bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slow‐release fertilisers based on natural rubber
Authors: Hepburn Claude , Arizal Ridha 
Published: April 2007

AbstractIt is estimated that only between 30‐70% of the fertiliser applied in agriculture is used for plant nutrition, the rest is carried away by ground water or lost through nitrification‐denitrification. Apart from the economic loss due to wastage, severe environmental problems arise due to increasing nitrate concentrations in public drinking water. The research reports a method of binding the fertiliser urea into natural rubber thus forming a matrix of rubber encapsulated fertiliser. A special ‘split‐feeding’ mixing technique is necessary for a good product; also found important were mixing and vulcanisation temperatures with the optimum being in the 70−82°C range and 95°C respectively.
Polycarbonate adsorption on platinum: Thermal curing effects
Authors: Van Mark M. R. De , Guethon J. A. , Pasarin G. 
Published: April 2007

AbstractAdsorption of polycarbonate (I) from dilute chloroform solution on to ‘clean’ platinum flags was investigated through the use of Iodide‐125 radio tracer. Coverage versus concentration plots produced a logarithmic dependence of coverage on polymer concentration. A new method for clinging solvent removal was employed which increased the reproducibility of the coating. Both the effect of molecular weight and thermal stability of the polymer were investigated.
Thermotropic liquid crystalline main‐chain polyamides containing diaza‐18‐crown‐6‐ether units
Authors: Cowie John M. G. , Wu Hak H. 
Published: April 2007

AbstractPolymers incorporating conventional mesogens and diazo‐18‐crown‐6‐ether were prepared. The crown ether unit seems to be too flexible and only weak liquid crystal character can be observed by optical microscopy except when the mesogen is terphenyl. These liquid crystalline characteristics disappeared when the polymers were complexed with potassium ions.
Recent advances in secondary lon mass spectrometry (SIMS) for polymer surface analysis
Authors: Briggs David 
Published: April 2007

AbstractSince the first tentative applications of SIMS to study polymer surfaces around 1980 the field has developed very rapidly. The important experimental parameters which allow true ‘static’ SIMS analysis of polymers are now well established following systematic studies of ion beam damage cross‐sections and the methodology of surface potential control is sufficiently understood to allow both positive and negative ion spectra to be routinely obtained from highly insulating materials.The principal advantage of SIMS over X‐ray photoelectron spectroscopy (XPS or ESCA) comes from the molecular specificity inherent in a mass spectrometric technique. Several classes of polymers have been studied to establish fragmentation processes; in the case of acrylic polymers these studies have been extensive and detailed. From the technological point‐of‐view it is the ability to identify ‘small’ organic molecules on polymer surfaces which is most exploited. The information depth in typical systems has been established by correlation with angle‐resolved XPS studies to be ∼ å, this degree of surface sensitivity allows bulk‐surface segregation effects in block copolymers to be followed as exemplified by studies of segmented poly (ether urethanes). Use can also be made of the isotope specificity of SIMS in derivatisation schemes or in polymerisation mechanism studies. Quantification of SIMS intensity data is now being explored. In the case of random methacrylate copolymers quantitative information on sequence statistics has been obtained.SIMS also has the potential for high spatial resolution analysis. The problems associated with unacceptable damage rates when working with sub‐micron focussed beams have been studied and this has led to the development of the time‐of‐flight (TOF) imaging SIMS instrument. TOF SIMS is capable of accessing a mass range of an order of magnitude greater than the conventional quadrupole instrument and the application of both imaging and non‐imaging TOF instrumentation to polymer surface analysis has recently commenced.
Application of raman microscopy to the analysis of high modulus polymer fibres and composites
Authors: Young Robert J. , Day Richard J. 
Published: April 2007

