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SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS

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Chinese Journal of Polymer Science 2002年第6期20卷 565-572页

作者： Jie Bai Jin-yu Zheng Kun-yuan Qiu Yen wei Department of Polymer Science & engineering college of chemistry & molecular engineering, peking university beijing 100871, china Department of chemistry, Drexel university, Philadelphia, PA 19104, USA Department of Polymer Science & engineering College of Chemistry & Molecular Engineering Peking University 北京 100871 Department of chemistry Drexel University Philadelphia PA 19104 美国

Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radical polymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent and followed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy OR), N-2 adsorption-desorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The results indicate that the materials prepared with 50 wt%-60 wt% template contents have average pore sizes of 2-3 nm and large surface areas (ca. 886 m(2)/g) as well as high pore volumes (ca. 0.53 cm(3)/g). The mesoporosity arises from interconnected channels and pores with disordered arrangements. The pore diameters and pore volumes increase as the template content is increased. The pore diameters show a little change upon heating at 200degreesC overnight. However, the materials do not have good hydrothermal stability.

关键词： atom transfer radical polymerization hybrid material mesoporous polystyrene silica

IMPACT PROPERTIES OF METALLOCENE - CATALYZED ETHYLENE-α-OLEFIN COPOLYMERS

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Chinese Journal of Polymer Science 2002年第5期20卷 473-480页

作者： Xu-rong Xu Jun-ting Xu Lin-xian Feng Department of Polymer Science and engineering Zhejiang university Hangzhou 310027,china Department of Polymer Science and engineering college of chemistry & molecular engineering peking university beijing 100871, china Department of Polymer Science and engineering Zhejiang University Hangzhou 310027

The impact properties of two selected metallocene-catalyzed ethylene-butene copolymers and one conventionalcopolymer were evaluated using Izod impact test. It is found that the metallocene-catalyzed copolymer shows superior impactproperties. This result was explained on the basis of the more homogeneous inter-molecular composition distribution andnarrower molecular weight distribution, which leads to more homogeneous morphology with fewer defects. Stepwisecrystallization improves the impact properties, especially in the crack propagation process, to a large extent. This is due to thedecrease of entanglements by stepwise crystallization, which is advantageous for the chain slip and shear. The polymer withheterogeneous intra-molecular composition distribution exhibits a more evident improvement of impact properties understepwise crystallization.

关键词： Metallocene-catalyzed ethylene-butene copolymer Impact properties molecular heterogeneities Thermal treatment

CONTROLLED RELEASE FROM PDMAEMA GELS PREPARED BY GAMMA RADIATION

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Chinese Journal of Polymer Science 2002年第5期20卷 409-412页

作者： Ning Liu Min Yi Shuang-ji Chen Hong-fei Ha college of chemistry and molecular engineering peking university beijing 100871, china Department of Biochemistry college of Applied Arts and Science, beijing Union university beijing 100083. china college of chemistry and molecular engineering Peking University 北京 100871 Department of Biochemistry College of Applied Arts and Science Beijing Union University 北京 100083

Poly(N,N-dimethylaminoethyl methacrylate) (polyDMAEMA) hydrogels prepared by gamma-irradiation showed obvious temperature-sensitivity in a temperature range of 38-40degreesC and pH-sensitivity at pH=2.5. They also showed electric response behavior although it was not typical. The hydrogels were used in controlled release at different pH, temperature, and electric voltage. The release rates of methylene blue (MB) from the gels at 52degreesC and pH=1.24 were faster than those at 20degreesC and pH=10.56, respectively. In addition, the release rate at a field voltage of 5.0 was also faster than that without electric field.

