POLYMER BULLETIN
·
2017
·Vol. 75
·期 7
·2917-2931
·
IF 1.43
Ding Amin,Teng Lijing,Zhou Yifeng,Chen Pengpeng,Nie Wangyan
The star-shaped poly( l -lactide) (s-PLLA) was synthesized via ring-opening polymerization of l -lactide, with xylitol as a multifunctional initiator and stannous octoate as a catalyst. The structures of s-PLLA were characterized by 1 H NMR spectroscopy, while the molecular weight ( M
w ) and polydispersity index were determined by gel permeation chromatography. Bovine serum albumin (BSA) loaded s-PLLA microspheres were fabricated by a water–oil–water ( W
1 / O / W
2 ) double-emulsion solvent evaporation method. The morphology, drug encapsulation efficiency (EE), and in vitro release behavior of the prepared microspheres were studied in detail. Results indicated that the average diameters of s-PLLA microspheres could be controlled between 7 and 15 µm by varying the s-PLLA’s concentration or M
w , and the drug encapsulation efficiency of BSA-loaded microspheres were 10–42%. The in vitro study shows that the BSA-loaded microspheres prepared by high molecular weight s-PLLA had a slow cumulative release behavior in phosphate buffer saline (PBS, pH 7.4) and the release process followed the Baker–Lonsdale equation. Present work supposes that the synthesized s-PLLA is a good candidate for drug delivery.
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高影响因子
MACROMOLECULAR RESEARCH
·
2019
·Vol. 28
·期 5
·480-493
·
IF 1.758
Li Qiong,Ma Songqi,Wei Jingjing,Wang Sheng,Xu Xiwei,Huang Kaifeng,Wang Binbo,Yuan Wangchao,Zhu Jin
Non-planar-ring epoxies together with non-planar-ring hardeners could achieve thermosets combining ultra-high shape recovery speed and excellent thermal properties. High shape recovery speed reflected high efficiency, and could decrease the energy consumption and the harmful effect of external stimuli on the materials, while it often conflicts with the thermal properties of shape memory polymers. In this paper, for the first time, epoxy resins with the super-short shape recovery time within 3 s were developed from non-planar-ring epoxies and hardeners, and their glass transition temperature ( T g ) were ~127 °C much higher than their benzene ring analogues. The effects of non-planar-ring structures of the epoxies and hardeners on the curing behavior, thermal properties as well as the shape memory properties of the thermosets were systematically investigated; the structure-property relationships were disclosed with the help of computational simulation of structure parameters and ESP maps. The faster shape recovery speed of the non-planar-ring epoxy thermosets is from their higher molecular mobility contributed by the conformational transition of non-planar-rings as well as their higher recovery force compared with benzene ring analogs. Their higher T g s are from the steric hindrance by the larger molecular volume of the non-planar-rings than benzene ring. This work will provide an effective method to produce shape memory polymers with excellent shape memory effects and high performance.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2021
·Vol. 147
·期 7
·4597-4610
·
IF 4.626
Dou Yanli,Li Xuefei,Zheng Kaiyue,Liu Jiawen,Hou Jiazi
A UV-curing flame-retardant coating with varying mass content of bisphenol A epoxy acrylate (BAEA), 2-hydroxyethyl methacrylic acid phosphate (PM-2) and polyurethane acrylate (PUA) were prepared, improving the flame-retardant and mechanical properties of jute/polypropylene (PP) composites. BAEA is the main film-forming prepolymer. Phosphate ester groups in PM-2 can promote the formation of carbon layer during combustion, and PM-2 can also be used as a good adhesion binder to improve the coating adhesion levels. The flexible long chain in PUA could reduce the shrinkage of the coating and provide further adhesion. To avoid the oxygen inhibition of the radical polymerization, isopropylthioxanthone and triethanolamine were used to reduce the reaction between photoinitiator phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide and oxygen. Compared to the uncoated composites (J–P), the peaks of heat release rate and total smoke production of coated composites decreased and limiting oxygen index values increased significantly, which revealed that the coatings showed effective fire protection effect. The bending strength of the coated composites can increase by 90% over uncoated sample J–P. This simple, low-cost and environmentally friendly UV-curing coating has good adhesion and can effectively improve the flame-retardant and mechanical properties of composites, which expand application of the flame-retardant fiber composites.