AbstractRaman microscopy has been used to study the deformation of carbon fibres and an experimental grade carbon‐fibre/PEEK composite prepreg. It has been found that the peak position of the Raman‐active bands in the fibres are sensitive to the level of applied strain. Examination of the peak positions from the carbon fibres near the surface of the prepreg shows that the fibres are subjected to a residual compressive strain. The application of a tensile stress to the composite causes the fibre strain to become tensile although significant scatter is found in the measurements. The scatter is thought to be due to variations in the local carbon‐fibre strain at the 1 μm level. It is demonstrated that residual compressive strain is expected from differential shrinkage between the fibres and matrix on cooling the composite from the processing temperature to room temperature.
Pyrolysis‐GLC applied to composition analysis, general characterisation and the detailed specification of polymers
Authors: Hammond Timothy , Lehrle Roy S. 
Published: April 2007

AbstractSince its inception in the late 1950s, pyrolysis gas‐liquid chromatography has rapidly become an important tool for the polymer chemist. Applications range from polymer characterisation to the elucidation of polymer degradation mechanism. Typical analytical applications include the characterisation of complex polymer mixtures, the assessment of copolymer composition and microstructure, structural analysis and the assignment of polymer tacticity. Recent advances in the technique are reviewed and examples of results are given.Most current GLC equipment is perfectly adequate for polymer/copolymer analysis provided that certain basic requirements are satisfied. For polymer characterisation, furnace and Curie‐Point methods are not the most appropriate and even simple filament methods are preferable to these. Refined filament techniques are the most suitable methods for studying degradation kinetics, and can provide a highly precise specification of polymer structure.For example, studies on the dependence of the specific rate of pyrolysis can distinguish anionic and free‐radical polymers. Analysis of the energetics of the degradation may indicate the activation energy for end initiation; this may be compared with bond‐strengths of possible end‐group structures. A similar process can be used to elucidate the nature of possible ‘weak‐links’ within the polymer backbone. The effects of polymer modification, for example oxidation, may also be assessed. Examples are quoted for these situations and the requirements of the technique are stressed.
Coupled column chromatography for copolymer characterisation
Authors: Dawkins John V. , Montenegro Ana M. C. 
Published: April 2007

AbstractCoupled column chromatography has been performed with two chromatographic systems in which fractions from a size exclusion column are injected into a second column where retention is determined by non‐exclusion mechanisms. This has been accomplished by directing the eluent from the first column system through the injection valve of the second column system. The first column system contained crosslinked polystyrene gel with the eluent tetrahydrofuran as good solvent. The second column system contained crosslinked polystyrene gel (or crosslinked polyacrylamide gel) with a mobile phase consisting of a solvent/non‐solvent mixture which is a poor solvent promoting non‐exclusion mechanisms for statistical copolymers of styrene and n‐butyl methacrylate. Separations dependent on copolymer composition as a function of the non‐solvent component in the mobile phase and the polarity of the stationary phase in the second column system have been accomplished by isocratic elutions.
Mass spectral studies of some epoxy resin precursors
Authors: Crossland The Late Barbara , Lau Chung H. , Hodd Kenneth A. , Wright Walter W. 
Published: April 2007

AbstractThe mass spectra were determined of three epoxy resin precursors: N,N‐bis‐(2,3‐epoxypropyl)‐N′,N′‐dimethyl‐4,4′‐diaminodiphenylenemethane (G2A); N,N′‐bis‐(2,3‐epoxypropyl)‐N,N′‐dimethyl‐4,4′‐diaminodiphenylene methane (G2S); and N′,N′,N′,N′‐tetrakis‐(2,3‐epoxypropyl)‐4,4′‐diaminodiphenylene methane (TGDDM); and of three related model compounds: N,N‐dimethylaniline (DMA); N‐methyl‐N‐glycidylaniline (MGA) and N,N‐digrycidylaniline (DGA). The results helped to confirm the structure of the resin precursors and are intended to pave the way for subsequent thermal degradation studies of cured resin samples. Despite the similarity in chemical structure of the compounds studied there are quite large differences in the mass spectral results obtained.
A kinetic study of acetoxylation of benzyl chloride—a model of activated allylic chlorides in PVC—using a crown ether complex
Authors: Naqvi M. K. , Lewis J. , Park G. S. 
Published: April 2007

