bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Nano Structured Blend Membrane for Gas Separation
Authors: Ghalei Behnam , Semsarzadeh Mohamad‐Ali 
Published: March 2007

AbstractThis investigation involves the preparation and characterization of poly (urethane)/poly (vinyl acetate) (PU/PVAc) blend membranes. PU was synthesized by two step polymerization from toluene diisocyanate (TDI), poly (propylene glycol) (PPG) and 1, 4‐butanediol (BDO).Fourier transform infrared (FTIR) spectroscopy was used to verify the chemical structure of the resulting polymer. Blend membranes with a thickness of 100 µ were prepared from the solution of PU and PVAc in chloroform by a solution‐evaporation method. The amount of PVAc was varied among 10, 20 and 30 percent by weight of the membrane. Scanning Electron Microscopy (SEM) was used to investigate the morphology of the prepared membranes. The membrane containing 20% by weight of PVAc displayed a more homogenous dispersion of PVAc domains and was selected for gas permeation tests. For this purpose; oxygen (O2), nitrogen (N2), carbon dioxide (CO2) and methane (CH4) gases were used and the gas pressure was varied between 2, 4, 6, 8 and 10 bars. Comparison of the results with that of the pure PU membrane revealed that the blend membrane had a higher permeability to CO2 and a lower permeability to the other gases and therefore had a higher value of CO2/N2 and CO2/CH4 ideal selectivity.
Synthesis and Characterization of Diazonium Containing Block Copolymers via Controlled Ring Opening Metathesis Polymerization (ROMP) and the Subsequent Chemical Modification
Authors: Moon Bongjin , Kang Minhyuck 
Published: March 2007

Abstract7‐Oxanorbornene‐5,6‐dicarboximide derivatives bearing either an alkyl‐ or a nitrophenyl group were prepared and these monomers were subjected to the controlled ring opening metathesis polymerization (ROMP). The resulting polymer, poly[N‐(n‐butyl)‐7‐oxanorbornene‐5,6‐carboximide‐b‐N‐(2‐(4‐nitrobenzoyl)ethyl)‐7‐ oxanorbornene‐5,6‐dicarboxiimide] P(BuONDI‐b‐NbONDI) (8), showed good molecular weight and narrow polydispersity control (PDI < 1.1). The alkene and the nitrophenyl groups in the block copolymer were selectively reduced using tosyl hydrazide and ammonium sulfide, respectively. The resulting aryl amines in the block polymer were then oxidized to the corresponding diazonium salts by treatment with nitrosyl tetrafluoroborate. The presence of the diazonium groups was verified by IR and cyclic voltammetry (CV), and also by several chemical reactions which are unique for diazonium salts.
Polymer‐Supported Chiral 1,2‐Diamines by Radical Copolymerization with Vinyl Monomer for Asymmetric Hydrogenation of Aromatic Ketones
Authors: Haraguchi Naoki , Chiba Masahiro , Takahashi Miyuki , Itsuno Shinichi 
Published: March 2007

AbstractNovel polymer‐supported chiral 1,2‐diamines have successfully synthesized by radical copolymerization of N‐Boc protected enantiopure 1,2‐diamine bearing two vinylphenyl moieties ((S,S)‐5) with various achiral vinyl monomer including methyl methacrylate, 2‐hydroxyethyl methacrylate, butyl acrylate, and N‐isopropyl acrylamide, followed by deprotection of N‐Boc moiety. Hydrogenation of acetophenone in 2‐propanol/DMF mixed solvent was performed with use of polymeric catalyst system prepared from the polymer‐supported chiral 1,2‐diamine and RuCl2/(S)‐BINAP. The reaction proceeded smoothly to give 1‐phenylethanol in quantitative yield with high level of enantioselectivity. In addition, various other aromatic ketones could be asymmetrically hydrogenated by the polymeric catalyst system. Furthermore, the polymeric catalyst could be reused several times in hydrogenation of aromatic ketones without loss of the enantioselectivity.
Spontaneous Copolymerization of 1,3‐Dehydroadamantane
Authors: Ishizone Takashi , Matsuoka Shin‐ichi , Ogiwara Naoto , Uehara Yosuke , Kobayashi Shingo 
Published: March 2007

