bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a dibenzylchitin‐type polysaccharide by acid‐catalyzed polymerization
Authors: Kadokawa Jun‐ichi , Watanabe Yoshikatsu , Karasu Masa , Tagaya Hideyuki , Chiba Koji 
Published: April 2003

AbstractThis paper describes the polymerization of 2‐methyl‐(3,6‐di‐O‐benzyl‐ 1,2‐dideoxy‐α‐D‐glucopyrano)‐[2,1‐d]‐2‐oxazoline (1) with an acid catalyst. The polymerization proceeds involving stereoregular glycosylation to give polysaccharide 2. The polymer structure, 2‐acetamido‐3,6‐di‐O‐benzyl‐2‐deoxy‐(l→4)‐β‐D‐glucopyranan was determined by means of 1H NMR, 13C NMR, and IR spectra as well as elemental analysis. The molecular weight was at most 4900 (degree of polymerization ≈ 13).
A new method for the polymerization of methyl methacrylate
Authors: Reetz Manfred T. , Herzog H. Martin , Könen Werner 
Published: April 2003

AbstractDialkyl iodomethylmalonates in the presence of tetrabutylammonium iodide initiate the polymerization of methyl methacrylate, but not of methyl acrylate or acrylonitrile. Typically, at 60°C in 1,3‐dimethyltetrahydro‐2‐1H‐pyrimidone (DMPU) as the solvent, poly(methyl methacrylate (PMMA)) is obtained in the number‐average molecular weight range of 2 000 to 8 000, the molecular weight distribution being fairly narrow (ratio of weight‐ to number‐average molecular weights M̄w/M̄n 1.2–1.3).
Poly(methacrylates) with different kinds of dendritic moieties as side groups
Authors: Chen Yong‐Ming , Chen Chuan‐Fu , Liu Wei‐Hong , Li Yu‐Fei , Xi Fu 
Published: April 2003

AbstractAlkyl methacrylate monomers with three kinds of dendritic fragments as alkyl groups, two kinds of Fréchet‐type and a new type with 3,5‐diphenoxybenzyl as first generation, were prepared by reaction of the corresponding dendritic bromides with methacrylic acid in good yield and were homopolymerized with a radical initiator. Polymers with side groups in first generation had a degree of polymerization (P̄n) of 17–24, markedly higher than those with side groups in second generation, P̄n ≈ 6–7.
Isospecific homo‐ and copolymerization of styrene with ethylene in the presence of VCl3, AlCl3 as catalyst
Authors: Riberio M. Rosário , Portela Manuel F. , Deffieux Alain , Cramail Henri , Rocha Manuel F. 
Published: April 2003

AbstractThe homopolymerization of styrene and its copolymerization with ethylene in the presence of a vanadium‐based supported catalyst, {VCI3, 1 AICI3}, associated to triethylaluminium is examined. As indicated by means of 13C nuclear magnetic resoance and differential scanning calorimetry analysis, the homopolystyrenes obtained present a highly isotactic microstructure and are semicrystalline (melting temperature 220°C).In the case of styrene/ethylene random copolymerization, the formation of both, polyethylene blocks and isotactic polystyrene sequences was identified by analysis of the crude polymer. Solubility characteristics and structural characteristics from nuclear magnetic resonance spectra of these products support the formation of copolymers with ethylene and isotactic styrene blocks rather than that of two distinct homopolymers.
Metal‐polymer “superglue” for dirty polymer surfaces
Authors: Noolandi Jaan , Shi An‐Chang 
Published: April 2003

AbstractCurrent methods of bonding metals to polymeric surfaces involve chemical reactions between atomically clean surfaces (S. Paul, Surface Coatings, Wiley, New York 1985). We propose a novel method of attaching metals to polymeric surfaces which does not require chemical bonding and is designed to be effective for polymeric surfaces which are not clean.
Enzymatic synthesis of a soluble polyphenol derivative from 4,4′‐biphenyldiol
Authors: Kobayashi Shiro , Kurioka Hideharu , Uyama Hiroshi 
Published: April 2003

