bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydroboration, haloboration and phenylboration polymerizations
Authors: Chujo Yoshiki
Published: March 2011

A polyaddition between diene and monoalkylborane produced a polymer consisting of C‐B bonds in the main chain. The resulting organoboron polymers can be used as a novel type of reactive polymers. On the other hand, hydroboration polymerization of dicyano compounds produced air‐stable poly(cyclodiborazane)s having B‐N four‐membered rings via dimerization of iminoborane species. Poly(organoboron halide)s were prepared either by haloboration polymerization between diynes and boron tribromide or by hydroboration polymerization of dienes with monobromoborane. Furthermore, phenylboration polymerization of diynes or diisocyanates gave new organoboron mainchain polymers.
Synthesis and properties of polyamides containing imidazoline rings
Authors: Chen Leo‐Wang , Kuo Yao‐Hsing
Published: March 2011

The novel polyamide containing an imidazoline ring(PAI) was synthesized by a two‐stage melt polymerization of dimethyl terephthalate (DMT) with diethylenetriamine (DETA) or triethylenetetramine (TETA). The heat resistance of PAI was superior to that of polyamide which was synthesized only in the first‐stage reaction and didn't contain imidazoline ring. Their chemical structures were identified by infrared spectroscopy and NMR. The optimum condition for production was studied by varying several reaction factors, including the contents of H2O and H3PO4, the reaction temperature and the reaction time at second‐stage reaction under vacuum. According to study of the characteristics of solution behavior of PAI, both the viscosity and the degree of cyclization could be described by equation of magnified image in m‐cresol at 30°C.
Syndiospecific polymerizations of styrene with siloxane‐bridged dinuclear titanocenes and mao catalyst systems
Authors: Lee Dong‐Ho , Yoon Keun‐Byoung , Noh Seok‐Kyun , Woo Sang‐Sun
Published: March 2011

The syndiotactic polymerizations of styrene are carried out with dinuclear titanocenes such as tetramethyldisiloxanediylbis(cyclopentadienyltitanium trichloride), Cl3Ti‐CpSi(CH3)2‐O‐Si(CH3)2Cp‐TiCl3 (1), hexamethyltrisiloxanediylbis(cyclopentadienyltitanium trichloride), Cl3Ti‐CpSi(CH3)2‐O‐Si‐(CH3)2‐0‐Si(CH3)2Cp‐TiCl3 (2) and hexamethyl‐trisiloxanediylbis(dicyclopentadienyltitanium dichloride), Cl2CpTi‐CpSi(CH3)2‐O‐Si‐(CH3)2‐O‐Si(CH3)2Cp‐TiCpCl2 (3) in the presence of modified methylaluminoxane (MMAO). Although the catalyst activity of dinuclear titanocenes is lower than that of the corresponding mononuclear titanocenes CpTiCl3 and Cp2TiCl2, the former produce polystyrene of higher weight‐average molecular weight and higher syndiotactic index than the latter. Among the dinuclear titanocenes examined, 2 has the largest catalyst activity. In addition, the copolymerizations of styrene and ethylene are carried out with 2.
Toward uniform polymer architecture through stereospecific living polymerization and chromatographic separation technique
Authors: Hatada Koichi , Nishiura Takafumi , Kitayama Tatsuki , Ute Koichi
Published: March 2011

Isotactic (it‐) and syndiotactic (st‐) poly(methyl methacrylate)s (PMMAs) were fractionated into uniform PMMAs (without molecular weight distribution) by supercritical fluid chromatography (SFC). The SFC technique was applied to the isolation of uniform it‐ and st‐PMMAs with a hydroxy group (it‐ and st‐PMMA‐OH) at the chain end. Equimolar amounts of uniform it‐ and st‐PMMA‐OHs were coupled with sebacoyl dichloride to form uniform stereoblock PMMA. The reaction of uniform st‐PMMA‐OH with methacryloyl chloride gave uniform PMMA macromonomer with methacryloyl group at the chain end. The resulting uniform macromonomer was polymerized radically and the products were fractionated into uniform comblike polymers (1mer to 4mer) by means of gel‐permeation chromatography (GPC). The uniform st‐PMMA‐OH was reacted with 1, 3, 5‐benzenetricarbonyl trichloride to form uniform st‐tri‐armed star polymer. Some of the properties of these uniform stereoregular polymer architectures were studied.
Synthesis of gel type dispersion polymers via living dispersion polymerization (LDP)
Authors: Kim Kwang Ung , Kim Jungahn , Ahn Young Hye , Im Sung Soon
Published: March 2011