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高影响因子
IONICS
·
2019
·Vol. 26
·期 3
·1109-1117
·
IF 2.289
Xie Ming,Li Libo,Zhang Yonghong,Du Jintian,Li You,Shan Yuhang,Zheng Huanyu
In this work, an all-solid-state biomaterial electrolyte derived from phthaloyl starch and poly(vinylidene fluoride) (PVDF) was introduced. Phthaloyl starch (PS) was prepared with the starch and the phthalic anhydride via a chemical method. The introduction of C=O group through the starch esterification improved the migration of the lithium ions in the all-solid-state electrolyte membrane. The AC impedance test revealed that the addition of the phthaloyl starch promoted the conductivity of electrolytes, which can reach up to 2.04 × 10 −4 S cm −1 at room temperature, and the electrochemical stability window (ESW) can achieve 4.20 V. Herein, the phthaloyl starch-PVDF–based electrolyte membrane possessed the lithium-ion transference number of 0.396. The half-cell Li/SPE/LiFePO 4 had a better charge and discharge performance, that is, 93.9 mAh g −1 and 92.2 mAh g −1 after the 50th cycle at 0.5 C and at room temperature.
Graphical abstract
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 2
·701-712
·
IF 3.442
Yang Wangyang,Shen Honglie,Min Huihua,Ge Jiawei
In recent years, Ti 3+ self-doped TiO 2 (B-TiO 2 ) exhibits great potential as a photocatalyst. In this work, Ti vapor-assisted annealing is first demonstrated for Ti 3+ doping and improving the visible absorption of TiO 2 . TEM results exhibit the formation of disordered layer, indicating the successful fabricating of B-TiO 2 . The absorption increase in TiO 2 caused by Ti vapor annealing reaches nearly 50% in the visible wavelength range. Benefiting from the absorption increase, the photocatalytic performance of TiO 2 after Ti vapor annealing increases by 60–70%. Surface modification of Ag onto B-TiO 2 is also carried out to further improve its optical property. Ag-modified Ti 3+ self-doped TiO 2 (B-TiO 2 @Ag) exhibits great visible photodegradation behavior to RhB. The RhB degradation rate reaches 97.76% after 60 min of visible light irradiation. Electrochemical performance tests demonstrate that as-prepared TiO 2 @Ag has lower resistance than W-TiO 2 . The results indicate that B-TiO 2 @Ag has great potential in solar photocatalytic degradation of pollutant.
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高影响因子
JOURNAL OF FLUORESCENCE
·
2020
·Vol. 31
·期 1
·141-149
·
IF 2.093
Wu Wei-hui,Wang Xin,Zong Liang,Li Dan,Xiao Yan-hua,Sui Shao-hui,Li Jian,Liu Meng,Chen Gao-yun,Luo Teng,Liu Min,Wang Xin-ming,Jiang Zhi-gang
A coumarin-based probe, FP2, was designed for the differential detection of fluoride anions and thiols, i.e., the corresponding nucleophilic substitution products from fluorine-containing G agents and sulfur-containing V agents, thus having the potential to discriminate between these two nerve agents. FP2 with two functional reaction groups, α, β-unsaturated ketone and silyl groups, can react selectively with fluoride anions and thiols at the μM level respectively. Intriguingly, in the THF solution, FP2 reacts with the fluoride anion but not with the thiol, whereas in the EtOH/HEPES solution, FP2 reacts with the thiol but not with the fluoride anion. As a result, FP2 can produce different fluorophores in the two detection solutions, thus displaying significant fluorescence changes. In addition, the FP2 detection system can show a significant color change from colorless to yellow within seconds when detecting fluoride anions in THF detection solutions, and from yellow to light blue when detecting thiols in EtOH/HEPES solutions, which will facilitate visual detection by emergency responders at the scene of an incident involving a nerve agent.
