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231.
Liping Zhao Zhenghong Guo Zhenhu Cao Tao Zhang Zhengping Fang Mao Peng 《Polymer Degradation and Stability》2013
Fullerene (C60)/high density polyethylene (HDPE) composites were studied in order to understand for their behaviors on thermal and thermo-oxidative degradation. Under different atmosphere, the influences of C60 on the thermal stability of HDPE are different. Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) demonstrate that in N2 the addition of C60 increases the onset decomposition temperature by about 10 °C with more heavy compounds (more than 34 carbon). Also the thermal stability of HDPE in air is remarkably improved with the addition of C60. When the content of C60 is 2.5 wt% the onset decomposition temperature increases by about 91 °C. The results of viscoelastic behavior and gel content reveal that C60 can trap the alkyl radicals and alkyl peroxide radicals to inhibit hydrogen abstraction to suppress the chain scission and preserve the long chain structure. However, in the absence of C60 or with low C60 concentration, hydrogen abstraction occurs, resulting in the formation of a series of alkyl radicals and alkyl peroxide radicals, which accelerates the chain scission and plays a leading role in the thermal oxidative degradation. 相似文献
232.
Mao Chen Ting Zhao Zhong‐Xin Zhu Chao Niu Dan‐dan Ruan Mao‐Wei Ni Xuan Zhou Li‐Tai Jin 《Electrophoresis》2013,34(24):3277-3286
An improved Stains‐All (ISA) staining method for phosphoproteins in SDS‐PAGE was described. Down to 0.5–1 ng phosphoproteins (α‐casein, β‐casein, or phosvitin) can be successfully selectively detected by ISA stain, which is approximately 120‐fold higher than that of original Stains‐All stain, but is similar to that of commonly used Pro‐Q Diamond stain. Furthermore, unlike the original Stains‐All protocol that was time consuming and light unstable, ISA stain could be completed within 60 min without resorting to protect the gels from light during the whole staining procedure. According to the results, it is concluded that ISA stain is a rapid, sensitive, specific, and economic staining method for a broad application to the research of phosphoproteins. 相似文献
233.
Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively (designated as BAPNCP, BAPBACP and BAPNPGCP, respectively), were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly(BAPNPGCP) were 8 °C and 7% higher than those of poly(BAPBACP). Meanwhile, the total heat release of poly(BAPNPGCP) was less than half of that for poly(BAPBACP), indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly(BAPNCP) gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine. 相似文献
234.
Binglian Bai Xiyue Mao Zhanhu Xi Jie Ma Xiaolong Lin Haitao Wang 《Liquid crystals》2013,40(2):214-221
Two series of dissymmetric hydrazide derivatives containing alkoxyazobenzene with nitro terminal group and octyloxy terminal group, N-4-alkoxyphenyl-N′-4-((4-nitrophenyl)azophenyl) benzohydrazide (Bn-NO2, n indicates the number of carbon atoms) and N-4-octyloxyphenyl-N′-4-((4-octyloxyphenyl)azophenyl) benzohydrazide (B8-B8), were designed and synthesised, and their liquid crystalline properties were investigated by means of differential scanning calorimetry, polarised optical microscopy and wide-angle X-ray diffraction. It was found that B8-B8 with octyloxy terminal chains displayed monolayer smectic C phase, whereas Bn-NO2 with nitro terminal group displayed SmAd phase, and intermolecular hydrogen bonding was confirmed as the driving force. In addition, the effect of hydrogen bonding, dipole–dipole interactions and steric hindrance effect on the liquid crystalline structures were also discussed. 相似文献
235.
Takuya Adachi Yasuhisa Yamamura Mafumi Hishida Mao Ueda Shunji Ito 《Liquid crystals》2013,40(11):1340-1344
Molecular dynamics in the soft crystal, E phase of 6-octyl-2-phenylazulene was studied by X-ray diffraction, and dielectric and Fourier transform infrared spectroscopies. Clear dielectric dispersion is observed due to the head-to-tail disordering in a kHz range around 400 K. The CH stretching frequencies exhibit more pronounced shifts at the phase transition point from the high-temperature ordered crystal to the E phase than that at the melting from the E phase to the isotropic liquid. The results are discussed in comparison with a typical E series, 4-n-alkyl-4′-isothiocyanatobiphenyl (n being the number of carbon atoms in the alkyl group). 相似文献
236.