A gel type disperse polystyrene/divinylbenzene (DVB) copolymer was successfully prepared in hydrocarbon via ‘living dispersion polymerization (LDP)’ method. Characterization of the dispersed polymers was performed by a combination of size‐exclusion chromatographic and transmission electron microscopic analyses. Poly(t‐butylstyryl)lithium with 3,5 × 104 g/mol of molecular weight was used as a steric stabilizing moiety in the living dispersion polymerization. The particle size of the dispersed polymers was able to be controlled by both the mole ratio of the concentration of poly(t‐butylstyryl)lithium to n‐butyllithium and the amount of monomer to over 2 μm.
Radical/cation transformation polymerization and its application to the preparation of block copolymers
Authors: Kamachi Mikiharu , Guo Hai‐Qing , Kajiwara Atsushi
Published: March 2011

p‐Methoxystyrene (MOS), butyl vinyl ether (BVE), and N‐vinylcarbazole (VCZ) were polymerized in high yield by azoinitiators such as 2, 2'‐azodiisobutyronitrile (AIBN) in the presence of electron acceptors such as Ph2I+PF6−. An electron paramagnetic resonance (ESR) study of the model radicals of the propagating radical showed the transformation of the radical to the corresponding cation in the presence of the electron acceptors. In the case of BVE, the polymer formation was caused by cationic species produced by the transformation of the initiating radical. The polymerizations of MOS and VCZ were ascribed to the transformation of the growing radical to the corresponding cation during the propagation step which was classified as the radical/cation transformation polymerization. Block copolymers of MOS/cyclohexene oxide (1, 2‐epoxycyclohexane) (CHO) and VCZ/CHO were effectively prepared by the radical/cation transformation polymerization of the appropriate monomers in the presence of AIBN, electron acceptor and CHO. The formation of block copolymers was characterized by turbidimetry, thin‐layer chromatography, and solubility tests.
Preparation of copoly(amide‐imide)s via direct polycondensation
Authors: Choi Kil‐Yeong , Hong Young‐Taik
Published: March 2011

Preparation of various kinds of copoly(amide‐imide) was carried out via direct polycondensation of trimellitic anhydride (TMA) with the corresponding diamine mixture in the presence of an equimolar amount of thionyl chloride (TC) as a condensing agent followed by thermal imidization. The resulting copoly(amide‐imide)s had inherent viscosities in the range of 41 to 68 mL g−1 and glass transition temperatures of 215°C to 291°C. These copoly(amide‐imide)s had relatively good thermomechanical properties. That is, the initial decomposition temperature (IDT) and tensile strength were 350–409°C and 104–121 MPa, respectively. The melt viscosities of the copoly(amide‐imide)s measured at 345°C under a frequency of 102 rad s−1 were in the range of 4.8 × 102 ∼ 4.5 ˜ 103 Pa s depending on comonomers, which are somewhat lower than that commerciallized PAI with 5.6 × 103 Pa s.
Controlled macromolecular synthesis by the nucleophile/lewis acid binary systems
Authors: Aida Takuzo , Takeuchi Daisuke , Sugimoto Hiroshi , Inoue Shohei
Published: March 2011

Amphiphilic initiator systems consisting of bulky nucleophiles as propagating species and bulky electrophiles (Lewis acids) as monomer activators bring about high‐speed living anionic polymerization of polar vinylic and heterocyclic monomers to give narrow molecular weight distribution (MWD) polymers.
Partially imidized poly[(amic ester)‐alt‐imide]: A novel polyimide pregursor
Authors: Lee Myong‐Hoon , Park Jiwoong , Rhee Suh Bong
Published: March 2011

Partial imidization of poly[(amic ester)‐alt‐(amic acid)], a precursor for the “strictly alternating” copolyimides, was performed via selective chemical imidization of amic acid units in the copolymer precursor. The resulting, poly[(amic ester)‐alt‐imide], showed superior properties such as an excellent solution stability, good processibility and improved optical transparency, which are essential for the use as a precursor for the polyimide.
Formation, structure and properties of polymer networks
Authors: Dutton S. , Stepto R. F. T. , Taylor D. J. R.
Published: March 2011

The systematic study of intramolecular reaction and gel points together with measurements of moduli of trifunctional and tetrafunctional end‐linked networks show that gel points are always delayed and network imperfections always result from the intramolecular reaction which must occur when such networks are formed. The quantitative interpretation and prediction of gel points and moduli directly from reactant structures and reaction conditions are discussed.
Relationship between structure and conformation in liquid crystalline polymers
Authors: Hardouin F. , Lecommandoux S.
Published: March 2011

