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Superparticles Formed by Amphiphilic Tadpole-like Single Chain Polymeric Nanoparticles and Their Application as an Ultrasonic Responsive Drug Carrier
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作者 江力 李会亚 陈道勇 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第2期211-218,I0002,共9页
Herein, we report self-assembly of tadpole-like single chain polymeric nanoparticles (TPPs) and the ultrasonic response of the resultant superparticles. The TPPs are with an intramolecularly crosslinked poly(2-(me... Herein, we report self-assembly of tadpole-like single chain polymeric nanoparticles (TPPs) and the ultrasonic response of the resultant superparticles. The TPPs are with an intramolecularly crosslinked poly(2-(methacryloyloxy)ethyl pent-4-ynoate)-rpoly(hydroxyethyl methacrylate) (PMAEP-r-PHEMA) chain as the "head" and a poly(2- (dimethylamino)ethyl methacrylate (PDMAEMA) linear chain as the "tail", and are pre- pared simply and emciently by Glaser-coupling of the pendant alkynes in the PMAEP-r- PHEMA block in the common solvent methanol. The formation of the TPPs was confirmed by gel permeation chromatograph, nuclear magnetic resonance spectroscopy, dynamic light scattering, static dynamic scattering, and transmission electron microscopy. In aqueous solution, the amphiphilic TPPs could self-assemble into regular superparticles, driven by aggregation of the hydrophobic "heads". Since in the structure there is no chain entanglement and the embedding of PDMAEMA chains disturb close-packing of the "heads", the superpartieles are responsive to a low-energy ultrasonic vibration, as evidenced by greatly enhanced release of the functional molecules from the superparticles by treatment of a low-energy ultrasound. Therefore, the superparticles should be very promising in the use as the drug carriers that can be manipulated from a long distance, considering that ultrasonic energy can be focused at a small area in a relatively long distance from the ultrasound-radiating source. 展开更多
关键词 Single chain polymer nanoparticles Superparticles Ultrasonic response Drug carrier
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Structure of the Heterobimetallic Linear-Chain Polymeric Complex [NH_4]_n [WAgS_4]_n and Influence of Cationic Valence State on Configurations of Polymeric W/Ag/S Complexes
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作者 HUANG Qun WU Xin-Tao LU Jia-Xi(State Key Laboratory of Structural Chemistry, Fujian Institute of Research onthe Structure of Matter, the Chinese Academy of Sciences, Fuzhou 350002) 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 1997年第4期253-257,共5页
The title complex [NH4]n [WAgS4]n crystallizes in the tetragonalspace group I4 with crystallographic parameters: a = b = 7. 994 (2 ), c = 5. 855 (2 ):A,V = 373. g(2) A3, Z=2, Dc= 3. 89 g/cm3, F(000) = 392, μ= 19. 27 ... The title complex [NH4]n [WAgS4]n crystallizes in the tetragonalspace group I4 with crystallographic parameters: a = b = 7. 994 (2 ), c = 5. 855 (2 ):A,V = 373. g(2) A3, Z=2, Dc= 3. 89 g/cm3, F(000) = 392, μ= 19. 27 mm-l , A(MoKα) = 0. 71069, Mr = 438. 01, and the convergence factors R = 0. 045, Rw =0. 055 for 341 observed reflections (I>3σ(I)). The anion structure can be viewed as apolymeric single chain consisting of unlimited extended rhombic fragruents of -AgS2W-which are alternately perpendicular to each other. Additionally, influence of di- and tri-valent complex cations on the assembIy of WS2-4 and Ag+ is briefly discussed. 展开更多
关键词 tungsten COMPLEX silver COMPLEX polymerIC LINEAR-chain COMPLEX crystal STRUCTURE
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Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization
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作者 Zhengquan Dong Pei Li +1 位作者 Guoyong Xu Fuzhou Wang 《Open Journal of Organic Polymer Materials》 2024年第1期1-12,共12页
The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, ... The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature. 展开更多
关键词 Ethylene polymerization α-Diimine Ni(II) Complex chain-Walking polymerization Branched Polyethylene
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Evaluation of the clenbuterol imprinted monolithic column prepared by reversible addition-fragmentation chain transfer polymerization 被引量:2