AbstractBenzyl chloride has been used in a kinetic study of chlorine replacement by acetoxy groups to model the behaviour of allylic chlorine during the acetoxylation of poly(vinyl chloride). Chlorine substitution was carried out in tetrahydrofuran at 30°C using a potassium acetate‐crown ether complex with methanol to ensure homogeneous solution. The process followed an SN2 mechanism. The orders of reaction with respect to benzyl chloride and potassium acetate were close to one, and the second order velocity constant was 4.2 x 10−5 litre mol−1 s−1 when the molar ratio of crown ether to potassium acetate was approximately unity. Higher ratios caused a slight increase in rate constant. Substitution was followed by NMR spectroscopy which also revealed a proton exchange between methanol and acetate anion with an equilibrium constant 9.4 x 10−2. This observation has suggested an explanation for the effect of some free‐radical inhibitors on the rate of acetoxylation of poly(vinyl chloride) by potassium acetate in the presence of crown ether.
Investigation of an indirect GC method for the determination of water content of rubbers
Authors: Burfield David R. , Eng Aik‐Hwee , Loi Patrick S. T. 
Published: April 2007

AbstractA method is proposed for the determination of low levels of moisture in rubbers and other soluble polymers. The material for analysis is dissolved in an appropriate solvent and triethylaluminium is added to react with the water contained in the sample. The liberated ethane is analysed by a simple GC technique. The method is calibrated using an internal standard and by addition of known amounts of water. A series of natural and synthetic rubbers dried under varying conditions were found to have water contents in the range 0.01‐2% w/w. Removal of proteinaceous material from natural rubber reduces the equilibrium water content of the stored rubber. Active hydrogen impurities in the rubbers are shown to interfere with the determination and consequently the observed water content must be assumed to represent the upper limit of water unless such impurities are known to be absent, or present only in negligible amounts.
Photoresponsive optically active polymers—a review
Authors: Ciardelli Francesco , Pieroni Osvaldo , Fissi Adriano , Carlini Carlo , Altomare Angelina 
Published: April 2007

AbstractPhotoresponsive macromolecules are of interest both as novel organic materials for applications in photodevices and as models for photomodulated biological processes. The presence in polymer chains of photosensitive groups and of chiral groups capable of inducing optical activity into the polymer is very useful for the analysis of photomodulated structural variations and allows storage of the light effect in the form of chiral information. Polypeptides bearing photochromic groups in the side chains are very convenient as the chiroptical properties of the peptide chromophore can be correlated to the backbone conformation. Thus polymers of L‐aspartic acid, L‐glutamic acid and L‐lysine with azobenzene or stilbene groups attached covalently to the side chains are discussed in terms of photoinduced conformational changes and chiroptical information storage in the spectral region of the peptide and of the photoresponsive chromophore. Optically active photochromic macromolecules with hydrocarbon backbone, such as copolymers of (—)‐menthyl acrylate with vinyl or acryloyl derivatives of azobenzene, stilbene and indolinospirobenzopyran, also show in some cases photodependence of chiroptical properties with evidence of at least local conformational changes as a consequence of light irradiation which can be used for chiral information.
Effects of lonenes on structure and catalytic activity of cobaltphthalocyanine, part 4. Reaction mechanism and immobilization of the catalyst on latex particles
Authors: Van Herk Alex M. , Van Streun Karel H. , Van Welzen Joke , German Anton L. 
Published: April 2007

AbstractThe catalytic oxidation of 2‐mercaptoethanol was investigated kinetically for the system cobalt(II)phthalocyanine‐tetra (sodium sulphonate) in the presence of poly(quaternary ammonium salts) at pH = 8.85. From a comparison with other kinetic data a reaction mechanism could be proposed in which the specific effects of the polyelectrolyte become manifest. The effect of ionic strength on the catalytic activity was also studied.The soluble catalytic system was immobilized on latex particles by using a polymeric soap containing quaternary ammonium groups. The latex particles with the ammonium groups at the surface were used to bond the cobalt catalyst by ionogenic interaction. Using this latex supported polymeric catalyst the activity of its homogeneous counterpart could be maintained while at the same time immobilization was accomplished.
Surface analysis and adhesion properties of coalesced latex films
Authors: Zhao Cheng‐Le , Holl Yves , Pith Tha , Lambla Morand 
Published: April 2007

