bluuebunny/crossref_metadata_2025 huggingface dataset:
Approaches to deal with the issue of plastic packages and the environment
Authors: Miltz Joseph
Published: March 2011

Methods of treating the solid plastic waste are reviewed. The diffusion coefficients of toluene and benzyl alcohol in PET were determined from sorption experiments. For toluene, desorption (into water) experiments were also carried out and the diffusion coefficients were determined for various initial toluene concentrations in the polymer. The diffusion coefficients from the latter experiments were significantly lower than those determined from the sorption studies. In migration of toluene from the contaminated PET into water, a reduction of two orders of magnitude in the level of migration was achieved by sandwiching the contaminated PET between two layers of the virgin polymer. In another study, properties of Nylon 6/PE blends reprocessed at various shear rates were evaluated. The results showed that after minimum mixing of the blend obtained from a Nylon 6/PE laminate, the low oxygen permeability of the original film was preserved.
Food pollution by bilayer package with a recycled polymer: Effect of some parameters
Authors: Laoubi S. , Vergnaud J. M. , Mouffok B.
Published: March 2011

A way of recycling waste polymers consists in reusing them as new food packages. Because of potential contamination, bilayer packages are made with a virgin polymer located between the recycled polymer layer and the food. The virgin polymer layer plays the role of a functional barrier to contamination. Some emphasis is placed on the thickness of each polymer layer by keeping the thickness of the package constant as well as on the volume of food. The process of contaminant transfer is controlled by transient diffusion through the bilayer package and convection into the liquid food. A numerical model, predicting the kinetics of contaminant transfer in the food and the profiles of concentration of contaminant developed through the package, was elaborated. The thickness of the package is 0.03 cm and the volume of food around 730 cm3. The characteristics are those of polypropylene for packaging and olive oil for food. The effect of the volume of the food in liquid state on the kinetics of transfer is also considered.
Supramolecularly organized systems based on transition metal complexes with schiff's bases. Photo‐ and electrochemical activity
Authors: Shagisultanova Galina , Orlova Irina , Ardasheva Luydmila , Popova Elena
Published: March 2011

In the present paper we report about the last advances concerning the structure and properties of electrochromic photosensitive metallopolymers based on the complexes of Pt, Pd, Ni, Co, Cu with Schiff's bases. The criteria of selection of the object for the synthesis of new polymers with one‐dimensional, reversible, controlled photo‐ and electroinduced charge transfer was determined. A model for the polymer structure was proposed. The ohmic resistance in the direction parallel and perpendicular to the microelectrode surface of gold‐coated α‐Al2O3 differs as 1: 106‐109 depending on the polymer and film thickness. A qualitative model of the processes of light energy accumulation was proposed.
Liquid crystal polymers containing permanent dipole azobenzene chromophores
Authors: Altomare Angelina , Andruzzi Luisa , Ciardelli Francesco , Mader Michele , Tirelli Nicola , Solaro Roberto
Published: March 2011

Three photochromic monomers containing a permanent dipole photochromic azobenzene group spaced from the methacryloyl moiety by a polymethylene segment were synthesized in three steps starting from 4‐cyanoaniline. The monomers were homopolymerized and copolymerized with an optically active monomer, (‐)‐menthyl methacrylate, in the presence of AIBN as a radical initiator. Structurally similar amphiphilic polymers were obtained by homopolymerization of analogous methacrylates in which oligo(oxyethylene) segments replaced the polymethylene spacers. The polymeric materials, having a molar content of photochromic units between 5 and 100% and molecular weights of about 15,000, were characterized by thermal analysis, X‐ray diffraction, 1D and 2D NMR. Mobility and photochromic properties in solution were also investigated.
Photorecording in the “isotropic smectic phase” of dyed side chain polymers
Authors: Kozlovsky Mikhail V. , Haase Wolfgang
Published: March 2011

The “isotropic smectic” phase of chiral side chain polymers combines layered liquid crystalline ordering with macroscopic transparency and low light scattering without any pretreatment, thus providing considerable advantages for photo‐optical applications. Photoinduced birefringence in that mesophase of dye containing copolymers has been investigated.

A novel LCPT (Light Controlled Phase Transition) photorecording technique has been developed. The light intensity required for the method is as low as 0.3 mW/cm2, and both writing and reading of the image can be performed by nonpolarized light.
Influence of the substituent on azobenzene side‐chain polyester optical storage materials
Authors: Pedersen Marianne , Hvilsted SØRen , Holme Niels C.R. , Ramanujam P. S.
Published: March 2011

A number of poly(1,3‐propylenetetradecanedioates) or poly(1,3‐propyleneadipates) with pendant p‐substitued azobenzenes linked through a hexylene spacer in the 2‐position are prepared. The substituents comprise: cyano, nitro, methoxy, hydrogen, methyl, n‐butyl, phenyl, fluoro, trifluoromethyl, chloro, and bromo. 13C NMR spectroscopic and molecular mass investigations substantiate good film forming characteristics. The optical storage performance of thin polyester films are investigated through polarization holography. The resulting diffraction efficiency is mapped and discussed as a function of irradiation power and exposure time. Polytetradecanedioates with cyano‐, nitro‐, methyl‐, fluoro‐, or trifluoro‐methyl‐azobenzene reach more than 50% diffraction efficiency. Investigations of anisotropy induced at different temperatures reveal that the polyesters are only photosensitive in a narrow temperature range around Tg.
NMR observation of the conformations and motions of polymers confined to the narrow channels of their inclusion compounds
Authors: Shin I. Daniel , Huang Lei , Tonelli Alan E.
Published: March 2011

