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Effect of the third acrylated vinyl comonomer on absorption and desorption properties of styrene–divinylbenzene–alkyl acrylate terpolymers, imbibing solvent on a water surface

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Journal of Applied polymer science 2000年第3期79卷

作者： W. Kangwansupamonkon S. Damronglerd S. Kiatkamjornwong Multidisciplinary Program of Petrochemistry and Polymer Science Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Department of Chemical Technology Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Department of Imaging Science and Printing Technology Faculty of Science Chulalongkorn University Bangkok 10330 Thailand

A series of imbiber terpolymer beads was prepared by radical suspension copolymerization of styrene–divinylbenzene with varied contents of acrylated vinyl monomers, n‐ butyl acrylate and 2‐ethyl hexyl acrylate, as the third comonomer. A DVB content of 6 wt % and a mixture of 60/40 wt % toluene/ n ‐heptane as the diluent were used throughout this study. The influence of acrylated vinyl comonomers on bead properties and swelling properties was investigated. The imbiber beads are capable of absorption and desorption of organic solvents having solubility parameters in the range of 14.9–20.9 (MPa) 1/2 . Styrenic imbiber beads were swelled in a toluene/ n ‐heptane mixture of 50% by volume and the kinetics of absorption was studied. The imbiber beads could absorb the toluene/ n ‐heptane mixture completely within 20 min and yielded a maximum swelling ratio of 6.8. The diffusion coefficient values of these beads were in the range of 6.40 × 10 −6 to 1.52 × 10 −5 cm 2 s −1 . © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 504–516, 2001

关键词： styrene–divinylbenzene styrene–divinylbenzene–n‐butyl acrylate styrene–divinylbenzene–2‐ethyl hexyl acrylate absorption–desorption solubility parameters spilled organic solvents

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Structure development and physical properties achieved in the drawing and/or annealing of PEN fibers

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Journal of polymer science 2000年第11期38卷

作者： Gang Wu Ming Liu Xiaoning Li John A. Cuculo College of Material Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Fibrous Material Engineering Beijing Institute of Clothing Technology Beijing 100029 China Fiber & Polymer Science Program College of Textiles North Carolina State University Raleigh North Carolina 27695

As-spun poly(ethylene-2,6-naphthalate) (PEN) fibers (i.e., precursors) prepared from high molecular weight polymer were drawn and/or annealed under various conditions. Structure and property variations taking place during the treatment process were followed via wide-angle X-ray scattering (WAXS), small-angle X-ray scattering, differential scanning calorimetry (DSC), and mechanical testing. Both the WAXS and DSC measurements of the cold-drawn samples stretched from a low-speed-spun amorphous fiber indicate that strain-induced crystallization can occur at a temperature below the glass-transition temperature and that the resultant crystal is in the α-form modification. In contrast, when the same precursor was subjected to constrained annealing, its amorphous characteristics remained unchanged even though the annealing was performed at 200 °C. These results may imply that the application of stretching stress is more important than elevated temperatures in producing α-form crystallization. The crystalline structure of the hot-drawn samples depends significantly on the morphology of the precursor fibers. When the precursor was wound at a very low speed and in a predominantly amorphous state, hot drawing induced the formation of crystals that were apparently pure α-form modification. For the β-form crystallized precursors wound at higher speeds, a partial crystalline transition from the β form to the α form was observed during the hot drawing. In contrast with the mechanical properties of the as-spun fibers, those of the hot-drawn products are not improved remarkably because the draw ratio is extremely limited for most as-spun fibers in which an oriented crystalline structure has already formed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1424–1435, 2000

关键词： poly(ethylene-2,6-naphthalate) fiber drawing annealing structural change crystalline transition

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Control of various morphological changes of poly(meth)acrylate microspheres and their swelling degrees by SPG emulsification

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Journal of polymer science 2000年第22期38卷

作者： Sumalee Tawonsree Shinzo Omi Suda Kiatkamjornwong Multidisciplinary Program of Petrochemistry and Polymer Science Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Graduate School of Bio-Application and System Engineering Tokyo University of Agriculture and Technology 2-24-16 Nakamachi Koganei Tokyo 184 Japan Department of Imaging and Printing Technology Faculty of Science Chulalongkorn University Bangkok 10330 Thailand