AbstractEnzymatic oxidative polymerization of 4,4′‐biphenyldiol was performed in an aqueous organic solvent using horseradish peroxidase as catalyst. In the polymerization using a mixture of 1,4‐dioxane and phosphate buffer (pH 7.0) (80:20 vol‐%) as solvent, the monomer was quantitatively consumed to give powdery polymeric materials in a high yield. The resulting polymer is soluble in polar solvents such as N,N‐dimethylformamide, dimethyl sulfoxide, and acetone. The molecular weight of the methylated product is 7.3 × 103. The polymer exhibits high thermal stability under nitrogen.
Polymerization of styrenes carrying dendrons of the first, second and third generation
Authors: Neubert Ingo , Amoulong‐Kirstein Evelin , Schlüter A.‐Dieter , Dautzenberg Herbert 
Published: April 2003

AbstractThe synthesis of styrene monomers 5(G‐1,2,3) with Fréchet‐type dendrons of the first, second and third generation, and their radically initiated polymerization to result in high molecular weight dendrimers 6(G‐1,2,3) are reported. First light‐scattering investigations using 6(G‐2) show that this polymer is best described as a Gaussian chain.
Polymerization of an azastyrene derivative, 1. 1,6‐addition polymerization of 2,6‐diisopropyl‐N‐methyleneaniline
Authors: Hashidzume Akihito , Kajiwara Atsushi , Harada Akira , Kamachi Mikiharu 
Published: April 2003

AbstractThe polymerizability of an azastyrene derivative, 2,6‐diisopropyl‐N‐methyleneaniline (DiPMAn), was studied. Although DiPMAn could not be polymerized by radical and anionic initiators, it was polymerized with cationic initiators, such as trifluoroacetic acid (TFA), TiCl4‐TFA, and SnCl4‐TFA. The polymer is formed by 1,6‐addition with electrophilic substitution of an activated monomer in para‐position of the aromatic ring.
Command surfaces, 20. Fixation of surface‐assisted homogeneous alignment of nematic liquid crystals by cationic photopolymerization
Authors: Ichimura Kunihiro , Kidowaki Masatoshi , Akiyama Haruhisa , Kudo Kazuaki , Strehmel Veronika , Strehmel Bernd 
Published: April 2003

AbstractThe surface‐assisted alignment of a nematic liquid crystal yields a persistent ordered structure upon cationic photopolymerization of liquid‐crystalline epoxides. Linearly polarized light irradiation of a photocrosslinkable polymer containing azobenzene moieties played a crucial role in this procedure since the photoinduced alignment is not deteriorated by heating for polymerization.
Synthesis of a polystyrene‐arm‐polybutadiene‐arm‐poly(methyl methacrylate) triarm star copolymer
Authors: Hückstädt Hanno , Abetz Volker , Stadler Reimund 
Published: April 2003

AbstractThe straightforward synthesis of a polystyrene‐arm‐polybutadiene‐arm‐poly(methyl methacrylate) triarm star copolymer has been successfully realized by a sequence of reactions which involves the sequential addition of a living polybutadienyllithium to a polystyrene macromonomer with a terminal 1,1‐diphenylethylene unit and subsequent polymerization of methyl methacrylate. The high‐molecular‐weight polystyrene‐arm‐polybutadiene‐arm‐poly(methyl methacrylate) star copolymer shows microphase separation into three phases.
First application of an X‐ray imaging plate system for the accurate evaluation of the crystallite modulus of polymers
Authors: Tashiro Kohji , Nishimura Hirokazu , Kobayashi Masamichi 
Published: April 2003

AbstractAn X‐ray imaging plate system has been applied for the first time to evaluate the crystallite modulus Ec of orthorhombic polyethylene along the chain axis. The Ec evaluated by using the 002 reflection was 234.9 ± 12.6 GPa and that for the 004 reflection was 236.7 ± 3.4 GPa. The dispersion of the data was smaller for the 004 reflection than that for the 002 reflection. The so evaluated modulus has been found to be in good agreement with that reported by previous researchers.
New evidence of the presence of internal electron donors in active sites of heterogeneous Ziegler‐Natta catalysts
Authors: Xu Junting , Feng Linxian , Yang Shilin , Wu Yinan , Yang Yiqing , Kong Xiangming 
Published: April 2003

