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121.
用WAXD和SAXS研究交联1,4-顺式聚丁二烯的取向结晶。结果表明:该试样在拉伸状态时,形成折叠链片晶,而不是伸直链纤维晶。片晶之间断产生新的片晶,使长周期减小,并且片晶的横向尺寸不断增大,由此导致结晶度增大。 相似文献
122.
123.
以聚乙烯醇(PVA)-戊二醛(GA)体系作为研究对象, 系统地研究了分子内环化对凝胶体系的影响, 为水凝胶体系的网络结构评价奠定了一定的实验基础. 相似文献
124.
The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized byhydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage modulus below andabove the glass transition temperature occurred and the complexes exhibited shape memory behaviors. The morphology ofcomplexes was studied by using DSC, WAXD, and DMA. The results indicate that the fixed phase of this kind of novelshape memory materials is the network, and the reversible phase is the amorphous state of PEG:PMAA complex phase. Theshape recoverability almost reaches 100%. This type of complexes can be regarded as a novel shape memory network. 相似文献
125.
比值导数荧光光谱法同时测定色氨酸和5-羟基色氨酸 总被引:2,自引:0,他引:2
建立了比值导数荧光光谱法同时测定色氨酸和5-羟基色氨酸的方法。在比值导数荧光光谱法中,色氨酸浓度在4.0×10-6~2.0×10-5mol/L范围内比值导数荧光光谱峰高与其浓度成正比,线性相关系数为0.9901,检出限为1.3×10-7mol/L。5-羟基色氨酸浓度在4.0×10-8~2.0×10-5mol/L范围内比值导数光谱峰高与其浓度成正比,线性相关系数为0.9996,检出限为1.3×10-8mol/L。同时测定了实际样品中的色氨酸和5-羟基色氨酸,测定结果与高效液相色谱法有良好的一致性。 相似文献
126.
Polymeric membranes based on cellulose acetate (CA)--sulfonated polysulfone blends at three different polymer compositions were prepared by solution blending and phase inversion technique, characterized and subjected to annealing at 70, 80 and 90 °C. The permeate water flux, separation of bovine serum albumin and its flux by the blend membranes before and after thermal treatment, have been compared and discussed. Similarly, CA and epoxy resin (diglycidyl ether of bisphenol-A) were blended in various compositions, in the presence and in the absence of polyethyleneglycol 600 as non-solvent additive, using N,N′-dimethylformamide as solvent, and used for preparing ultraflltration membranes by phase inversion technique. The polymer blend composition, additive concentration, casting and gelation conditions were optimized. Blend membranes were characterized in terms of compaction, pure water flux, water content and membrane resistance. The effects of polymer blend composition and additive concentration on the above parameters were determined and the results are discussed. 相似文献
127.
Dong-shanZhou Xiao-liangWang BoChe LiangLi Jin-luChen GiXue 《高分子科学》2005,(2):159-163
Entropic contribution to the interaction parameter xeff in the model incompressible polymer/oligomer system is calculated by the lattice cluster theory (LCT). It is found that in the oligomer solvent, there exists a wide concentration range that the non-combinatorial “entropic interaction” term xeff φ1φ2 perceptibly counteracts the mean field combinary entropy ΔSMF. With the increase of the solvent size, both xeff and the ratio xefc φ1φ2/ΔSMF first reach their maximum and finally become trivially to zero. It is worth noting that no any demixing was found in the current calculation. This makes the controversial idea “entropically driven demixing” even elusive. However, we propose that further work on compressible polymer solution with structured monomer will witness the demixing owning to an increased configurational correlation. 相似文献
128.
A high-powered, microwave-induced nitrogen–oxygen plasma (N2–O2–MIP) generated by using an Okamoto cavity at atmospheric pressure was investigated when the observation height, the flow rate of carrier gas, and the oxygen content were varied as the experimental parameters. The emission characteristics of the plasma were evaluated with regard to the excitation temperature and the intensity ratio of atomic line to ionic line. The excitation temperature of the N2–O2–MIP was in the range of 5100–5700 K when the oxygen content was varied from 0 to 30% at the observation height of 7 mm and the carrier gas flow rate of 0.6 l/min. The intensity ratio of atomic line to ionic line was elevated with an increase in the oxygen content. 相似文献
129.
The infrared spectra of phosphinic acid R2POOH dimers (R=CH3, CH2Cl, C6H5) have been studied in CCl4 and CH2Cl2 solutions (T=300 K). The infrared spectra of deuterated R2POOD dimers (R=CH3, CH2Cl) were also studied in the gas phase (T=400–550 K) and solid state (T=100–300 K). They are compared with previously studied spectra of the light (non-deuterated) dimers in the gas phase, in the solid state and in low-temperature argon matrices (T=12–30 K) in the 4000–400 cm−1 spectral region. It is found that the strong and broad ν(OH) dimer bands have similar shapes, nearly equal values of bandwidth and low-frequency shift, and possess the Hadzi ABC structure irrespective of the type of acid, significant differences of dimerization enthalpies, influence of solvent, the type of H-bonded complexes (cyclic dimers in the gas phase, in solutions, and in inert matrices, and infinite chains in the solid state), and temperature in the range 12–600 K. Isotopic ratio of the first moments of light and deuterated acid bands has been measured. Analysis of the ν(OH/OD) band of hydrogen bonded dimers of phosphinic acids shows that the interaction between the two intermolecular bonds O–HOP in a cyclic complex plays virtually no role in the mechanism of the ν(OH/OD) band formation; the shape of ν(OH/OD) band is controlled mainly by the POOH(D)O fragment; and the band shape of strong hydrogen bonded complexes is formed by a number of vibrational transitions from the ground state to different combination levels in the region 3500–1500 cm−1. 相似文献
130.
YU Jian-Chang WANG Chang-Yun 《结构化学》2007,26(10):1139-1144
In this paper,zinc acetate,manganese acetate and thiacetamide are used as raw materials to successfully synthesize monodispersed ZnS:Mn2+ microspheres by using hydrothermal method and taking P123 surfactant as a template. The products were characterized by XRD,STEM,FT-IR and N2 adsorption-desorption. And the results show that the diameter of this microsphere is 1.0 μm or so,which is larger than that of ZnS microsphere without Mn2+ doping,and it has monodispersion,smooth surface and uniform size. The doping of Mn2+ does not obviously change the structure of monodispersed ZnS microsphere. The photoluminescence peak lies in a wide band ranging from 450 to 650 nm,and the microspheres emit orange light; with the increase of Mn2+ concentration,fluorescence intensity of ZnS:Mn2+ microsphere changes,and when the mole ratio of Mn2+:Zn2+ is 0.3:1,the fluorescence intensity is the strongest. 相似文献