检索结果-南通市图书馆

RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

在线全文

学校读者我要写书评

暂无评论

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

molecular SIMULATION STUDY ON THE CHANGE OF polymer STRUCTURE DURING YIELDING

在线全文

学校读者我要写书评

暂无评论

chinese Journal of polymer science 2001年第5期19卷 527-529页

作者： Chen-guang xu Tai-ning Liang Juan Sun Xiao-zhen Yang 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

A better understanding of a recently raised argument on whether there occurs a structure change during yielding has been acquired by using molecular simulation. That is, when monitoring the displacements of all atoms before and after the yield, a structure transition does occur, which is the 'atomic jump' that coordinates the amount of the atoms in the polymer and makes a large step beyond similar to0.05 nm for all those atoms. Results indicate that the complex of polymer chain packing induces the multiple atomic jumps around the yield point. This explains why polymers have a broader yielding peak.

关键词： polymer deformation yield structure transition atomic jump multiple yields

STUDY ON PYROLYSIS OF POLYPHENYLSILSESQUIOXANE

在线全文

学校读者我要写书评

暂无评论

chinese Journal of polymer science 2002年第6期20卷 573-577页

作者： Jun Ma Liang-he Shi jian-min Zhang Bai-yu Li De-yan Shen jian xu 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

X-ray photoelectron spectroscopy and Raman spectroscopy were' used to determine the chemical change of polyphenylsilsesquioxane (PPSQ) during pyrolysis in flowing nitrogen. Two temperature ranges were found for pyrolysed PPSQ below and above 600degreesC, respectively. The former is related to the rearrangement of PPSQ backbone and the latter reflects that most of backbone structure of PPSQ might be broken down and unorganized. Carbon formed in carbonization of PPSQ sample pyrolysed at 900degreesC should be sp(3) bonded carbon with crystallite size effects or defects.

关键词： pyrolysis polyphenylsilsesquioxane

STRESS-INDUCED CRYSTALLIZATION OF POLYURETHANE/MONTMORILLONITE NANOCOMPOSITE

在线全文

学校读者我要写书评

暂无评论

chinese Journal of polymer science 2002年第5期20卷 481-483页

作者： Xin-hua Dai Xiang-dong Luo Qun Gu Xiao-li Zhang De-yan Shen Liang-he Shi jian xu state key laboratory of polymer physics and Chemiscy 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

Exfoliated polyurethane/montmorillonite nanocomposites with both high elongation at break and high tensilestrength were studied by dynamic-infrared spectroscopy (dynamic-IR). The results show that crystallization indu... 详细信息

关键词： PU/montmorillonite nanocomposite dynamic-IR crystallization

FABRICATION OF SELF-ASSEMBLY DNA-C_(60) MULTILAYER FILMS

在线全文

学校读者我要写书评

暂无评论

chinese Journal of polymer science 2002年第6期20卷 591-593页

作者： Shu-guang Yang Yong-jun Zhang Xin-hua Dai Wen-hong Tang Chun-yan Liu Wei-xiao Cao Yu-liang Li jian xu state key laboratory of polymer physics and chemistry, institute of chemistry, chinese academy of sciences,beijing 100080, china Technology institute of physics and chemistry chinese academy of sciences, beijing 100101, china College of chemistry and molecular engineering Peking university beijing 100871, china chinese Acad Sci Inst Chem State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China chinese Acad Sci Technol Inst Phys & Chem Beijing 100101 Peoples R China Peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China

Electrostatic layer-by-layer self-assembly multilayer films were successfully fabricated from C-60-ethylenediamine adduct (C-60-EDA) and DNA. Under visible light irradiation, DNA is ready to be cleaved and the films a... 详细信息

关键词： self-assembly photo-induced cleavage DNA C-60

In-situ Investigation of molecular Diffusion in Hydrogels

在线全文

学校读者我要写书评

暂无评论

In-situ Investigation of Molecular Diffusion in Hydrogels

Characterization of the sequence distribution of poly （ethylene-co-vinyl acetate）with NMR spectroscopy

2006年海峡两岸高分子学术研讨会

作者： Lihui Weng, Songmiao Lian, Hongjun Dai, Xianmin Zhang, Lina Zhang, jian xu state key laboratory of polymer physics & chemistry, institute of chemistry, chinese academy of sciences, beijing department of chemistry, Wuhan university, Wuhan department of information & electronic engineering, zhejiang university, hangzhou

＜正＞Hydrogels are three-dimensional polymeric networks swollen by a large amount of water. The ability of hydrogels to restrict the diffusive movement of entrapped solutes and the ease of regulation of the release or adsorption such solutes by controlling the structure of hydrogels offered hydrogels applications in a wide variety of biomedical fields, such as drug delivery systems, biosensors, and biotechnological separation methods. When applying a particular hydrogel, it is therefore important to understand the

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Characterization of the sequence distribution of poly （ethy...