When polymers are guests in crystalline inclusion compounds (ICs) formed with small‐molecule hosts, they occupy a unique environment. In a cocrystallization process the small‐molecule host forms a crystalline lattice containing long narrow channels where the guest polymer chains are included. Because of the narrow channel diameter and because neighboring channels are separated by walls formed exclusively from the small‐molecule host lattice, the included polymer chains are highly extended and separated from polymer chains in other IC channels. As a consequence, polymer‐IC crystals provide a unique solid state environment for the included polymer chains and serve as models useful for assessing the contributions made by the inherent behavior of individual polymer chains to the properties of ordered, bulk polymers, which can be obscured by pervasive interactions between their tightly packed polymer chains. In this paper we describe the conformations and motions of polymer chains confined to the narrow channels of the following polymer‐ICs: i. polyethylene and trans‐1, 4‐polybutadiene in their ICs with perhydrotriphenylene, ii. polyepsilon caprolactone and its diblock and triblock copolymers with polybutadiene and poly (ethylene oxide) in their ICs with urea, and iii. nylon‐6 in its ICs with alpha‐, beta‐, and gamma‐cyclodextrins. High resolution, solid state NMR serves as both the conformational (C‐13 chemical shifts) and motional (relaxation times and line shapes) probe. Comparison with identical NMR measurements performed on the bulk homo‐ and copolymer samples permits us to draw several conclusions regarding the relationships between the conformations and motions of polymers and their dependence on their ordered solid state environments.
Spectral properties of hemicyanine dye in confinement by helical amylose
Authors: Heuer William B. , Lee H. S. , Kim Oh‐Kil
Published: March 2011

Hemicyanine dye structure is modified with a C16‐alkyl chain to amino‐head and a C1, C8 or C16 alkyl to pyridinium‐tail. Spectral properties of the dyes in supramolecular inclusion complexation with amylose are studied in order to assess the mono‐functional polarity sensing activity of the pyridinium cations in DMSO‐H2O mixtures. Inclusion complexation brings the γmax of C16DASPC1 dye to a blue‐shift (relative to that of the free dye state) while that of C16DASP(C8 and C16) dyes remains almost unchanged.
Solid state NMR studies of syndiotactic polystyrene/ethylbenzene and poly(ethylene oxide)/LiCF3SO3 molecular complexes
Authors: Spêváček Jiří , Brus Jiři
Published: March 2011

Solvent dynamics and polymer‐solvent interactions in syndiotactic (s) polystyrene (PS)/ethylbenzene (PhEt) clathrates, as well as polymer‐salt interactions in the poly(ethylene oxide) (PEO)/LiCF3SO3 complex, were characterized by solid state 1H and 13C NMR. 1H static and 1H MAS NMR spectra have shown that PhEt molecules in s‐PS clathrates retain relatively large, but spatially anisotropic mobility. 13C CP/MAS (cross polarization/magic angle spinning) spectra and CP dynamics measured for s‐PS‐dg/PhEt system indicate that at least a part of PhEt molecules are intercalated between phenyl rings of s‐PS. 13C CP/MAS NMR spectra show that PEO carbons in complex with LiCF3SO3 are more shielded in comparison to neat crystalline PEO. The results (distances) obtained from CP dynamics are in agreement with the published crystal structure of the PEO/LiCF3SO3 complex. 13C spin‐lattice relaxation time measurements have shown that the mobility of PEO in the complex is lower than that in neat crystalline PEO.
Ultrasonic characterization of the kinetics of water sorption in hydrogels
Authors: Maffezzoli A. , Tarzia A. , Cannoletta D. , Montagna G. , Luprano V. A. M.
Published: March 2011

A complex mechanism characterizes the water uptake kinetics in hydrogels, as a consequence of the strong structural changes occurring in the material during the sorption process. Water acts as a plasticizer, reducing the glass transition temperature of the polymer below the sorption temperature and determining a glass transition in the polymer. In this study the changes in the ultrasonic attenuation and velocity in semicrystalline Poly‐vinyl‐alcohol (PVA) hydrogel films during water sorption are measured by a pulse‐echo system. The ultrasonic wave propagation is applied to monitor the position of the swollen/unswollen fronts and to the measurement of velocity and attenuation. The structural changes in PVA hydrogels, monitored by Wide Angle X‐ray Diffractometry (WAXD), performed during the sorption process, are correlated with the ultrasonic data.
Study of platinum and palladium aggregates intercalation into cellulose by waxs, spectroscopic, and microscopic methods
Authors: Kotelnikova N. E. , Paakkari T. , Serimaa R. , Wegener G. , Windeisen E. , Kotelnikov V. P. , Demidov V. N. , Schukarev A. V.
Published: March 2011

The WAXS, SAXS, SEM, TEM, XPS were used to study methods of platinum and palladium aggregates intercalation into the cellulose matrix and changes of cellulose structure after this intercalation. As a result new microcrystalline cellulose ‐ metal compounds containing aggregates of platinum, and palladium were synthesised for the first time using the redox interaction reaction.
Interfaces between coexisting phases in polymer mixtures: What can we learn from Monte Carlo simulations?
Authors: Binder Kurt , Müller Marcus , Schmid Friederike , Werner Andreas
Published: March 2011

