Effect of shear on the crystallization behavior of glass bead filled polypropylene

Linkam CSS450 optical shearing stage, wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering(SAXS) were used to investigate the effect of shear on crystal structure and crystallization morphology of the glass bead filled polypropylene( PP). The results indicate that the glass bead worked as nucleating agent for the glass bead filled PP, compared with pure PP it restrained the formation of beta-crystal after shear treatment. When the mean size of glass bead is smaller(4 mu m) shear rate had less effect on the formation of beta-crystal of PP obviously.

ELECTROCHEMICAL DEPOSITION OF MAGNESIUM IN ETHEREAL GRIGNARD SALT SOLUTION WITH IONIC LIQUID ADDITIVE

The electrochemical deposition of magnesium was investigated in ethereal Grignard salt solution with tetraethylammonium bistrifluoro-methanesulfonimidate additive, using cyclic voltammetry, potentiostatic transients, and scanning electron microscope measurements. The voltammograms showed the presence of reduction and oxidation peaks associated with the deposition and dissolution of magnesium. From the analysis of the experimental current transients, it was shown that the magnesium deposition process was characterized as a three-dimensional nucleation. The deposited product obtained from potentiostatic reduction presented a generally uniform and dense film.

稀土三元催化剂下正辛酸缩水甘油酯-二氧化碳-环氧丙烷的三元共聚合

研究了稀土三元催化剂(三氯乙酸稀土配合物/二乙基锌/甘油)催化下的正辛酸缩水甘油酯、CO2和环氧丙烷三元共聚合。红外光谱、核磁共振和DSC结果表明,所获得的聚合物是一种新型的三元共聚物。随着反应单体中正辛酸缩水甘油酯比例的增加,所得聚合物在20℃下的断裂伸长率由二氧化碳-环氧丙烷共聚物的31.0%增大至二氧化碳-正辛酸缩水甘油酯共聚物的983.9%,相应的玻璃化转变温度由39.6℃降低至-12.3℃。所得三元共聚物中长碳链侧基单元含量为5.6%时,其断裂伸长率就已经达到481.1%,而拉伸强度仍然维持在24.9MPa的较高水平。

Preparation of TiO2, CeO2, and ZrO2 hierarchical structures in "one-pot" reactions

In this paper, a novel template of carbon foam is used in building hierarchical structures of TiO2, CeO2, and ZrO2. They had multiscale morphologies, from nanowalls, nanoparticles to layer nanostructures. Oil a hundred-micron scale, the product was a sponge-like material constructed by nanowalls. On a hundred-nanometer scale, the electron microscope images showed that the nanowalls were porous and assembled by polycrystalline nanoparticles. Meanwhile, on one nanometer scale, many nanoparticles exhibited layer nanostructures with about 1.1 run of thickness and spacing. In mechanism section, the process analysis and characterizations suggested that the hierarchical structures were the combined result of two templates in a "one-pot" reaction. The mesoporous nanowalls were derived from carbon foams, while the layer nanostructures were the replicas of graphite sheets. The method has potential utilizations in preparation of various adsorbent and catalyst.

Influence of the degree of grafting on the morphology and mechanical properties of blends of poly(butylene terephthalate) and glycidyl methacrylate grafted poly(ethylene-co-propylene) (EPR)

Poly(ethylene-co-propylene) (EPR) was functionalized to varying degrees with glycidyl methacrylate (GMA) by melt grafting processes. The EPR-graft-GMA elastomers were used to toughen poly(butylene terephthalate) (PBT). Results showed that the grafting degree strongly influenced the morphology and mechanical properties of PBT/EPR-graft-GMA blends. Compatibilization reactions between the carboxyl and/or hydroxyl of PBT and epoxy groups of EPR-graft-GMA induced smaller dispersed phase sizes and uniform dispersed phase distributions. However, higher degrees of grafting (>1.3) and dispersed phase contents (>10 wt%) led to higher viscosities and severe crosslinking reactions in PBT/EPR-graft-GMA blends, resulting in larger dispersed domains of PBT blends. Consistent with the change in morphology, the impact strength of the PBT blends increased with the increase in EPR-graft-GMA degrees of grafting for the same dispersion phase content when the degree of grafting was below 1.8. However, PBT/EPR-graft-GMA1.8 displayed much lower impact strength in the ductile region than a comparable PBT/EPR-graft-GMA1.3 blend (1.3 indicates degree of grafting).

