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Studies on the heterogeneity of St/DVB copolymers by phenyl aggregate fluorescence

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Science China Chemistry 1995年第9期38卷 1046-1054页

作者：王国昌叶彦春高焕何炳林栗凤珍高传喜 Institute of Polymer Chemistry Nankai UniversityTianjin 300071China Experimental Centre Tianjin Normal UniversityTianjin 300068China

A new method for characterizing St/DVB copolymer heterogeneity by phenyl aggregatefluorescence has been developed and used to study the effects of crosslinking degree,crosslinker and diluent onthe heterogeneity of the copolyruer *** results show that St/m-DVB copolymer gel is more homogeneousin structure than St/p-DVB copolymer gel,whereas increasing crosslinking degree and the proportion of goodsolvent in diluent lead to an increase of gel *** results provide structural evidence which mayserve as a bridge between St/DVB crosslinking reaction and the copolymer properties.

关键词： phenyl aggregate fluorescence crosslinked copolymers gel heterogeneity.

Mechanism for the Self-Assembly of Hollow Micelles from Rod-Coil Block copolymers

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Chinese Physics Letters 2019年第7期36卷 111-115页

作者： Lingyun Zhang Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

The mechanism for the self-assembly of hollow micelles from rod-coil diblock copolymers is proposed. In a coilselective solvent, the diblock copolymers self-assemble into a layered structure. It is assumed that the rigid rods form an elastic shell whose properties are dictated by a bending energy. For a hollow micelle, the coils outside the micelle form a brush, while the coils inside the micelle can be in two different states, a brush or an adsorption layer, corresponding to symmetric or asymmetric configurations, respectively. The total energy density of a hollow micelle is calculated by combining the interfacial energy, elastic bending energy and the stretching energy of the brushes. For the asymmetric configuration with a polymer brush on one side, the competition between the elastic bending energy and the brush stretching energy leads to a finite spontaneous curvature, stabilizing hollow spherical micelles. Comparison of the free energy density for different geometries demonstrates that transitions for the different geometry micelles are controlled by the degree of polymerization of the coils and the length of the rods. These results are in agreement with the experimental results.

关键词： the self-assembly of hollow diblock copolymers is proposed agreement with the experimental results

Biodegradable amphiphilic block copolymers containing functionalized PEO blocks:Controlled synthesis and biomedical potentials

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Science China Chemistry 2010年第3期53卷 519-527页

作者： ZHANG Yu1,2,SUN PeiJian1,2 & GAN ZhiHua1 1CAS Key Laboratory of Engineering Plastics,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China 2Graduate University of Chinese Academy of Sciences,Beijing 100039,China CAS Key Laboratory of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

A series of controllable amphiphilic block copolymers composed of poly(ethylene oxide)(PEO) as the hydrophilic block and poly(ε-caprolactone)(PCL) as the hydrophobic block with the amino terminal group at the end of the PEO chain(PCL-b-PEO-NH2) were *** on the further reaction of reactive amino groups,diblock copolymers with functional carboxyl groups(PCL-b-PEO-COOH) and functional compounds RGD(PCL-b-PEO-RGD) as well as the triblock copolymers with thermosensitive PNIPAAm blocks(PCL-b-PEO-b-PNIPAAM) were *** well-controlled structures of these copolymers with functional groups and blocks were characterized by gel permeation chromatography(GPC) and 1H NMR *** copolymers with functionalized hydrophilic blocks were fabricated into microspheres for the examination of biofunctions via cell culture experiments and in vitro drug *** results indicated the significance of introducing functional groups(e.g.,NH2,COOH and RGD) into the end of the hydrophilic block of amphiphilic block copolymers for biomedical potentials in tissue engineering and controlled drug release.

关键词： amphiphilic block copolymers biodegradable polymers functional terminal group cell growth drug release

Synthesis of polyethylenimine grafted with copolymers of polyethylene glycol and polycaprolactone and its potential for siRNA delivery

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Chinese Chemical Letters 2011年第6期22卷 749-752页

作者： Wei Huang Ming Lv Zhong Gao Gao Institute of Materia Medica Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100050 China

copolymers mPEG-PCL were prepared and grafted onto polyethylenimine（PEI） to synthesize copolymers mPEG-PCL-g-PEI with low *** mPEG-PCL-g-PEI could condense siRNA to form nanoparticles with positive zeta *** nanoparticles could delivery siRNA into cells to effectively inhibit the expression of target gene,which suggested that mPEG-PCL-g -PEI could serve as a highly efficient vector for siRNA delivery.

关键词： copolymers Nanoparticles Vector Synthesis

ANTIMICROBIAL ACTIVITY OF copolymers OF 2,4-DICHLOROPHENYL ACRYLATE WITH STYRENE:SYNTHESIS,CHARACTERIZATION AND REACTIVITY RATIOS

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Chinese Journal of Polymer Science 2009年第1期27卷 121-130页

作者： Hetal J.Patel Mitesh G.Patel Kirit H.Patel Arabinda K.Ray Rajni M.Patel Department of Chemistry Sardar Patel UniversityVallabh Vidyanagar-388120GujaratIndia

Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR *** copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) *** molecular weight,as well as intrinsic viscosity,was obtained by vapor pressu...