Symmetric binary polymer mixtures are studied by Monte Carlo simulation of the bond fluctuation model, considering both interfaces between coexisting bulk phases and interfaces confined in thin films. It is found that the critical behavior of interfacial tension and width is compatible with that of the Ising model, as expected from the universality principle. In the strong segregation limit, only qualitative but not quantitative agreement with the self‐consistent field (SCF) theory is found. It is argued that the SCF theory requiresmagnified imagebut for the short chains studied (N = 32 effective monomer units per chain), the limit is only reached formagnified imageclose to unity. Also, the effective χ‐parameter decreases in the interface. It is shown that the interfacial width w does not increase by the adsorption of block copolymers as long as their areal density is still dilute (“mushroom” regime). But a broadening of interfaces does occur for thin films confined between walls at distance D, due to fluctuations that lead tomagnified imagefor short‐range forces, in agreement with experiment.
Modification of surfaces by covalent attachment of polymer micelles
Authors: Hahn Jungseok , Webber Stephen E.
Published: March 2011

Polymer micelles composed of polystyrene‐block‐poly(methacrylic acid) have been chemically attached to amino‐modified SiO2 surfaces by carbodiimide coupling. The density of coverage is very high (ca. 3 × 1010 micelles/cm2) and fairly uniform. The diameter of the micelles is ca. 50 nm and the distribution of micelle sizes is essentially undisturbed by this coupling reaction. These modified surfaces might be of interest in surface modification because of the very high density of reactive groups that are associated with each micelle.
Plasma deposition of silicon‐containing layers on polymer substrates
Authors: Garbassi Fabio , Occhiello Ernesto
Published: March 2011

Plasma‐polymerized coatings have been deposited on polymer substrates using mixtures of silicon‐containing monomers with O2 and/or CF4. With ternary gas mixtures, novel silicon oxyfluoride coatings were obtained. By oxygen plasma post‐treatment, improvements in barrier properties of polymer substrates to gases were observed.
Modification of the polycarbonate/poly(vinylidene fluoride) interface by poly(methyl methacrylate). Effect on the interfacial adhesion and interfacial tension
Authors: Moussaif Noureddin , Jérôme Robert
Published: March 2011

Polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) are two immiscible polymers which form two‐phase blends with weak interfacial adhesion and high interfacial tension. This situation may be changed by the addition of poly(methyl methacrylate) (PMMA), which concentrates preferably in the PVDF‐rich phase, but also at the PVDF/PC interface. The interfacial activity of PMMA was estimated by the measurement of the interfacial adhesion and interfacial tension in relation to the PMMA content in the PVDF/PC blends. The interfacial adhesion between PC and homogeneous PVDF/PMMA blends of various compositions was measured by the dual cantilever beam technique. The imbedded fiber retraction method was used for the measurement of the interfacial tension. A very beneficial effect was observed when PVDF was premixed with PMMA amounts increasing up to ca. 35 wt.‐%. Beyond that content, the improvement tends to level off.
Guarnt® bland, a reduced odor stabilizer and soluble dietary fiber
Authors: Ward Florian M.
Published: March 2011

The odor and flavor of guar gum may emanate from the breakdown of lipid, protein and/or isoflavones. Guar gum is a galactomannan isolated from the annual plant, Cyamopsis tetragonolobus, Guar is widely used as a thickening agent but due to its characteristic off‐flavor and odor, its usage level has been limited. GuarNT bland, subjected to a proprietary process to reduce its off‐flavor and odor, offers the food formulator more options. GuarNT bland can be subjected to a prehydration process to improve its dispersion and increase hydration rate and avoid lumping problems during large‐scale production. It is used as a thickening agent, suspending agent and a “natural” source of soluble dietary fiber (80% minimum, dry basis). Rheological data using a programmable Brookfield rheometer, hexanal levels (index of grassy flavor), PCA analyses (Aroma Scan, Foss NA) and sensory tests by trained panelists were obtained. Prototype formulations using GuarNT Bland are available and usage levels permitted by CFR are included.
Effect of glass transitions on the rheological properties of food polymers
Authors: Huang Victor T.
Published: March 2011

The rheological properties of food products are highly dependent on the physical state of the structural matrix, which ranges from the glassy state, the glass‐rubber transition region, the rubbery plateau region, the rubbery flow region, and viscous flow region. Depending upon the combination of temperature and/or moisture content, the viscosity could be anywhere from 1015 mPa.s for glassy material and 1 mPa.s for flowable, low viscosity liquid. During the glass transition range alone, the rheological properties can change as large as 1000 times. The rheological properties of ingredients, in‐process intermediates, and finished products also affect the processing techniques, textural quality, physical and chemical stability during storage. In this paper, the similarity in rheological behaviors between synthetic and food polymers, as affected by degree of crystallinity, cross‐linking, plasticization, and phase separation is reviewed. Various mathematical equations for modeling the changes in rheological properties during glass transitions are also discussed. The advantages and shortcomings of each model will also be compared.
Physicochemical properties of plasticized corn zein films: NMR and adsorptivity studies
Authors: Wei W. , Baianu I. C.
Published: March 2011

Water sorption isotherms of corn zein‐based films are typical sigmodial curves. The presence of plasticizers greatly increase film water sorption at intermediate and high water activities. The presence of a plasticizer increases water vapor permeabilities of zein films. The extent of such effect depends on the plasticizer type and concentration used for film formation.
Hydration behavior of heart muscle studies by nuclear magnetic relaxation: Deuterium exchange of water protons in the myocardium
Authors: Lee Jeonghae Rho , Baianu Ion C. , Bechtel Peter J.
Published: March 2011

