检索结果-南通市图书馆

Microstructure Characterization of Short-chain Branching Polyethylene with Differential Scanning Calorimetry and Successive Self-nucleation/Annealing Thermal Fractionation

引用

Chinese Journal of polymer Science 2014年第6期32卷 751-757页

作者： Yan-hu Xue Yan-hui Wang Yan-di Fan he-ran yangstate key laboratory of polymer physics and chemistry Changchun Institute of Applied chemistry Chinese Academy of Sciences Tao Tang Shu-qin Bo 姬相玲 State key laboratory of polymer physics and chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

A series of the copolymers of ethylene with 1-hexene （M1-M9） synthesized by metallocene catalyst Et[Ind]2ZrC1JMAO was studied by differential scanning calorimetry and successive self-nucleation and annealing （SSA） thermal fractionation. The distribution of methylene sequence length （MSL） in the different copolymers was determined using the SSA method. The comonomer contents of samples M4 and M5 are 2.04 mol% and 2.78 mol%, respectively. Both M4 and M5 have low comonomer content and their MSL distribution profiles exhibit a monotonous increase trend with their MSL. The longest MSL of M5 is 167, and its corresponding molar percent is 43.95%, which is higher than that of M4. Moreover, the melting temperature （Tm） of M5 is also higher than that of M4. The comonomer contents of samples M7, M8, and M9 are 8.73 mol%, 14.18 mol% and 15.05 mol%, respectively. M7, M8, and M9 have high comonomer contents, and their MSL distribution profiles display unimodality. M7 has a lower peak value of 33 and a narrow MSL distribution, resulting in a Tm lower than that of M8 and M9. The MSL and its distribution are also key points that influence the melting behavior of copolymers. Sometimes, MSL and its distribution of copolymers have a greater impact on it than the total comonomer contents, which is different from traditional views.

关键词： Polyethylene Methylene sequence length (MSL) Microstructure Successive self-nucleation and annealing(SSA) SCB.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis and Crystal Structure of [Cis-1,10phenanthroline-palladium(Ⅱ)(THF)_2]dinitrate (THF = Tetrahydrofuran)

引用

Chinese Journal of Structural chemistry 2003年第5期22卷 547-549页

作者： HUANG Hui YU Shu-Yan② (State key laboratory of polymer physics and chemistry, Joint laboratory of polymer Science and Materials, Institute of chemistry, The Chinese Academy of Sciences, Beijing 100080, China) Institute of chemistry The Chinese Academy of Sciences State Key Laborator6y of Polymer Physics and Chemistry Joint Laboratory of Polymer Science and Materials CAS 北京 100080

A mononuclear complex, cis-1,10-phenanthroline-palladium(Ⅱ)(THF)2]dinitrate (THF = tetrahydrofuran) [Pd(C10H8N2)(C4H8O)2](NO3)2 1, has been prepared and structurally characterized by single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P21/c with a = 7.881(1), b = 27.371(3), c = 10.178(1) ? ?= 103.313(3)? V = 2136.5(4) 3, Mr = 554.83, Dc = 1.725 g/cm3, Z = 4, F(000) = 1128 and (MoK) = 0.926 mm-1. The structure was refined to R = 0.0678 and wR = 0.1651 for 1687 observed reflections with I > 2(I). It is revealed that the central Pd(Ⅱ) ion in the title complex is bonded to two THF and two phenanthroline molecules in a cis-configuration to form the coordination geometry, deviating slightly from the square plane.

关键词： crystal structure Pd(Ⅱ) complex 1,10-phenanthroline

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

MELTING CRYSTALLIZATION BEHAVIOR OF NYLON 66

引用

Chinese Journal of polymer Science 2001年第3期19卷 237-246页

作者： Qing-xin Zhang Zhi-shen Mo State key laboratory of polymer physics & chemistry Changchun Institute of Applied chemistry Chinese Academy of Sciences, Changchun 130022, China Chinese Acad Sci Changchun Inst Appl Chem State Key Lab Polymer Phys & Chem Changchun 130022 Peoples R China

Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differential scanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and nonisothermal crystallizations of nylon 66. In the isothermal crystallization process, mechanisms of spherulitic nucleation and growth were discussed. The lateral and folding surface free energies determined from the Lauritzen-Hoffman treatment are sigma = 9.77 erg/cm(2) and sigma (e) = 155.48 erg/cm(2), respectively; and the work of chain folding is q = 33.14 kJ/mol. The nonisothermal crystallization kinetics of nylon 66 was analyzed by using the Mo method combined with the Avrami and Ozawa equations. The average Avrami exponent (n) over bar was determined to be 3.45. The activation energies (DeltaE) were determined to be -485.45 kJ/mol and -331.27 kJ/mol, respectively, for the isothermal and nonisothermal crystallization processes by the Arrhenius and the Kissinger methods.