AbstractPoly(propylene) samples produced by heterogeneous Ziegler‐Natta catalysts containing different internal electron donors were fractionated by using temperature rising elution fractionation; some key fractions were analyzed with 13C NMR. It was found that internal electron donors with different structures can convert aspecific active sites into different isospectrific ones. The employment of bis(2‐ethylhexyl) phthalate as internal electron donor leads to chemically inverted structures in the atactic fraction. This suggests that an internal electron donor may also exist in the environment of aspecific active sites.
Novel amine‐containing biodegradable polyester via copolymerization of aspartic anhydride and 1,4‐cyclohexanedimethanol
Authors: Won Chee‐Youb , Chu Chih‐Chang , Yu Tarng‐Jenn 
Published: April 2003

AbstractA novel biodegradable polyester having pendant amine functional groups was snythesized from N‐(benzyloxycarbonyl)‐L‐aspartic anhydride (2) and 1,4‐cyclohexanedimethanol (3) by polycondensation reaction using p‐toluenesulfonic acid as a catalyst. The synthesized polymer 4 shows the characteristic ester carbonyl absorption peak at 1732 cm−1 in the IR spectrum, and the NMR spectra were consistent with the IR data. Also, the elemental analysis showed that the experimental and calculated values were very close to each other. The weight‐average molecular weight of the polymers ranged from 1140 to 5050 and increased with increasing reaction time. This new polymer would have the potential of a drug delivery biomaterial.
Synthesis and characterization of poly(1‐benzoylsemicarbazide) and poly(1,3,4‐oxadiazole amine) from 2‐(p‐aminophenyl)‐1,3,4‐oxadizolin‐5‐one via ring‐opening
Authors: Saegusa Yasuo , Ozeki Yasuhiro , Nakamura Shigeo 
Published: April 2003

AbstractA novel thermally stable and semiconducting polyheterocycle, poly(1,3,4‐oxadiazole amine), was synthesized from 2‐(p‐aminophenyl)‐1,3,4‐oxadiazolin‐5‐one via ring‐opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4‐oxadiazole heterocyclic units. The polymer is highly thermally stable and exhibits no weight loss up to 370°C in air. Its electric conductivity is less than 10−10 S · cm−1 at ambient temperature, but markedly increases to 6,5 · 10−7 S · cm−1 upon doping with iodine.
The first report on a convenient synthesis of novel reactive amphiphilic polysaccharides
Authors: Heinze Thomas , Rahn Kerstin 
Published: April 2003

AbstractNew amphiphiles with reactive tosylate groups and ionic sulfuric acid half esters based on the rod‐like polysaccharide cellulose were designed via homogeneous tosylation followed by sulfation with the SO3‐pyridine complex in N,N‐dimethylacetamide. At appropriate degrees of functionalization the polymers are soluble both in water and dimethyl sulfoxide, and they are promising starting materials for self‐organizing systems.
Copolymerization of 3,3,3‐trifluoro‐1,2‐epoxypropane with N‐phenylmaleimide using organozinc initiators
Authors: Ikeda Yoji , Yoshida Yasuhiko , Ishihara Kenji , Hamana Hiroshi , Narita Tadashi , Hagiwara Tokio 
Published: April 2003

AbstractNovel copolymers consisting of 3,3,3‐trifluoro‐1,2‐epoxypropane (TFEP) and N‐phenylmaleimide (PMI) units were prepared by the copolymerization of TFEP with PMI initiated with an organozinc compound. Using [Zn(OCH3)2 · (C2H5ZnOCH3)4] as an initiator, the copolymer chains consisted mainly of TFEP‐TFEP sequences. The TFEP‐PMI sequence content in the copolymer chains was small. On the other hand, using (C2H5ZnOCH3)4 as an initiator, only low molecular weight copolymers were formed. Those copolymers were suggested to have block structure, poly(TFEP)‐block‐poly(PMI), by the 19F NMR analysis. The copolymers showed higher thermostability than poly‐(TFEP).
Propene polymerization catalyzed over MCM‐41 and VPI‐5‐supported Et(ind)2ZrCl2 catalysts
Authors: Ko Young Soo , Han Taek Kyu , Park Je Woo , Woo Seong Ihl 
Published: April 2003

