CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Renjie Chen,Xinyu Huang,Ruizhi Zheng,Delong Xie,Yi Mei,Ruqiang Zou
Organic phase change materials are flammable, which limits their applications in heat storage and conversion. In the presented study, a phosphorus-grafted hexadecanol was blended with pentaerythritol phosphate (PEPA) to prepare flame-retardant phase change material (FRPCM). The thermal properties of FRPCM were evaluated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cone calorimetry. The flame-retardant mechanism was examined by thermogravimetric analysis-Fourier transform infrared spectrometry (TG-FTIR) and scanning electron microscopy (SEM) tests. The FRPCM maintains a promising heat storage capacity (186.9 J/g) and thermal stability after grafting and blending. The flame retardance analysis reveals that the grafted phosphorus group helps to promote char formation. PEPA extends the time before exposed combustible material ignites. The cone calorimeter test demonstrated that the peak heat release rate and total heat release are further decreased by more than 50%, owing to the synergistic effect between the phosphorus group and PEPA. The SEM results showed that a porous structure is formed during combustion. Self-extinguishment testing indicates that the FRPCM is extinguished in a much shorter time than is hexadecanol.
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POLYMER
·
2019
·
IF 3.771
Tao Guan,Zhukang Du,Xueyi Chang,Dongli Zhao,Shurui Yang,Ning Sun,Biye Ren
Hydrophobically modified ethoxylated urethanes (HEURs), as a representative class of associative polymers, are widely used as rheology modifiers in waterborne systems such as coatings, emulsions, inks etc. due to their unique associative network structure and finite relaxation behavior in solution. However, conventional HEURs are non-reactive and generally stay free in final cured films, which may induce some damages to the performance of the coatings. To solve the problem, a new concept of reactive HEUR has been proposed. That is, a reactive HEUR should bear reactive hydrophobic end-groups which can chemically crosslink with matrix resins during the curing process of waterborne coatings. In this work, with the help of the hydrogen abstraction photo-initiating reactivity of benzophenone (BP) group, a reactive HEUR (BPC 11 HEUR) end-functionalized by a photo-initiator BP moiety has been prepared. In aqueous solution, as demonstrated by steady shear measurement, an exponential increment of solution viscosity along with the increasing of polymer concentration ( C ) was found when C surpassed its critical percolation concentration ( C p ≈ 23.6 g/L). Besides, ultraviolet (UV) light induced photolysis in aqueous solution manifested a typical photochemical reaction behavior of BPC 11 HEUR polymer with a final photolysis degree ( D ) of approximate 78% after 300 s of irradiation. In situ 1 H NMR and rheological measurements collectively revealed the efficient photo-initiating reactivity of BPC 11 HEUR for waterborne UV monomers or resins. Further, rheological measurements demonstrated that the emulsion zero/low shear viscosity can be greatly enhanced by ca. 50 folds for a commercially available waterborne UV polyurethane acrylate emulsion when the addition amount of BPC 11 HEUR varied from 0 to 1.0 wt%. These results shown that the reactive BPC 11 HEUR polymer can not only be used to efficiently modify the rheological properties of solutions or emulsions but also can chemically crosslink with waterborne UV acrylic monomers or resins by light irradiation . The work may be of interest for development of reactive HEURs used in waterborne UV coatings, inks, and adhesives, etc.
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ENERGY & FUELS
·
2018
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IF 3.024
Wenda Jia,Guangyue Xu,Xiaohao Liu,Feng Zhou,Huixia Ma,Ying Zhang,Yao Fu
Inedible natural oils are desired resources for renewable fuel and chemical production. Herein, a nonprecious metal cobalt catalytic system was developed for selectively hydrogenating fatty acids and natural oil into fatty alcohols or long-chain alkanes. The cobalt-based catalysts were prepared by a wet-impregnation method with a series of supports including HZSM-5, CeO2, ZrO2, SiO2, Al2O3, TiO2, and hydroxyapatite (HAP) for hydrogenating stearic acid. Among these catalysts, Co/HAP exhibited the highest activity and 97.1% yield of 1-octadecanol was obtained at 190 °C and 4 MPa H2 in water. Additionally, the Co/HAP was capable of directly hydrogenating the natural oil, Jatropha oil, to fatty alcohols without any preprocessing, and 83.1 wt % yield of alcohols could be achieved at 190 °C and 4 MPa H2 in water. Co/HAP could also catalyze the complete conversion of stearic acid and Jatropha oil to long-chain alkanes when dodecane was used as solvent. X-ray power diffraction, transmission electron microscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption were carried out, and the high catalytic activity of Co/HAP could be due to its desired acidity, cobalt particle dispersion, and stronger metal–support interaction. The Fourier transform infrared results indicated that the high efficiency of Co/HAP could also be due to the absorption of fatty acid on the surface of catalyst which thus promoted the hydrogenation process over Co species. The possible reaction pathway was also proposed according to the conversion process tracking of stearic acid.
