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structure and properties of UV-irradiated LLDPE and alloy of PA66 and the irradiated LLDPE

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Structure and properties of UV-irradiated LLDPE and alloy of...

Studies on Synthesis, structure and properties of Cobalt Complex [Co( Ⅰ ) (dppe)_2CO]_2[Co_2( Ⅱ ) (dppe)Cl_6O_2]

The 1st Asian-Pacific Symposium on Radiation Chemistry

作者： Qianping RAN 1 2 Hua ZOU 1 Shishan WU 1 Jian Shen 1 1School of Chemistry and Chemical Engineering Nanjing University Nanjing 210093 China 2 Jiangsu Institute of Building Science Nanjing 210008 China

Some oxygen-containing groups such as C=O, C-O and -OH were introduced onto linear low-density polyethylene （LLDPE） chains by UV irradiation in air. Their concentration increased with the irradiation time. Crystal shape of the irradiated LLDPE remained an orthorhombic structure, while space of the crystalline plane kept unchanged. The melting temperature and crystallinity decreased due to the LLDPE chain scission into small molecules compound and crystalline defects caused by UV irradiation [1,2]. Compared with pristine LLDPE, hydrophilicity of the irradiated LLDPE increased due to the introduction of polar oxygen-containing groups, but the tensile strength decreased due to the LLDPE chain degradation and reduction of crystallinity. The temperature of initial weight loss of the irradiated LLDPE was lower than that of pristine LLDPE.

关键词： Ultraviolet irradiation Functionalization LLDPE structure and properties

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Chemical Research in Chinese Universities 1993年第2期9卷 99-103页

作者： WANG Tao FAN Yu-guo (Institute of Theoretical Chemistry, Jilin University, Changchun, 130023)

A cobalt complex with mixed valence state [Co( Ⅰ ) (dppe)2CO]2 [Co2 ( Ⅱ )(dppe) Cl]6O2] (dppe = 1,2 - bis(diphenylphosphino) ethane) has been prepared. The compound crystallizes in triclinic space group P1 with unit cell parameters: a=1. 1763(3) nm, b = 1. 2943(6) nm, c=2. 1507(9) nm, a=81. 44(4)°? ,β=82. 58(3)°, r = 79. 82(3)°, V = 3. 1691 nm3 and Z=1. The structure was solved by direct method according to ALPHA criterion and was refined by a block diagonal matrix least-squares procedure to final R= 0.084, Moreover, infared spectra, electronic reflection spectra and cyclic voltammetry curve were mearsured.

关键词： Cobalt Synthesis structure and properties

Density functional theory study on the structure and properties of Si3N4 clusters

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Density functional theory study on the structure and propert...

Structural and mechanical properties of amorphous carbon films deposited by the dual plasma technique

第十三届全国原子与分子物理学术会议

作者：张材荣

＜正＞The hybrid density functional theory B3LYP with basis sets 6-31G * has been used to study on the e-quilibrium geometries and electronic structures of possible isomers of Si3N4 clusters. 24 possible isomers are obtained. The most stable isomer of Si3N4 is a 3D structure with 7 Si-N bonds and 2 N-N bonds that could be formed by 3 quadrangles. The bond properties of the most stable isomer was analyzed by using natural bond orbital method （NBO）, the results suggest that the charges on Si and N atoms in Si-N bonds are quite large, so the interaction of N-Si atoms in Si3N4 cluster is of strongly electric interaction. The primary IR and Raman vibra-tional frequency located at 1033. 40 cm-1, 473. 63 cm-1 respectively. The polarizabilities and hyperpolarizabilities of the most stable isomer are also analyzed.