Our studies on the nematic phase of different kinds of thermotropic liquid crystalline polymers tend to focus on the following question: what about the anisotropy of the backbone conformation in the orientational medium imposed by its mesogenic groups ? By means of small angle neutron scattering (SANS) different features are qualitatively and quantitatively discussed. In the case of liquid crystal side chain polymers, the chain anisotropy is essentially driven by thermodynamical, structural and chemical considerations. In addition, in the case of liquid crystal main chain polymers, hairpin defects are observed for sufficiently long polymers.
Structure evolution and properties in a rigid polyimide prepared from its flexible poly(amic acid) precursor
Authors: Ree Moonhor , Woo Sung Ho , Shin Tae Joo , Kim Kyungjun , Chang Heesook , Zin Wang Cheol , Lee Ki‐Bong , Park Yong Joon
Published: March 2011

Soluble poly(p‐phenylene biphenyltetracarboxamic acid) precursor was converted to the polyimide by thermal imidization at various conditions. The structure evolution being occurred during its thermal imidization over 25–400°C was investigated as a function of imidization temperature and time by X‐ray scattering with synchrotron radiation sources of Pohang Accelerator Laboratory in Korea and with conventional radiation sources. In addition, properties in the polyimide films were investigated by dynamic mechanical thermal analysis, stress‐strain analysis, prism coupling, and residual stress analysis.
Fluorescence study on dynamics of liquid‐crystalline polymers
Authors: Horie Kazuyuki , Huang Hsuwen
Published: March 2011

Fluorescence measurements of various main‐chain liquid‐crystalline (LC) polyesters, poly[oxybiphenyl‐4, 4'‐diyloxy(2, 5‐dihexadecyloxy)‐1, 4‐pyromellitoyl] (B‐C16), poly[(ethylene terephthalate)‐co‐(p‐oxybenzoate)] (PET40/OBA60), poly(oxybiphenyl‐4, 4'‐diyloxy‐1, 10‐decanedioyl) (PB‐10), low‐molecular‐weight LC bis(p‐hexyloxyphenyl) terephthalate (PP6), and a lyotropic LCP, poly(sulfo‐1, 4‐phynelene 3'‐nitroterephthalate) (PSPNT), were carried out to investigate their dynamics and intermolecular interaction changes.
Structure and thermodynamics of polymeric liquids: Polymer kirkwood integral equation method
Authors: Gan Hin Hark , Eu Byung Chan
Published: March 2011

A statistical mechanical theory is employed to predict the structural and thermodynamic properties of polymeric liquids. The theory consists of a coupled set of self‐consistent integral equations for the pair correlation functions which relates the polymer structure to molecular interaction potentials. In this article, the essentials of the method are reviewed and the results are shown in comparison with other theories and simulation data. Quantitative agreements are found between the results of the theory and those of the simulations for a wide range of density and temperature.
High performance liquid chromatography characterization of macromolecules
Authors: Chang Taihyun , Lee Hee Cheong , Lee Wonmok
Published: March 2011

A new method, temperature gradient interaction chromatography(TGIC) is employed for the characterization of macromolecules. Fine and reproducible control of interaction between polymer chains and the alkyl chain bonded silica packing material can be achieved by varying the temperature of the column. This method provides a far superior resolution to the conventional size exclusion chromatography. In addition, this method has a high sample loading capacity to be effective for preparative purpose. Furthermore, this method can be used to characterize binary polymer mixtures, where one component of a polymer mixture is separated by the size exclusion mechanism and the other is by the interaction mechanism simultaneously from single isocratic elution.
The thermal behaviors of latexes: Wet latex glass transition temperatures
Authors: Lee Do Ik , Walker Lynn C. , Kan Charles S.
Published: March 2011

The thermal behaviors of latexes were studied by using MicroCal MC‐2 Scanning Calorimeter which is a differential scanning micro‐calorimeter capable of handling fluids under pressure. The MC‐2 unit was found to be uniquely capable of measuring not only the glass transition temperatures (Tg's) of wet latexes, but also the extent of annealing (enthalpy relaxation) that has a profound impact on the deformability of latex particles and, in turn, the film formation of latexes. The effects of polar monomers, the neutralization of carboxylated latexes, and coalescing agents on the wet latex Tg's were also studied.
Understanding the rheological behavior and processing of complex polymer systems from a molecular point of view
Authors: Han Chang Dae
Published: March 2011

The rather complex rheological behavior of block copolymers and thermotropic liquid‐crystalline polymers is illustrated, putting emphasis on transient shear flow and stress relaxation behavior.
Polymer processing research in industry: Role of academic‐industrial cooperation for fundamental research
Authors: Hyun Kun Sup
Published: March 2011