关键词： poly(N,N-dimethylaminoethyl methacrylate) environmental sensitivity hydrogel controlled release

TARTARIC ACID TEMPLATED SYNTHESIS OF MESOPOROUS Ti-INCORPORATED SILICA AND ITS CATALYTIC ACTIVITY FOR THE RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE

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Chinese Journal of Polymer Science 2002年第4期20卷 361-368页

作者： Jie-bin Pang Chang-ming Dong Kun-yuan Qiu Yen wei Department of Polymer Science and engineering college of chemistry and molecular engineering peking university beijing 100871, china Department of chemistry Drexel university Philadelphia, Pennsylvania 19104, USA Department of Polymer Science and engineering College of Chemistry and Molecular Engineering Peking University 北京 100871 Department of chemistry Drexel University 美国 Pennsylvania

Ti-incorporated mesoporous silica materials with pore diameters of 3-4 nm have been prepared via the co-hydrolysis and co-condensation reactions, that is the sol-gel reactions, of titanium (IV) tetrabutoxide and tetraethylorthosilicate in the presence of tartaric acid as template, followed by extraction with ethanol to remove the templatemolecules. The materials were characterized in detail by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption test, powder X-ray diffraction, transmission electron microscopy and X-ray energy dispersive spectroscopy. Theresults indicate that the Ti-containing silica materials have large specific surface areas (ca. 1200 m^2 g^(-1)) and pore volumes(ca. 0.900 cm^3 g^(-1)). The mesoporosity arises from disordered interconnecting channels or pores. The Ti-incorporated silicasexhibit catalytic activity for the ring-opening polymerization of ε-caprolactone, otherwise, the pure mesoporous silicamaterial shows no catalytic activity under the identical conditions.

关键词： Mesoporous material Ti-incorporated silica ε-Caprolactone Ring-opening polymerization Sol-gel reactions

Formation of nanotubes and secondary assemblies of cyclodextrins induced by BBOT

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Science china chemistry 2010年第9期53卷 2019-2025页

作者： ZHANG JingJing,SHEN XingHai,WU Aihua,ZHANG ChunFen,CHEN QingDe & gao HongCheng beijing National Laboratory for molecular Sciences Radiochemistry and Radiation chemistry Key Laboratory of Fundamental Science college of chemistry and molecular engineering,peking university,beijing 100871,china beijing National Laboratory for molecular Sciences Radiochemistry and Radiation chemistry Key Laboratory of Fundamental Science college of chemistry and molecular engineering Peking University Beijing China

The study of cyclodextrin nanotubes is a significant topic among the self-assembly behaviors of *** report herein the interaction of 2,5-bis(5'-tert-butyl-2-benzoxazoyl)thiophene(BBOT) with α-,β-,γ-cyclodextrins(CDs).It has been discovered that the reaction patterns of BBOT with CDs are remarkably different.α-CD forms a simple inclusion complex with BBOT in a stoichiometry of 1:2(guest:host).β-CD forms a 1:1 inclusion complex with BBOT at its low *** higher concentration of BBOT,the nanotube and secondary assembly of β-CD are *** for γ-CD,the nanotube and secondary assembly are formed within the whole concentration range of BBOT *** structure of γ-CD nanotubes is different from that of β-CD nanotubes to a certain extent.

关键词： BBOT cyclodextrin nanotube secondary assembly

Applications of functionalized ionic liquids

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Science china chemistry 2006年第5期49卷 385-401页

作者： LI Xuehui1, ZHAO Dongbin2,3, FEI Zhaofu2 & WANG Lefu1 1. Department of Chemical engineering, Guangdong Provincial Laboratory of Green Chemical Technology, South china Uni-versity of Technology, Guangzhou 510641, china 2. Swiss Federal Institute of Technology, Lausanne, EPFL, CH-1015 Lausanne, Switzerland 3. PKU Green chemistry Center, beijing National Laboratory for molecular Sciences, college of chemistry and molecular engineering, peking university, beijing 100871, china Department of Chemical engineering Guangdong Provincial Laboratory of Green Chemical Technology South China University of Technology Guangzhou China Lausanne EPFL Swiss Federal Institute of Technology Lausanne Switzerland PKU Green chemistry Center Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing China

Recent developments of the synthesis and applications of functionalized ionic liquids (including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are at-tracting attention as alternative solvents in green chemistry, but as more functionalized ILs are pre-pared, a greater number of applications in increasingly diverse fields are found.