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作者 Mamat Turson Xiao Lei Zhuang +2 位作者 Hui Na Liu Ping Jiang Xiang Chao Dong 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第9期1136-1140,共5页
To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer (RAFT) process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influen... To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer (RAFT) process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures. The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation. 2009 Xiang Chao Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. 展开更多
关键词 Reversible addition-fragmentation chain transfer polymerization Monolithic column Molecularly imprinted polymer CLENBUTEROL
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SHAPE OF POLYMER CHAINS ON A TETRAHEDRAL LATTICE 被引量:1
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作者 Jian-hua Huang Me+ng-bo Luo +1 位作者 Wen-hua Jiang Shi-jun Han Department of Chemistry, Zhejiang University, Hangzhou 310027, China Department of Physics, Zhejiang University, Hangzhou 310027, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2000年第5期419-422,共4页
The shape of unperturbed polymer chains was studied using the Monte Carlo technique on a tetrahedral lattice. The asphericity A, the ratios <L-2(2)>/<L-1(2)> and <L-3(2)>/<L-1(2)> were calculat... The shape of unperturbed polymer chains was studied using the Monte Carlo technique on a tetrahedral lattice. The asphericity A, the ratios <L-2(2)>/<L-1(2)> and <L-3(2)>/<L-1(2)> were calculated for different Values of polymer chain length n, conformational energy epsilon (epsilon greater than or equal to 0) and temperature T. The asphericity A decreases with the increase of chain length and tends to reach its limiting value rapidly with the decrease of gamma (gamma = epsilon/k(B)T). For large n, A is about 0.525 +/- 0.005, the ratios <L-2(2)>/<L-1(2)> and <L-3(2)>/<L-1(2)> are about 2.7 and 12.0, respectively, and are almost independent of gamma, but for short chains, they depend on gamma. 展开更多
关键词 SHAPE polymer chain Monte Carlo technique
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One-dimensional Zigzag Chain Coordination Polymer [Zn(μ-phth)(imi)_2]_∞ Bridged by ο-Phthalato 被引量:1
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作者 刘庆燕 刘平 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2002年第5期509-512,共4页
The reaction of zinc carbonate with o-phthalic acid and imidazole in an aqueous-alcohol solution led to the formation of colorless crystals of [Zn(-phth)(imi)2]∞. Single-crystal X-ray analysis has revealed that the c... The reaction of zinc carbonate with o-phthalic acid and imidazole in an aqueous-alcohol solution led to the formation of colorless crystals of [Zn(-phth)(imi)2]∞. Single-crystal X-ray analysis has revealed that the complex crystallizes in a monoclinic system, space group Pn with a = 8.394(2), b = 9.976(3), c = 9.959(3) ? ?= 104.409(4)? V = 807.6(4) ?, Z = 2, C14H12N4O4Zn, Mr = 365.65, Dc = 1.504 g/cm3, ?= 1.544 mm-1, F(000) = 372, the final R = 0.0466 and wR = 0.1171 for 1834 reflections with I >2(I). The complex displays a zigzag infinite chain structure in which each zinc (Ⅱ) center is coordinated by two oxygen atoms and two nitrogen atoms to generate a ZnN2O2 distorted tetrahedral geometry. The neighboring zinc atoms are bridged by the o-phthalate ligand. Each chain is linked by hydrogen bonds with its neighbors to form a three-dimensional coordination polymer. 展开更多
关键词 zinc (Ⅱ) complex o-phthalate crystal structure chain coordination polymer
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Synthesis,Crystal Structure and Fluorescence Property of the Ag(Ⅰ) Coordination Polymer Constructed by 2D[Ag(1,3-BIP)(PMA)_(0.5)]_n^(n-)Layers and 1D[Ag(1,3-BIP)(H_2O)]_n^(n+) Chains 被引量:11
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作者 LU Jiu-Fu GE Hong-Guang SHI Juan 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第8期1259-1264,共6页
