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Ji X.,CAS Changchun Institute of Applied Chemistry | Ji X.,University of Chinese Academy of Sciences | Yan J.,CAS Changchun Institute of Applied Chemistry | Liu X.,Shandong Non metallic Materials Institute | Wang Z.,CAS Changchun Institute of Applied Chemistry
High Performance Polymers | Year: 2017

Several partially bio-based polyimides have been successfully synthesized by polycondensation between bis(4-aminophenyl)isohexides with various commercial dianhydrides. Flexible and free-standing films were readily obtained from their poly(amic acid) or polyimide solutions. A systematic investigation of the structure-property relationship of polyimides highlights the significant impact of the isohexides moieties on their physical and mechanical properties (glass transition temperature, inherent viscosity, thermal stability, solubility, and mechanical properties). The results revealed that these polyimides exhibited comparable thermal stability and mechanical properties to those of petrochemical-based ones. © The Author(s) 2016.


Qian Y.,Shanghai JiaoTong University | Wei P.,Shanghai JiaoTong University | Jiang P.,Shanghai JiaoTong University | Li Z.,Shanghai JiaoTong University | And 3 more authors.
Energy Conversion and Management | Year: 2013

Shape-stabilized co-crystallized poly (ethylene glycol) (PEG) composites were prepared by sol-gel process. Tetraethoxysilane was utilized as supporting matrix precursor. The crystallization property as well as thermal energy storage properties of PEG was influenced by silica network. The combination of PEG 2k and PEG 10k with suitable ratio (3:1 by weight) led to synergistically increased fusion enthalpy attributed to cocrystallization effect. Furthermore, halogen-free flame retarded PEG composites were obtained using diammonium phosphate as flame retardant. With suitable composition, the latent heat value of flame retarded PEG composite was 96.7 kJ/kg accompanied with good thermal stability and improved flame retardancy properties. Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), polarized optical microscope (POM) and scanning electron microscope (SEM) were used to characterize the structure of PEG composites. Thermal stability properties of PEG composites were investigated by thermogravimetric analyzer (TGA). Char residue obtained from muffle furnace of PEG composites was analyzed by SEM and FT-IR. Flame retardancy properties of PEG composites were estimated by pyrolysis combustion flow calorimeter. Results showed that it was potential for shape-stabilized halogen-free flame retarded PEG composite to be applied in thermal energy storage field. © 2013 Published by Elsevier Ltd.


Qian Y.,Shanghai JiaoTong University | Wei P.,Shanghai JiaoTong University | Jiang P.,Shanghai JiaoTong University | Li Z.,Shanghai JiaoTong University | And 2 more authors.
Composites Science and Technology | Year: 2013

In this article, mesoporous flame retardant (Al-SBA-15) was prepared by post-grafting of aluminum isopropoxide on the surface of mesoporous silica (SBA-15). X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectrum (FT-IR) and N2 adsorption-desorption measurement were utilized to investigate the structure of mesoporous materials. Al-SBA-15, SBA-15 and fumed silica were added into polylactide, respectively, to carry on comparative study. Results showed limiting oxygen index (LOI) of polylactide composite was significantly increased by Al-SBA-15, accompanied with UL-94V-0 rating. Moreover, the incorporation of 0.5wt% of Al-SBA-15 reduced the peak of heat release rate of PLA composite by 15.1% compared with pure PLA and decreased the produced smoke amount. Al-SBA-15 reduced the volatile products of PLA during thermal degradation process that was detected by mass spectroscopy (MS). Al-SBA-15 also improved the hydrolysis resistance and tensile properties of PLA composite. Results showed that Al-SBA-15 was a high-effective additive to improve the fire-resistance, smoke inhibition, hydrolysis resistance and mechanical properties of PLA. © 2013 Elsevier Ltd.


Dong B.,Jilin University | Dong B.,CAS Changchun Institute of Applied Chemistry | Zhang H.,CAS Changchun Institute of Applied Chemistry | Li H.,Shandong Non Metallic Materials Institute | And 7 more authors.
Polymer (United Kingdom) | Year: 2016