Proton transverse relaxation, deuterium and oxygen‐17 NMR measurements on functional animal heart muscle were employed to study the distribution and exchange of water protons in the heart. Our nonlinear regression analysis of such data showed the presence of three proton transverse relaxation components that are likely to correspond, respectively, to two major types of water compartments in the heart muscle and the heart muscle matrix. A deuterium exchange study was undertaken to obtain additional information concerning the chemical exchange of water protons/deuterium within these two water compartments, and the effects of proton intermolecular dipolar interactions on the transverse relaxation of water protons. Our results are likely to influence the analysis and interpretation of MRI data for myocardium since it provides details of the microscopic water distribution in the myocardium which is important to the heart function.
Vibrational and 29Si NMR spectroscopies of soluble silicate oligomers
Authors: Bass Jonathan L. , Turner Gary L. , Morris Michael D.
Published: March 2011

Vibrational spectroscopy has been used to correlate the features of silicate solution spectra with 29Si NMR spectra, as a function of SiO2:Na2O ratio and SiO2 concentration. Assignments of infrared and Raman component bands have been made for different anion types and are consistent with results reported for crystalline silicates and silicate glasses. The extent of depolymerization of larger anions has been found to differ, depending on both the degree of dilution and alkalinity. The relative amounts of polymeric (Q4) silica and larger three dimensional (Q34R) anions are greater for the more siliceous solutions (3.3 and 2.95 ratio) at high concentrations. These large anions continue to be major contributors to the anion distribution even at 15 to 50 fold dilution. In the case of more alkaline solutions, especially below 2.5 ratio, the relative contribution of the large anions to the distribution drops rapidly, even with 2 or 3 fold dilution. At low concentrations, in very alkaline solutions, the anion distribution is mainly monomer, dimer and cyclic trimer. Vibrational spectroscopies show great promise for observing changes in anion distribution on a much shorter time scale than is possible with 29Si NMR and can be useful for following reactions involving silicate solutions.
Multi‐dimensional spectroscopy of polymer films; surface and interfacial interactions
Authors: Urban Marek W.
Published: March 2011

Behavior of macromolecules near surfaces and interfaces of polymeric thin films and coatings may play a vital role in numerous applications. Therefore, understanding of molecular level processes responsible for durability, adhesion, and many other macroscopic processes is of a particular importance. This presentation will focus on stratification processes in multi‐component polymeric films, with particular emphasis to polymer‐surfactant interactions in latexes, responsiveness of individual components during coalescence of water‐borne polyurethanes, and behavior of thermoplastic olefins (TPO). The presence of macromolecular arrangements and interactions among various components near the film‐air (F‐A) and the film‐substrate (F‐S) interfaces can be effectively monitored using attenuated total reflectance (ATR) and step‐scan photoacoustic (SS‐PA) Fourier transform infrared (FT‐IR) spectroscopy. Both approaches are capable of obtaining information from various surface depths and complement each other if one seeks molecular level information from 0 – 150 μm into the film. If one combines ATR and PA information with IR and/or Raman surface imaging, it is possible to obtain a 3‐dimensional representation of polymeric films.
Shedding light upon macromolecular behaviour: Luminescence studies of polymers
Authors: Soutar I. , Swanson L. , Cowie J. M. G. , Barker I. C. , Flint N. J. , Conroy M. J.
Published: March 2011

In this paper the use of two time‐resolved luminescence techniques in the study of polymer behaviour is illustrated.

Time‐resolved anisotropy measurements, TRAMS, have been used to study macromolecular mobilities both in solution and bulk phases. The first use of TRAMS involving phosphorescent labels in the study of synthetic polymers is reported and the potential of the technique for future applications in polymer science is discussed.

Time‐resolved energy transfer has been used to study polymer compatibility and interdiffusion in blends of PS‐PMMA. The data offer clear evidence of the fact that the local concentration of chain termini in phase‐separated systems is enriched in the interphase regions compared to that in the two bulk phases of the blend.
A polymer double‐layer studied by step‐scan FTIR photoacoustic spectroscopy
Authors: Wahls M. W. C. , Leyte J. C. , Swart J. M. F. , van Woerkom P. C. M.
Published: March 2011

Photoacoustic (PA) magnitude and phase spectra of a polyethylene/polyurethane double‐layer are presented. The extension of the Rosencwaig‐Gersho theory to a double‐layered polymer film introduced by N.C. Fernelius in 1980 is applied to compare the experimental spectra with simulations. A reasonable agreement between experiment and simulation is observed. It is shown that FTIR‐PAS in combination with simulation provides an important technique for depth profiling in polymeric laminates.
Drift spectral study of polyacrylate (PAA) and polymethyl methacrylate (PMMA) on various ceramics and glasses
Authors: Lee Donghun , Condrate Robert A.
Published: March 2011