A new AgO) coordination polymer, {[Ag(1,3-BIP)(H20)][Ag(1,3- BIP)(PMA)0.5.- 4H20}n (PMA = 1,2,4,5-benzenetricarboxylic acid, 1,3-BIP = 1,3-bis(imidazole)propane), have been synthesized and characterized b... A new AgO) coordination polymer, {[Ag(1,3-BIP)(H20)][Ag(1,3- BIP)(PMA)0.5.- 4H20}n (PMA = 1,2,4,5-benzenetricarboxylic acid, 1,3-BIP = 1,3-bis(imidazole)propane), have been synthesized and characterized by single-crystal X-ray diffraction, powder XRD, FTIR, TGA and elemental analysis techniques. The single-crystal X-ray diffraction reveals that the title complex is formed by 1D polymeric cationic chains of [Ag(1,3-BIP)(H2O)]n^n+ and 2D polymetric anionic layer of [Ag(1,3-BIP)(PMA)0.5]n^n-, which are further linked by intermolecular H-bonding to form a 3D supramolecular framework. In addition, the photoluminescence property of the title complex in the solid state at room temperature was also investigated. 展开更多
关键词 Ag(I) coordination polymer helical chains photoluminescence property
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Stretching strongly confined semiflexible polymer chain 被引量:1
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作者 王记增 李润华 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2014年第10期1233-1238,共6页
By the so-called wormlike chain (WLC) model in polymer physics envision- ing an isotropic rod that is continuously flexible, the force-extension relations of semi- flexible polymer chains strongly constrained by var... By the so-called wormlike chain (WLC) model in polymer physics envision- ing an isotropic rod that is continuously flexible, the force-extension relations of semi- flexible polymer chains strongly constrained by various confinements are theoretically investigated, including a slab-like confinement where the polymer chains are sandwiched between two parallel impenetrable walls, and a capped nanochannel confinement with a circular or rectangular cross-section where the chains are bounded in three directions. The Brownian dynamics (BD) simulations based on the generalized bead-rod (GBR) model are performed to verify the theoretical predictions. 展开更多
关键词 semiflexible polymer chain CONFINEMENT wormlike chain (WLC) model Brownian dynamics (BD) simulation
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Rheological Behaviour for Polymer Melts and Concentrated Solutions Part Ⅰ:A New Multiple Reptation Model to Predict the Nonlinear Visco-elasticity with Nagai Chain Constraints in Entangled Polymer Melts 被引量:2
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作者 Mingshi SONG and Sizhu WU(Dept. of Polymer Science, Beijing University of Chemical Technology Beijing, 100029, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第1期15-30,共16页
An approach of stochastically statistical mechanics and a unified molecular theory of nonlinear viscoelasticity with constraints of Nagai chain entanglement for polymer melts have been proposed. A multimode model stru... An approach of stochastically statistical mechanics and a unified molecular theory of nonlinear viscoelasticity with constraints of Nagai chain entanglement for polymer melts have been proposed. A multimode model structure for a single polymer chain with n tail segments and N reversible entanglement sites on the test polymer chain is developed. Based on the above model structure and the mechanism of molecular flow by the dynamical reorganization of entanglement sites, the probability distribution function of the end-to-end vectr for a single polymer chain at entangled state and the viscoelastic free energy of deformation for polymer melts are calculated by using the method of the stochastically statistical mechanics. The four types of stress-strain relation and the memory function are derived from this thery. The above theoretical relations are verified by the experimentaf data for various polymer melts. These relations are found to be in good agreement with the experimental results 展开更多
关键词 Rheological Behaviour for polymer Melts and Concentrated Solutions Part A New Multiple Reptation Model to Predict the Nonlinear Visco-elasticity with Nagai chain Constraints in Entangled polymer Melts
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Syntheses,Structures,and Photoluminescent Properties of Two Zn(Ⅱ)Coordination Polymers with Helical Chains Structures 被引量:1
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作者 徐伏 李付安 +1 位作者 杨维春 李松田 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第5期831-840,共10页