Understanding how polymers will process in such as extruders, injection molding machines, and dies can be met through academic‐industry cooperation. With declining R&D budgets and globalization of businesses, this cooperation is extremely valuable for continuing fundamental research in polymer processing and fabrication technologies. This paper illustrates some examples and suggests how industry can best benefit from these programs
Polyolefin alloys and blends
Authors: Utracki Lechoslaw Adam M.
Published: March 2011

Blends of polyolefins are reviewed from the perspective of a historic evolution of technology. Blends of polyethylenes, polypropylene, and ethylene‐propylene copolymers, with either a commodity, engineering or specialty resin, are discussed.
Metastable phase diagrams for simultaneous interpenetrating networks
Authors: Sperling Leslie H. , Mishra Vinay
Published: March 2011

A 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

A 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

Assuming 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

Control 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

The 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

Mono‐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

Utilization 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

A 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

The 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

Several 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

Photozymes 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

Intelligent 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

Charge 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

Three 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

The 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

The 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

Four 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

Two 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

Surface 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

We 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

Soluble 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

Small 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

An 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

Optical 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.
A new kind of ultrathin film—The assembly of amphiphilic polymer
Authors: Shen Jiacong , Li Hongbin , Xiong Huiming , Zhang Xi
Published: March 2011

Various organized behaviors of a new kind of amphiphilic polymer was investigated in organic solvents, at air‐water interface and in ordered cast film
Environmental interaction of polymers‐natural metabolites as opposed to the degradation products of synthetic polymers
Authors: Albertsson Ann‐Christine , Karlsson Sigbritt
Published: March 2011

Natural 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

The 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.
Polymer education in korea
Authors: Jung Jin Chul
Published: March 2011

The present article deals with the education on polymer science and technology in Korea. It starts first in Middle Schools with introduction of plastics as an industrial material and their classification into thermoplastics and thermosets. Korean university‐level polymer educations are conducted in 17 universities having separate polymer departments as well as in those without polymer departments. In the former intensive education on polymers is conducted and in the latter various polymer courses are independently offered in various departments, merely as electives.
Dielectric relaxation spectroscopy in poly(ethylene oxide)/water systems
Authors: Kyritsis Apostolos , Pissis Polycarpos
Published: March 2011

The dielectric properties of poly(ethylene oxide) (PEO) are studied by dielectric relaxation spectroscopy measurements in wide ranges of frequency (5–2×109 Hz) and temperature (193 − 300 K). PEO/water systems are also studied in a wide range of water content h (0 − 0.85 grams of water per grams of dry PEO). The measurements allow to distinguish between the dipolar secondary mechanism γ and effects related to free charge motion. The data are analyzed within the formalisms of permittivity, ϵ*, and electric modulus, M*. The water has been found to plasticize the dipolar process and to affect strongly the conduction process. A critical water content hc, hc = 0.13, has been found for the mechanism of charge transport.
Understanding polymers by vibrational spectroscopy: Some recent advances in theory and experiment
Authors: Meier Robert J.
Published: March 2011

A rapid‐scan version of 2D‐IR spectroscopy is introduced and applied to study the phases of an acrylonitrile‐butadienestyrene polymer system. Then, as the main part of this paper and in particular to stimulate further application in this field, some recent advances in the application of computational chemistry to the evaluation of vibrational spectra are presented. Some specific applications are discussed.
Polymers, additives, surfactants and their mixtures: Computer‐based search with special ftir libraries
Authors: Hummel Dietrich O.
Published: March 2011

This investigation was done with a PC of 850 MB/33 MHz, Windows 3.1 and the SPECTACLE program of LabControl/Cologne. The libraries contained standardized FTIR spectra of 3061 defined polymers, 530 industrial polymers and resins, 1969 additives (pigments, stabilizers, plasticizers etc.) 1190 surfactants and 1614 monomers, pyrolyzates and educts. For searches, the data density was reduced to 4/cm.

Similarity search with standardized full spectra yields quantitative dissimilarity figures; it allows an experimental definition of identity. The derivative functions 3 and 4 of Lowry and Huppler increase the gap between identical and similar spectra. With the LH2 algorithm spectra are defined as identical if their dissimilarity values are within 103. Since all organic matter has some spectral similarity the LH2 dissimilarity for organics will not go far beyond 105. ‐ The quality of IR preparation has a strong impact on search results. If a library contains spectra with false‐light, Christiansen effect, high noise or other artefacts, peak search yields better results than similarity search with full spectra.