Carboxylate‐containing organic coatings can be used for their dispersion, lubrication, durability or hydrophobic applications with ceramic or glass surfaces. Such applications intimately depend upon the nature of the structural interaction of the organic coating on the surface of the inorganic material. In this study, organic polymers such as polymethyl methacrylate (PMMA) and polyacrylate (PAA) were coated on either ceramic or silicate‐containing glass powders. Investigated ceramic materials included alumina, barium titanate and bismuth oxide‐containing cuprate superconductors. The structural interactions between the organic coatings and the inorganic materials were determined by analyzing and interpreting Diffuse Reflection Infrared Fourier Transform (DRIFT) spectra. Depending upon the nature of the investigated materials, various metal‐carboxylate complexes were formed at the interfaces along with hydrogen‐bonded or non‐hydrogen‐bonded protonated PAA or PMMA.
Two‐dimensional near‐infrared correlation spectroscopy studies of polymer blends I: Composition‐dependent spectral variations of blends of atactic polystyrene and poly[2,6‐dimethyl‐1,4‐phenylene ether]
Authors: Ren Yanzhi , Ozaki Yukihiro , Murakami Tsuyoshi , Nishioka Toshikatsu , Nakashima Kenichi
Published: March 2011

Generalized two‐dimensional (2D) near‐infrared (NIR) correlation spectroscopy has been applied to study the conformational changes and molecular interactions in blends of atactic polystyrene (PS) and poly[2,6‐dimethyl‐1,4‐phenylene ether] (PPE). NIR diffuse reflectance spectra have been measured for PS, PPE and their blends of different compositions, i.e., PS/PPE=90/10, 70/30, 50/50, 30/70, 10/90. The 2D synchronous correlation analysis of these composition‐dependent NIR spectral variations separates the bands of PS from those of PPE. The 2D asynchronous analysis identifies spectral features indicative of the conformational changes or the specific interaction of PS and PPE. It can also detect “blend bands” whose origin is attributed to the formation of the polymer blends. Two “blend bands” of PS are identified at 6887 and 4836 cm−1, and three “blend bands” of PPE are observed at 5752, 5679 and 4647 cm−1. These “blend bands” are due to vibrations of the aromatic rings of PS or PPE and of the CH3 of PPE. Thus, not only the aromatic rings of PS and PPE but also the CH3 groups of PPE play important roles in the formation of the blends.
Advantages of near infrared spectroscopy for the analysis of polymers and composites
Authors: Lachenal Gilbert , Ozaki Yukihiro
Published: March 2011

There is an ever increasing need for better quality control of polymers and polymeric composites in order to improve product quality and reduce production costs. Measurements need to be performed rapidly and give precise chemical and physical information to enable a good understanding to be made of the parameters leading to higher quality products. NIR spectroscopy is ideally suited for studies of a large variety of composites and requires minimal sample conditioning. The composition, degree of conversion, crystallinity, water content and interaction, and filler content can be monitored in real‐time using NIR spectroscopy. Moreover, the water content and the water interactions can be analyzed simultaneously. Water can be used therefore as a probe molecule to study polymers and composites.
Polyethyloxazoline monolayers for polymer supported biomembrane models
Authors: Lehmann Thomas , Rühe Jürgen
Published: March 2011

The synthesis of polymer monolayers, which are designed to act as “cushions” for lipid membranes attached to solid surfaces, is described. Monolayers of poly(ethyloxazolines) which could act as a polymeric support for biomimetic membranes have been attached to silicon oxide or gold surfaces following different strategies for the surface‐attachment of the polymer chains. The polymers are either bound to the surface through a chemisorption process (“grafting‐to”) or “grown” on the surface of silicon oxide substrates through a cationic ring‐opening polymerization started from the surface of the substrate, creating a surface‐attached polymer monolayer in situ (“grafting from”). The characterization of the surface attached films by various surface analytical techniques and the swelling behavior of the surface‐attached polymer films in moist air are described. The non‐specific adsorption of fibrinogen as a typical example for a strongly adsorbing protein onto the surface attached monolayers is studied.
Synthesis of nonlinear optical polymers with large photoconductive sensitivity and transparency
Authors: Pyun Seong Yong , Moon Hyunsik , Lee Jin Kyun , Kim Nakjoong , Park Soo Young
Published: March 2011

Novel nonlinear optical (NLO) chromophore, 2‐{3‐[2‐(4‐methylsulfonylphenyl)vinyl]carbazol‐9‐yl}ethanol was synthesized and subsequently reacted with methacryloyl chloride to give a photoconducting NLO monomer (M1). 2‐Methylacrylic acid 2‐[3‐(diphenylhydrazonomethyl)carbazol‐9‐yl]ethyl ester (M2) was also synthesized as a comonomer to enhance the carrier mobility of the NLO polymer. Photoconducting NLO polymers, P1 and P2 were obtained by the copolymerization of Ml with methyl methacrylate and M2, respectively. These polymers were well soluble in organic solvents and showed glass transition at 177 °C and 196 °C, respectively. Polymer films of P1 and P2 were optically clear, and were transparent at wavelengths longer than 420 nm. The electro‐optic coefficient (r33) of poled P1 films was measured to be ∼5 pm/V at 632.8 nm. The photoconductive sensitivities of P1 and P2 were 6.2 × 10−14 S·cm−1/mW·cm−2 and 5.6 × 10−11 S·cm−1/mW·cm−2.
Structure and properties of aromatic 6‐membered polyimides compared to 5‐membered ones
Authors: Jung Jin Chul , Baehr Christoph , Lee Chang‐Hun , Park Sang‐Bong , Son Young‐Sub , Kim Kwang S.
Published: March 2011

