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1.
Junchai Zhao Shichun Jiang Xiangling Ji Lijia An Bingzheng Jiang 《Journal of Polymer Science.Polymer Physics》2004,42(18):3496-3504
The surface morphologies of poly(styrene‐b‐4vinylpyridine) (PS‐b‐P4VP) diblock copolymer and homopolystyrene (hPS) binary blend thin films were investigated by atomic force microscopy as a function of total volume fraction of PS (?PS) in the mixture. It was found that when hPS was added into symmetric PS‐b‐P4VP diblock copolymers, the surface morphology of this diblock copolymer was changed to a certain degree. With ?PS increasing at first, hPS was solubilized into the corresponding domains of block copolymer and formed cylinders. Moreover, the more solubilized the hPS, the more cylinders exist. However, when the limit was reached, excessive hPS tended to separate from the domains independently instead of solubilizing into the corresponding domains any longer, that is, a macrophase separation occurred. A model describing transitions of these morphologies with an increase in ?PS is proposed. The effect of composition on the phase morphology of blend films when graphite is used as a substrate is also investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3496–3504, 2004 相似文献
2.
John M. Brown 《Journal of organometallic chemistry》2004,689(24):4006-4015
An overview of the contribution of NMR to the development of our understanding of homogeneous catalysis is presented, with an emphasis on work from the author’s research group. 相似文献
3.
用HAAKE、DSC、IR等方法研究了侧基含有过氧键的反聚苯乙烯与LDPE之间的反应,并将其应用到LDPE/PS共混体系。考察了不同添加方式,交联助剂等对共混物力学性能、流变性能及微观结构的影响。 相似文献
4.
Yunshan Dong 《Applied Surface Science》2006,252(14):5057-5062
A series of Zr-Si-N composite films with different Si contents were synthesized in an Ar and N2 mixture atmosphere by the bi-target reactive magnetron sputtering method. These films’ composition, microstructure and mechanical properties were characterized by energy dispersive spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy and nanoindentation. Experimental results revealed that after the addition of silicon, Si3N4 interfacial phase formed on the surface of ZrN grains and prevented them from growing up. Zr-Si-N composite films were strengthened at low Si content with the hardness and elastic modulus reaching their maximum values of 29.8 and 352 GPa at 6.2 at% Si, respectively. With a further increase of Si content, the crystalline Zr-Si-N films gradually transformed into amorphous, accompanied with a remarkable fall of films’ mechanical properties. This limited enhancement of mechanical properties in the Zr-Si-N films may be due to the low wettability of Si3N4 on the surface of ZrN grains. 相似文献
5.
Hua Zhang Nabil A. Amro Robert Elghanian Joseph Fragala 《Applied Surface Science》2006,253(4):1960-1963
A method, combining micro-contact printing (μCP), wet chemical etching and reactive ion etching (RIE), is reported to fabricate microstructures on Si and SiOx. Positive and negative structures were generated based on different stamps used for μCP. The reproducibility of the obtained microstructures shows the methodology reported herein could be useful in Micro-Electro-Mechanical Systems (MEMS), optical and biological sensing applications. 相似文献
6.
7.
Yonggang Shangguan Li Zhao Liyang Tao Qiang Zheng 《Journal of Polymer Science.Polymer Physics》2007,45(13):1704-1712
The effects of preparation method, composition, and thermal condition on formation of β‐iPP in isotactic polypropylene/ethylene–propylene rubber (iPP/EPR) blends were studied using modulated differential scanning calorimeter (MDSC), wide angle X‐ray diffraction (WAXD), and phase contrast microscopy (PCM). It was found that the α‐iPP and β‐iPP can simultaneity form in the melt‐blended samples, whereas only α‐iPP exists in the solution‐blended samples. The results show that the formation of β‐iPP in the melt‐blended samples is related to the crystallization temperature and the β‐iPP generally diminishes and finally vanishes when the crystallization temperature moves far from 125 °C. The phenomena that the lower critical temperature of β‐iPP in iPP/EPR obviously increases to 114 °C and the upper critical temperature decreases to 134 °C indicate the narrowing of temperature interval, facilitating the formation of β‐iPP in iPP/EPR. Furthermore, it was found that the amount of β‐iPP in melt‐blended iPP/EPR samples is dependent on the composition and the maximum amount of β‐iPP formed when the composition of iPP/EPR blends is 85:15 in weight. The results through examining the effect of annealing for iPP/EPR samples at melt state indicate that this annealing may eliminate the susceptibility to β‐crystallization of iPP. However, only α‐iPP can be observed in solution‐blended samples subjected to annealing for different time. The PCM images demonstrate that an obvious phase‐separation happens in both melt‐blended and solution‐blended iPP/EPR samples, implying that compared with the disperse degree of EPR in iPP, the preparation method plays a dominant role in formation of β‐iPP. It is suggested that the origin of formation of β‐iPP results from the thermomechanical history of the EPR component in iPP/EPR. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1704–1712, 2007 相似文献
8.
Unintentionally doped and zinc-doped indium nitride (U-InN and InN:Zn) films were deposited on (0 0 0 1) sapphire substrates by radio-frequency reactive magnetron sputtering, and all samples were then treated by annealing to form In2O3 films. U-InN and InN:Zn films have similar photon absorption characteristics. The as-deposited U-InN and InN:Zn film show the absorption edge, ∼1.8-1.9 eV. After the annealing process at 500 °C for 20 min, the absorption coefficient at the visible range apparently decreases, and the absorption edge is about 3.5 eV. Two emission peaks at 3.342 eV (371 nm) and 3.238 eV (383 nm) in the 20 K photoluminescence (PL) spectrum of In2O3:Zn films were identified as the free-exciton (FE) or the near band-to-band (B-B) and conduction-band-to-acceptor (C-A) recombination, respectively. 相似文献
9.
多组分单体接枝聚丙烯/尼龙6反应共混物结晶行为研究 总被引:10,自引:0,他引:10
用多组分熔融接枝的方法将甲基丙烯酸缩水甘油酯 (GMA)和苯乙烯 (St)共同接枝到聚丙烯 (PP)上 ,制得具有较高GMA接枝率的多单体接枝聚丙烯 ,PP g (GMA co St) .将PP g (GMA co St)与尼龙 6 (PA6 )进行共混 ,利用扫描电镜 (SEM) ,差示扫描量热计 (DSC)和广角X射线衍射 (WAXD)对共混物的形态和结晶进行了研究 .在共混过程中 ,PP g (GMA co St)与PA6反应原位生成了PP g PA6 ,有效改善了共混物的相容性 ,分散相尺寸明显减小 .在PP g (GMA co St) PA6为 3 7的体系中 ,PP g (GMA co St)出现分级结晶现象 ,其在较低温度下的结晶属于均相成核结晶 .在PP g (GMA co St) PA6为 7 3的体系中 ,由于PA6相分散细微 ,在通常结晶温度下不结晶 ,而是在低温下均相成核与PP g (GMA co St)同时结晶 .WAXD证实体系中接枝PP ,PA6为分别结晶 ,无共晶或新的晶型产生 相似文献
10.
在滴汞电极上研究了硝基苯、对硝基甲苯、间二硝基苯及2,4-二硝基氯苯的电化学行为,并用量子理论对四种硝基苯化合物的反应活性进行了预测,理论与试验结果基本一致,据此提出了预测分子的电化学活性的方法。 相似文献