Two novel coordination polymers with helical chains, {[Zn(L)(H2O)]·H2O}n(1) and {[Zn(L)(p-bix)]·3.5H2O}n(2), where H2 L = 5-(4-hydroxypyridinium-1-ylmethyl) isophthalic acid and p-bix = 1,4-bis... Two novel coordination polymers with helical chains, {[Zn(L)(H2O)]·H2O}n(1) and {[Zn(L)(p-bix)]·3.5H2O}n(2), where H2 L = 5-(4-hydroxypyridinium-1-ylmethyl) isophthalic acid and p-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, have been hydrothermally synthesized, and charac-terized by elemental analysis, powder X-ray diffraction(PXRD), IR, thermal gravimetric analyses(TGA) and also by single-crystal X-ray diffraction. Both complexes 1 and 2 crystallize inmonoclinic, space group P21/c. Compound 1 displays a two-dimensional(2D) structure with two distinct types of helical chains; 2 shows a layered coordination polymer with two types of helical chains and features an interesting 2D→3D interdigitated architecture. Meanwhile, the luminescent properties of 1 and 2 have also been investigated in detail. 展开更多
关键词 ZINC 5-(4-hydroxypyridinium-l-ylmethyl)isophthalic acid coordination polymer helical chains
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RAFT Miniemulsion Polymerization of MMA with Cumyl Dithiobenzoate as Chain Transfer Agent 被引量:1
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作者 Tian Ying GUO Dong Lin TANG Jing Wei ZHU Mou Dao SONG Bang Hua ZHANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第9期1247-1250,共4页
Reversible addition-fragmentation transfer (RAPT) miniemulsion polymerizations for PMMA with cumyl dithiobenzoate (CDB) as a chain transfer agent (CTA) has been carried out. Higher temperature made the polymeriz... Reversible addition-fragmentation transfer (RAPT) miniemulsion polymerizations for PMMA with cumyl dithiobenzoate (CDB) as a chain transfer agent (CTA) has been carried out. Higher temperature made the polymerization much faster and the PDI remained below 1.20, when the temperature was upon 70 ℃. 展开更多
关键词 RAFT polymerization MINIEMULSION chain transfer agent cumyl dithiobenzoate.
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SYNTHESIS OF HETEROARM STAR-SHAPED POLYMER BY THE USE OF POLYFUNCTIONAL CHAIN-TRANSFER AGENT via CONVENTIONAL FREE RADICAL POLYMERIZATION 被引量:2
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作者 石艳 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2008年第3期321-329,共9页
Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methac... Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methacrylate was carried out in the presence of a polyfunctional chain transfer agent,pentaerythritol tetrakis(3-mercaptopropinate).At appropriate monomer conversions,two-arm PMMA having two residual thiol groups at the chain center or three-arm PMMA having one residual thiol group at the core were o... 展开更多
关键词 Heteroarm star-shaped polymer Conventional free radical polymerization Polyfunctional chain-transfer agent
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MONTE CARLO STUDY ON THE CRITICAL ADSORPTION POINT OF BONDFLUCTUATED POLYMER CHAINS TETHERED ON ADSORBING SURFACES
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作者 陆文琴 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第1期109-114,共6页
The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing fiat surface was simulated by the Monte Carlo method.The dependence of the number of surface contacts M on the interaction stren... The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing fiat surface was simulated by the Monte Carlo method.The dependence of the number of surface contacts M on the interaction strengthεand the chain length N was investigated by a finite-size scaling law M = N;[a;+a;N;κ+ O((N;κ);)]forεnear the critical adsorption pointε;,i.e.,κ=(ε-ε;)/ε;closes to 0.The critical adsorption point was estimated to beε;=0.93,and the exponentsφ= 0.49 and l/v= 0.57. 展开更多
关键词 Critical adsorption polymer chain Bond fluctuation model SCALING Monte Carlo
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STUDY OF CHIRAL SIDE CHAIN LIQUID CRYSTALLINE POLYMERS
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作者 张树范 林敏钦 宝净生 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1992年第4期336-342,共7页
Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spec... Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spectroscopy. The liquid crystalline behaviour of the polymers is affected by the length of flexible spacer, which links the mesogenic side chain to the polymer backbone and mesogenic moiety. The characteristic of smectic phase is observed for all the polymers. 展开更多
关键词 Chiral side chain crystalline polymer Smectic phase Phase transition temperature.