Three half-titanocene complexes 2a-3a bearing dibenzhydryl-substituted aryloxide ligands CpTiCl2(O-2,6-Ph2[Formula presented]6H2-4-Me), 2a; CpTiCl2 (O-2,6-Ph2[Formula presented]6H2-4-OMe), 2b; Cp*TiCl2(O-2,6-Ph2[Formula presented]6H2-4-Me), 3a were synthesized. All the complexes were characterized by NMR spectroscopy and elemental analysis. The molecular structures of complex 2a and 2b were further determined by single crystal X-ray diffraction, both of them adopt a three-legged distorted tetrahedral geometry in which the aryl substituents are orthogonally to the aryloxide group. Activated by methylaluminoxane (MAO), these complexes showed high activities (up to 2100 kg mol−1 (Ti) h−1) for ethylene polymerization. The resultant polyethylenes had high molecular weight and narrow molecular weight distributions. Furthermore, for the ethylene/1-hexene copolymerization, these complexes exhibited moderate activites and moderate to high 1-hexene incorporation ability. The sequence distributions of poly (ethylene-co-1-hexene)s are greatly influenced by the substituent on the cyclopentadineyl group of titanium complexes. © 2016 Elsevier Ltd


Lin B.,Shandong University | Su H.,Shandong University | Ma G.,Shandong University | Liu Y.,Shandong University | Hou Q.,Shandong Non metallic Materials Institute
RSC Advances | Year: 2016

Serum paraoxonase 1 (PON1) is a calcium-dependent enzyme that can catalyze the hydrolysis of multiple substrates, including lactones, thiolactones, carbonates, esters and phosphotriesters, as well as the formation of a variety of lactones. To better understand the lactonase mechanism of PON1, the hydrolysis of dihydrocoumarin, which is considered as a native substrate of PON1, has been investigated by using a combined quantum mechanics and molecular mechanics (QM/MM) approach. Two possible reaction pathways with either Glu53 or His115 acts as the general base have been considered. On the basis of our calculations, these two pathways correspond to the overall energy barriers of 12.5 and 9.0 kcal mol-1, respectively. During the catalytic reaction, if one of the two residues (Glu53 and His115) acts as the catalytic base, the other one forms strong hydrogen bonding interaction with the attacking hydroxide to facilitate the hydrolysis. However, mutation studies reveal that Glu53 is necessary for hydrolysis, whereas His115 is not essential but can promote the activity of PON1. Natural population analysis indicates that the catalytic Ca2+ does not act as Lewis acid but plays structural role in fixing the orientations of the substrate and related residues. In addition, Asp269 is found to coordinate with Ca2+ cation and facilitate the protonation of the alkoxide leaving group by forming hydrogen bond with lactone. These results can explain the fact that mutation of Glu53 results in the loss of activity of PON1, and the hydrolysis of dihydrocoumarin is unaffected by mutation of H115. © The Royal Society of Chemistry 2016.


Fan W.,CAS Changchun Institute of Applied Chemistry | Fan W.,University of Chinese Academy of Sciences | Liu X.,Shandong Non metallic Materials Institute | Yan J.,CAS Changchun Institute of Applied Chemistry | And 4 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2016

A series of imide oligomers with a degree of polymerization of 1,2 and 3 was synthesized via a conventional two-step procedure, using 2-phenyl-4,4'-oxydianiline (p-ODA) and isomeric oxydiphthalic anhydrides as the monomers, and 4-phenylethynyl phthalic anhydride (4-PEPA) as the end-capping reagent. These imide oligomers were fully characterized in terms of solubility, melt viscosity, and thermal properties of cured resins. The solubility of imide oligomers based on 2-phenyl-4,4'-oxydianiline were higher than 30% in common organic solvents, such as N, N-dimethylacetamide (DMAc), tetrahydrofuran (THF), and 1,4-dioxane. The minimum melt viscosities for these oligomers were lower than 10 Pa·s, which was indicative of their excellent processability. Furthermore, the cured resins possessed good thermal properties, with glass transition temperatures (Tg) and 5% weight loss temperatures (T5%) being up to 300 and 545℃, respectively. These resins were then formulated into carbon-fiber-reinforced composites, and the composite properties were studied. Composite PIC-4,4'-ODPA-2 displayed the best mechanical properties at both ambient and elevated temperatures. © 2016, Higher Education Press. All right reserved.


