bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metastable phase diagrams for simultaneous interpenetrating networks
Authors: Sperling Leslie H. , Mishra Vinay 
Published: March 2011

AbstractA metastable phase diagram for SIN and related compositions is constructed, using a net‐polyurethane‐inter‐net‐poly(methyl methacrylate) system as the model material. In addition, the thermodynamics of having small amounts of remaining monomer in the system was examined, with the conclusion that the partition coefficient for many such systems should be close to unity.
Preparation and use of diacetylene‐containing polyesters for studying deformation micromechanics in model polyester‐polyolefin blends
Authors: Casado Rosa , Lovell Peter A. , Stanford John L. , Young Robert J. 
Published: March 2011

AbstractA range of diacetylene‐containing polyesters have been prepared by polycondensation of terephthaloyl chloride with diacetylene diols of structure HO—(CH2)n—C≡C—C≡C—(CH2)n—OH, where n = 1, 2, 3, 4 and 9. The results from characterization of the polyesters by DSC and Raman spectroscopy are presented. The polyesters from the diols with n = 3 and n = 9 have melting points (Tm) of 186 and 88 °C, respectively, and cross‐polymerise under irradiation, but not thermally. These polyesters were blended with isotactic polypropylene (Tm = 167 °C) and the blends compression‐moulded into dumbbell specimens, which then were exposed to 60Co γ‐radiation to effect cross‐polymerization of the polyester phases. The dumbbell specimens were subjected to simultaneous tensile testing and resonance Raman spectroscopy, and the shift in wavenumber of the C≡C stretching band of the polydiacetylene crosslinks used to determine the local stress in the polyester phases independent of the overall applied stress, thereby facilitating determination of the efficiency of stress transfer in the blends.
Adsorbent‐filled polymeric membranes
Authors: Hwang Sun‐Tak 
Published: March 2011

AbstractAssuming three‐dimensional isotropy for the suspended particles of cubes or spheres in a polymer matrix, resistance models are developed for adsorbent‐filled polymer membranes. These are compared with the existing models in the literature and they agree very well. Monotonically increasing or decreasing permeabilities of composite membrane are well described by these models. The model calculations are compared with several experimental sets of data for alcohols and gases in the literature and proven to be very good. However, there are unexplained experimental observations of permeability behavior as the amount of fillers increase in polymer. Further studies are recommended to directly measure the zeolite permeabilities by measuring the actual throughput. This information is vital in interpreting the data of permeations and separations through filled membranes.
Some factors in membrane structures on permselectivity for organic liquid mixtures
Authors: Uragami Tadashi 
Published: March 2011

AbstractControl of permselectivity based on the structure of the microphase separation of graft copolymer membranes, improvement of ethanolpermselectivity by surface modification of polymer membranes, and enhancement of ethanol‐permselectivity with improvements in the membrane separation technique for aqueous ethanol solutions are discussed.
Electro‐optic applications of soluble polypyrrole
Authors: Kim Young Chul , Lee Jun Young , Kim Dong Young , Cho Hyun Nam , Kim Chung Yup 
Published: March 2011

AbstractThe optical transmittance of the film spin‐cast from the polypyrrole(PPy) solution in chloroform depended on the thickness of the film. The film with 80% transmittance showed a surface resistivity of 23kΩ/□. A TN‐LCD cell with rubbed PPy films as the LC alignment layers responded properly to an applied potential of 3.0V. Reflective mode cholesteric LCD cells made with black PPy film electrodes responded to AC fields to switch between the planar and focal conic states. PPy with imine structures introduced by deprotonation of doped PPy with NaOH solution was used as a diode material to exhibit a photo‐current on exposing to light.
Light‐emitting properties of mono‐substituted ppv derivatives
Authors: Shim H. K. , Kang I. N. , Hwang D. H. , Jung J. S. , Jin J. I. , Zyung T. 
Published: March 2011

AbstractMono‐substituted PPV derivatives were synthesized through the watersoluble or the organic soluble precursor methods and their optical properties were characterized. The EL devices were fabricated with mono‐substituted PPV derivatives as emitting polymers, and ITO and aluminum as a positive and a negative electrode, respectively. Operating voltages of these devices ranged from 10 to 20 V, and emitting peaks were at about 540 ‐ 590 nm depending on the polymers. Photoluminescence of mono‐substituted PPV derivatives were also studied.
Synthesis of fullerenol‐derived elastomers and conductive elastomers
Authors: Chiang Long Y. , Wang Lee Y. , Kuo C. S. , Lin J. G. , Huang C. Y. 
Published: March 2011