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DYNAMIC MONTE CARLO STUDY ON THE CORRELATION BETWEEN SHAPE AND SIZE OF LINEAR POLYMER CHAINS
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作者 黄建花 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2003年第1期65-70,共6页
The correlation between shape and size of linear chains on the simple cubic lattice is investigated using a dynamicMonte Carlo technique. A positive correlation between the asphericity parameter A and the square of th... The correlation between shape and size of linear chains on the simple cubic lattice is investigated using a dynamicMonte Carlo technique. A positive correlation between the asphericity parameter A and the square of the end-to-end distanceR^2, as well as that between A and the square of the radius of gyration S^2, is found for both RW and SAW chains, indicatingthat a chain conformation of small size is usually more spherical than one of large size. The result can explain why the shapeof the SAW chain deviate much more from a sphere than that of the RW chain, and can also explain the similar dependenceof size and shape on chain stiffness and on the distance of the first bead of a chain from an infinitely large flat surface. 展开更多
关键词 CORRELATION Dynamic Monte Carlo polymer chain
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Dynamic Monte Carlo study on the probability distribution functions of tail-like polymer chain
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作者 陈英才 罗孟波 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE EI CAS CSCD 2005年第11期1130-1134,共5页
The configurational properties of tail-like polymer chains with one end attached to a flat surface are studied by using dynamic Monte Carlo technique. We find that the probability distribution of the free end in z dir... The configurational properties of tail-like polymer chains with one end attached to a flat surface are studied by using dynamic Monte Carlo technique. We find that the probability distribution of the free end in z direction P(Rz) and the density profile p(z) can be scaled approximately by a factor β to be a length independent function for both random walking (RW) and self-avoiding walking (SAW) tail-like chains, where the factor β is related to the mean square end-to-end distance 〈RE〉. The scaled P(Rz) of the SAW chain roughly overlaps that of the RW chain, but the scaled p(z) of the SAW chain locates at smaller βz than that of the RW chain. 展开更多
关键词 Probability distribution Monte Carlo simulation Tail-like polymer chain
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DIGITAL ANALYSIS TECHNOLOGY FOR MORPHOLOGY OF POLYMER CHAIN COILS IN FLOW FIELDS
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作者 Chi-xingZhou HongZheng WeiYu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2005年第2期155-158,共4页
Polymer chain coils with entanglement is a crucial scale of structures in polymer materials since their relaxationtimes are matching practical processing times.Based on the phenomenological model of polymer chain coil... Polymer chain coils with entanglement is a crucial scale of structures in polymer materials since their relaxationtimes are matching practical processing times.Based on the phenomenological model of polymer chain coils and a new finiteelement approach,we have designed a computer software including solver,pre-and post-processing modules,and developeda digital analysis technology for the morphology of polymer chain coils in flow fields(DAMPC).Using this technology wemay simulate the morphology development of chain coils in various flow fields,such as simple shear flow,elongational flow,and any complex flow at transient or steady state.The applications made up to now show that the software predictions arecomparable with experimental results. 展开更多
关键词 Morphology of polymer chain Complex flows Conformation tensor Finite element method(FEM) Software DAMPC.