AbstractEt(ind)2ZrCl2 (C2H5(indenyl)2ZrCl2) confined inside regular pores of molecular sieves MCM‐41 and VPI‐5 were prepared and used to polymerize propene with high activity. Stereoregularity, melting point and molecular weight of polypropene obtained were increased and the polymerization behavior was quite different from that prepared with homogeneous Et(ind)2ZrCl2. The small, regular and cylindrical pores of MCM‐41 and VPI‐5 suppress the formation of inactive binuclear complexes between metallocene and metallocene, or between metallocene and methylaluminoxane, resulting in stable active sites and high activity in propene polymerization.
Synthesis and photocrosslinking of maleimide‐type polymers
Authors: Kim Woo‐Sik , Seo Kwan‐Ho , Chang Won‐Suk 
Published: April 2003

AbstractSelf‐sensitizable photocrosslinking maleimide‐type polymers were synthesized by using (N‐cinnamoyloxymethyl)maleimide (1) as a maleimide having a photodimerizable group, nitrophenyl acrylate as a sensitizer monomer, and styrene or methyl acrylate. The fluorescence spectra of these polymers exhibit an excimer band around 455 nm. The excimer intensity of the polymers decreased mainly during the early irradiation time. This decreasing tendency was similar to the increasing tendency of the insoluble fractions of the polymers with irradiation time. These results suggest that the photocrosslinking reaction of the polymers occurs via an excimer formation of the cinnamoyl groups and can be traced by fluorescence spectroscopy.
Water soluble, conjugated main chain azo polymer: Synthesis and characterization
Authors: Balasubramanian Srinivasan , Kim Jaehyun , Yu Kim Dong , Kumar Jayant , Tripathy Sukant K. 
Published: April 2003

AbstractThe monomer 2,5‐diaminobenzenesulfonic acid has been polymerized to a high molecular weight, conjugated main chain azo polymer. The presence of the azo group in the polymer was confirmed using Raman spectroscopy. The polymer is highly soluble in water over a wide pH range. It is also soluble in common polar organic solvents such as N,N‐dimethylformamide, dimethyl sulfoxide and N‐methyl‐2‐pyrrolidone.
Biochemical synthesis of water soluble polyanilines: Poly(p‐aminobenzoic acid)
Authors: Alva K. Shridhara , Marx Kenneth A. , Kumar Jayant , Tripathy Sukant K. 
Published: April 2003

AbstractThis report describes the synthesis of a water soluble polyaniline through a biochemical synthetic route. The oxidative free radical coupling mechanism for the synthesis of poly(p‐aminobenzoic acid) is catalyzed by horseradish peroxidase in the presence of hydrogen peroxide. The resulting polymer is electrochemically active and undergoes reversible redox reactions. The polymer as synthesized is self doped and undergoes undoping in alkaline or ammonia solutions.
Living ring‐opening polymerization of cyclic carbonate using cationic zirconocene complex as catalyst
Authors: Hayakawa Michiya , Mitani Makoto , Yamada Tohru , Mukaiyama Teruaki 
Published: April 2003

AbstractLiving ring‐opening polymerization of the cyclic carbonate 1,3‐dioxepan‐2‐one was achieved by using the cationic zirconocene complex [Cp2ZrMe]+[B(C6F5)4]− as catalyst at room temperature. A linear relation between conversion and molecular weight of the obtained polymer was observed. Furthermore, block copolymerization of the cyclic carbonate and ε‐caprolactone was successfully performed.
Optimum measurement temperature for elucidating incomplete phase separation in core‐shell latexes by solid state NMR
Authors: Landfester Katharina , Spiess Hans‐Wolfgang 
Published: April 2003