Crosslinked poly(meth)acrylate polymers with a variety of morphologies were synthesized with two steps. In the first step, a microporous glass membrane (Shirasu Porous Glass, SPG) was employed to prepare uniform emulsion droplets by applying an adequate pressure to the monomer phase, which was composed of the ADVN initiator, solvent of toluene or heptane or their mixture, and a mixture of (meth)acrylate monomers. The droplets were formed continuously through the membrane and suspended in the aqueous solution, which contained a PVA-127 suspending agent, SLS emulsifier, and NaNO 2 inhibitor to suppress the nucleation of secondary particles. SPG pore sizes of 0.90, 5.25, and 9.25 μm were used. Then the emulsion droplets were polymerized at 343 K with a rotation rate 160 rpm for 24 h. The (meth)acrylate monomers 2-ethylhexyl acrylate (2-EHA), 2-ethylhexyl methacrylate (2-EHMA), cyclohexyl acrylate (CHA), methyl methacrylate (MMA), lauryl acrylate (LA), and lauryl methacrylate (LMA) were used in this research. The influences of the ratios of the monomer and crosslinking agent EGDMA, the amount of diluents, the monomer type on the polymer particle morphology, the swelling degree, and the polymer particle size were investigated. It was found that an increase in the concentrations of EGDMA and heptane resulted in higher coarse porous spheres and smaller polymer particle sizes. A coefficient with a variation close to 10%, or a standard deviation of about 4, was obtained. The capacity of these spheres as solvent absorption materials was examined. The highest swelling degrees of heptane and toluene were obtained when LA was employed as the monomer with 30% (by weight) of EGDMA and 70% (by weight) of heptane as an inert solvent. The highest capacity of the solvent absorption was obtained when using a polymer particle size of 4.81 μm, as prepared by SPG pore size 0.9 μm. The polymer particles were able to absorb aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, and

关键词： Shirasu porous glass 2-ethyl hexyl acrylate 2-ethyl hexyl methacrylate cyclohexyl acrylate methyl methacrylate lauryl acrylate swelling degree crosslinking agent diluent solvent absorption

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Synthesis and properties of poly(1-naphthylacetylene) and poly(9-anthrylacetylene)

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Journal of polymer science 2000年第3期37卷

作者： Kazunari Nanjo S. M. Abdul Karim Ryoji Nomura Tatsuo Wada Hiroyuki Sasabe Toshio Masuda Department of Polymer Chemistry Kyoto University Kyoto 606-8501 Japan Core Research for Evolutional Science and Technology (CREST) JST and Frontier Research Program The Institute of Physical and Chemical Research (RIKEN) 2-1 Hirosawa Wako Saitama 351-0198 Japan

polymerizations of 1-naphthylacetylene (1-NA) and 9-anthrylacetylene (9-AA) by various transition metal catalysts were studied, and properties of the polymers were clarified. 1-NA polymerized with WCl 6 -based catalysts to offer dark purple polymers in good yield. Especially, a binary catalyst composed of WCl 6 and Ph 3 Bi gave a polymer with high molecular weight ( M w = 140×10 3 ) and sufficient solubility in common solvents. The use of Mo and Rh catalysts, in contrast, resulted in the formation of insoluble red poly(1-NA)s. 9-AA gave insoluble polymers by both WCl 6 - and MoCl 5 -based catalysts in moderate to good yields. Copolymerization of 9-AA with 1-NA by WCl 6 –Ph 3 Bi provided a soluble copolymer which exhibited the largest third-order nonlinear optical susceptibilities (χ (3) (−3ω; ω, ω, ω) = 40×10 −12 ) among all the substituted polyacetylenes synthesized so far. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 277–282, 1999

关键词： metathesis polymerization poly(arylacetylene) conjugated polymer tungsten catalyst molybdenum catalyst nonlinear optical property

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Spinodal Dewetting of Thin polymer Films

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Physical Review Letters 1998年第6期81卷 1251-1251页

作者： R. Xie A. Karim J. F. Douglas C. C. Han R. A. Weiss Polymer Science Program and Department of Chemical Engineering University of Connecticut Storrs Connecticut 06269 Polymers Division National Institute of Standards and Technology Gaithersburg Maryland 20899

Dewetting of polystyrene films on a silicon substrate is investigated as a function of film thickness h. We observe the nucleation of holes in the early stage of dewetting for relatively thick films (h>100Å), as observed previously, but the breakup of thinner films occurs through the growth of uniformly distributed surface undulations (“spinodal dewetting”). The average amplitude δh of these undulations increases exponentially up to the film rupture point where δh becomes comparable to h, as predicted by a capillary wave instability model.