When various properties of poly[2,5‐di(n‐alkyloxy)methyl‐p‐phenylenenaphthalene‐1,8:4,5‐diimide]s (Cm‐NAPIs, m = 4, 6, 8) as aromatic 6‐membered polyimides were compared with those of poly[2,5‐di(n‐alkyloxy)methyl‐p‐phenylenepyromellitimide]s (Cm‐PYPIs, m = 4, 6, 8) as 5‐membered ones, it was deduced that O atoms of C=O of Cm‐NAPIs are not coplanar with their imide ring plane. This noncoplanarity led us necessarily to assuming that the 6‐membered ring polyimide chains should have cis/trans‐like isomeric structures. Detailed spectroscopic studies and ab initio calculations for appropriate model compounds are provided to support our assumption.
Mechanism of inhibiting action of quinones in oxidizing polymers and model compounds
Authors: Denisov Evguenii T.
Published: March 2011

Quinones (Q) do not affect the liquid‐phase oxidation of hydrocarbons and retard the solid‐phase oxidation of polymers terminating chains in reactions with alkyl macroradicals. This difference is the result of specific influence of a polymer matrix on the kinetics of free radical reactions. Quinones were found to terminate chains in oxidizing polypropylene containing hydroperoxide groups by the reaction with hydroperoxyl radicals. This is the result of peroxide group's decomposition with hydrogen peroxide production and chain termination in the following reactions:

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The equilibrium reaction between hydroquinone (QH2) and quinonimine (QI) was evidenced to proceed as a chain reaction with chain propagation in reactions of •QH with QI and HQI• with QH2. Analysis of the reactions of quinone with phenols (ArOH)

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proved that it can be important as an additional way of chain termination in oxidizing polymers and hydrocarbons at elevated temperatures.
Design of new materials for environmental control
Authors: Economy James , Mangun Chris
Published: March 2011

During the past several years we have pursued a program here at UIUC to tailor the pore size and surface chemistry of activated carbon fibers (ACFs) to greatly increase their efficiency and selectivity for removal of trace contaminants from the environment. In addition we have evolved new ways of preparing the ACFs to sharply reduce their cost (typically ∼$100/lb) to be more competitive with activated carbon granules ($1‐2/lb), but also to greatly improve the abrasion resistance of the fibers. This was accomplished by coating glass fibers with a phenolic resin and then activating the coating under a controlled atmosphere to produce a variety of tailored micropores. Using chemically tailored ACFs, we describe major improvements over current activated carbons for adsorption of environmental contaminants.
Precision and control in polymer synthesis why it's important and some recent examples of how to do it
Authors: Feast W. James. , Cacialli Franco , Daik Rusli , Friend Richard H. , Herzog Erwin , Heywood Brigid R. , Hobson Lois , Megson Joanna L. , Snowden David
Published: March 2011

This paper discusses some of the reasons why precision and control in polymer synthesis is of importance. By way of illustration it describes in outline recent results from the authors' laboratories in three areas. Namely; the controlled syntheses of poly(arylene vinylene)s and the influence of cis/trans vinylene content on luminescence in such polymers; the living polymerisation of highly functionalised polymers in water and the regulation of the crystallisation of calcium carbonate from water by the resultant well‐defined water soluble polymers; and a simple route to hyperbranched polymers and the influence of the structure and topology of the products on solution properties. In each case the influence of control of architecture on properties will be discussed.
Structurally controlled polymers with ultimate precision ‐ synthesis, characterization and properties
Authors: Hatada Koichi , Kitayama Tatsuki , Ute Koichi , Nishiura Takafumi
Published: March 2011

The fusion of polymer synthesis and characterization and their interactive stimulation is inevitable not only for the formation of polymers with highly controlled structures but also for the development of polymer characterization, thereby bringing about the spiral progress of both fields. As a typical example of precise polymer synthesis, the preparation of uniform PMMA with 100% isotacticity is described. Stereospecific living polymerization of 1‐phenyldibenzosuberyl methacrylate with methyl α‐lithioisobutyrate in tetrahydrofuran at −78°C gave an isotactic polymer with narrow molecular weight distribution. The PMMA derived therefrom was found by 750 MHz 1H NMR spectroscopy to consist of 89% of the PMMA which is 100% isotactic in the whole chain, and 11% of the PMMA which is 100% isotactic in the chain with only one racemo diad at the initiating chain end. The PMMA was fractionated into uniform PMMAs by supercritical fluid chromatography. The isotactic uniform PMMAs, crystallized from methanol solutions, showed the degree of crystallinity close to 100%. Highly syndiotactic PMMA was derived from poly(trimethylsilyl methacrylate) prepared with t‐C4H9Li/bis(2,6‐di‐t‐butylphenoxy)methyl‐aluminum in toluene at −95°C. Stereocomplex formation of isotactic and syndiotactic uniform PMMAs were studied by on‐line GPC/NMR measurements at 750 MHz and −15°C in acetone/acetone‐d6. Stereocontrol of ditactic polymers of crotonates (structural isomers of methacrylates) has been achieved for several polymerization systems, i.e., threodiisotactic, disyndiotactic, and diheterotactic polymerizations, which demonstrates another state‐of‐the‐art structural control at ultimately high level.
Enthalpic relaxation and the glass transition in polymer blends
Authors: Hay James N. , Jenkins Michael J.
Published: March 2011

The kinetics of enthalpic relaxation are reviewed and applied to the ageing of a range of blends made from polyether imide and polyether ether ketone. DSC has been used to follow the development of enthalpic relaxation and a Williams‐Watt stretched exponential equation relating the extent of relaxation, ϕ(t), to the ageing time t and an average relaxation time, t́a', has been used to quantify the ageing process.