AbstractUtilization of polyhydroxylated C60 in a condensation reaction with diisocyanated oligo(tetramethylene oxide) led to the successful fabrication of elastomeric poly(urethane‐ether) networks. These polymer networks exhibit interesting thermal behavior at low temperatures, improved tensile strength and elongation at ambient temperatures, and enhanced thermal mechanical stability at high temperatures. Design of conducting elastomers was made by carrying out an in situ polymerization of conductive polymer precursors in an interpenetrating fashion at the near‐surface of polyhydroxylated C60‐hypercrosslinked elastomers. Results demonstrated that elastomers with an appreciable conductivity while retaining desirable elastic properties of the network can be achieved. The room‐temperature conductivity of polyaniline interpenetrated (IPN) conducting elastomer was found to be 2.0 Scm−1. The tensile strength and elongation at break of one conductive IPN elastomer was found to be 20 MPa and 480%, respectively. Interestingly, the strain dependent conductivity of these conducting elastomers was found to increase progressively above 200% of elongation. These results demonstrated, for the first instance, conductivity measurements of organic conducting elastomers at an elongation length of higher than 300%, showing a r.t. conductivity of >4.0 Scm−1.
Photoregulation of the optical properties of comb‐shaped polymers with mesogenic side groups
Authors: Shibaev Valery , Kostromin Sergey , Ivanov Sergey 
Published: March 2011

AbstractA new approach for photoregulation of supramolecular structure and optical properties of polyacrylic copolymers bearing azobenzene and cyanobiphenyl mesogenic groups is presented. The detailed study of photooptical behaviour, kinetics of photoinduced optical birefringence and mechanism of structural transformations taking place during a laser illumination are discussed.
Relationship between alignment layer polymer surface structures and liquid crystal display parameters
Authors: Lee Kang‐Wook , Lien Alan , Paek Sang‐Hyon , Durning Christopher , Fukuro Hiroyoshi 
Published: March 2011

AbstractThe polar alignment layer (AL) surface provided relatively small liquid crystal (LC) pretilt angles while polyimides with long alkyl side chains gave relatively large LC pretilt angles. The results suggest that LC pretilt angles, in addition to an anchoring effect, are greatly affected by both electronic and steric interactions between LC molecules and a polyimide alignment layer surface. Rubbing with a cotton cloth induces functional groups, side chains, and repeat units at the surface of a liquid crystal polyimide AL to re‐orient. It was discovered that rubbing induced polar functional groups and repeat units to re‐orient out‐of‐the‐plane of the surface, and it made non‐polar aliphatic side chains partially re‐orient inwards, toward the bulk of the film.
Highly efficient and thermally stable second‐order nonlinear optical polymers
Authors: Lee Kwang‐Sup 
Published: March 2011

AbstractSeveral functionalized polyurethanes with highly active nonlinear optical chromophores were prepared. The alignment of the chromophores in poled samples exhibited an extended temporal stability due to the hydrogen bonding between the urethane linkage. Thermally stable polyetherimides with an excellent long‐term stability of nonlinear activity were also developed. The detailed characterization, including thermal and optical properties, indicated very promising features for photonics applications of these polymers.
Photoinduced electron transfer in photozyme systems
Authors: Guillet James E. , Burke Nicholas A. D. , Nowakowska Maria 
Published: March 2011

AbstractPhotozymes are novel water‐soluble polymers usually constructed by copolymerization of a mixture of water‐soluble and water‐insoluble comonomers, some of which contain chromophores capable of absorbing light and transmitting the excitation energy by means of the antenna effect to selected traps. The interactions between the hydrophobic and hydrophilic groups in the polymer with water cause the formation of hypercoiled pseudomicellar conformations of the polymer coil, leading to hydrophobic regions or pockets in the interior of the macromolecular coil. If the water contains hydrophobic organic molecules, they will locate preferentially in these hydrophobic polymer microdomains, and in the presence of light they can be photochemically transformed into useful products with high efficiency and selectivity. This paper reviews some recent results on photochemical reactions initiated by photoinduced electron transfer in these novel systems, and their possible commercial applications to pollution abatement, and solar production of hydrogen from water.
Conjugates of stimuli‐responsive polymers and biomolecules: Random and site‐specific conjugates of temperature‐sensitive polymers and proteins
Authors: Hoffman Allan S. , Stayton Patrick S. , Shimoboji Tsuyoshi , Chen Guohua , Ding Zhongli , Chilkoti Ashutosh , Long Cindi , Miura Morikazu , Chen Jingping , Park Taegwan , Monji Nobuo , Cole Carol‐Ann , Milton Harris J. , Nakamae K. 
Published: March 2011