关键词： nylon 66 crystallization kinetics activation energy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation and Characterization of Palladium Colloidal Nanoparticles by Thermal Decomposition of Palladium Acetate with Microwave Irradiation

引用

Journal of Materials Science & Technology 2005年第2期21卷 187-190页

作者： Yixian CheN, Baolin he and Hanfan LIU Hubei key laboratory for Catalysis and Material Science, University of South-Central for Nationalities, Wuhan 430074, China PCLCC, State key laboratory of polymer physics and chemistry, Institute of chemistry, Chinese Academy of Sciences, Beijing 100080, China Lab. for Catalysis and Mat. Sci. Univ. of South-Central for Natl. Wuhan 430074 China Lab. of polymer Phys. and Chem. Inst. of Chem. Chinese Acad. of Sci. Beijing 100080 China

A series of solvent-stabilized palladium colloidal nanoparticles were prepared via thermal decomposition of palladium acetate methylisobutylketone (MIBK) solution in the presence of alkali and alcohol with microwave irradiation. The colloidal nanoparticles were characterized with TEM, XPS and XRD. The average diameters of nanoparticles increase from 30 to 40 nm with the increase in concentration of palladium acetate. TEM and XRD observation demonstrated that the palladium colloidal nanoparticles were clusters agglomerated from hundreds of smaller palladium crystallines with size of 3-4 nm. The influence of the concentrations of alkali and alcohol to the particle size was also discussed.

关键词： Thermal decomposition Microwave Palladium acetate Methylisobutylketone

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

RheOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

引用

Chinese Journal of polymer Science 2001年第5期19卷 471-476页

作者： Zhen-zhong Yang Yuan-ze Xu De-lu Zhao State key laboratory of polymer physics & chemistry, Center for Molecular Science Institute of chemistry, Chinese Academy of Sciences, Beijing 100080 China Chinese Acad Sci Inst Chem State Key Lab Polymer Phys & Chem Ctr Mol Sci Beijing 100080 Peoples R China

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

关键词： epoxy resin waterborne dispersion rheological behavior cluster-cluster aggregation percolation transition

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

TranSIENT EFFECT OF A BOGER FLUID FLOWING AROUND A CONFINED CYLINDER

引用

Chinese Journal of polymer Science 2001年第4期19卷 377-384页

作者： Xian-feng Li Huai-tian Bu De-lu Zhao State key laboratory of polymer physics and chemistry Center for Molecular Science,Institute of chemistry, Chinese Academy of Sciences, Beijing 100080, China Chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

This paper is concerned with the numerical simulation of the transient effect of an inertialess Boger flow past a confined circular cylinder and the comparison of predictions with particle image velocimetry (PIV) measurements given by Shiang et al.. Dynamic simulation based on the Oldroyd-B constitutive model was carried out using a Lagrangian-Eulerian algorithm. The evolution of velocity field was obtained for the flow at two Deborah (De) numbers, i.e. De = 1.2 and 3.0. At low De, the flow reached steady state rapidly, and showed a symmetric flow regime. However, at high De, the time required to reach steady flow behind the cylinder increased significantly, and the distribution of the velocity field appears to be asymmetric with respect to the stagnation line. Fairly good agreement between the numerical results and the experimental observations is reported. It can be concluded that both the experimental measurements and the present simulations indicate that the elasticity of the polymeric flow strongly affect the flow regime of viscoelastic flow around a confined cylinder.

关键词： transient effect flow around a cylinder Lagrangian-Eulerian algorithm Oldroyd-B model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Monte Carlo simulation on kinetic behavior of one-pot hyperbranched polymerization based on AA*+CB_2

引用

Science China chemistry 2010年第12期53卷 2481-2489页

作者： ZHAN Jie,LIN Ying,LIU XiaoHui & LI YueSheng State key laboratory of polymer physics and chemistry Changchun Institute of Applied chemistry,Chinese Academy of Sciences,Changchun 130022,China 1. State key laboratory of polymer physics and chemistry Changchun Institute of Applied chemistry Chinese Academy of Sciences Changchun 130022 China

Monte Carlo simulation was applied to investigate the kinetic behavior of AA*+CB2 *** algorithm consisted of two procedures to simulate the in-situ synthesis of AB2-like intermediate and the subsequent polymerization,*** order to improve the accuracy of the prediction,the mobility distinction between different scale molecules in polymerization was taken into account by relating the reaction rate constants to the collision possibility of each pair of *** feed ratio of initial monomers and the activity difference between the two functional groups within AA* were studied systematically to catch the essential features of the *** results have revealed that the achievable maximum conversion primarily depends on the extent of the reactivity difference between A and A*-groups,and it is suggested that A*-group should be at least 10 times more active than A-group to achieve high number-average degree of polymerization.