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where β' is inversely related to the breadth of the relaxation spectrum such that 0<β>1.0. The relationship was modified to incorporate non‐linearity in the relaxation behaviour. ϕ(t) was measured directly from the enthalpy change observed in the endotherms on heating aged specimens through the glass transition in the DSC.

The PEI/PEEK blends were compatible over the full composition range in that they exhibited a single glass transition with a temperature that varied almost linearly with composition between those of the homopolymers. Enthalpic relaxation was found to be a useful technique for probing the molecular relaxations of polymer blends and confirming the degree of compatibility of the system. The β' values changed systematically with the blend composition between those of the homopolymers suggesting that the breadth of the relaxation spectra were similar in the blends to that in the homopolymers.

Physical ageing was observed to embrittle the blends, and there was a close correlation between the extent of enthalpic ageing and the change in mechanical and impact behaviour. The yield stress increased and the elongation to break decreased progressively with ϕ(t) in addition to a reduction in impact strength.

The model of enthalpic relaxation and the kinetic relationships, outlined above, have been used to determine the onset of the glass transition temperature and subsequent progress of enthalpic relaxation at fixed ageing temperatures, for direct comparison with the change in specific heat observed in DSC experiments. Good agreement was observed between experiment and calculated glass transitions and the effect of variables, such as activation enthalpies, pre‐exponential factors, non‐linear factors such as X and β' and fictive temperature on the observed glass transition temperatures and the temperature range over which the glass transition occurred determined. Modifications to the model for the enthalpic relaxation have been suggested.
Surface, thermal and mechanical characteristics of polymeric solids
Authors: Kajiyama Tisato , Satomi Noriaki , Tanaka Keiji , Takahara Atsushi
Published: March 2011

Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of lateral force microscopic (LFM) and scanning viscoelasticity microscopic (SVM) measurements. SVM measurement revealed that the molecular motion at the surface of the monodisperse polystyrene (PS) film with Mn less than ca.30k was fairly activated compared with that in a bulk region, mainly due to the surface segregation of chain end groups. Temperature dependent LFM and SVM measurement revealed that the surface glass transition temperature, Tg of the monodisperse PS film was lower than the bulk one, even though Mn was fairly large as 140k and also, that the time‐temperature superposition was applicable to the surface relaxation process. The chain end group segregation at the air/PS interface was verified from the dynamic secondary ion mass spectroscopic (DSIMS) depth profiling of the proton and deuterium ion for the end‐labeled deutrated‐PS (dPS) film. These results suggest that the surface Tg is depressed due to an increase in free volume near surface region, being induced by the preferential surface localization of chain end groups.
Adherent and slippery walls for extrusion of entangled polymer melts and compounds
Authors: Piau Jean‐Michel
Published: March 2011

A brief overview is given of the distortions observed when polymer melts or compounds are extruded. It appears that extrusion through steel dies can be done either with macroscopic slip or with no‐slip wall conditions.

Recent experimental and theoretical progress made in understanding the various aspects of slip at the wall, and its measurement techniques, are presented. Boundary conditions for rubber compounds flowing through steel‐walled dies could be seen to be much more complex than those for melts. However many aspects of the methodologies developed are of common interest both for melts and rubber.

It has already been suggested that advantages can be obtained from the use of slippery walls in extrusion. Such wall properties have already been used indeed for a long time with compounds, where processing additives are introduced.

New experimental data are presented concerning two typical EPDM compounds series, obtained using several laboratory techniques at the same time. Constitutive equations for the bulk and for friction at the wall can be introduced at present and adjusted to experimental data. Die extrusion can be simulated numerically, and significant improvements can be expected in quality and productivity.
Biodegradable polymers derived from aminoacids
Authors: Huang Samuel J. , Ho Luang‐Hua
Published: March 2011

Poly(amide‐ester)s derived from five α‐amino acid mixtures including glycine, DL‐and L‐alanines, DL‐ and L‐phenylalanines, and three different diols including 1,6‐hexanediol, 1,4‐butanediol and trans‐1,4‐cyclohexanedimethanol were synthesized by interfacial, solution and melt polymerizations. All of the polymers had Tg's ranging from −6 to 50°C. The incorporation of rigid trans‐1,4‐cyclohexanedimethanol in the main chain significantly increased the Tg of these polymers. The degree of crystallinity depended on the type of amino acid and decreased with the size of substituent on the α‐carbon in the amino acid. Biodegradation of these polymers were tested semi‐quantitatively by turbidity measurements. Enzymes used included subtilisin, pronase E, α‐chymotrypsin, fusarium, and lipase. The incorporation of trans‐1,4‐cyclohexanedimethanol unit slowed down degradation rate. Polymers containing L‐amino acid generally degraded faster than the polymers containing DL‐amino acids. Quantitative biodegradation testings using ninhydrin analysis, total organic analysis, and weight loss done on alanine derived polymers indicated that the degradation of the polymers by pronase E occurred at the ester bonds first and was specific against L‐amino acid. The degradation was followed by slower amide bond degradation.
R&D status of biodegradable polymers in Korea
Authors: Kim Soo Hyun , Kim Young Ha
Published: March 2011