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高影响因子
Science China-Chemistry
·
2021
·Vol. 64
·期 5
·861-872
·
IF 9.445
Bai Xue,Yong Jiale,Shan Chao,Fang Yao,Hou Xun,Chen Feng
Droplet manipulation plays a significant role in the fields of biomedical detection, microfluidics, and chemical engineering. However, it still remains a great challenge to simultaneously achieve remote, selective, and in situ droplet manipulation on the same surface. Here, Fe 3 O 4 nanoparticles were doped in a shape-memory polymer (SMP) to prepare a photothermal-responsive Fe 3 O 4 -SMP composite which showed remarkable near-infrared (NIR) light-triggered shape-memory property. Superhydrophobic micropillar array was constructed on such Fe 3 O 4 -SMP composite through femtosecond laser microfabrication and fluoroalkylsilane modification. The surface wettability of the as-prepared surface can transform from a low-adhesive sliding state to a high-adhesive pinning state as the micropillars are deformed by pressing. Interestingly, the deformed micropillars can stand up and restore to their original morphology under remote NIR light irradiation, resulting in the reversible and repeatable recovery of the ultralow-adhesive superhydrophobicity. With such light-triggered wettability switching, the droplets pinning on the sample surface can be remotely, selectively, and in situ released. Furthermore, the superhydrophobic Fe 3 O 4 -SMP surface is successfully applied in lossless liquid transfer, selective droplet release, and droplet-based microreactor. The as-fabricated superhydrophobic surfaces with NIR light-controlled reversible wettability will hold great promise in the fields of liquid manipulation, lab-on-a-chip, and microfluidics.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 141
·期 4
·1341-1350
·
IF 2.471
Liu Hao,Wu Hongjuan,Song Qingyi,Zhang Jingyi,Li Weihao,Qu Hongqiang
Polyphosphate (copper polyphosphate: CuPPA, zinc polyphosphate: ZnPPA, cobalt polyphosphate: CoPPA and nickel polyphosphate: NiPPA) was used as surface modifiers, smoke suppressants and flame retardants to modify the magnesium hydroxide (MH). Core–shell flame retardants composed of transition metals (Cu, Zn, Co, Ni) and P were prepared. The morphology, chemical composition and structure of core–shell flame retardants were characterized by scanning electron microscopy, Fourier-transform infrared spectrum and X-ray diffraction. Compared with MH, the core–shell flame retardant endows EVA resin with better flame retardant, smoke suppression and mechanical properties. Under the same loading of flame retardant, the peak heat release rate, total heat release and CO production of EVA + Cu decreased by 41.45%, 7.51% and 54.84%, respectively, and the mass residue increased by 12.42%. These improvements can be attributed to the catalytic carbonation of transition metal compounds and better protection of char layer formation. The synergistic effect between polyphosphate and MH was discussed. Due to the extensive synergy between flame retardant metal ion and polyphosphate group, it had a potential application prospect in the preparation of various flame retardant polymers.
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高影响因子
Scientific Reports
·
2020
·Vol. 10
·期 1
·1-12
·
IF 3.998
Bo Caiying,Shi Zhongyu,Hu Lihong,Pan Zheng,Hu Yun,Yang Xiaohui,Jia Puyou,Ren Xiaoli,Zhang Meng,Zhou Yonghong
A novel eco-friendly halogen-free cardanol-based flame retardant with P, Si, and N on the chain backbone (PSNCFR) was synthesized and incorporated into phenolic foams (PFs). PSNCFR was comprehensively investigated via Fourier transform infrared spectroscopy and nuclear magnetic resonance. PSNCFR endowed PFs with flame retardancy, contributed to generating a composite char defense against flames, and efficiently prevented smoking from PFs. PSNCFR introduction improved the flexural strength of the PFs to approximately 155% of that of pristine PF. PSNCFR-modified PFs displayed a high limiting oxygen index value of 41.9%. The results of cone calorimeter show that the mean heat release rate, mean effective heat of combustion, and total heat release of the PSNCFR-modified PFs reduced by 26.92%, 35.71%, and 31.25%, respectively. In particular, the total smoke production of the PSNCFR-modified PFs decreased by 64.55%, indicating excellent smoke inhibition. As for the mechanism, the condensation and gas phases during pyrolysis were responsible for the synergistic flame retardancy in the modified PFs. The findings demonstrate that PSNCFR can be used in PF preparation to overcome their drawbacks of internal brittleness and flammability.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 24
·10399-10411
·
IF 3.553
Yang Wangyang,Shen Honglie,Min Huihua,Ge Jiawei
The application of TiO 2 acetone monitor is highly limited by the high operating temperature and poor sensitivity. In this work, black TiO 2 (B-TiO 2 ) is produced by Ti 3+ self-doping and is followed by Ag modification to form B-TiO 2 @Ag. It is first demonstrated that the operating temperature and sensitivity of TiO 2 to acetone can be promoted evidently. By introducing a Ti 3+ self-doped layer on the surface of TiO 2 , as observed in TEM images, the band gap of TiO 2 is reduced to 3.01 eV. Ag surface decoration is carried out for the enhancement of electron generation. Optical absorption and the Hall effect results prove that B-TiO 2 @Ag exhibits highest photoelectrical properties. As a result, the B-TiO 2 @Ag gas sensor with a low operating temperature at 250 °C and high response of 68.19 to 50 ppm acetone is realized. The low detection limit of B-TiO 2 @Ag sensor reaches 887 ppb, which provides an applicable way for non-invasive detection of blood glucose.