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Contributory presentations/posters

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Journal of Biosciences 1999年第1期24卷 33-198页

作者： N. Manoj V. R. Srinivas A. Surolia M. Vijayan K. Suguna R. Ravishankar R. Schwarzenbacher K. Zeth Diederichs G. M. Kostner A. Gries P. Laggner R. Prassl Madhusudan Pearl Akamine Nguyen-huu Xuong Susan S. Taylor M. Bidva Sagar K. Saikrishnan S. Roy K. Purnapatre P. Handa U. Varshney B. K. Biswal N. Sukumar J. K. Mohana Rao A. Johnson Vasantha Pattabhi S. Sri Krishna Mira Sastri H. S. Savithri M. R. N. Murthy Bindu Pillai Kannan M. V. Hosur Mukesh Kumar Swati Patwardhan K. K. Kannan B. Padmanabhaa S. Sasaki-Sugio M. Nukaga T. Matsuzaki S. Karthikevan S. Sharma A. K. Sharma M. Paramasivam P. Kumar J. A. Khan S. Yadav A. Srinivasan T. P. Singh S. Gourinath Neelima Alam A. Srintvasan Vikas Chandra Punit Kaur Ch. Betzel S. Ghosh A. K. Bera S. Bhattacharya S. Chakraborty A. K. Pal B. P. Mukhopadhyay I. Dey U. Haldar Asok Baneriee Jozef Sevcik Adriana Solovicova K. Sekar M. Sundaralingam N. Genov Dong-cai Liang Tao Jiang Ji-ping Zhang Wen-rui Chang Wolfgang Jahnke Marcel Blommers S. C. Panchal R. V. Hosur Bindu Pillay Puniti Mathur S. Srivatsun Ratan Mani Joshi N. R. Jaganathan V. S. Chauhan H. S. Atreya S. C. Sahu K. V. R. Chary Girjesh Govil Elisabeth Adjadj Éric Quinjou Nadia Izadi-Pruneyre Yves Blouquit Joël Mispelter Bernadette Heyd Guilhem Lerat Philippe Milnard Michel Desmadreil Y. Lin B. D. Nageswara Rao Vidva Raghunathan Mei H. Chau Prashant Pesais Sudha Srivastava Evans Coutinho Anil Saran Leizl F. Sapico Jayson Gesme Herbert Lijima Raymond Paxton Thamarapu Srikrishnan C. R. Grace G. Nagenagowda A. M. Lynn Sudha M. Cowsik Sarata C. Sahu S. Chauhan A. Bhattacharya G. Govil Anil Kumar Maurizio Pellecchia Erik R. P. Zuiderweg Keiichi Kawano Tomoyasu Aizawa Naoki Fujitani Yoichi Hayakawa Atsushi Ohnishi Tadayasu Ohkubo Yasuhiro Kumaki Kunio Hikichi Katsutoshi Nitta V. Rani Parvathy R. M. Kini Takumi Koshiba Yoshihiro Kobashigawa Min Yao Makoto Demura Astushi Nakagawa Isao Tanaka Kunihiro Kuwajima Jens Linge Seán O. Donoghue Michael Nilges G. Chakshusmathi Girish S. Ratnaparkhi P. K. Madhu R. Varadarajan C. Tetreau Molecular Biophysics Unit Indian Institute of Science Bangalore India Austrian Academy of Sciences Institute of Biophysics and X-ray Structure Research Graz Austria Faculty of Biology University of Konstanz Germany Institute of Medical Biochemistry University of Graz Austria Howard Huges Medical Institute Department of Chemistry & Biochemistry University of California La Jolla USA Department of Chemistry & Biochemistry University of California San Diego La Jolla USA Molecular Biophysics Unit India Department of Microbiology &Cell Biology Indian Institute of Science Bangalore India Macromolecular Structure Laboratory NCI - Frederick Cancer Research and Development Center ABL - Basic Research Program Frederick USA Department of Crystallography and Biophysics University of Madras Chennai Biochemistry Department Indian Institute of Science Bangalore India Condensed Matter Physics Division B.A.R.C. Trombay Mumbai Condensed Matter Physics Division Bhabha Atomic Research Centre Trombay Mumbai IMCB The University of Tokyo Tokyo Japan Mitsubishi Chemical Corporation Yokohama Research Center Yokohama Japan Faculty of Pharmaceutical Sciences Chiba University Chiba Japan Department of Biophysics All India Institute of Medical Sciences New Delhi India Department of Biophysics All India Institute of Medical sciences New Delhi India Institüt Physiologische Chemie Hamburg Germany Biophysics Department Bose Institute Calcutta India Slovak Academy of Sciences Institute of Molecular Biology Bratislava Slovakia Indian Institute of Science Bioinformatics Centre Bangalore Departments of Chemistry and Biochemistry Biological Macromolecular Structure Center USA Bulgarian Academy of Sciences Institute of Organic Chemistry Sofia Bulgaria Chinese Academy of Sciences Institute of Biophysics Beijing China Novartis Pharma AG Preclinical Research Basel Switzerland Department of Chemical Sciences Tata Institute of Fundamental Research Mumbai India Solid State Physics Div

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Electrical properties of block copolymers containing silver nanoclusters within oriented lamellar microdomains

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Journal of Applied polymer science 1998年第4期65卷

作者： B. H. Sohn R. E. Cohen Program in Polymer Science and Technology Massachusetts Institute of Technology Cambridge Massachusetts 02139 Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139