Several companies have developed inherently biodegradable plastics based on starch and foam for loose‐fill packaging material was the representing case. It is water soluble, but the change of the resilience and volume is less than several % when it is laid open at 32 °C, RH 70%. Starch‐based polyvinylalcohol, aliphatic polyester, polycaprolactone biodegradable polymers were developed also. The PET fiber manufacturing companies have developed aliphatic polyester biodegradable plastics based on diol (butanediol, ethylene glycol) and diacid (succinic acid, adipic acid). The polymers have shown good mechanical properties and processibilities. They have succeeded to apply for injection, films, sheets, extrusion coatings, filaments, non‐woven products, foams, and blow molding and lead this area in Korea. Polyhydroxybutyrate(PHB) and its copolymer were the first biodegradable polymer introduced in Korea. The gene cloning and recombinant technology was succeeded to produce PHB and PHB/V by E‐coli and to yield the higher productivity than before. Lactic acid production and direct condensation polymerization of lactic acid is also being developed.
Biodegradation of PVA‐based formulations
Authors: Chiellini Emo , Corti Andrea , D'Antone Salvatore , Solaro Roberto
Published: March 2011

Investigation of the biodegradability of water soluble poly(vinyl alcohol) (PVA) based blown films was carried out under different lab‐scale environmental conditions. In particular respirometric tests were utilized in order to evaluate the biodegradability of PVA films in composting, in modified Sturm test and in soil burial simulation tests. Several microbial inocula present in river water, mature compost, forest and farm soils as well as sewage sludge from municipal and paper mill wastewater treatments plants were utilized for the relevant tests. A mixed PVA‐degrading microbial culture was obtained by a common enrichment procedure by using sewage sludge from paper mill as inoculum; this culture was tentatively utilized for the isolation of single PVA‐degrading microorganisms. As a first result we can stress that significant biodegradation extent in fairly low incubation time can be obtained only in the presence of acclimated microbial populations such as those deriving from paper mill sewage sludge, in liquid cultures. Nevertheless separation of single degrading microbial species was impossible most likely due to the establishment of symbiotic or commensal interactions between the single components of the PVA‐degrading mixed cultures. On the other hand, limited mineralization rates were recorded in solid cultures in the presence of soil or compost. Finally, a mechanism of degradation of polymer chains unlike random or unzipping was suggested in the presence of either PVA‐degrading mixed culture and its filtrate by means of viscometric determinations of molecular weight within the time.
Chemoenzymatic synthesis of biodegradable polymers containing glucobiose branches
Authors: Kitagawa Masaru , Chalermisrachai Panpaka , Fan Hong , Tokiwa Yutaka
Published: March 2011

Polymerizable sugar esters including glucobiose were synthesized from maltose or trehalose and divinyl adipate using enzyme in DMF. 13C NMR data showed that 6'‐position of maltose and mono‐6‐position of trehalose were esterified. Further, these glucobiose esters was polymerized with azo‐initiator to give the corresponding polymers.
Direct condensation polymerization of lactic acid
Authors: Kim Soo Hyun , Kim Young Ha
Published: March 2011

In order to synthesize the higher molecular weight poly(lactic acids) by direct condensation polymerization of lactic acid, dipentaerythritol was used as a chain branching agent. Poly(lactic acids) of high molecular weight, 67000(Mn), was obtained by using antimony trioxide catalyst with good color. This poly(lactic acids) showed Tg of 54.8 °C, Tm of 147 °C and cold crystallization temperature of 115 °C. The polymer could be melt processed into transparent films. Tensile modulus of 311 Kg/ mm2, tensile strain of 21% and tensile strength of 12.41 Kg/ mm2 were obtained for film collected at 400%/min and drawn 4 times.
Effect of additives on gelatinization, rheological properties and biodegradability of thermoplastic starch
Authors: Yu L. , Christov V. , Christie G. , Gray J. , Dutt U. , Harvey T. , Halley P. , Coombs S. , Jayasekara R. , Lonergan G.
Published: March 2011

Effect of additives on the starch gelatinization was governed by the processing conditions. The order‐disorder transition of starch in water can occur in more than one way and the effect of polar additives on gelatinization can also be in more than one way. The additives appear to be plasticising thermoplastic starches, resulting in improving rheological properties. The thermoplastic starches with the additives are all biodegradable although the rates of biodegradability are slightly different.
Studies on degradation of PET in mechanical recycling
Authors: Frounchi Masoud
Published: March 2011

PET Poly(ethylene terephthalate) was processed repeatedly in a twin extruder. Effect of reprocessing on molecular structure of PET was evaluated in terms of reduction in molecular weight and mechanical properties. This study shows that weight‐average molecular weight Mw drops more notably compared with mechanical properties. Mechanical blending of virgin polymer with recycled PET was studied. The results of mechanical testings indicate that there is only slight loss in mechanical properties. The results suggest that mechanical recycling is a suitable method for recycling of PET for economic and environmental purposes.
Molecular mobility, structural organization and complexing properties of copolymer macromolecules
Authors: Anufrieva Elizaveta V. , Gromova Raisa A. , Kirsh Yurii E. , Krakovyak Mark G. , Yanul Natalya A. , Lushchik Vanda B. , Pautov Vladimir D. , Sheveleva Tamara V.
Published: March 2011

Intramolecular mobility, an intramolecular structure formation, and complexing properties of VP‐VC (N‐vinylpyrrolidone and N‐vinylcaprolactame) copolymer macromolecules with a low content of the “hinge” VP units in aqueous solutions upon heating, phenol or SDS (sodium dodecyl sulfate) adding were studied by luminescence. The data obtained show that a slight modification of a polymer chain structure with the aid of the “hinge” units inclusion leads to a considerable change in structural and complexing properties of the copolymers.