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SEGMENT DENSITY PROFILES OF COMPACT POLYMER CHAINS CONFINED BETWEEN TWO PARALLEL PLANE WALLS
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作者 章林溪 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第5期525-533,共9页
We use the pruned-enriched Rosenbluth method to investigate systematically the segment density profiles of compact polymer chains confined between two parallel plane walls. The non-adsorption case of adsorption intera... We use the pruned-enriched Rosenbluth method to investigate systematically the segment density profiles of compact polymer chains confined between two parallel plane walls. The non-adsorption case of adsorption interaction energy ε = 0 and the weak adsorption case of ε= -1 are considered for the compact polymer chains with different chain lengths N and different separation distances between two walls D. Several special entropy effects on the confined compact polymer chains, such as a damped oscillation in the segment density profile for the large separation distance D, are observed and discussed for different separation distances D in the non-adsorption case. In the weak adsorption case, investigations on the segment density profiles indicate that the competition between the entropy and adsorption effects results in an obvious depletion layer. Moreover, the scaling laws of the damped oscillation period Td and the depletion layer width Ld are obtained for the confined compact chains. Most of these results are obtained for the first time so far as we know, which are expected to understand the properties of the confined compact polymer chains more completely. 展开更多
关键词 Compact polymer chains Entropy and adsorption effects Segment density profiles Two parallel plane walls.
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A steered molecular dynamics study on the elastic behaviour of knotted polymer chains
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作者 沈瑜 章林溪 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第4期1480-1489,共10页
In this paper the influence of a knot on the structure of a polymethylene (PM) strand in the tensile process is investigated by using the steered molecular dynamics (SMD) method. The gradual increasing of end-to-e... In this paper the influence of a knot on the structure of a polymethylene (PM) strand in the tensile process is investigated by using the steered molecular dynamics (SMD) method. The gradual increasing of end-to-end distance, R, results in a tighter knot and a more stretched contour. That the break in a knotted rope almost invariably occurs at a point just outside the 'entrance' to the knot, which has been shown in a good many experiments, is further theoretically verified in this paper through the calculation of some structural and thermodynamic parameters. Moreover, it is found that the analyses on bond length, torsion angle and strain energy can facilitate to the study of the localization and the size of a knot in the tensile process. The symmetries of torsion angles, bond lengths and bond angles in the knot result in the whole symmetry of the knot in microstructure, thereby adapting itself to the strain applied. Additionally, the statistical property of the force-dependent average knot size illuminates in detail the change in size of a knot with force f, and therefore the minimum size of the knot in the restriction of the potentials considered in this work for a PM chain is deduced. At the same time, the difference in response to uniaxial strain, between a knotted PM strand and an unknotted one is also investigated. The force-extension profile is easily obtained from the simulation. As expected, for a given f, the knotted chain has an R significantly smaller than that of an unknotted polymer. However, the scaled difference becomes less pronounced for larger values of N, and the results for longer chains approach those of the unknotted chains. 展开更多
关键词 steered molecular dynamics knotted polymer chain united atom (UA) model
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Reversible addition-fragmentation chain transfer graft polymerization of acrylonitrile onto PE/PET composite fiber initiated by γ-irradiation 被引量:2
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作者 马垚 虞鸣 +3 位作者 李林繁 马红娟 王自强 李景烨 《Nuclear Science and Techniques》 SCIE CAS CSCD 2015年第2期32-37,共6页
Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial sourc... Reversible addition-fragmentation chain transfer(RAFT) mediated grafting of acrylonitrile onto Polyethylene/Poly(ethylene terephthalate)(PE/PET) composite fibers was performed using γ-irradiation as the initial source at ambient temperature. Different initial concentrations of 2-cyanoprop-2-yl dithiobenzonate were used as the chain transfer agent. The kinetics of graft polymerization is in accordance with the living RAFT polymerization. The successful grafting of acrylonitrile is proved by Fourier transform infrared spectroscopy analysis.The results of monofilament tensile test show that mechanical properties of the fibers change slightly after grafting. Scanning electronic microscopy images of the fibers show that the surface of RAFT grafted fibers is smoother than that of fibers grafted conventionally. 展开更多
关键词 RAFT聚合 复合纤维 接枝聚合 链转移剂 PET 丙烯腈 傅里叶变换红外光谱分析 加成
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