revealed a significant improvement on the heat resistant properties. In particular, after having been thermal oxidative aged for 70 h at 250°C, FSR containing 2 wt % of modified N-CeO2 maintained 72.6% of tensile strength and 63.9% of elongation at break, respectively, while FSR without ceria completely failed. © 2016 Wiley Periodicals, Inc.


Jiang H.,Key Laboratory for Ultrafine Materials of Ministry of Education | Zhang H.,Key Laboratory for Ultrafine Materials of Ministry of Education | Fu Y.,Key Laboratory for Ultrafine Materials of Ministry of Education | Guo S.,Peking University | And 5 more authors.
ACS Nano | Year: 2016

One of the biggest challenging issues of carbon nanomaterials for Li ion batteries (LIBs) is that they show low initial Coulombic efficiency (CE), leading to a limited specific capacity. Herein, we demonstrate a simple template self-volatilization strategy for in situ synthesis of mesoporous carbon nanotube/Ag nanoparticle (NP) hybrids (Ag-MCNTs) to boost the LIBs' performance. The key concept of Ag-MCNTs for enhancing LIBs is that a small trace of Ag NPs on MCNTS can greatly restrict the formation of a thicker solid electrolyte interphase film, which has been well verified by both transmission electron microscopy results and quantum density functional theory calculations, leading to the highest initial CE in all the reported carbon nanomaterials. This uncovered property of Ag NPs from Ag-MCNTs makes them exhibit a very high reversible capacity of 1637 mAh g-1 after 400 discharge/charge cycles at 100 mA g-1, approximately 5 times higher than the theoretical value of a graphite anode (372 mAh g-1), excellent rate capability, and long cycle life. © 2015 American Chemical Society.


Wang J.,East China University of Science and Technology | Wang J.,Key Laboratory for Ultrafine Materials of Ministry of Education | Sun F.,East China University of Science and Technology | Sun F.,Key Laboratory for Ultrafine Materials of Ministry of Education | And 6 more authors.
Journal of Donghua University (English Edition) | Year: 2013

Chitosan (CS) was successfully modified in supercritical carbon dioxide (scCO2) by grafting method to enhance its water solubility. In this work, a three-arm star-like fluorinated polymer was synthesized by atom transfer radical polymerization (ATRP) method and applied as a surfactant in supercritical carbon dioxide (scCO2). Then 2-acrylamido-2-methyl propane sulfonic acid (AMPS) was grafted onto CS (CS-g-PAMPS) in H2O/scCO2 inverse emulsion. The effects of mass ratio of water and surfactants (Rw/s) and pressure of scCO2 on the grafting reaction were investigated. The grafting rate, particle size, and dispersity in water of CS-g-PAMPS varied greatly as Rw/s and pressure of scCO2 changed. It could be found that the value of Rw/s at 12 and the pressure of scCO2 at 30 MPa were the optimum conditions for the grafting reaction. CS-g-PAMPS prepared in this reaction system has higher grafting rate, smaller particle sizes, and better dispersity in water than those prepared via conventional methods. Copyright © 2013 Editorial Department of Journal of Donghua University.


Zhang Y.,Key Laboratory for Ultrafine Materials of Ministry of Education | Wang M.,Key Laboratory for Ultrafine Materials of Ministry of Education | Ye J.,Institute of Stomatology | Lang M.,Key Laboratory for Ultrafine Materials of Ministry of Education
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2016

Novel poly(ε-caprolactone)-b-poly(ethylene glycol)-b-poly(ε-caprolactone) (PCL-PEG-PCL) bearing pendant hydrophobic γ-(carbamic acid benzyl ester) groups (PECB) and hydrophiphilic amino groups (PECN) were synthesized based on the functionalized comonomer γ-(carbamic acid benzyl ester)-ε-caprolactone (CABCL). The thermal gelation behavior of the amphiphilic copolymer aqueous solutions was examined. The phase transition behavior could be finely tuned via the pendant groups, and an abnormal phenomenon occurred that the sol-gel transition temperature shifted to a higher temperature for PECB whereas a lower temperature for PECN. The micelles percolation was adopted to clarify the hydrogel mechanism, and the effect of the pendant groups on the micellization was further investigated in detail. The results demonstrated that the introduction of γ-(carbamic acid benzyl ester) pendant groups significantly decreased the crystallinity of the copolymer micelles whereas amino pendant groups made the micelles easy to aggregate. Thus, the thermal gelation of PEG/PCL aqueous solution could be finely tuned by the pendant groups, and the pendant groups modified PEG/PCL hydrogels are expected to have great potential biomedical application. © 2016 Wiley Periodicals, Inc.


Su Y.,Key Laboratory for Ultrafine Materials of Ministry of Education | Zhu Y.,Key Laboratory for Ultrafine Materials of Ministry of Education | Yang X.,Key Laboratory for Ultrafine Materials of Ministry of Education | Shen J.,Key Laboratory for Ultrafine Materials of Ministry of Education | And 4 more authors.
Industrial and Engineering Chemistry Research | Year: 2013

A nanocomposite of cobaltosic oxide and nitrogen-doped graphene (Co 3O4/N-G) was prepared by the facile hydrothermal method. Morphology characterizations show that the Co3O4 nanoparticles with crystalline spinel structure are uniformly dispersed on the nitrogen-doped graphene nanosheets, and the graphene weight fraction in Co 3O4/N-G composite is estimated to be ∼20%. Meanwhile, electrochemical measurements reveal that the as-prepared Co3O 4/N-G nanocomposite exhibits a high catalytic activity and long-term stability in neutral electrolyte. Moreover, the use of Co3O 4/N-G as cathode catalyst for oxygen reduction in microbial fuel cells (MFCs) to produce electricity was also investigated. The obtained maximum power density was 1340 ± 10 mW m-2, which was as high as almost four times that of the plain cathode (340 ± 10 mW m-2), and only slightly lower than that of a commercial Pt/C catalyst (1470 ± 10 mW m-2). All the results prove that a Co3O 4/N-G hybrid can be a good alternative to platinum catalysts for practical MFC applications. © 2013 American Chemical Society.

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