AbstractThe surface composition of films obtained from acrylic latexes (45 wt% MMA, 55 wt% BuA) stabilized by two anionic surfactants (either sodium dodecyl sulphate (SDS) or sodium dodecyl diphenyl ether disulphonate (SDED) has been studied by attenuated total reflection with Fourier transformed infrared spectroscopy (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The results of this surface analysis are summarized and used to interpret adhesion properties of the films on glass substrate. Adhesion properties were derived from peeling tests. In the case of SDED, the peel strength increases with surfactant surface concentration. This is due to strong polar interactions between the hydrophilic part of the surfactant and the polar groups of the glass surface and to the anchorage of the hydrophobic part of the surfactant in the copolymer matrix. In the case of SDS, the peel strength decreases with increasing surfactant surface concentration. The same polar interactions as with SDED exist, but the SDS layer at the interface is very thick. It forms what is called a ‘weak boundary layer’ in which rupture propagates easily.
Photopolymerization of N, N‐Didodecyl‐ N‐methyl‐N‐ethylmethacrylate ammonium chloride, a reverse micelle forming surfactant
Authors: Voortmans Gilbert , Jackers Carine , De Schryver Frans 
Published: April 2007

AbstractA detailed study of the photopolymerization of N,N‐didodecylmethylethylmethacrylate ammonium chloride, a reverse micelle forming surfactant, is presented. The polymerization was photochemically initiated at 350 nm using AIBN and p‐AIBN as initiators. However, the polymerization could also be initiated through direct excitation of the methacrylate group. High rates of polymerization resulted because of the organization of the monomer in reverse micellar assemblies. The molecular weights of the polymer decrease with increasing initiator concentration and are always larger than the molecular weight of the reverse micelle.The properties of the monomeric reverse micellar system are compared with those of the polymeric system and show that the dynamic character of the reverse micellar system can be lowered upon polymerization. The properties of the polymeric aggregates, however, differ if a given amount of water is solubilized before or after polymerization. The mean aggregation number of the monomeric and polymeric aggregates as well as the aggregation behaviour of both systems are compared. This comparison suggests that a polymeric aggregate consists of more than one polymer chain.
Advances in room temperature curing adhesives and sealants—a review
Authors: Melody David P. 
Published: April 2007

AbstractRoom temperature curing adhesives and sealants, defined here as those which cure without a mixing process under the influence of substrates or environmentally available reagents such as daylight, oxygen or moisture, include polyurethane, silicone, anaerobic adhesives, cyanoacrylate and certain acrylic types.Advances in cure chemistry, built‐in adhesion promotion, and in formulating techniques have created the scope for significant new properties within all the mentioned systems. In addition, development of resins having two (or more) different functionalities, which respond to substrate and or atmospheric cure agents, has created the potential to achieve new advanced performance levels. Examples of these include compositions which give light curing through acrylic functions while having RTV (room temperature vulcanising) silicone resin chemistry polymerising under the influence of atmospheric moisture. The properties can be tailored by molecular design, formulation and choice of cure accelerators.
Torsional braid analysis of the cure of some tetra‐N‐glycidyl‐4,4′‐diaminodiphenylmethane systems
Authors: Hill S. M. , Wright W. W. 
Published: April 2007

AbstractTorsional braid analysis has been used to study the curing reaction of some resin systems based upon tetraglycidyldiaminodiphenylmethane. TBA gives isothermal times to gelation and vitrification and hence the processing window for the particular systems studied at any intermediate isothermal temperature. The activation energies for the processes involved were also derived allowing extrapolation outside the range of the experiments.
Proton spin‐lattice and spin‐spin relaxation times in annealed poly(ethylene terephthalate)
Authors: Tanaka Hiroshi 
Published: April 2007

AbstractProton spin‐lattice, T1, and spin‐spin, T2, relaxation times of poly(ethylene terephthalate) film annealed at various temperatures were measured using a broad line pulse spectrometer. The value of T1 is closely related to the crystallinity of the sample and only one T1 was observed for each sample, indicating that the spin diffusion is effectively operating. Even in the amorphous sample there are some nuclear spins, the motion of which is strongly restricted.
Effect of molecular weight on the mechanical properties of polytetrafluoroethylene (PTFE)
Authors: Włochowicz Andrzej , Ṡacigała Ryszard 
Published: April 2007