关键词： copolymers Reactivity ratios Vapor pressure osmometry Thermal analysis Antimicrobial screening

Synthesis and Characterization of Degraded Gelatin Grafted Poly(ε-caprolactone) copolymers

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Transactions of Tianjin University 2013年第3期19卷 182-187页

作者：冯亚凯房子琛王贺云郭锦棠 School of Chemical Engineering and Technology Tianjin University

Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting ***,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as ***,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of ***-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin *** gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H *** results confirmed the conjugation of PCL onto gelatin *** PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.

关键词： Amino acids Biocompatibility Biodegradation Biomaterials copolymers Functional groups

HOMOPOLYMERS AND copolymers OF GLYCOLIDE AND LACTIDE

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Journal of China Textile University(English Edition) 1991年第2期9卷 57-61页

作者：朱建民邵耀民张守中眭伟民 Department of Textile Chemical Engineering

The homopolymerization and copolymerization of glycolide (GA) and lactide (LA) are des-cribed. The resulting polymers are characterized by differential scanning calorimetry (DSC),thermogravimetric analysis (TGA), 300 MHz proton nuclear magnetic resonance spectroscopy(NMR), infrared spectroscopy, and X-ray diffraction. The rheological properties of PGA andPGLA 910 are evaluated by shear experiments. The biodegradation has been studied in vivo. Theresults show that the polyesters can be absorbed by the muscles of rabbits after 60 days.

关键词： biological materials suture line ring open polymerization polyglycolide polylactide, PGA/PLA copolymers

Synthesis and Properties of a New Kind of High Performance Composite Resin Matrix-Poly (Aryl Ether Ketones)/Poly (Ether Sulfone) Block copolymers

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High Technology Letters 1997年第1期3卷 85-91页

作者：王军佐

A new kind of high performance composite resin matrix PEEK/PES, PEEKK/PES block copolymers have been prepared from the corresponding oligomers via a nucleophilic aromatic substitution reaction. The different properties of the copolymers are investigated by differential scanning calorimetry (d. s. c), thermogravimetric analysis (t. g. a) and dynamic mechanical analysis (d. m. a). The results show that the relationship between Tg and the compositions of the copolymers approximately follows the formula 1/Tg=W1/Tg1 +W2/Tg2 for PEEKK/PES block copolymers, and Tg=Tg1W1 +Tg2W2 for PEEK/PES block copolymers. The PES content and the segment length of the copolymers have a significant influence on their melting point. The thermal properties and dynamic mechanical behaviour of the copolymers are also studied. The introduction of PES segment into the molecular main chain increases the glass transition temperature of poly aryl ether ketones and decreases their melting temperature, that is to say it decreases their melting processing temperature. The block copolymers keep the high temperature stability and solvent resistance of poly aryl ether ketones. They are expected to be a new kind of high performance composite resin matrix.

关键词： PEEKK PEEK PES PEEKK/PES block copolymers PEEK/PES block copolymers

Biodegradable Blend Nanoparticles of Amphiphilic Diblock copolymers Prepared by Nano-Precipitation Method

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Journal of Biomaterials and Nanobiotechnology 2011年第5期2卷 561-566页

作者： Wichuda Nanthakasri Mangkorn Srisa-Ard Yodthong Baimark 不详

Nanoparticles of biodegradable methoxy poly(ethylene glycol)-b-polyester amphiphilic diblock copolymers have widely investigated for use as controlled release drug delivery carriers. In this work, blend nanoparticles of methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (MPEG-b-PDLL) and methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) (MPEG- b-PCL) were prepared by nano-precipitation method without any surfactants. 1H-NMR spectra showed significant difference in integral peak areas, suggesting the nanoparticles with different MPEG-b-PDLL/MPEG-b-PCL blend ratios can be prepared. Transmission electron microscope revealed the blend nanoparticles had nearly spherical in shape with smooth surface. Average size of the blend nanoparticles obtained from light-scattering analysis slightly decreased with increase in blend ratio of MPEG-b-PCL. The MPEG-b-PDLL and MPEG-b-PCL were amorphous and semi-crystalline, respectively. Thermal transition properties of the blend nanoparticles were studied with differential scanning calorimetry (DSC). The DSC results showed that glass transition temperatures of the blend nanoparticles decreased and heats of melting steadily increased, while the melting temperature did not change as the MPEG-b-PCL blend ratio increased. This indicates the miscibility of MPEG-b-PDLL and MPEG-b-PCL in the amorphous phase of the blend nanoparticles. Thermogravimetric analysis showed that the blend nanoparticles clearly exhibited two thermal decomposition steps due to MPEG-b-PDLL decomposition followed with MPEG-b-PCL. The blend nanoparticles had two temperatures of maximum decomposition rate (Td, max) accorded to each blend component. The Td, max of MPEG-b- PDLL phase significantly decreased, while Td, max of MPEG-b-PCL phase did not change as the MPEG-b-PCL blend ratio increased. These results suggested that the desired thermal properties of blend nanoparticles can be tailored by varying the blend ratio.

关键词： D L-Lactide ε-Caprolactone Diblock copolymers Blend nanoparticles Nano-Precipitation