AbstractCore‐shell latexes with a core of poly(buty1 acrylate) (PBuA) and a shell of poly(methyl methacrylate) were studied by solid‐state nuclear magnetic resonance (NMR) methods at different temperatures. 13C cross polarization/magic angle spinning spectra show differences in mobility in the mobile PBuA phase. In spin‐diffusion experiments the sensitivity of the NMR parameters towards the interphase structure and towards the entire core‐shell structure changes with varying temperature. For an efficient characterization of interphase structures in core‐shell systems the measuring temperature has to be optimized, i.e. the mobility gradient between the two phases within the particle must be sufficiently high to allow for effective selection by the dipolar filter. Yet, the spin diffusion coefficient of the mobile component should be high enough to allow quantitative evaluation of length scales. It is shown that a measuring temperature of about 60–70 K above the glass transition temperature of the mobile component represents an optimum for fulfilling the different requirements simultaneously.
MALDI‐TOF characterization of macromonomers
Authors: Spickermann Jochen , Räder Hans‐Joachim , Müllen Klaus , Müller Beate , Gerle Markus , Fischer Karl , Schmidt Manfred 
Published: April 2003

AbstractMethacryloyl endfunctionalized oligostyrene macromonomers were characterized by matrix assisted laser desorption ionization/time of flight (MALDI‐TOF) spectroscopy and by isocratic and gradient high performance liquid chromatography (HPLC). The molar mass distribution derived by the different techniques coincide for the investigated oligomers. Mixing experiments revealed that the MALDI‐TOF peak areas do not necessarily represent the mixing ratio of the components. Combination of gradient HPLC and MALDI‐TOF has resolved the chemical composition of the coupling products formed by reaction of the living anion with oxygen.
Synthesis, characterization and properties of a soluble polymer with a poly(phenylenevinylene) structure
Authors: Babudri Francesco , Cicco Stefania R. , Farinola Gianluca M. , Naso Francesco , Bolognesi Alberto , Porzio William 
Published: April 2003

AbstractSoluble poly(2,5‐dialkoxy‐1,4‐phenylenevinylene) has been prepared via Stille coupling reaction between 2,5‐dialkoxy‐1,4‐diiodobenzene and E‐1,2‐bis(tributylstannyl)‐ethene in the presence of palladium complexes. Characterization of this material by means of 1H and 13C nuclear magnetic resonance (NMR), ultraviolet/visible (UV/VIS) and infrared (IR) spectra is described. Molecular weights, determined by means of gelpermeation chromatography (GPC) analysis and referred to standard polystyrene, were in the range number‐average molecular weights Mn = 2061–2544 and weight‐average molecular weights Mw = 3347–3878. X‐ray diffraction (XRD) analysis of the polymer showed semicrystalline structure. Tg = 57°C, transition to a stable smectic mesophase at 115°C and clearing point at 210°C were revealed by differential scanning calorimetry analysis, optical microscopy observation and XRD of the annealed polymer.
Sequence control on the ring‐opening oligomerization of cyclic imino ethers
Authors: Aoi Keigo , Okada Masahiko , Miyamoto Masatoshi 
Published: April 2003

AbstractSequence‐controlled oligomers of cyclic imino ethers were synthesized by the one‐pot multi‐stage feeding method. Selective formation of the sequence was clearly demonstrated by equimolar reactions between the monomers and 1:1 adducts of an initiator with the monomers. Efficiency of the sequence control is determined by the difference of reactivities of the active ends. A new general prerequisite to synthesize a well‐defined sequence by multi‐stage oligomerization was proposed.
Relationship between molecular structure and thermal properties of poly(aryl ether ketone)s
Authors: Shibata Mitsuhiro , Yosomiya Ryutoku , Wang Junzuo , Zheng Yubin , Zhang Wanjin , Wu Zhongwen 
Published: April 2003

AbstractFive kinds of poly(aryl ether ketone)s (PAEKs) having para‐substituted linear molecular chains were synthesized via nucleophilic substitution reaction of the corresponding difluoro‐ and dihydroxy‐compounds. The glass transition temperature and melting temperature of the PAEKs measured through differential scanning calorimetry in addition to those of other PAEKs reported are approximately proportional to the logarithm of the ratio of the mole fractions of ketone and ether groups in the repeating unit of the PEAKs. On the other hand, this ratio does not affect the crystal structure of the PAEKs.
Mechanistic study of enzyme catalyzed polymerization of 8‐hydroxyquinoline‐5‐sulfonate using nuclear magnetic resonance spectroscopy
Authors: Alva K. Shridhara , Marx Kenneth A. , Kumar Jayant , Tripathy Sukant K. 
Published: April 2003