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高影响因子
Journal of Cleaner Production
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2018
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IF 5.651
Heng Zhong,Cailing Jiang,Xi Zhong,Jie Wang,Binbin Jin,Guodong Yao,Ligang Luo,Fangming Jin
Conversion of biomass and waste oils to alkanes for the production of aviation fuel is attracting increasing research interests since it can provide sustainable energies from renewable resources to substitute the fossil fuels. In this process, the deoxygenation of fatty acids to alkanes is the key reaction. However, previous methods of fatty acids deoxygenation require gaseous hydrogen, noble metal catalyst and/or organic solvent, which are adverse to the sustainable development. In this work, a novel and simple method of deoxygenation of fatty acids to alkanes is proposed by using a commercial nickel (Ni) powder as the catalyst without any pre-treatment and water as both environmental-friendly solvent and sustainable hydrogen source . The hydrogen in situ generated from water exhibited a much higher activity than gaseous hydrogen for the deoxygenation of fatty acids, and an alkane yield of 90% was successfully achieved. The Ni catalyst is stable and still maintains high activity after recycles. This proposed process is simple, economical, sustainable and environmental-friendly, thus is promising for the practical application.
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COLLOID AND POLYMER SCIENCE
·
2018
·Vol. 296
·期 5
·895-906
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IF 1.967
Zhang Ming,Chen Mingqing,Ni Zhongbin
We investigated the rheology behaviors of diglycidyl ether of bisphenol-A (epoxy resin) composite pastes with various biscarbamates and compared them with those of epoxy composites with fumed SiO 2 . Thermal and rheological measurements showed thermal reversible rheology behaviors of shear thinning for all epoxy composites with various biscarbamates. Some biscarbamates endowed their epoxy composites’ stronger shear thinning behaviors than fumed silica did even at the low concentrations. Polarized microscopic, FT-IR, and DSC analyses demonstrated that excellent rheological responses of biscarbamates in epoxy composite pastes could be attributed to their various crystallization self-assemblies formed in epoxy matrix by the intermolecular interactions mainly including hydrogen bonding and van der Waals interactions, and these interactions were closely related to the molecular structures of biscarbamates.
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RSC Advances
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2014
·Vol. 4
·期 106
·61759-61766
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IF 3.708
Hongmei Chen,Xingrong Tan,Juanjuan Zhang,Qiyi Lu,Xin Ou,Yuan Ruo,Shihong Chen
In this article, a new electrochemiluminescent (ECL) biosensor based on a g-C3N4–hemin nanocomposite and hollow gold nanoparticles (HGNPs) was constructed to detect lactate. Firstly, the g-C3N4 nanosheets were prepared through ultrasonication-assisted liquid exfoliation of bulk g-C3N4, which was obtained through polymerizing melamine under 600 °C. Then, the nanocomposites of g-C3N4 nanosheets and hemin were prepared to modify a glassy carbon electrode. Subsequently, HGNPs were self-assembled onto the electrode for adsorbing lactate oxidase to achieve a lactate biosensor. Due to the excellent catalytic effect of g-C3N4–hemin and HGNPs on the luminol/H2O2 ECL system, the as-prepared biosensor exhibited a good response performance to lactate with a linear range of 1.7 × 10−8 to 5.0 × 10−4 M and a detection limit of 5.5 × 10−9 M. In addition, the prepared ECL biosensor exhibited satisfying reproducibility and stability. The g-C3N4–hemin nanocomposite might have great potential application in a luminol/H2O2 ECL system.
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E-POLYMERS
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2015
·Vol. 15
·期 4
·263-270
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IF 0.569
Kai Liang,Qingquan Liu,Meixuan Peng
Cross-linked cationic polystyrene (CCPS) nanospheres with monodispersity were successfully generated by soap-free miniemulsion polymerization of styrene and divinylbenzene with 2,2′-azobis (2-amidinopropane) dihydrochloride as a water-soluble initiator. The effects of output power of the homogenizer and the concentration of the initiator and cross-linking agent on the particle size and coefficient of variation of CCPS nanospheres were systematically investigated and discussed. The weight percent of N element on the particle surface and the ζ potential were determined as different initiator concentrations were employed for the preparation of CCPS nanospheres. Furthermore, the technique of nitrogen adsorption/desorption was applied to characterize the specific surface area and the total pore volume of the CCPS nanospheres, which were generated from different amounts of divinylbenzene. Overall, the present study provides a simple route for producing cross-linked polymer nanospheres with monodispersity.
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FOOD CHEMISTRY
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2014
·
IF 3.259
Songbai Liu,Yuanqing Fu,Si Nian
Anthocyanins are intriguing natural pigments with beneficial bioactivities and their colour is extremely susceptible to acidity variation. Minimisation of colour fluctuation is essential to maintain quality consistency in food industry. A new strategy employing surfactants to mimic encapsulation was attempted with typical anionic, cationic and nonionic surfactants and proved effective although the traditional copigmentation method was inactive. The exceptional colour fluctuation buffering effect of anionic surfactants especially sodium dodecyl sulphate (SDS) was revealed and then carefully analysed by colorimetric and spectroscopic methods. The outstanding activity of SDS presumably resulted from effective shielding of anthocyanins from external acidity through strong interaction with the positively charged flavylium cations owing to its anionic nature. These results suggest SDS is a valuable additive for buffering colour fluctuation of anthocyanins. The strategy of surfactant will be useful for buffering colour fluctuation of natural colourants.