AbstractCopolymerizations of 1,3‐dehydroadamantane, 1, and various vinyl monomers were carried out in THF at room temperature. On mixing of 1 with electron‐deficient vinyl monomers such as acrylonitrile and methyl acrylate in the absence of initiator, the copolymerization spontaneously proceeded to give alternating copolymers in 28–88% yields. By contrast, no reaction of 1 occurred at all, when isobutyl vinyl ether or styrene was mixed under the similar conditions. These results indicate the high electron density of a central σ‐bond in a strained [3.3.1]propellane derivative, 1. Alternating sequences of the resulting copolymers were characterized by NMR and MALDI‐TOF‐MS measurements. DSC and TGA measurements revealed the high thermal stability of the alternating copolymers containing bulky, stiff, and strain‐free adamantane skeletons.
Controlled Synthesis of Reactive Polymeric Architectures Using 5‐Norbornene‐2‐carboxylic Acid Pentafluorophenyl Ester
Authors: Vogel Nicolas , Théato Patrick 
Published: March 2007

AbstractExo‐5‐norbornene‐2‐carboxylic acid pentafluorophenyl ester was synthesized from 5‐norbornene‐2‐carboxylic acid and polymerized by ring‐opening metathesis polymerization. The obtained polymers were soluble polymeric active esters that could be used for the preparation of multifunctional polymers. The molecular weight of the polymers was controlled by variation of the monomer to initiator ratio. The precursor polymers reacted quantitatively with primary and secondary amines. Time resolved FT‐IR studies at different temperatures of the polymer analogous reactions were performed and rate constants were determined.
Controlled Polymerization of Glycidyl Methyl Ether Initiated by Onium Salt/Triisobutylaluminum and Investigation of the Polymer LCST
Authors: Labbé Amélie , Carlotti Stéphane , Deffieux Alain , Hirao Akira 
Published: March 2007

AbstractNew initiating systems developed for monomer activated anionic polymerization of propylene oxide, i.e. onium salt/triisobutylaluminum, were applied to the polymerization of glycidyl methyl ether. At low to medium temperature they yield fast polymerization and allow the synthesis of poly(glycidyl methyl ether) with high molar masses in a controlled way. Poly(glycidyl methyl ether) exhibits a critical solubility temperature (LCST) in water which is influenced by the polymer molar masses. Surprizingly Poly(glycidyl methyl ether)s show also some tendency to crystallize in water at low temperature, which perturb their solubility characteristics and behaviour in water.
Synthesis of Star Polymers Based on Xanthate‐Mediated Controlled Radical Polymerization of N‐Vinylcarbazole
Authors: Mori Hideharu , Ookuma Hiroshi , Endo Takeshi 
Published: March 2007

AbstractPoly(N‐vinylcarbazole) [poly(NVC)] stars were synthesized by macromolecular design via interchange of xanthate (MADIX)/reversible addition‐fragmentation chain transfer (RAFT) polymerization. Four‐armed poly(NVC) stars with controlled molecular weights and low polydispersities were obtained using a tetrafunctional xanthate, in which the stabilizing groups are linked to the core. The controlled character of the polymerization was also confirmed by the linear increase in the molecular weight with the conversion. The comparison of the polymerization behaviors using the tetrafunctional xanthate and a monofunctional one suggested that the multifunctional core has a clear effect on the polymerization kinetics, but has no significant influence on the controlled character of the polymerization.
Anionic Polymerization of N‐Methacryloyl‐2‐methylaziridine and N‐Methacryloylazetidine
Authors: Suzuki Takashi , Kusakabe Jun‐ichi , Ishizone Takashi 
Published: March 2007