Films containing silver nanoclusters within a lamellar morphology were obtained via postprocessing reduction of the silver‐containing regions of block copolymers synthesized by ring opening metathesis polymerization. Solution‐cast films (0.1 mm thickness) of the block copolymer exhibited an oriented lamellar morphology with lamellar normals perpendicular to the film plane. The slightly anisotropic dielectric properties, perpendicular and parallel to the film plane, were investigated by direct measurement and by model calculations. The conductivity was highly anisotropic, differing by at least four orders of magnitude in directions parallel and perpendicular to the film plane. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 723–729, 1997

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Structure Pinning During Phase-Separation of Polyamide/Ionomer Blends

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MRS Online Proceedings Library 1996年第1期461卷 3-11页

作者： R. A. Weiss Y. Feng R. Tucker R. Xie C. C. Han A. Karim Dept. of Chemical Engineering and Polymer Science Program University of Connecticut USA Polymer Section National Institute of Standards and Technology Gaithersburg

Blends of lightly sulfonated polystyrene and poly(N,N′-dimethylethylene sebacamide) (Li-SPS/mPA) are miscible as a result of strong ion-amide complexation. The blends exhibit LCST phase behavior and an increase of the sulfonation level from 4 to 9.5 mol% raises the critical temperature by 150°C. Phase separation may be thermally induced and isthermodynamically reversible. The phase separation kinetics that occur following a temperature-jump deep into the spinodal region of the phase diagram deviate from conventional Cahn-Hilliard theory and the phase separation process stalls after a couple of hours, essentially pinning the structure at that point. The extent of phase-separation that occurs before pinning is temperature-dependent.

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Oriented noncrystalline structure in PET fibers prepared with threadline modification process

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Journal of polymer science 1996年第12期34卷

作者： Gang Wu Jiao-Dong Jiang Paul A. Tucker John A. Cuculo Department of Polymer Science Beijing University of Chemical Technology Beijing 100029 China Department of Fibrous Material Engineering Beijing Institute of Clothing Technology Beijing 100029 China Fiber & Polymer Science Program College of Textiles North Carolina State University Raleigh North Carolina 27695

The development of an oriented noncrystalline phase in a semicrystalline polymer filament has been studied via X-ray scattering. These unique PET fibers contain a relatively high noncrystalline content and also have high tenacity, high modulus, and low breaking elongation. Fiber properties were found to be very responsive to the oriented amorphous phase content. This phase was utilized for interpreting noncrystalline orientation in PET fibers produced by a new extrusion technique. Here, the oriented noncrystalline regions in a series of PET fibers varies from 6% to 63%, depending strongly on the production conditions. In particular, samples produced with a newly developed threadline modification process possess a high content of oriented noncrystalline polymer. Measurements such as dynamic and static mechanical properties have been performed on various samples, and these properties are related to the oriented noncrystalline phase. The results provide direct evidence for the existence of highly oriented noncrystalline material in these unique PET fibers spun with a threadline modification process. © 1996 John Wiley & Sons, Inc.

关键词： poly(ethylene terephthalate) controlled threadline dynamics orientation oriented noncrystalline phase fiber properties crystallinity

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Effect of crystallization on the morphologies of block copolymer/homopolymer blends cast in an electric field

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Journal of polymer science 1996年第2期34卷

作者： Yijun Ye Gary E. Wnek Sonja Krause Thomas W. Smith Department of Chemistry and Polymer Science and Engineering Program Rensselaer Polytechnic Institute Troy New York 12180-3590 Xerox Corporation Joseph C. Wilson Center for Research and Technology Webster New York 14580

Blends of polystyrene (PS) and poly(styrene- b -ethylene oxide) (PS- b -PEO) were cast from a ternary solvent mixture containing 85% toluene, 10% tetrahydrofuran, and 5% methanol under conditions that favor crystallization of the PEO phase. Electric fields (2–14 kV/cm) were applied during casting to explore the possibility of morphology control by the field. It was observed that films cast in the absence of an electric field, in the temperature range of 0–25°C, from solutions initially cooled to 0°C were translucent. Their transmission electron micrographs exhibited thread-like, fibrillar structures. Micrographs of films cast in dc fields of 2–14 kV/cm at 16.3 ± 0.4°C also showed fibrillar structures, with the fibrils in the presence of fields greater than 8 kV/cm being substantially oriented in the field direction. We suggest that the morphologies developed under these conditions result from crystallization from preexisting crystal nuclei in the cooled solutions with the fibrillar crystals being oriented by the electric field. This method provides a possible way of processing anisotropic polymer blends. © 1996 John Wiley & Sons, Inc.

关键词： electric field effect crystalline fibrils poly(styrene) poly(ethylene oxide) poly(styrene-b-ethylene oxide)

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