关键词： Silicon nitride cluster structure and properties density functional theory

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Journal of University of Science and Technology Beijing 2008年第5期15卷 622-626页

作者： Yaohui Wang,Xu Zhang,Xianying Wu,Huixing Zhang,and Xiaoji Zhang Key Laboratory of the Ministry of Education of China for Beam Technology and Material Modification,Institution of Low Energy Nuclear Physics,Beijing Normal University Beijing Radiation Center,Beijing 100875,China [a]Key Laboratory of the Ministry of Education of China for Beam Technology Material Modification Institution of Low Energy Nuclear Physics Beijing Normal University Beijing Radiation Center Beijing 100875 China

Direct current metal filtered cathodic vacuum arc （FCVA） and acetylene gas （C2H2） were wielded to synthesize Ti-containing amorphous carbon films on Si （100）. The influence of substrate bias voltage and acetylene gas on the microstructure and mechanical properties of the films were investigated. The results show that the phase of TiC in the （111） preferential crystallographic orientation exists in the film,and the main existing pattern of carbon is sp2. With increasing the acetylene flow rate,the contents of Ti and TiC phase of the film gradually reduce; however,the thickness of the film increases. When the substrate bias voltage reaches -600 V,the internal stress of the film reaches 1.6 GPa. The micro-hardness and elastic modulus of the film can reach 33.9 and 237.6 GPa,respectively,and the friction coefficient of the film is 0.25.

关键词： metal containing amorphous carbon amorphous carbon films filtered arc acetylene flow rate bias voltage structure and properties

Electrical and Mechanical properties of PMMA/nano-ATO Composites

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Journal of Materials Science & Technology 2009年第2期25卷 247-250页

作者： Wei Pan Huiqin Zhang Yan Chen Institute of Materials and Chemical Engineering Zhongyuan University of Technology Zhengzhou 450007 China

Conducting nanocomposites of poly （methyl methacrylate）（PMMA） and antimony doped tin oxide （ATO） were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stability, and mechanical properties of the nanocomposites were investigated. A homogeneous dispersion of silane coupling agent modified ATO was achieved in PMMA matrix as evidenced by scanning electron microscopy. The resultant PMMA/silane-ATO nanocomposites were electrically conductive with significant conductivity enhancement at 4 wt pct. It was found that the composition at 4 wt pct ATO gave the higher tensile strength. Furthermore, it gave the largest elongation at break value among all the compositions. Thermal stability of the nanocomposites was remarkably enhanced by the incorporation of silane-ATO.

关键词： Antimony doped tin oxide PiVIMA Nanocomposites structure and properties

structures and electronic properties of Si_m N_(8-m)(0

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Chinese Physics B 2008年第8期17卷 2938-2950页

作者：张材荣陈玉红王道斌吴有智陈宏善 Department of Applied Physics Lanzhou University of Technology School of Material Science and Engineering Lanzhou University of Technology College of Physics and Electronic Engineering Northwest Normal University

The geometries, electronic structures and related properties of SimN8-m（0 〈 m 〈 8） clusters are studied using density functional theory （DFT） with hybrid functional B3LYP. The calculated results reveal several trends. For any stoichiometric clusters, the lowest energy isomers with an alteration of N and Si atoms are favourable in energy if the numbers of Si and N atoms are large enough to form ... Si N-Si-N... alternative chains. The bond lengths of single Si-N bonds are very close to the corresponding values of the bulk and other SiN clusters. The geometries for N-rich and Si4N4 clusters are planar structures, but three-dimensional structures are favourable in energy for Si-rich clusters. With the increase of m, the isotropic polarizability and average polarizability increase, the total binding energies generally decrease, the HOMO-LUMO gap and vertical ionization potential oscillate with increasing number of valence electrons, and their values with even valence electrons are larger than those with odd valence electrons. The atomic charges, IR and Raman properties are also reported.

关键词： cluster structure and properties density functional theory silicon nitride

Mechanical behavior of C/SiC T-section under pulling load

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Journal of Materials Science & Technology 2019年第12期35卷 2950-2956页

作者： Zongbei He Bo Chen Yi Zhang Yongsheng Liu Litong Zhang State Key Laboratory for nuclear fuel and materials Nuclear Power Institute of ChinaChengdu610213China Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi'an710072China