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2013
·Vol. 131
·期 3
·
IF 1.395
Mingliang Xin,Yujie Ma,Kai Xu,Mingcai Chen
Octyl gallate (OG), dodecyl gallate (DG), and hexadecyl gallate (HG) were synthesized and characterized by Fourier transform infrared (FTIR) and NMR, and their thermal stability was measured by thermogravimetric analysis (TGA). The antioxidant effect of these derivatives in polypropylene (PP) was measured by oxidation induction temperature measurement on DSC, and by measurement of carbonyl groups in the polymer on attenuated total reflectance FTIR spectroscopy after they were aged at 120°C. The results indicated that the gallate derivatives could provide long-term stabilization to PP under conditions of oxidative degradation. The antioxidant performance of HG with longer alkyl chain was superior to the OG and DG, making the former a good candidate to be used as antioxidant additive in PP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 39850.
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BIOMATERIALS
·
2017
·
IF 8.402
Zhu Jin,Keqin Wu,Jingwen Hou,Kunhong Yu,Yuanyuan Shen,Shengrong Guo
An antitumor drug/esophagus stent combination can palliatively relieve malignant esophageal stricture and exert local chemotherapy to cancer. It is vital for effective treatment of cancer to control drug release and facilitate drug penetration into deep tissue after the combination is placed in the malignant strictured esophagus part. In this study, we firstly designed and prepared a novel antitumor drug/esophagus stent combination: a magnetocaloric nitinol stent coated with a bilayered film that consisted of one ethylene-vinyl acetate copolymer (EVA) layer as drug blocking layer and one EVA layer containing 10% paclitaxel (PTX) and 30% temperature sensitive phase-change fatty alcohol (1-tetradecanol, 1-hexadecanol or 1-octadecanol). The drug release and penetration into rabbit esophagus wall from the combination were investigated. It was found that, under an alternating electromagnetic field at a power of 0.1 kW, the combination was heated to 43 °C, the PTX was faster and more released from the combination, as well as the amount of PTX in esophagus tissue or its deep muscle tissue penetrated from the combination was much higher than that without alternating electromagnetic field. The pathological data showed that the combination was biocompatible and safe after placement in rabbit esophagus even under an alternating electromagnetic field. Overall, the PTX could be magnetocalorically released and effectively penetrated into esophagus wall from the PTX/nitinol stent combination.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 64
·40581-40590
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IF 3.108
Xiao Fang,Yanchun Shi,Kejing Wu,Junmei Liang,Yulong Wu,Mingde Yang
The addition of phosphotungstic acid (PTA) to the synthesis mixture of PdCu@FeIII–MOF-5 yields the direct encapsulation of PTA inside the MOF structure (i.e. PTA@PdCu@FeIII–MOF-5) through a facile solvothermal approach. The deoxygenation reaction of palmitic acid has been investigated over PdCu@FeIII–MOF-5 and PTA@PdCu@FeIII–MOF-5 under a hydrogen atmosphere in the supercritical fluid (SCF) of n-hexane. The results showed that palmitic acid can be converted completely at 240 °C on PTA@PdCu@FeIII–MOF-5 with a high selectivity of hexadecane. Owning to the improvement of acidity of the MOF catalyst by the encapsulation of PTA inside the hollow octahedral nanostructures of PdCu@FeIII–MOF-5, the selectivity for hexadecane over the PTA@PdCu@FeIII–MOF-5 catalyst is higher than that over PdCu@FeIII–MOF-5. The excellent performance in the catalytic hydrodeoxygenation (HDO) of palmitic acid is associated with the synergistic effect between yolk–shell PTA@PdCu@FeIII–MOF-5 nanostructures and SCF medium.
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Scientific Reports
·
2016
·Vol. 6
·期 1
·1-10
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IF 5.228
Wang Zefeng,Ye Weiwei,Luo Xinran,Wang Zhonggang
The motivation of this work is to create luminescent rare earth/polymer films with outstanding water-resistance and superhydrophobicity. Specifically, the emulsion polymerization of styrene leads to core particles. Then core-shell-structured polymer nanoparticles are synthesized by copolymerization of styrene and acrylic acid on the core surface. The coordination reaction between carboxylic groups and rare earth ions (Eu 3+ and Tb 3+ ) generates uniform spherical rare earth/polymer nanoparticles, which are subsequently complexed with PTFE microparticles to obtain micro-/nano-scaled PTFE/rare earth films with hierarchical rough morphology. The films exhibit large water contact angle up to 161° and sliding angle of about 6° and can emit strong red and green fluorescence under UV excitation. More surprisingly, it is found that the films maintain high fluorescence intensity after submersed in water and even in aqueous salt solution for two days because of the excellent water repellent ability of surfaces.
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高影响因子
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