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111.
Ze-yong Zhao Wei-wei yao Rong-ni Du Qin Zhang Qiang Fu
Ze-hao Qiu Su-lan Yuan
《高分子科学》1996,(1):137-143
Ze-hao Qiu Su-lan Yuan
《高分子科学》1996,(1):137-143
A series of polydimethylsiloxane (PDMS) with varied molecular weights (Mw = 3 61620; 106, 1 61620; 106 and 0.5 61620; 106) were melt blended with PP to investigate the effect of PDMS molecular weight (MW) on the morphology and mechanical properties of PP/PDMS blends. Scanning electron microscopic (SEM) examination showed that the size of PDMS domains was dependent on the MW of PDMS. It was found that the lower the value of PDMS MW, the better dispersion of the PDMS domains in the PP matrix. Tensile and Izod impact tests revealed that the addition of PDMS with lower MW would lead to a more significant increase in impact strength of the blends compared with the blends with higher MW ones, while the influence of the molecular weight on tensile strengths of the blends was relatively small in the MW range studied. Differential scanning calorimetry (DSC) results also showed that the crystallization temperature of PP was increased with decreasing PDMS MW, indicating a better nucleation capability of lower MW of PDMS. Melting flow rate (MFR) measurements indicated that the processibility of PP could be enhanced by adding PDMS, and again the lower MW PDMS resulted in better data. Our work demonstrates that not only the processibility but also the mechanical properties of PP could be enhanced to a more significant degree by using low MW PDMS than the higher ones. 相似文献
112.
水热合成CdS纳米晶体的形貌控制研究 总被引:4,自引:0,他引:4
研究了水热合成CdS纳米晶体形貌的化学控制,选择不同的络合试剂为模板,研究其对水热合成CdS纳米晶体形貌的影响.实验发现若以络合试剂乙二胺、甲胺为模板时,产品CdS晶体的形貌分别为(20~30) nm×(200~600) nm和(40~50) nm×(200~600) nm尺寸的纳米棒;而以络合试剂吡啶、 氨为模板时,产品CdS晶体的形貌分别为平均尺寸约30 nm和20 nm的纳米颗粒.用XRD、TEM、XPS、PL和Raman光谱等技术对所得CdS纳米棒进行了表征.同时对水热合成CdS纳米晶体形貌的模板控制机制进行了探讨,提出了一种水热合成CdS纳米棒的络合物结构诱导生长机理. 相似文献
113.
114.
L. N. Yang S. J. Qiu F. Xu L. X. Sun Z. B. Zhao J. G. Liang C. G. Song 《Journal of Thermal Analysis and Calorimetry》2007,89(3):875-879
The effects of Amoxicillin Sodium and Cefuroxime Sodium on the growth of E. coli DH5α were investigated by microcalorimetry. The metabolic power-time curves of E. coli DH5α growth were determined by using a TAM air isothermal microcalorimeter at 37°C. By evaluation of the obtained parameters,
such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (P
m) and the time of the maximum heat power (t
m), one found that the inhibitory activity of Amoxicillin Sodium vs. E. coli DH5α is enhanced with the increasing of the Amoxicillin Sodium concentration, and the Cefuroxime Sodium has a stimulatory effect on the E. coli DH5α growth when the concentration is about 1 μg mL−1. The IC50 for the Amoxicillin Sodium and the Cefuroxime Sodium are 1.6 and 2.0 μg mL−1, respectively, it implicates that the E. coli DH5α is more sensitive to Amoxicillin Sodium than Cefuroxime Sodium. 相似文献
115.
Semiconductor alpha-MoTe2 nanorods have been synthesized by annealing Te-seeded particles of an amorphous MoTe2 intermediate. This intermediate is prepared by a solution reaction between Mo(CO)6 and elemental Te in diphenylmethane. The as-synthesized products were characterized by structural, compositional, and morphological techniques of X-ray diffraction, selected area electron diffraction, selected area energy dispersive spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The results of the annealing process are MoTe2 nanorods with diameters of 50-200 nm and lengths ranging from 0.1 to 3.0 microm. Here, the rodlike structure of MoTe2 is reported for the first time, and added to the list as one kind of new morphology of MoTe2 nanomaterials. A mechanism for the formation of the nanorods is proposed. The sandwich-layered structure of Te-Mo-Te and the similarity in the structure between hexagonal alpha-MoTe2 and hexagonal Te are responsible for the formation of nanorods of MoTe2. 相似文献
116.
117.
Two novel sesquiterpene dimers, compounds 1 and 2 , were isolated from the rhizome of Ligularia virgaurea, together with the six known sesquiterpenoids 3 – 8 . Their structures were established by physico‐chemical and spectroscopic methods, especially by means of 1D‐ and 2D‐NMR as well as HR‐MS analyses. A mechanism based on a classical Diels–Alder cyclization is proposed for the formation of the dimer 1 from the precursors 8 and the quinone form of 6 (Scheme). 相似文献
118.
测定了亲水性甲基丙烯酸羟烷基酯如HEMA、MHPMA分别与AN或AAM,在60℃不同溶剂中自由基聚合反应的竞聚率。AN(M_1)-HEMA(M_2)共单体,在DMSO或DMF溶剂以AIBN或KPS-IPA引发剂条件下共聚,用Kelen-Tüds法计算的竞聚率变化不大,r_1=0.22-0.25、r_2=0.97-1.05,说明在此均相溶液共聚中,所用的溶剂及引发剂对竞聚率的影响较小,这两种单体能很好共聚。但AAM-MHPMA或AAM-HEMA共单体时,r_1与r_2值相差很大,如前者r_1=0.0433、r_2=3.98,后者r_1=0.0535、r_2=1.89,说明不易共聚,共聚物中主要是MHPMA或HEMA组分。 相似文献
119.
Yun‐Yu Liu Guang‐Shan Zhu Guo‐Zhen Fan Shi‐Lun Qiu 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(4):m159-m160
In the title compound, poly[μ5‐pyrazine‐2,3‐dicarboxylato‐cadmium(II)], [Cd(C6H2N2O4)]n or [Cd(pdc)]n, where pdc is the pyrazine‐2,3‐dicarboxylate anion, the CdII atom is six‐coordinated by five carboxylate O atoms and one N atom from five different pdc ligands in a distorted octahedral CdO5N coordination geometry. Two CdII atoms are bridged by carboxylate groups of the pdc ligands to create a dimeric unit. The dimeric units are further connected by the pdc ligands to generate an interesting two‐dimensional structure. 相似文献
120.
Ohsuna T Slater B Gao F Yu J Sakamoto Y Zhu G Terasaki O Vaughan DE Qiu S Catlow CR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(20):5031-5040
High-resolution electron microscopy (HREM) has been used to image the surface structure of nano- and micrometer-sized synthetic crystals of zeolite-Linde-L (LTL). Columnar holes and rotational, nano-sized, wheel-like defects were observed within the crystals, where the hole has a minimum size equal to that of the rotational defect. Predictions of surface structure from atomistic computer simulation concur with the observations from HREM and provide insight into the crystal growth mechanism of perfect and defective LTL. Analysis of the energetics of the formation of rotational defect structures reveals that the driving force for defect creation is thermodynamic and furthermore, the rotational defects could be created in high concentrations. Formation of a columnar hole is found to be slightly energetically unfavourable and therefore we speculate that the incidence of both rotational and nano-sized vacancy defects is strongly dependent on kinetic factors and reaction conditions. The morphology of nano- and microcrystalline LTL is contradistinct and we use insights from simulation to propose an explanation of the disparity in crystal shape. 相似文献