AbstractHorseradish peroxidase catalyzed polymerization of 8‐hydroxyquinoline‐5‐sulfonate (HQS) has been studied by in‐situ NMR spectroscopy. The 2, 4 and 7 positions of the HQS are involved in oxidative free radical coupling with other HQS molecules with the order of reactivity being 7 ≥ 2 > 4. A mechanism for the oxidative free radical coupling and structure of the resulting polymer is proposed, which is supported by 13C NMR spectroscopy.
Synthesis and polymerization of N,N‐diallylpyrrolidinium bromide
Authors: De Vynck Valérie , Goethals Eric J. 
Published: April 2003

AbstractThe synthesis of N,N‐diallylpyrrolidinium bromide (DAPB) and its free‐radical initiated polymerization are described. It is shown that DAPB polymerizes via a cyclopolymerization mechanism leading to a polyelectrolyte consisting of azoniaspiro[4.4]‐nonane containing repeating units.
Immobilization of trypsin in polycation‐polyanion complexes
Authors: Dautzenberg Herbert , Karibyants Natalia , Zaitsev Sergei Yu. 
Published: April 2003

AbstractTrypsin was immobilized in quasi‐soluble polyanion‐polycation complexes with retention of the enzyme activity. The activity of the immobilized enzyme strongly depends on pH of the prepared solution, composition, relative concentrations and molar masses of the polyelectrolytes. The highest activity of trypsin (about 93%) was found in the case of the complexes Na‐poly(styrenesulfonate)‐poly(diallyldimethylammonium chloride): trypsin = 10:1, prepared at pH 3.0, with high molar mass of the polyanion (about one million). This method can be proposed for immobilization of various serine proteases.
Ruthenium catalyzed polymerization of 4‐acetylstilbenes and 1,3‐divinyltetramethyldisiloxane
Authors: Londergan Timothy Martin , Weber William P. 
Published: April 2003

AbstractSuccessful dihydridocarbonyltris(triphenylphosphine)ruthenium (Ru‐complex) catalyzed polymerization of 4‐acetylstilbene with 1,3‐divinyltetramethyldisiloxane to yield poly(3,3,5,5‐tetramethyl‐4‐oxa‐3,5‐disila‐1,7‐heptanylene‐alt‐4‐acetyl‐3,5‐stilbenylene) is reported. Polymerization results from Ru‐complex catalyzed activation of aromatic C‐H bonds which are ortho to the acetyl for selective anti‐Markovnikov addition across the terminal C‐C double bonds of 1,3‐divinyltetramethyldisiloxane. The internal C‐C double bond of 4‐acetylstilbene does not react.
Synthesis of a novel poly[2]‐catenane containing rigid catenanes
Authors: Muscat Dirk , Witte Andreas , Köhler Werner , Müllen Klaus , Geerts Yves 
Published: April 2003

AbstractA novel poly[2]‐catenane containing rigid catenane subunits connected by semirigid spacers has been synthesized. This new macromolecular architecture is the second example of a polymer containing topological bonds in the main chain. The poly[2]‐catenane structure was proved by spectroscopic methods, especially 1H NMR, IR and MALDITOF. The polymer is thermally stable up to 380°C and shows a high glass transition temperature of ca. 265°C.
1,3,5,5‐tetraphenyl‐Δ3‐1,2,4‐triazolin‐2‐yl radical–properties in the controlled radical polymerization of poly(methyl methacrylate) and polystyrene
Authors: Colombani Daniel , Steenbock Marco , Klapper Markus , Müllen Klaus 
Published: April 2003

AbstractThe triazoline derivative 1 was used as an additive in the chain‐growth controlled radical polymerization of vinylic monomers to afford narrowly distributed polymers. This new system is applicable to styrene as well as to methacrylates. The monomer consumption and the variation of the molar mass were monitored with time. Thermal properties of the obtained polymers were also studied. After isolation of the polymers, the growth of the chains was re‐initiated in the presence of a second monomer and yielded block copolymers.