Yang F.F.,Shandong University | Yang F.F.,Shandong Non metallic Materials Institute | Yan S.S.,Shandong University | Yu M.X.,Shandong Non metallic Materials Institute | And 10 more authors.
Physica B: Condensed Matter | Year: 2012

A series of FeCoBSiO 2/SiO 2 multilayered granular films with various thickness were prepared by alternating co-sputtering FeCoB and SiO 2 targets and single-sputtering SiO 2 target. As-deposited films were annealed in a magnetic field at different temperature. The high-frequency magnetic and electrical transport properties were investigated. The films annealed above 250 °C show good soft magnetic properties and obvious uniaxial magnetic anisotropy. The resistivity (ρ), coercivity (H ce) decrease and complex permeability (μ̃), ferromagnetic resonance frequency (f r) increase with increasing annealing temperature and thickness. The desirable high ρ (∼5.92 mΩ cm), considerable frequency linewidth (Δf∼4.02 GHz) and high μ̃ (μ′=120 at low frequency, μmax″=80) were obtained for the 252 nm films annealed at 250°C. The amorphous or nanograin phase and strong exchange coupling effect are responsible for the good high-frequency magnetic performance. The electrical transport properties show the films with high ρ and large μ̃ are near the conductive percolation threshold. Moreover, the Δf, damp coefficient (α) and Gilbert damping parameter (G) were discussed based on phenomenological LandauLifshitzGilbert equation. © 2012 Elsevier B.V. All rights reserved.


Yang F.F.,Shandong University | Yang F.F.,Shandong Non metallic Materials Institute | Yan S.S.,Shandong University | Yu M.X.,Shandong Non metallic Materials Institute | And 11 more authors.
Journal of Alloys and Compounds | Year: 2013

A series of FeCoB-SiO2 granular films were deposited on Kapton flexible substrates by magnetron co-sputtering technique at room temperature. All films are amorphous with granular morphology. The coercivity in the easy axis (Hce) and the resistivity (ρ) decrease with the decrease of the Ar pressure, but they decrease with the increase of the film thickness. The granular films deposited at low Ar pressure exhibit obvious in-plane uniaxial magnetic anisotropy. Excellent soft magnetic properties with the Hce as low as 1.57 Oe was obtained in the 500 nm films deposited at 0.3 Pa. In addition, high ρ (∼3.5 mΩ cm), relatively high complex permeability (μ′ = 152.8 at low frequency and μmax″=221.2) and ferromagnetic resonance frequency (fr ∼ 3.61 GHz) were simultaneously obtained. © 2012 Elsevier B.V. All rights reserved.


Liu A.,Shandong University | Han S.,Shandong University | Che H.,Shandong University | Hua L.,Shandong Non metallic Materials Institute
Langmuir | Year: 2010

A fluorescent material with methylene viologen units bonded into the pore walls of the mesoporous MCM-48 silica is synthesized using the method of periodic mesoporous organosilicas with bridging groups (PMOs), in which the methylene viologen units are located within the channel walls through the cohydrolysis and cocondensation of dichloride of N,N'-bis(trithoxysilylmethyl)- 4,4'-bipyridinium (VP) and tetraethoxysilane (TEOS). It is found, that the suspension of the hybrid emits fluorescence at ca. 380 and 420 nm, which is attributed to the Si state (π*→π) of the viologen and the charge-transfer complex between the bipyridinium units as electron acceptor and accompanying halide (Br-, Cl-) as donor components, respectively. The fluorescent emission intensity increases with increasing the amount of the VP covalently bonded to MCM-48 framework. The fluorescent intensity of VP adsorbed on the surface of the pore channel, of MCM-48 was greatly weaker than that of the hybrid MCM-48-VP at the same molar ratio of TEOS to VP. No fluorescence was observed for pure VP. The different fluorescent intensity is ascribed to the fact that restricted degree of the rotation between two pyridine rings is different. It could be prospected that this material is potentially applied in drug delivery and. fluorescence probing for medical diagnosis and synchronous therapy. © 2010 American Chemical Society.


Yang F.F.,Shandong University | Yang F.F.,Shandong Non metallic Materials Institute | Yan S.S.,Shandong University | Yu M.X.,Shandong Non metallic Materials Institute | And 11 more authors.
Journal of Applied Physics | Year: 2012

In order to break through the conductive percolation threshold limitation of the conventional granular films to increase resistivity (ρ), while keeping large complex permeability (μ̃), a series of compositionally graded FeCoB-SiO 2 granular films with different multilayer structures were deposited on flexible substrates. The high-frequency electromagnetic properties were investigated. The experimental results showed that the compositionally graded granular films had obvious in-plane uniaxial magnetic anisotropy and the coercivity in the easy axis (H ce) was as low as 3.97 Oe. Both the ρ (∼15.4 mΩ·cm) and μ̃ (μ i′ = 276. 3 and μ″ max = 441. 4) of the compositionally graded FeCoB-SiO 2 granular films were simultaneously higher than those of the conventional FeCoB-SiO 2 granular films. Two resonance peaks of complex permeability spectrum were also observed. © 2012 American Institute of Physics.

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