bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grafting and initiation reactions
Authors: Rånby Bengt 
Published: March 2011

AbstractGrafting of acrylic monomers onto cellulose substrates in acid aqueous medium using complex of Mn3+ ions as a redox initiator is described. Assuming that the /Mn3+/ ions react with aldehydes and vicinal diols, the rate of these reactions has been measured spectroscopically. (ESR and visible light) using model compounds. It is concluded that the /Mn3+/ grafting onto cellulose is a radical reaction initiated mainly by oxidation of aldehydes at reducing end groups and C‐C bond scission of vicinal diols at the end groups and along the cellulose chains. The initiation rates of the Ce4+, /Mn3+/ and VO22+ redox ions are related to their oxidation potential.
Intra‐ and intermolecular reactions of nucleophilic carbenes
Authors: Warkentin John 
Published: March 2011

AbstractGeneral properties of nucleophilic carbenes are addressed briefly. The preparation of oxadiazoline precursors of such carbenes, and some of their chemical reactions, are presented. Intramolecular reactions include rearrangement and attack by the carbene center on a tethered functional group. Intermolecular reactions include nucleophilic attack at the carbonyl carbon of isocyanates and at the triple bond of dimethyl acetylenedicarboxylate.
Catalytic degradation of polyethylene and polypropylene to fuel oil
Authors: Sakata Yusaku 
Published: March 2011

AbstractThermal and catalytic degradation of plastic polymers, polyethylene and polypropylene to fuel oil were carried out in batch operations. The catalysts employed were acid silica‐alumina (SA‐1, SA‐2) and zeolite ZSM‐5, and non‐acidic mesoporous silica FSM (folded sheet material). The yields of product gas, liquid and residues, recovery rate of liquid products, and boiling point ranges of liquid products due to degradation were compared with those of non‐catalytic thermal degradation. Both the effect of catalytic contact mode and of catalyst type on the degradation were studied.In liquid‐phase degradation of PP over SA‐1, liquid hydrocarbon products were obtained in a yield of 69 wt.‐% with a boiling point range 36‐270°C, equivalent to the boiling point of normal paraffins C6 ‐ C15. The liquid products from catalytic degradation have a carbon‐number distribution very similar to commercial motor gasoline. In vapor‐phase contact, the yield of liquid products was much lower (54%) and the rate of liquid recovery was much slower.With FSM, the initial rate of degradation of PP and PE to liquid products was as fast as that over acid catalyst SA‐1, but the yield of liquid products was higher. The liquid products from catalytic degradation over FSM have a carbon‐number distribution similar to kerosene and diesel oil. In repeated use, SA‐1 deactivated very rapidly due to coke deposition on the catalyst, whereas FSM deactivated much more slowly. These findings suggest that mesopores surrounded by the silica sheet may act as reservoir for radical species, which accelerate the degradation of plastic melt.
New approach to recycling of thermosets
Authors: Kresta J. E. , Xiao H. X. , Suthar B. , Li X. H. , Sun S. P. , Klempner D. 
Published: March 2011

AbstractThe decrosslinking of thermosetting reaction injection molded (RIM) polyurethane‐urea products with the smallest amounts of glycols was studied. The effects of the reaction conditions on the properties of liquid oligomers were determined. Successful scale‐up studies and utilization of the resulting liquid oligomers for preparation of RIM products, coatings and adhesives are described.
Recycling of mixed automotive plastics
Authors: Deanin Rudolph D. , Barry Carol M. , Woramongconchai Somsak , Parikh Sona C. 
Published: March 2011

AbstractMixed plastics from junked autos were homogenized by milling or extrusion, modified by addition of low‐molecular‐weight low‐melt‐viscosity polymers, and processed by compression or injection molding. Properties were comparable with high‐density polyethylene and common building panel materials.
Recycled injection‐molded and fibre‐reinforced polyethylene/polypropylene
Authors: Riedl Bernard 
Published: March 2011

AbstractIn this presentation, we are concerned with the fabrication and characterization of samples of compression‐molded and injection‐molded recycled polyethylene, with, in some cases, addition of cellulose fibre. We wish to know what is the performance of such plastics, as compared to the virgin materials and what is the effect of added fibre in both molding modes.
Recycling of polymeric composites
Authors: Mang Thomas , Haulena Friedhelm 
Published: March 2011

AbstractFor material recycling, composites have to be separated into their components, as only non‐mixed raw materials can grant high quality standards. A combined mechanical and subsequent electrostatic separation can be classified as highly economic because it is a dry treatment. This is demonstrated on wire scrap. The separated copper and synthetic materials are obtained in a high degree of purity.Chemical disaggregation of composites has been worked out with medicinal blister packs and beverage packs. Two methods of separation were used: separating the plastic‐aluminium composite by dissolving the plastic material or dissolving the adhesive that bonds together the plastic and aluminium. To demonstrate the technical feasibility of the processes, a pilot plant with a capacity of up to 25 tons of blister pack material per year was built. Chemical separation with non‐problematic aqueous media was demonstrated with flocked plastics.When integrating composites into chemical processes, questions concerning material specification as well as preparation and chemical utilization must be answered. Mechanical preparation of appropriate raw materials has been exemplified by mixed packing waste, carpet‐floor waste, and synthetic material from electrical waste. After the raw materials were analyzed and studies of their quantity and compositions were made, their possible re‐use as raw material within a chemical process has been elaborated.
Approaches to deal with the issue of plastic packages and the environment
Authors: Miltz Joseph 
Published: March 2011

AbstractMethods 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

AbstractA 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

AbstractIn 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

AbstractThree 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

AbstractThe “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

AbstractA 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

AbstractWhen 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

AbstractHemicyanine 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

AbstractSolvent 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

AbstractA 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

AbstractThe 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

AbstractSymmetric 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

AbstractPolymer 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

AbstractPlasma‐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

AbstractPolycarbonate (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

AbstractThe 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

AbstractThe 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

AbstractWater 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.