Switchable Polyolefins from Polar Functionalization to Degradability

第四届全国高聚物分子表征学术讨论会

作者： Zhiqiang Su, Ying Zhao, Xiuqin Zhang, Shannong Zhu, Dujin Wang, Duanfu xu state key laboratory of polymer physics and chemistry, Joint laboratory of polymer science and Materials, center for molecular science, institute of chemistry, chinese academy of sciences, beijing 100080, china

＜正＞ High-resolution NMR,either solution or solid-state spectra,can provideabundant structure information and has been paid more attention inrecent years, capable of elucidating not only the details of thechemical structure of a polymer,but also its dynamic *** help of high-resolution NMR techniques, the sequence distributionand condensed state of EVA copolymers can be clearly characterized,helping to further understand the structure-property correlations ofthe corresponding materials on a molecular level.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

CCS chemistry 2024年第8期6卷 1941-1950页

作者： Kangkang Li Zhongbao jian state key laboratory of polymer physics and chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022 School of Applied chemistry and engineering University of Science and Technology of ChinaHefei 230026

Polyolefins are synthetic plastics that exist on the largest scale and are ubiquitous in human *** are also the most frequently discarded ***,the ability to either upgrade polyethylene(PE)plastic for value-added applications or to degrade PE plastic for value-added chemicals and monomers is highly desirable and sought after to mitigate the plastic waste ***,we report an advanced strategy for tackling the issue of PE plastics,first through a sequential upgrading and then through a degrading *** optimal Diels–Alder-type polar comonomer diester-substituted norbornadiene is copolymerized with ethylene to produce the desired polar-functionalized PEs with both high comonomer incorporations of 42.4 mol%(-COOMe:as high to 59.6 mol%)and high molecular weights of up to 224 kg mol^(−1)in high catalytic activities of>100 kg mol^(−1)h^(−1).By means of a decisive retro-Diels–Alder reaction,this upgraded PE,namely polar-functionalized PE,can completely switch to a clean and soluble vinylene PE with a high content(28.7 mol%)of dispersed internal double bonds,which are *** of the highmolecular–weight(∼30 kg mol^(−1))vinylene PE with ethylene yields industrially relevant telechelic oligomers(∼360 g mol^(−1))of long-chainα,ω-dienes and C9/C9+hydrocarbon *** chemical upgrading and recycling method makes polyolefin plastic more sustainable.

关键词： chemical recycling plastics polar polyolefin degradable polyolefin cyclic olefin

Development of in situ characterization techniques in molecular beam epitaxy

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

Journal of Semiconductors 2024年第3期45卷 9-32页

作者： Chao Shen Wenkang Zhan Manyang Li Zhenyu Sun jian Tang Zhaofeng Wu Chi xu Bo xu Chao Zhao Zhanguo Wang laboratory of Solid state Optoelectronics information Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials science and Opto-electronic Technology University of Chinese Academy of SciencesBeijing 101804China School of physics science and Technology Xinjiang UniversityUrumqi 830046China School of New Energy and electronics Yancheng Teachers UniversityYancheng 224002China key laboratory of Optoelectronic Materials and Devices Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

Ex situ characterization techniques in molecular beam epitaxy(MBE)have inherent limitations,such as being prone to sample contamination and unstable surfaces during sample transfer from the MBE *** recent years,the need for improved accuracy and reliability in measurement has driven the increasing adoption of in situ characterization *** techniques,such as reflection high-energy electron diffraction,scanning tunneling microscopy,and X-ray photoelectron spectroscopy,allow direct observation of film growth processes in real time without exposing the sample to air,hence offering insights into the growth mechanisms of epitaxial films with controlled *** combining multiple in situ characterization techniques with MBE,researchers can better understand film growth processes,realizing novel materials with customized properties and extensive *** review aims to overview the benefits and achievements of in situ characterization techniques in MBE and their applications for material science *** addition,through further analysis of these techniques regarding their challenges and potential solutions,particularly highlighting the assistance of machine learning to correlate in situ characterization with other material information,we hope to provide a guideline for future efforts in the development of novel monitoring and control schemes for MBE growth processes with improved material properties.

关键词： epitaxial growth thin film in situ characterization molecular beam epitaxy(MBE)