AbstractIntelligent polymers exhibit sharp, reversible phase changes in response to small changes in environmental conditions. For example, a small temperature change can cause a sharp precipitation or gelation of a smart polymer solution. Conjugation of these unusual polymers to biomolecules such as enzymes, ligands, lipids, and drugs can lead to many new and exciting applications in medicine and biotechnology. (1–4) This presentation reviews the principles, methodolgies and applications of these “smart” polymer‐biomolecule systems, with special focus on temperature‐sensitive polymer‐protein conjugates.
Interactions of proteins and cells on functional group gradient surfaces
Authors: Lee Jin Ho , Khang Gil Son , Lee Jin Whan , Lee Hai Bang 
Published: March 2011

AbstractCharge gradient and comb‐like polyethylene oxide (PEO) gradient surfaces were prepared on low density polyethylene (PE) sheets by corona discharge treatment with gradually increasing power and the following graft copolymerization of chargeable functional group‐ and PEO‐containing vinyl monomers, respectively. Those gradient surfaces were used to investigate protein or cell interactions in relation to the surface functional groups and their density of polymeric materials.
Polymeric carriers of drugs for site‐specific therapy
Authors: Ulbrich Karel , Pechar Michal , Strohalm Jiři , Šubr Vladimír , říhová Blanka 
Published: March 2011

AbstractThree types of water‐soluble polymeric drug carrier systems facilitating targeted drug delivery and controlled drug release were synthesized. All systems consist of an inert soluble synthetic polymer, drug and homing device (targeting moiety). In the first “classical” system, both drug and targeting moiety are bound to a nondegradable polymer by means of biodegradable oligopeptide side chains statistically distributed along the polymer chain. The second, “star‐like” system contains a targeting moiety (antibody) in the centre and a hydrophilic polymer, bearing drug molecules, in the shell of the system. The third, “biodegradable” carrier system is based on block copolymers of poly(ethylene glycol) containing biodegradable oligopeptide sequences both in the main polymer chain and in the spacers between main chain and drug molecules. Strategy and details of the synthesis of all three systems are given.
Multifunctional polymeric materials for biomedical applications
Authors: Solaro Roberto , Chiellini Elisabetta E. , Giannasi Donatella , Morganti Fabrizio , Chiellini Emo 
Published: March 2011

AbstractThe work performed by our research group during the last few years in the area of bioerodible‐biodegradable polymers as designed to the formulation of systems for the controlled delivery of drugs and as specific sorbents of uraemic toxins is broadly reviewed. In particular, attention has been focused on the strategies adopted in the preparation of functional polymers containing hydroxyl or carboxyl groups, suitable to establish specific bonding and non‐bonding interactions with conventional and proteic drugs.
Syntheses and antitumor and anti‐aids activities of polymers containing pyrimidine derivative
Authors: Choi Won‐Moon , Lee Neung‐Ju , Lee Young‐Woo , Ha Chang‐Sik , Cho Won‐Jei 
Published: March 2011

AbstractThe new monomer, 5'‐O‐methacryloyl‐3'‐azido‐3'‐deoxy‐thymidine (MAZT), was synthesized from methacryloyl chloride (MAC) and 3'‐azido‐3'‐deoxythymidine (AZT). Poly(MAZT), poly(MAZT‐co‐AA) and terpoly(MAZT‐FUR‐MAH) were synthesized by radical polymerizations. The average molecular weights of synthesized polymers were in the range of 8,800 ∼23,000 depending on polymers. The in vivo antitumor activities of polymers at 800mg/kg were increased in the following order: terpoly(MAZT‐FUR‐MAH) >x poly(MAZT‐co‐AA) > poly(MAZT) > AZT > 5‐FU. The in vitro anti‐HIV activities of synthesized polymers were less effective than those of AZT and D4T. But the cytotoxicities of the polymers on the MT‐4 cell line were found to be much less toxic than AZT.
Synthesis and drug controlled release of block copolymers of poly(l‐lactide) with poly(d, l‐lactide) and related monomers
Authors: Feng Xin‐De , Jia Yan 
Published: March 2011