AbstractAnionic polymerizations of N‐methacryloyl‐2‐methylaziridine (1) and N‐methacryloylazetidine (2) were carried out in THF with 1,1‐diphenyl‐3‐methylpentyllithium (DMPLi) and with diphenylmethylpotassium (Ph2CHK) in the presence of LiCl or Et2Zn. Poly(1) and poly(2) possessing predicted Mns based on the molar ratios between monomer to initiators and narrow molecular weight distributions (MWD, Mw/Mn < 1.1) were quantitatively obtained at −40 °C within 24 h. The stability of the propagating chain end of poly(1) was confirmed by the quantitative initiation efficiency in the postpolymerization. The radical polymerizations of 1 and 2 with AIBN gave the polymers in 77 and 40% yields, respectively. These are first examples demonstrating the positive polymerizability of N,N‐dialkylmethacrylamide derivatives, while N,N‐dimethylmethacrylamide showed the negative polymerizability under the radical and anionic polymerization conditions.
The Control of Surface Structure of Fluorocarbon End‐Capped Poly(L‐lactide)/Stereochemical Polylactide Blend Films
Authors: Yoon Seog‐Young , Lee Jin‐Kook , Chung Ildoo , Park Seong Soo 
Published: March 2007

AbstractThe propose of this study is to investigate stereocomplexation‐induced surface structure of enantiomeric PLA blends on the basis of complex formation between L‐ (LLA) and D‐lacide (DLA) unit sequences. In order to control the complexation, stereochmical PLAs with % D repeat unit contents of 100, 98, 95, 90, and 80 were synthesized from the mixtures of DLA and LLA using stannous octoate as catalyst. Fluorocarbon end‐capped PLLA (F‐PLLA) instead of PLLA was used as a surface probe material because of the surface segregation of fluorocarbon groups. Large changes in the melting temperature (Tm) behavior and the surface structure for (F‐PLLA/stereochmical PLA) blend films were observed by differential scanning calorimetry and electron spectroscopy for chemical analysis, respectively. (F‐PLLA/stereochmical PLA) blend films showed the increase in both Tm and heat of fusion from the stereocomplexes with the optical purity of stereochmical PLAs in the blend. Also, the surface composition of fluorocarbon groups in the blends was proportionally increased with decreasing the optical purity in the blend because the stereocomplex formation in (F‐PLLA/stereochmical PLA) blends prevents the surface segregation of fluorocarbon groups. These results indicate that surface structure of (F‐PLLA/stereochmical PLA) blends could be controlled by changing a degree of complexation.
Nonradiative Energy Transfer in Chromophore‐Tagged PS–PEO Diblock Copolymers
Authors: Cho Eun‐Bum , Kim Dukjoon 
Published: March 2007

AbstractNonradiative energy transfer fluorescence was used to investigate the micelle behavior of polystyrene‐b‐poly(ethylene oxide) diblock copoly‐ mers tagged with either donor naphthalene or acceptor pyrene in solutions and solid films. The effects of the variation in the solvency and micelle collision frequency caused by changing the total block copolymer concentration and the difference in the micelle concentration between polystyrene–poly(ethylene oxide) block copolymers labeled with two different chromophores on the chain release and exchange of micelles were observed. It was noted that the chain exchange of the polymer micelles is clearly observed when the concentration difference and the total micelle concentration are sufficiently large. In the case of the solid film, the NRET efficiency is increased as the molecular weight of the matrix polystyrene homopolymer added is increased.
Shape‐Stabilized Phase Change Materials: Frozen Gel fom Polypropylene and n‐Octadecane for Latent Heat Storage
Authors: Son Tae‐Won , Kim Tae‐Hun , Kim Bong‐Sick , Kim Byung‐Giu 
Published: March 2007

AbstractWe prepared polymer‐PCM gels such as prepared frozen gel from polypropylene and n‐octadecane for thermal storage and release materials, their basic properties and possible applications especially in latent heat storage. The preparation methods are used to melting method and absorption method respectively. The composition and properties of prepared frozen gels from polypropylene and n‐octadecane were observed by DSC, WAXD, FT‐IR spectra, ARES and Elemental analysis. We can prepare frozen gels in different temperature for latent heat storage materials as controlling composition of phase change material as well as using different incorporating phase change materials. These frozen gels can be used to latent heat storage materials for several applications.
The Effects of MWD on the Rheological Properties of Shear‐Induced Structural Formation for PVA Solutions in DMSO
Authors: Lee Eun Jeoung , Kim Byoung Chul 
Published: March 2007