Single-molecule dynamics reveals cooperative binding-folding in protein recognition

The study of associations between two biomolecules is the key to understanding molecular function and recognition. Molecular function is often thought to be determined by underlying structures. Here, combining a single-molecule study of protein binding with an energy-landscape-inspired microscopic model, we found strong evidence that biomolecular recognition is determined by flexibilities in addition to structures. Our model is based on coarse-grained molecular dynamics on the residue level with the energy function biased toward the native binding structure ( the Go model). With our model, the underlying free-energy landscape of the binding can be explored. There are two distinct conformational states at the free-energy minimum, one with partial folding of CBD itself and significant interface binding of CBD to Cdc42, and the other with native folding of CBD itself and native interface binding of CBD to Cdc42. This shows that the binding process proceeds with a significant interface binding of CBD with Cdc42 first, without a complete folding of CBD itself, and that binding and folding are then coupled to reach the native binding state.

Synthesis and properties of optically active polyquinolines containing 1, 1 '-binaphthyl unit

Optically active 2,2'-dimethoxy-6,6'-diacetyl-1,1'-binaphthyl (DMDABN) was prepared from 2,2'-dimethoxy-1,1'-binaphthyl, and its structure was comfirmed by elemental analysis, NRM, IR and MS. Optically active polyquinolines were synthesized with DMDABN and 4,4'-diamino-3,3'-dibenzoyldiphenyl ether by Friedlander reaction. These polyquinolines showed high glass transition temperatures (474-578 K), high decomposition temperatures (703-770 K), insolubility in many common organic solvents and strong chiral activity.

含联萘基团的旋光性聚喹啉的合成与性质

由 2 ,2 -二甲氧基 -1 ,1 -联萘制备了旋光活性的 2 ,2 -二甲氧基 -6,6 -二乙酰基 -1 ,1 -联萘(DMDABN) .经元素分析 ,NRM,IR和 MS等方法对其进行结构表征 ,DMDABN与 3 ,3 -二苯甲酰基-4,4 -二氨基 -二苯基醚通过 Friedlander反应合成了旋光性聚喹啉 .所制备的聚喹啉具有较高的玻璃化转变温度 (4 74～ 5 78K)、热分解温度 (70 3～ 770 K)、很好的耐溶剂性能和较强的旋光活性

An encapsulation of the rare earth complex in modified mesoporous molecular sieve MCM-41

The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.

Stability of Mo/Si multilayer structure used in Bragg-Fresnel optics

The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation. Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K, treated with acetone and 5 parts per thousand NaOH solution, and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy, and Olympus microscopy.

Electrochemistry of vanadium hexacyanoferrate film

Two stable redox couples, accompanying clear color switches between yellow green and blue, can be observed when the VHCF-coated film platinum electrodes are cyclic potential scanned in 3.6 M H2SO4 and 0.2 M K2SO4 electrolyte solution. Electrochemical results and in situ Fourier transfer infrared (FT-IR) spectroscopy demonstrate that the redox reaction of the electroactive iron sites is related to the first redox couple (E-1/2 = 0.81 V) while the second redox couple (E-1/2 = 1.01 V) is due to the redox reactions of the electroactive vanadyl ions. Under the proper conditions, such as in high acidic solutions or thin films (deposition time is less than 2 min) and so on, the third redox couple (E-1/2 = 0.89-0.94 V) can be observed on the cyclic voltammograms, which originates from the redox reactions of the interstitial vanadyl ions. This electrochemical reaction mechanism is investigated by in situ probe beam deflection technique, exchange of K+ ions accompanies with redox reaction of the iron sites, but for redox reaction of the vanadyl ions, both H+ ions, K+ ions and water molecules are involved.

EPITAXIAL BEHAVIOR OF HDPE ON THE BOUNDARY OF HIGHLY ORIENTED IPP SUBSTRATES

The epitaxial crystallization behavior of high-density polyethylene on the boundary of highly oriented isotactic polypropylene (iPP) substrates has been investigated by means of atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results obtained from AFM and TEM indicate that the epitaxial nucleation of HDPE on the highly oriented iPP substrates occurs earlier than that in the pure HDPE phase, i.e., homogeneous nucleation. Therefore the epitaxially grown HDPE lamellae can grow across the boundary of the iPP substrate into the HDPE spherulitic phase with the epitaxial orientation relationship remaining.