关键词： ionic liquids functionalized ionic liquids dual-functionallzed ionicliquids reaction media asymmetric synthesis nano-materials porous materials lubricants flue-gas desulfurization oil desul-furization

Measurement of Monomer Reactivity Ratios of D,L-3-Methylglycolide with Glycolide or D,L-Lactide

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Chinese Chemical Letters 2000年第9期11卷 815-818页

作者： Chang Ming DONG Kun Yuan QIU Zhong wei GU Xin De FENG Department of Polymer Science and engineering, college of chemistry and molecular engineering, peking university, beijing 100871 National Research Institute for Family Planning, beijing 100081 Dept. of Poly. Sci. and engineering Coll. of Chem. and Molec. Eng. Peking University Beijing 100871 China Natl. Res. Inst. for Family Planning Beijing 100081 China

For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate at 140 degrees C. The copolymer compositions were determined by H-1 NMR spectroscopy. The monomer reactivity ratios were evaluated by Fineman-Ross method, Kelen-Tudos method and linear least-squares method. The monomer reactivity ratios of D,L-3-methylglycolide and glycolide or D,L-lactide are r(mg)= 0.73, r(ga)= 1.47; r(mg)= 1.71, r(la)= 0.92, respectively.

关键词： D,L-3-methylglycolide glycolide D,L-lactide ring-opening copolymerization monomer reactivity ratios

EFFECT OF molecular weiGHT OF PEO ON THE STRUCTURE AND PROPERTIES OF PDMAEMA/PEO HYDROGELS

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Chinese Journal of Polymer Science 2006年第1期24卷 35-40页

作者： Zhu-gen Liu Min Yi Mao-lin Zhai and Hong-fei Ha Department of Applied chemistry and The Key Laboratory of Polymer chemistry and Physics of Ministry of Education,college of chemistry & molecular engineering,peking university,beijing 100871,china Department of Applied chemistry and The Key Laboratory of Polymer chemistry and Physics of Ministry of Education College of Chemistry & Molecular Engineering Peking University Beijing 100871 China

A new kind of binary hydrogels composed of poly（dimethylaminoethylmethacrylate）（PDMAEMA） and poly（ethylene oxide）（PEO） with varying weight average molecular weights （M^-w = 5 × 10^4, 1 × 10^5 and 2.5 × 10^6） were prepared by У-irradiation technology. The properties of PDMAEMA/PEO hydrogels obtained were evaluated in terms of gel fraction, gel strength, thermal characterization and swelling behavior. The gel strength and swelling degree of the hydrogels could be improved obviously after adding PEO into the PDMAEMA system, while the degree of improvement decreased with increasing M^-w of PEO. The temperature sensitivity of PDMAEMA/PEO was retained only in the sample with PEO of M^-w = 5 × 10^4, and the pH sensitivity was retained in samples with PEO of M^-w = 5 × 10^4 and 1 × 10^5. When DMAEMA/PEO mixtures containing PEO of M^-w = 5 × 10^4 were irradiated, the main reaction could be the cross-linking of DMAEMA, and the linear PEO molecular chains could penetrate into the cross-linked network of PDMAEMA. With increasing M^-w of PEO, some side reactions were induced, such as grafting of DMAEMA onto PEO molecules, the scission or cross-linking of PEO.

关键词： Poly(dimethylaminoethylmethacrylate) Poly(ethylene oxide) molecular weight Binary hydrogels Irradiation.

Status of study on biological and toxicological effects of nanoscale materials

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Science china chemistry 2005年第5期48卷 385-394页

作者： WANG Bing1, FENG weiyue1, ZHAO Yuliang1, XING Gengmei1, CHAI Zhifang1, WANG Haifang2 & JIA Guang3 1. Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese Academy of Sciences, beijing 100049, china 2. college of chemistry and molecular engineering, peking university, beijing 100871, china 3. Department of Occupational and Environmental Health Sciences, School of Public Health, peking university, beijing 100083, china Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences Beijing China college of chemistry and molecular engineering Peking University Beijing China Department of Occupational and Environmental Health Sciences School of Public Health Peking University Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.