AbstractThe effects of molecular weight distribution (MWD) on the rheological responses of shear‐induced structural formation in the general‐purpose polyvinyl alcohol (PVA) solutions dissolved in dimethyl sulfoxide (DMSO) were investigated. On the whole, time‐dependence of rheological properties was more influenced by the PVA solutions with broad MWD at the similar weight average molecular weight (Mw). The dynamic viscosity (η′) of PVA/DMSO solution with broad MWD was lower than that with narrow MWD at the similar Mw until the second time sweep (T2) of PVA/DMSO solution. After the time‐sweep experiment was repeated, the η′ of PVA/DMSO solution with narrow MWD was lower than that of PVA/DMSO solution with broad MWD at the similar Mw. The G′ until 5 min of relaxation of PVA/DMSO solution with broad MWD was lower than that of PVA/ DMSO solution with narrow MWD at the similar Mw. After the time‐sweep experiment was repeated, the G′ of PVA/DMSO solution with narrow MWD was lower than that of PVA/DMSO solution with broad MWD at the similar Mw. It could be interpreted as a consequence of the formation of three‐dimensional gel structure through the polar interactions by hydroxyl groups whose strength was dependent on shearing conditions and MWD.
Morphology and Physical Properties of Binary Blend Based on PVDF and Multi‐Walled Carbon Nanotube
Authors: Nam Young Wan , Kim Woo Nyon , Cho Yong Han , Chae Dong Wook , Kim Gwang Ho , Hong Seung Pyo , Hwang Seung Sang , Hong Soon Man 
Published: March 2007

AbstractSemicrystalline Poly(vinylidene fluoride)(PVDF) was melt blended by multi‐ walled carbon nanotube (MWNT) at various contents (0.01 ∼ 5 wt%) using internal mixer. The relationships between morphology and physical properties based on PVDF and MWNT were investigated. As the MWNT content is increased, the apparent supercooling required for PVDF crystallization and the size of spherulites in PVDF decrease. In the WAXD profiles, the incorporation of MWNT produced a large shoulder at 2θ = 20.7° with increasing the MWNT content, corresponding to the polar β‐form crystal of PVDF. The experimental percolation threshold for the electrical conductivity in PVDF was estimated and clearly occured between 2 and 2.5 wt%. Similar tendency was also observed in thermal conductivity and permittivity.
Reactive Extrusion of Polypropylene and Nylon Blends from Commingled Plastic Wastes
Authors: Kim Gwang Ho , Hwang Seung Sang , Cho Bong Gyoo , Hong Soon Man 
Published: March 2007

AbstractReactive extrusion for recycled PP/nylon blends from commingled plastic wastes was investigated through thermal, morphological, mechanical and rheological studies. From SEM investigation, we found improved surface morphologies with homogeneous domains in the recycled 75/25 PP/nylon blends compatibilized with copolymers containing maleic anhydride (MA) as a reactive functional group; SEBS‐g‐MA, PP‐g‐MA, PE‐g‐MA. Especially, SEBS‐g‐MA thermoplastic elastomer which is highly reactive with amine terminal group of nylon, resulted in a large increase of impact strength above nearly 200%. This compatibilization effect resulted from the increase of interfacial adhesion and the reduction of domain size of dispersed phase in PP/nylon blend system. To confirm the existence of this network structure, we measured a dynamic rheological properties.
High Molecular Weight Poly(L‐lactide) and its Microsphere Synthesized in the Supercritical Dimethyl Ether
Authors: Yoon Cheol Soo , Park Hyun Deok , Kim Se Yoon , Kim Soo Hyun 
Published: March 2007