AbstractFour types of new biodegradable block copolymers AB, ABA, AC and AD, where A is poly(L‐lactide) (PLLA), B is poly(D, L‐lactide) (PDLLA), C is poly(p‐dioxanone) (PDON) and D is poly(ϵ‐caprolactone) (PCL) with different block lengths were synthesized and characterized by GPC, IR,1H‐NMR and DSC. There are phase‐separated and biodegradable block copolymers. Theirin vitrobiodegradation rates with the change of composition ratio were studied as well as the biodegradation rates of homopolymers with the series as PDON > PDLLA > PLLA in parallel with their crystallinities, i.e. from amorphous to semicrystalline. All these block copolymers were used as matrix to test their controlled release behavior of levo‐norgestrel (LNG) in the form of microspheres through solvent evaporation preparation with thoroughly long‐time washing to minimize the generally occurring bursting effect. As a result all of them showed almost constant rate of release even from the initial stage,
Synthesis and properties of tocopherol‐containing polymeric vesicle systems
Authors: Cho Iwhan , Kim Young‐Dae 
Published: March 2011

AbstractTwo different tocopherol‐containing amphiphilic monomers, [ [ (tocopheryloxy)‐carbonyl ]‐methyl ] [ 2‐(methacryloyloxy)ethyl ]dimethyl‐ammonium chloride(3a) and [[ (tocopheryloxy)penta(ethoxy)carbonyl ]methyl ]2‐(methacryloyloxy)ethyl]dimethylammonium chloride(3b), were synthesized and polymerized. The formation of polymeric closed vesicles having diameters ranging from 200 to 5200 Å was confirmed by electron micrographs, entrapment of [14C]sucrose, permeability measurements and gel filtration. The polymeric vesicles showed reduced permeability and enhanced thermodynamic stability. Antioxidative activities were determined by the thiocyanate method confirming that polymeric tocopherols also exhibited significant activities.
Surface polymerization of poly(γ‐alkyl‐l‐glutamate) on solid substrates
Authors: Chang Ying‐Chih , Frank Curtis W. 
Published: March 2011

AbstractSurface polymerization of poly(γ‐methyl‐L‐glutamate) and a copolymer of γ‐methyl and γ‐stearyl‐L‐glutamate are conducted on aminopropyl triethoxysilane modified silicon(100) native oxide substrates. The film formation is monitored by X‐ray photoelectron spectroscopy, and the conformation and orientation of surface‐bound polypeptides are characterized by transmission Fourier transform infrared spectroscopy. Both films are formed as β‐sheet material, and the film orientations are tilted from the solid substrate.
Multiple morphologies of amphiphilic diblock copolymer micelles in two and three dimensions
Authors: Clarke Chris J. , Zhang Lifeng , Zhu Jiayi , Yu Kui , Bruce Lennox R. , Eisenberg Adi 
Published: March 2011

AbstractWe show that in aqueous solution, diblock copolymers, where one block is hydrophobic and the other hydrophilic can undergo self‐assembly in three dimensions in a manner similar to small molecule amphiphiles. In addition, two dimensional self‐assembly has been studied at the air‐water interface. We describe the various morphologies which have been observed in these systems and the parameters which we can use to tailor them.
Preparation and characterization of multilayered structures with polyconjugated systems
Authors: Bolognesi Alberto , Bajo Giuseppe , Mazza Stefano 
Published: March 2011

AbstractSoluble poly(3‐alkylthiophenes) can be conveniently tailored by the introduction of polar groups in the side chain with the aim of obtaining structures able to give multilayered films with the Langmuir Blodgett technique. The films, uniform in thickness, show orientation of the polyenic backbone in the dipping direction as detected by UV‐visible measurements in polarised light. These materials can be conveniently used in electronic device preparation.
Small angle x‐ray analysis of the effect of temperature on the self‐assembling columnar structures formed by a polymethacrylate with highly tapered side groups and by one of its low molar mass precursors
Authors: Chvalun S. N. , Blackwell J. , Kwon Y. K. , Percec V. 
Published: March 2011