For the C/SiC T-section structures, fabrication defects such as pores and local delaminations can be easily formed in the intersection zone which significantly affect the load bearing capacity. In this work, the mechanical behavior of C/SiC T-section under pulling load was investigated, and especially the delamination behavior was studied by introducing the cohesive zone model into the finite element modeling. It was found that for C/SiC T-section under pulling load, the maximum critical delamination load was about1075 N in the present work, and the interface delamination was the main failure mode. It was verified that the effective interfacial strength influenced the critical delamination load, and the strain energy release affected the delamination behavior of the T-section specimen. The failure mechanisms of C/SiC T-section under pulling load depend on the interface bonding states. When the interface is well bonded,the failure mechanisms mainly include matrix stripping, matrix fracture and fiber breakage. Otherwise,only the matrix stripping can be found at the interface of the C/SiC T-section specimen.

关键词： C/SiC composites structure and properties Mechanical behavior Failure analysis

Effect of Low-temperature Imidization on properties and Aggregation structures of Polyimide Films with Different Rigidity

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Chinese Journal of Polymer Science 2024年第8期42卷 1134-1146页

作者： Yan Jia Lei Zhai Song Mo Yi Liu Li-Xin Liu Xin-Yu Du Min-Hui He Lin Fan Key Laboratory of Science and Technology on High-tech Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

The traditional high-temperature preparation process of polyimide can cause many problems and limits the wider application in extreme *** important challenge to be solved urgently is the reduction of imidization *** this work,twelve kinds of polyimide films with different chain rigidity were prepared at low temperature of 200℃,in the absence or presence of imidazole used as the *** molecular rigidity and free volume were theoretically calculated,and relationship between structure and properties were systematically *** results show that imidization reaction under low temperatures is significantly affected by the rigidity of molecula r *** rigid structure of polyimide is not conducive to the low-temperature imidization,but this adverse effect can be eliminated by adding catalyst,resulting the notably increased imidization *** optical and thermal properties can be improved to a certain extent for the chemically catalyzed system,resulting in relatively higher heat resistance and thermal *** the mechanical performance could be determined by com plicating factors,greatly different from polyimide films prepa red by high temperature *** investigate aggregation structures of film s,the effect of chain rigidity and catalyst on the stacking or orientation of molecular chains was further *** wo rk can contribute to the understanding of chemically catalyzed imidization that is rarely reported in the existing research,and will provide guidance for the low-temperature preparation of high-performance polyimides.

关键词： Polyimide Imidization Catalyst structure and properties Aggregation structures

Dynamically Photocrosslinking of Polypropylene/EPDM Blends as a Thermoplastic Elastomer

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Chemical Research in Chinese Universities 2004年第1期20卷 111-113页

作者： WANGWei-zhi WUQiang-hua QUBao-jun DepartmentofPolymerScienceandEngineering UniversityofScienceandTechnologyofChinaHefei230026P.R.China

The mechanical properties and the crystal morphological structures of the dynamically photocrosslinked polypropylene(PP)/ethylene-propylene-diene terpolymer(EPDM) blends have been studied by means of mechanical tests, wide-angle X-ray diffraction(WAXD), and differential scanning calorimetry(DSC). The dynamically photocrosslinking of the PP/EPDM blends can improve the mechanical properties considerably, especially the notched Izod impact strength at low temperatures. The data obtained from the mechanical tests show that the notched Izod impact strength of the dynamically photocrosslinked sample with 30% EPDM at -20 ℃ is about six times that of the uncrosslinked sample with the same EPDM component. The results from the gel content, the results of WAXD, and the DSC measurements reveal the enhanced mechanism of the impact strength for the dynamically photocrosslinked PP/EPDM blends as follows: (1) There exists the crosslinking of the EPDM phase in the photocrosslinked PP/EPDM blends; (2) The β-type crystal structure of PP is formed and the content of α-type crystal decreases with increasing the EPDM component; (3) The graft copolymer of PP-g-EPDM is formed at the interface between the PP and EPDM components. All the above changes of the crystal morphological structures are favorable for increasing the compatibility and enhancing the toughness of the PP/EPDM blends at low temperatures.

关键词： Polypropylene Ethylene-propylene-diene terpolymer Dynamical Photocrosslinking structure and properties