AbstractThe ring‐opening polymerization of L‐lactide initiated by stannous octoate was carried out in supercritical dimethylether(scDME) at various reaction conditions (time and temperature). The monomer conversion increased to ca. 90% on increasing the reaction time to 1hr. The molecular weight of the poly(L‐lactide)(PLLA) also increased to ca. 160,000 g · mol−1 over the same period. Increasing reaction temperature from 118 to 135 °C or reaction pressure from 280 to 520 bar resulted in increased monomer conversion and molecular weight. After the polymerization, PLLA microspheres were prepared in situ by using a continuous supercritical anti‐solvent process without residual organic solvent.
Rheological Properties of Starch‐Based Materials and Starch/Poly(lactic acid) Blends
Authors: Xie Fengwei , Xue Tao , Yu Long , Chen Ling , Li Xiaoxi , Zhang Ximei 
Published: March 2007

AbstractThe rheological properties of pure starch and blends of gelatinized starch/poly(lactic acid) (PLA) were studied using a rheometer incorporating a twin‐roll mixer and a single‐screw extruder. The mixer provides a useful and convenient tool to study the rheological properties and gelatinization processes of starch. The single‐screw extruder with a slit capillary die was used to measure shear stress and viscosity under different shear rates at different temperatures. Starch was shown to increase the shear viscosity of PLA. Methylenediphenyl diisocyanate (MDI) was used as a compatibilizer, and was distributed in different phases through controlled processing. The addition of MDI showed a stronger effect on rheological properties when it was distributed in the PLA phase prior to blending. Both the pure starch and blends showed a power law dependence of viscosity on shear rate.
Purification and Characterization of Poly(ethylene succinate) Hydrolase from the Mesophilic Fungus Aspergillus clavatus NKCM1003
Authors: Ishii Nariaki , Mitomo Hiroshi , Kasuya Ken‐ichi , Inoue Yoshio 
Published: March 2007

AbstractA poly(ethylene succinate) (PESu) hydrolase was purified from the culture supernatant of the PESu‐degrading fungus Aspergillus clavatus NKCM 1003, which was cultivated on a mineral medium containing PESu as the sole carbon source. The enzyme had a molecular mass of 57,000 Da and an isoelectric point of 5.6, and it was stable in the rage pH5‐8; the optimum pH was 7.0. Its PESu hydrolytic activity remained constant below 40 °C after incubation for 30 min. Liquid chromatography electrospray mass spectrometry analysis of enzymatic hydrolysates revealed that the major products are ES, ESE, SES, and ESES(S; succinate unit, E; ethylene glycol unit). This enzyme degraded not only PESu but also poly(3‐hydroxybutyrate) (P(3HB)) and its copolymers. Further, it showed high binding affinity to P(3HB). It was concluded that PESu hydrolase belongs to the class of P(3HB) depolymerases.
Synthesis of Hybrid Polyacetylene Gels Using Octafunctional POSS Initiator
Authors: Kim Kyung‐Min , Lim Jung‐Hyurk , Jang Nae‐Youn , Kim Sung‐Ryong 
Published: March 2007

AbstractHybrid polyacetylene gels having polyhedral oligomeric silsesquioxanes (POSS) moieties were prepared by polymerization of 2‐ethynylpyridine using octafunctional POSS as an initiator with changing the feed ratio of POSS to 2‐ethynylpyridine. The resulting black polyacetylene gels were not soluble in any organic solvents such as THF, chloroform, methanol, DMF, and acetone. The polyacetylene gels with higher mole ratio of 2‐ethynylpyridine to POSS show higher thermal stability because of the tight polymer network caused by high degree of polymerization. It is proposed that the tether structure between polyacetylene matrix and POSS cages was crucial to the great improvement in thermal stabilities of hybrid polyacetylene gels with POSS.
Thermal and Mechanical Properties of Carbon Fiber Reinforced Epoxy Composites Modified with CTBN and Hydroxyl Terminated Polyester
Authors: Park Jong‐Sung , Park Sung‐Sil , Lee Soo 
Published: March 2007