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高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2023
·Vol. 332
·期 4
·1353-1365
·
IF 1.6
Wang Zhaoyang,Shen Yubo,Zhang Yinshan,Liu Yuhui,Dong Zhimin,Quan Meiyang,Yu Fengtao,Cao Xiaohong,Zhang Zhibin,Wang Yingcai,Liu Yunhai
In order to improve the utilization of spent fuel, electrolysis is used to recover fissile elements from nuclear waste samarium. The electrochemical behaviors of Sm(III) and Pb(II) were examined by CV, SWV, and OCP techniques in LiCl–KCl molten salts at 773 K. The redox mechanism of Sm(III) ions on the liquid Pb thin film electrode was analyzed. The results demonstrate that Sm(III) electro-reduction at the inert W electrode only occurred in a soluble–soluble electrochemical transition Sm(III)/Sm(II). Additionally, the kinetic parameters of samarium and lead ions were computed. The activation energies of diffusion for Sm(III) and Pb(II) were 32.92 kJ mol −1 and 35.21 kJ mol −1 , respectively. SmPb 3 and Sm 2 Pb intermetallic compounds were derived using constant potential electrolysis and constant current electrolysis at the Pb electrode in a molten salt system. The cathodic deposition output was characterized by XRD and SEM–EDS. The ICP-AES results showed that the average extraction ratio of Sm on the Pb electrode was about 94.23%.
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高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2020
·Vol. 50
·期 2
·543-553
·
IF 1.774
Deng Lu,Xu Quan,Rao Liangmei,Yue Ruirui,Xu Jingkun,Duan Xuemin
In this paper, Pt/Pd-poly(3,4-ethylenedioxythiophene)/nitrogen doped graphene (Pt/Pd-PEDOT/NGE) nanocomposites with hierarchical structure were prepared via a one-pot method. In the first step, Pd-PEDOT composites with Pd nanoparticles scattered on the surface or embedded in coralloid PEDOT particles were obtained through the redox reaction between PdCl 4 2− and 3,4-ethylenedioxythiophene (EDOT) monomer. NGE was then added to improve the electrical conductivity and continuity of the nanocomposites. Finally, the added PtCl 6 2− as well as the residual PdCl 4 2− was reduced by ethanol through heating reflux. As a result, the Pt/Pd-PEDOT/NGE nanocomposites were obtained with Pt and Pd nanoparticles well-dispersed on the surfaces of PEDOT granules and NGE nanosheets. The obtained Pt/Pd-PEDOT/NGE nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectra. The electrochemical sensing performance of the Pt/Pd-PEDOT/NGE modified glassy carbon for caffeic acid (CA) was mainly studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions, Pt/Pd-PEDOT/NGE showed superior electrochemical sensing performance for detecting CA with the linear relationship ranging from 0.008 μM to 46 μM and a detection limit of 2.7 nM (a signal to noise ratio of 3 ( S / N = 3)). Moreover the nanocomposite also possesses high anti-interference capability and reproducibility. The real sample analysis of Pt/Pd-PEDOT/NGE was successfully carried out, implying the promising application of CA detection in food and beverages.
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