Multicomponent systems can be searched successfully for their constituents with an algorithm combining peak and similarity searches. This algorithm is superior to all other algorithms if a library contains spectra with artefacts.
Evidence of electron acceptor ‐ electron donor interactions in thermoplastic polymer blends by using FTIR ‐ ATR spectroscopy
Authors: Brogly M. , Nardin M. , Schultz J.
Published: March 2011

Specific interactions in binary blends of ethylene/vinyl acetate copolymer (EVA) with various low molecular weight terpene‐phenol tackifying resins (TPR) were systematically investigated, as a function of the composition of the blend and of the electron‐acceptor ability of the resin, by using attenuated total reflection‐Fourier transform infrared (ATR‐FTIR) spectroscopy. Molecular acid‐base were evidenced between TPR hydroxyl groups and EVA carbonyl groups. Quantitative information on the fraction of acid‐base bonded entities, the enthalpy and the equilibrium constant of pair formation were obtained. A crystalline transition of the EVA copolymer is observed and is discussed in terms of enthalpy and entropy considerations based on FTIR and calorimetric differential scanning calorimetry (DSC) investigations. Fundamental results are then summarized in order to predict the interfacial reactivity of such polymer blends towards acid or basic substrates.
Applications of photoacoustic step‐scan FT‐IR spectroscopy to polymeric materials
Authors: Gregoriou Vasilis G. , Hapanowicz Rick
Published: March 2011

Thin coatings technology demands that characterization tools are readily available to distinguish between the composition and physical state of the coated layers versus the substrate. In principle, infrared photoacoustic spectroscopy (PAS) possesses all the appropriate features to become a mainstream technique for these types of characterizations. These features include the ability to characterize coatings of a variety of thickness (monolayers to tens of microns) and the fact that the technique requires virtually no sample preparation. One category of such samples involves systems having few micron thin layered structures coated on relatively thick polyester substrates. The phase delay of the photoacoustic signal can be used in conjunction with the knowledge of the thermal properties of the coated fluids in the calculation of the relative as well as the absolute depths of these multi‐layered coatings. The phase delay is calculated at wavelengths that are characteristic of the various components of the different layers in the system. The technique is applied to the characterization of a coated system having a submicron layer as the top layer. Step‐scan FT‐IR photoacoustic data are presented that prove the ability of the technique to successfully isolate the infrared signature of the top layer from the infrared spectrum of the bulk material, proving the sub‐micron resolution capability of the method. In addition, results will be shown that underline the fact that the most serious problem in PAS is saturation at high absorptivities.
Analysis of polymer mobility by fluorescence spectroscopy
Authors: Klopffer Marie‐Hélène , Bokobza Liliane , Monnerie Lucien
Published: March 2011

Fluorescence spectroscopy using an intramolecular excimer‐forming probe has been used to investigate chain mobility in various polybutadienes. The spectroscopic technique is completed by a rheological study carried out in order to identify the molecular parameters governing polymer dynamics. The temperature dependence of the correlation time of the probe motion can be fitted to a WLF equation which shows that the probe mobility reflects the glass transition phenomenon of the host matrix.
Mechanical spectroscopy study on biodegradable synthetic and biosynthetic aliphatic polyesters
Authors: Choi Hyoung J. , Kim Jung H. , Kim Jinho , Park Sung H.
Published: March 2011

Miscibility behavior and rheological properties with mechanical spectroscopy study of both poly(3‐hydroxybutyrate) (PHB)/poly(ethylene oxide) (PEO) and biodegradable synthetic aliphatic polyester (BDP)/linear low density polyethylene (LLDPE) were investigated. Blends of BDP with LLDPE were immiscible, showing two separate Tg values in all compositions; whereas blends of PHB with PEO were miscible, showing a single Tg in the whole range of compositions. However, the shear viscosities of both synthetic and biosynthetic blend systems decrease with increasing shear rate. When a modified Cole‐Cole plot of the blend system is further considered, the logG′‐logG” plot shows little sensitivity to a variation in both LLDPE composition for synthetic BDP and PEO composition for biosynthetic PHB. Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (P(3HB‐co‐3HV)) random copolymers were also investigated.
Infrared absorption spectra of polymers from classical molecular simulation
Authors: Soldera Armand , Dognon Jean‐Pierre
Published: March 2011

A method is proposed to predict the infrared spectra of amorphous polymers. Based on classical molecular simulation and Kramers‐Kronig relations, it allows the computations of absorption and transmittance spectra of polymer films in near and middle infrared domains with good agreement with experimental data.