Donglin Mao Tingting Li Huarong Liu Zichao Li Hong Shao Min Li 《Colloid and polymer science》2013,291(7):1649-1656
PolyHIPEs are highly porous, crosslinked polymer foams typically synthesized within high internal-phase emulsions (HIPEs). Two kinds of polyHIPEs including poly(styrene-divinylbenzene) [P(St-DVB)] and poly(methyl methacrylate-divinylbenzene) [P(MMA-DVB)] foams are synthesized in this work, which are fabricated from HIPEs template via radiation-induced polymerization at room temperature. Traditional free radical polymerization initiated by potassium peroxydisulfate (KPS) at 60 °C for producing polyHIPE P(St-DVB) foams is also conducted for comparison. It is found that the amount of emulsifier can be reduced greatly in the radiation-induced polymerization of HIPEs at room temperature, compared with the traditional polymerization approach. Besides, P(MMA-DVB) PolyHIPE foams with a fine microstructure of highly interconnected pores have been successfully fabricated via radiation-induced polymerization in this work, which is usually difficult to be prepared by thermal-initiation method because of the intermediate hydrophobicity of methyl methacrylate monomer. The influences of the fraction of internal aqueous phase and the concentration of emulsifier on the structure and performance of foams are carefully explored. The structure and compression strength of the foams are characterized by scanning electron microscopy and a mechanical testing machine, respectively. Figure
Macroporous poly(styrene-divinylbenzene) and poly(methyl methacrylate-divinylbenzene) foams are synthesized from HIPEs template via radiation-induced polymerization at room temperature using a common surfactant Span 80. 相似文献
237.
Junsong Yang Juanjuan Zhao Hailong Wang Shengyi Zhang Jiming Song Changjie Mao Helin Niu Baokang Jin Yupeng Tian 《Journal of Sol-Gel Science and Technology》2013,67(3):660-664
By dipping-lifting in sol–gel solution and reducing process, the TiO2 composite film on the glass plate was first prepared. Then, the PbSe/BaTiO3/TiO2 composite film was fabricated by interface reaction with BaTiO3 and PbSe on the surface of TiO2 composite film. The characterization results show that the uniform porous TiO2 film is made up of the anatase crystal, and the PbSe/BaTiO3/TiO2 composite film is constructed by doping or depositing BaTiO3 and PbSe nanoparticles on the surface of TiO2 film. The photoelectrochemical measurement results indicate that the PbSe/BaTiO3/TiO2 composite film has an interesting photoelectrochemical conversion property. 相似文献
238.
Prof. Dr. Masaichi Saito Tomoki Akiba Misumi Kaneko Toshiaki Kawamura Dr. Minori Abe Prof. Dr. Masahiko Hada Prof. Dr. Mao Minoura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):16946-16953
Plumbacyclopentadienylidenes, in which the lead atoms have divalent states and are coordinated by THF, pyridine and N‐heterocyclic carbene, were synthesized and characterized. The THF‐ and pyridine‐stabilized compounds can be regarded as rare examples of hypervalent 10‐X‐4 species. The equilibrium between the THF adduct and the free plumbacyclopentadienylidene was evidenced by spectroscopic analysis and theoretical calculations. The THF adduct in benzene converted into a plumbylene dimer, where one of the lead centers is coordinated by THF and the other lead atom is coordinated by a divalent lead atom, the dimer gradually decomposing into spiroplumbole. The THF adduct unexpectedly reacted with trifluoroborane and trichlorogallane to afford fluoroborole and chlorogallole, which are the first examples of non‐annulated fluoroborole and gallole, respectively. 相似文献
239.
Jia Mao Anayancy Osorio-Madrazo Marie-Pierre Laborie 《Cellulose (London, England)》2013,20(4):1829-1840
Cellulose I nanowhiskers were prepared in relatively high yield (48 ± 2 %) by single-stage hydrolysis of microcrystalline cellulose with an aqueous solution of 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO4). This reaction occurred under mildly acidic reaction conditions with an [H+]/[AGU] ratio of 0.24 mol/mol, i.e., 2 orders of magnitude lower than with concentrated sulfuric acid. The nanowhiskers exhibited small width and width distribution and also smaller length than nanowhiskers obtained with concentrated acid. With a relatively low content of sulfur they also exhibited higher thermal stability than whiskers obtained with concentrated sulfuric acid. The lower solvating power of the aqueous ionic liquid compared to that of concentrated sulfuric acid likely contributes to the greater hydrolysis efficiency in the present system. 相似文献
240.
Shouwei Zhang Wentao Liu Jia Liang Xiaoya Li Wenna Liang Suqin He Chengshen Zhu Luyuan Mao 《Cellulose (London, England)》2013,20(3):1135-1143
Films with different numbers of layers have been built by alternating the adsorption of carboxymethyl cellulose (CMC) and chitosan (CHI) at different pH levels. The adsorption process was recorded by quartz crystal microbalance (QCM). The results showed that under all pH conditions considered, the growth of the films is nonlinear. The film construction performed at pH 4.0 (preferred assembly pH) with different numbers of bilayers (CMC/CHI as one bilayer) was also observed step by step by atomic force microscopy (AFM). Comparing the growth process from QCM with the surface morphological changes from AFM shows the existence of an inhomogeneous structure for the first nine bilayers, and, after a coalescence of islands, an increase in the number of bilayers was demonstrated. The possible growth mechanism was also evaluated. 相似文献