AbstractCarbon fiber reinforced epoxy composites toughened with carboxyl terminated acrylonitrile butadiene rubber (CTBN) and hydroxyl terminated polyester (HTP) were prepared by autoclave vacuum bag molding process. The influence of compositions and blending method with toughening agents on glass transition temperature (Tg) and impact energy of cured laminates was evaluated. To improve the blending capability, different pre‐treatment methods were adopted for CTBN and HTP. The toughness of the carbon fiber reinforced epoxy composite materials (C‐FRP) modified with HTP showed a maximum when the HTP contents was 3.1 wt%. In case of CTBN, the maximum was 5.7 wt%. In addition, the fracture surfaces of toughened epoxy resin were examined by scanning electron microscopy (SEM) and the morphology was also discussed in this study.
Preparation of Polypropylene Compatibilizer by Radiation Grafting and Its Effect on PP/Nylon 6 Blend
Authors: Jung Chan‐Hee , Choi Jae‐Hak , Lim Youn‐Mook , Jeun Joon‐Pyo , An Sung‐Jun , Kang Phil‐Hyun , Nho Young‐Chang 
Published: March 2007

AbstractThe polypropylene‐based compatibilizers, polypropylene‐g‐maleic anhydride (PP‐MAH), polypropylene‐g‐maleic anhydride/styrene (PP‐St/MAH), and polypropylene‐g‐acrylic acid (PP‐AA), were prepared by a high energy irradiation method. The compatibilizing effect of newly prepared graft copolymers on immiscible PP/Nylon6 blends has been studied by means of UTM, SEM and DSC techniques. The results indicate that PP‐MAH and PP‐ St/MAH are more effective compatibilizers for PP/Nylon6 blends than PP‐AA, and the compatibilizing effect on PP/Nylon6 blends depends on molecular structure of the compatibilizers and the composition of the blends.
Effects of High‐Intensity Ultrasound and Supercritical Nitrogen on PP‐MA Reactive Extrusion
Authors: Sohn Chang Hee , Shim Dong Chul , Lee Jae Wook 
Published: March 2007

AbstractThe reaction of polypropylene (PP) and maleic anhydride (MA) was successfully generated by imposition of ultrasonic energy during the mixing process of extrusion. The possibility of the various transformations by PP‐MA reaction became stronger under the sonicated supercritical fluid mixing. The properties of the compatibilizer and the nanocomposites as the final products in the presence of ultrasound and supercritical fluid nitrogen were properly obtained without the addition of any solvents or additives.
Improvement of Adhesion between Copper Layer and Polyimide Films Modified with Alkaline Potassium Permanganate and/or Alkali Surface Treatments
Authors: Lee Soo , Park Seong Sil , Lee Hong Kee 
Published: March 2007

AbstractThe adhesion strength of polyimide films were enhanced by treatment with alkali and/or alkaline potassium permanganate. No effect observered on the thermal decomposition as measured by TGA. The chemically modified PI film surface was then treated with a catalyst, coated with nickel by electroless plating, and a subsequent layer of electrolytically applied copper. Water contact angles on the treated PI surface were decreased. As surface roughness of treated PI films was increased, adhesion increased also. Even though the modified PI films had little decrease in their thermal properties, they demonstrated a maximum adhesion strength up to 837 gf/cm.
Rheological Investigation of the Effects of Introducing Diethylene Glycol on the Physical Properties of PVA Solutions and PVA Films
Authors: Chang Myung‐Hwan , Kim Byoung Chul 
Published: March 2007

AbstractThe effects of diethyl glycol (DEG) on the rheolgical properties of polyvinyl alcohol(PVA) solutions in dimethyl sulfoxide and on the physical properties of PVA films were investigated. DEG seemed to change the state of hydrogen bonding in the solutions and in the films. In the case of 6 wt% PVA solutions, incorporating DEG abruptly reduced shear viscosity if DEG content exceeded 30 wt% to PVA whereas a little decrease of them was observed in 12 wt% PVA solutions over the DEG content observed. Further, at the same DEG content 6 wt% PVA solutions showed a more notable increase of viscosity with time at a constant shear rate than 12 wt% solutions. Dynamic mechanical thermal analysis revealed that introducing DEG broadened the peak of tan δ curve and lowered the glass transition temperature of PVA. DEG imparted toughening effects to PVA film preferably in the range of 10 to 20 wt% to PVA.