AbstractSmall angle X‐ray methods have been used to investigate the self‐assembling columnar structures formed by a polymethacrylate with large highly tapered side groups, and by one of its low molar mass precursors. The polymer is poly{2‐{2‐[2‐(2‐methacryloyloxyethoxy)ethoxy] ethoxy}ethyl‐3, 4, 5‐tris(p‐dodecyloxybenzyloxy)‐benzoate} (H12‐ABG‐4EO‐PMA); the precursor is 2‐{2‐[2‐(2‐hydroxyethoxy)‐ethoxy]ethoxy}‐ethyl‐3, 4, 5‐tris(p‐dodecyl‐oxybenzyloxy)benzoate (H12‐ABG‐4EO‐OH). Both the polymer and the precursor form three dimensionally ordered structures at room temperature, consisting of hexagonally packed cylinders with diameters in the region of 60 and 53Å, respectively, in which the interiors of the columns probably have helical arrays of the stacked tapered groups. At higher temperatures these are converted to columnar hexagonal (ϕh) liquid crystalline phases. At temperatures close to this transition for the precursor we detect two coexisting columnar structures, with the ϕh structure having a diameter approximately 1Å higher than that in the solid state. For the polymer, the data are not so well resolved, and coexisting phases cannot be resolved. However, the changes in column dimensions are larger than for the precursor. Conversion of the room temperature phase to the ϕh phase at 40°C results in an increase of 3Å in the diameter, which then declines by approximately the same amount as the temperature rises to 90°C, close to the isotropization point. Cooling to room temperature does not immediately restore the room temperature structure. Rather, we obtain a quenched ϕh structure, with a column diameter almost 10% higher. These dimensional changes correlate well with the changes in diameter with temperature seen for the bulk fiber, and suggest a continuous rearrangement of the interiors of the columns in the ϕh phase, such as a partial unwinding of a disordered helical structure.
Analysis of the conformation of wormlike chains by combination of small‐angle x‐ray and small‐angle neutron scattering
Authors: Hickl Peter , Ballauff Matthias 
Published: March 2011

AbstractAn analysis of the conformation of a wormlike polymer by small‐angle scattering is presented. By a combined investigation of small‐angle X‐ray and of small‐angle neutron scattering the effect of the finite size of the repeating units can be eliminated. The procedure suggested herein therefore allows to obtain the scattering function for a respective infinitely thin chain. The latter quantity is compared to current models of the scattering function of wormlike chains.
Supra‐assembled membranes for optical resolutions
Authors: Ogata Naoya 
Published: March 2011

AbstractOptical resolutions through self‐assembled membranes were carried out by using poly(pyrrole) (PPy) doped with chiral anionic polymers such as poly(L‐glutamic acid) or dextran sulfonic acid. Preferential permeations of either L‐ or D‐Tryptophane occurred through the PPy membranes.
Environmental interaction of polymers‐natural metabolites as opposed to the degradation products of synthetic polymers
Authors: Albertsson Ann‐Christine , Karlsson Sigbritt 
Published: March 2011

AbstractNatural polymers degrade by a three‐step catabolism and each step generates well‐known metabolites. Detoxication transforms harmful compounds to less harmful ones by the action of microorganisms. Low concentration of degradation products may biomagnify and reach levels that have deleterious effects on humans, animals and plants. The prediction of the environmental interaction of polymers needs knowledge not only about the toxicity of the degradation products but also of the degree of exposure of the living cells to the degradation products.
Modified amylose biodegradability by α‐amylases
Authors: Roesser David S. , Gross Richard A. , Mccarthy Stephen P. 
Published: March 2011

AbstractThe site‐selective syntheses of water‐soluble (O‐2/O‐3)‐substituted amylose derivatives containing butyl ester, carboxymethyl, succinyl or quaternary ammonium side groups was carried out. In addition, routine chemical methods which did not employ protection‐deprotection steps provided water soluble (O‐2/O‐3/O‐6)‐substituted products. The biodegradation of these products as a function of site‐of‐substitution and degrees of substitution (ds) was studied by the α‐amylases from Aspergillus oryzae and Bacillus subtilis. Consistent with the results reported previously for acetyl amylose (Ref. 1), the O‐2/O‐3 substituted butyl amylose derivatives degraded faster and to higher percentages than the corresponding O‐2/O‐3/O‐6 substituted derivatives. Also, the overall rates and percentages of degradation for butyl amylose were much lower than acetyl amylose derivatives of comparable degree and site of substitution. Therefore, for the two enzymes studied, the introduction of longer chain length acyl side groups greatly reduced substrate degradability. For the charged derivatives, the rate and percentage of degradation decreased in the order carboxymethyl > succinyl > quaternary ammonium at comparable degree and site of substitution. We concluded that, as the length of the charged side chain substituent increased, the rate and extent of biodegradation decreased. Furthermore, in contrast to the results for neutral acetyl and butyl side groups, there was no significant difference in the rate and %‐degradation for charged side chain substituent groups when comparing O‐2/O‐3 and O‐2/O‐3/O‐6‐substituted derivatives. Finally, the introduction of anionic or cationic side chain groups resulted in decreased susceptibility to α‐amylase catalyzed chain cleavage when compared to similarly substituted acetyl and butyl amylose derivatives.