AbstractMolecular weight has a considerable influence on the mechanical properties and density of polytetrafluoroethylene. Empirical equations have been found relating tensile properties and density to the number‐average molecular weight.
The many hats of teaching in small colleges: The seamless web of student and academic affairs
Authors: Degen Greta , Sheldahl Erin 
Published: April 2007

AbstractUnique opportunities exist on small campuses for all professionals to interact without boundaries. The traditional boundaries of classroom learning and student life cease to exist; student life professionals often function as teachers, and academic affairs professionals are encouraged to support students outside the classroom. This partnership creates many student‐focused learning situations that blur the lines between student affairs and academic affairs.
Law and industrial buyer‐seller relationships: The privatization of a Mexican State‐Owned steel company
Authors: Husted Bryan W. 
Published: April 2007

AbstractThis article examines the impact of privatization on the purchasing practice of a state‐owned steel company in Mexico. It looks first at the changes in the law which affect the relationships of state‐owned enterprises with their suppliers. It then presents possible implications of these legal changes for buyer‐seller relationships drawn from transaction‐cost and institutional theory. Finally, it compares the predicted and actual impact of privatization and draws some preliminary conclusions. © 1993 John Wiley & Sons, Inc.
One Germany … but is there a common German consumer? east‐west differences for marketers to consider
Authors: Johnson Denise M. , Johnson Scott D. 
Published: April 2007

AbstractThe socialization process into the East German culture has created a lasting impression on millions of former East Germans which will not be erased easily by the turn of political climate or financial gain. Despite a reunited Germany, consumers in what was once East Germany are different in many regards from consumers in what was once West Germany. The results of an empirical study comparing former East and West Germans suggest that consumers socialized in the East have different attitudes toward information sources, advertising, pricing and product quality, as well as differing abilities in evaluating products when compared to those socialized in the West. © 1993 John Wiley & Sons, Inc.
ASEAN's role in Japan's economic policy in East Asia
Authors: Choi Chong Ju 
Published: April 2007

AbstractAlthough Japan's economic and trade policy with the United States and Europe has been widely researched in such works as Tyson (1992), relatively less research has been done on Japan's recent trade and economic policies towards other East Asian countries such as Korea and Taiwan. Since the mid‐1980s, because of rising labor costs and appreciation of the Japanese yen, Japan has increased manufacturing production in ASEAN countries such as Thailand and Malaysia. The purpose of this short article is to discuss Japan's increased economic focus in Asia, and implications for East Asian countries such as Korea and Taiwan. © 1993 John Wiley & Sons, Inc.
International reciprocal service agreements: An analysis of the international long distance service industryz
Authors: Kashlak Roger J. , Chandran Rajan 
Published: April 2007

AbstractInternational Reciprocal Service Agreements exist between entities of two countries and provide a bi‐directional service between those countries. Strategic implications arise at the organization‐specific profitability level and at national balance of payments level. Using data from the United States' International Telecommunications Industry, the uniqueness of these reciprocal alliances is explored, an alarming negative economic trend for the U.S. is noted. A typology for analyzing the dual challenge of firm profitability and national service deficit is proposed. Some strategic prescriptions are also provided. © 1993 John Wiley & Sons, Inc.
Results of the contract responsibility system in the people's republic of China: An analysis of two state enterprises
Authors: Maschmeyer Richard A. , Ji‐Liang Yang 
Published: April 2007

AbstractIn the People's Republic of China (PRC) market oriented reforms have resulted in several initiatives that promote entrepreneurial activities within state enterprises. One of these is the Contract Responsibility System (CRS) which provides the financial structure for allocating the profits of state enterprises between the government and the enterprises. The objective of the CRS is to increase the profits of state enterprises by transforming them into self‐supporting economic cells. It is the purpose of this study to examine the operation of the CRS. This study profiles two state enterprises operating under the CRS and discusses the reasons for their success or failure. © 1993 John Wiley & Sons, Inc.