关键词： Monte Carlo hyperbranched kinetic AA+CB2

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

KINETICS STUDY ON MELT GRAFTING ACRYLIC ACID ONTO LLDPE USING REACTIVE EXTRUSION

引用

Chinese Journal of polymer Science 2005年第6期23卷 603-610页

作者： Qiang Shi Lian-chao Zhu Chuan-lun Cai and Jing-hua Yin State key laboratory of polymer physics and chemistry,Changchun Institute of Applied chemistry,Chinese Academy of Sciences,Changchun 130022,China Chinese Acad Sci Changchun Inst Appl Chem State Key lab Polymer Phys & Chem Changchun 130022 Peoples R China

The kinetics of melt grafting acrylic acid （AA） onto linear low density polyethylene （LLDPE） by using reactive extrusion was investigated. The polymeric peroxides （POOP and POOH） generated by electron beam irradiation were used to initiate the graft reaction. The samples taken out from the barrel at five ports along screw axis were analyzed by FTIR. The spectra show that both the graft copolymerization and homopolymerization proceed in two stages： the graft degree （or mass of homopolymer） increases linearly with the reaction time in the initial stage, and then gradually in the second stage. The rate of graft copolymerization Rg is always faster than that of homopolymerization Rh in the present system and the activation energy is 131 kJ · mol^-1 for graft copolymerization and 127 kJ · mol^-1 for homopolymeirzation. These results were interpreted in terms of solubility and diffusion of monomer, as well as the reactivity and the concentration of reactive species. The relationships between reaction rate and monomer concentration and peroxide concentration were found to be： Rg ∞ [M]^1.46[POOP＋POOH]^0.53 and Rh ∞ [M] ^1.08[POOH]^0.51, which indicate that the addition of monomer to polymeric radicals is a slow step for the graft copolymerization.

关键词： Graft copolymerization Kinetics Reactive extrusion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SYNTheSIS AND CHARACTERIZATION OF NOVEL BIPOLAR PPV-BASED COpolymer CONTAINING TRIAZOLE AND CARBAZOLE UNITS

引用

Chinese Journal of polymer Science 2001年第6期19卷 615-621页

作者： Ze Liu Li-xiang Wang Xia-bin Jing Fo-song Wang The State key laboratory of polymer physics and chemistry Changchun Institute of Applied chemistry Chinese Academy of Sciences, Changchun 130022, China Chinese Acad Sci Changchun Inst Appl Chem State Key Lab Polymer Phys & Chem Changchun 130022 Peoples R China

Two new blue light-emitting PPV-based conjugated copolymers containing both an electron-withdrawing unit (triazole-TAZ) and electron-rich moieties (carbazole-CAR and bicarbazole-BCAR) were prepared by Wittig condensation polymerization between the triazole diphosphonium salt and the corresponding dialdehyde monomers. Their structures and properties were characterized by FT-IR, TGA, DSC, UV-Vis, PL spectroscopy and electrochemical measurements. The resulting copolymers are soluble in common organic solvents and thermally stable with a T-g of 147degreesC for TAZ-CAR-PPV and of 157degreesC for TAZ-BCAR-PPV. The maximum photoluminescence wavelengths of TAZ-CAR-PPV and TAZ-BCAR-PPV film appear at 460 nm and 480 nm, respectively. Cyclic voltammetry measurement demonstrates that TAZ-BCAR-PPV has good electrochemical reversibility, while TAZ-CAR-PPV exhibits the irreversible redox process. The triazole unit was found to be an effective pi-conjugation interrupter and can play the rigid spacer role in determining the emission colour of the resulting copolymer.

关键词： light-emitting polymer PPV-based bipolar polymer triazole-containing polymer carbazole-containing polymer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

EFFECT OF PARTICLE SIZE ON The FILMING PROCESS OF POLYSTYRENE LATEX STUDIED BY AFM

引用

Chinese Journal of polymer Science 2002年第6期20卷 509-515页

作者： Xiao-zhong Qu Yi Shi Liu-sheng Chen Xi-gao Jin State key laboratory of polymer physics & chemistry, Center for Molecular Science,Institute of chemistry, Chinese Academy of Sciences, Beijing 100080 China Chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

The film formation process of micro-PS particles (diameter 742 nm) and nano-PS particles (diameter 29 nm) was studied by atomic force microscopy and differential scanning calorimetry. During a step heating process, the particles were annealed for 0.5 h at each selected temperature. It was found that the deformation and interdiffusion temperatures of the micro-PS particles are ca. 120-130degreesC and 140-150degreesC, that of the nano-PS particles are 90degreesC and 100-110degreesC respectively. The DSC traces of nano-PS particles showed that there was an exothermic peak near T-g after annealing for 0.5 h at the selected temperatures below 90degreesC; otherwise, the exothermic peak disappeared after annealing at 100degreesC or above. Compared with the micro-PS particles, the sintering process of nano-PS particles occurs at much lower temperature determined by the confined state of polymer chains with higher conformational energy in nano-particles, and completes in a much narrower temperature range driven mainly by the larger total surface energy.

关键词： polystyrene latex filming process particle size effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：