bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial phenomena in PbBiSrCaCuO/Ag and AgIn: Wettability, AES and XPS studies
Authors: Polak M. , Baram J. , Froumin N.
Published: May 2005

Two complementary approaches have been applied to the study of interfacial processes between PbBiSrCaCuO ceramic and silver or silver alloys. One is based on wettability measurements of molten silver (and silver–indium) using the sessile‐drop technique (at 950 °C) followed by AES analysis, and the other approach uses XPS/depth profiling of silver films on PbBiSrCaCuO annealed at 20–700 °C. Extensive interfacial interactions and diffusion processes occur in these systems, which lead to enhanced wettability. Such phenomena are correlated with previously reported electrical properties and are relevant to the optimization of metal/superconductor composite materials and device applications.
Characterization of MoOx/ZrO2 system by XPS and IR spectroscopies
Authors: Gazzoli D. , Prinetto F. , Campa M. C. , Cimino A. , Ghiotti G. , Indovina V. , Valigi M.
Published: May 2005

MoOx/ZrO2 samples (Mo content, 0.7 to 4.0 atoms nm−2) have been investigated by XPS and Fourier transform Infrared (FTIR) spectroscopies. After heating in O2 (773K), XPS shows the presence of MoVI species; while the IR analysis shows bands in the 830–1012 cm−1 region, arising from MoVI species of various nuclearity. In the early stages of the reduction (H2 at 500 K) both XPS and IR show the formation of MoV. In agreement with previous ESR results, the intensity of IR and XPS bands from MoV does not appreciably change by further increasing the extent of reduction up to 803 K. On extensively reduced samples, both IR and XPS show the presence of MoIV in addition to MoVI and MoV. Upon NO adsorption at RT, dinitrosyls of MoIV were detected by IR. A further rise in the extent of reduction with H2 at 803 K, led to a drop in the intensity of the IR band from MoIV and XPS detected Mo metal.
High temperature corrosion characterization by the combined use of surface microsurgery and surface analysis
Authors: Bennett M. J.
Published: May 2005

Characterization of both the chemical and physical nature of interactions at interfaces is crucial to mechanistic understanding of the behaviour of metallic and ceramic materials, including coatings, in aggressive environments at high temperatures. This can be achieved post exposure by the use of defined surface analytical techniques but is reliant upon the deployment of appropriate surface microsurgery procedures, such as metallography, fractography, taper section polishing, selective etching, complete dissolution, etc., for the preparation of surfaces prior to analysis. Recent studies undertaken at the Harwell Laboratory on the combined use of surface microsurgery and surface analysis in the characterization of high temperature corrosion attack are reviewed. These have aimed to improve the precision and the effectiveness of surface microsurgery procedures to ensure the optimum exploitation of the capabilities of surface analytical techniques, especially those in more common usage, such as scanning electron microscopy, electron probe microanalysis, laser Raman spectroscopy, secondary ion mass spectrometry, etc. Although most of the examples presented are of thick (> 1 μm) corrosion scales and of internal attack, several of the surface microsurgery procedures have relevance to the analysis of sub‐micron layers.
Surface analytical investigations of Al and (Ti, Al) nitrides formed by ion implantation and their corrosion properties
Authors: Simson S. , Heide N. , Schultze J. W.
Published: May 2005

Nitrides of Ti, Al and TiAlx alloys were prepared by low energy ion implantation (3 keV N2+). The layer thickness was ∼ 10 nm. The nitride layers were characterized using XPS, UPS and a Kelvin probe. The insulating properties known for bulk AlN were found also for the prepared AlNimpl layers. The work functions for the alloys and the nitrides and their variation with the ion dose were determined. Peak parameters for the XP spectra deconvolution were established. Despite their thinness, the layers showed anodic stability in 0.5 M H2SO4 up to 1.3 V (SHE) for (TiAl)Nimpl and even up to 1.8 V (SHE) for AlNimpl. Above these potentials, the nitrides were oxidized to metal oxides.
Non‐destructive characterization of chromium phosphate coated aluminium with SE and FTIRS correlated to surface analytical analyses by AES and TEM
Authors: Goeminne G. , De Laet J. , Terryn H. , Vereecken J.
Published: May 2005

Non‐destructive optical investigations (SE and FTIRS) of chromium phosphate conversion layers on aluminium are correlated to AES and TEM investigations. The AES results support the duplex model of the structure. FTIR‐spectra provide a non‐destructive characterization in agreement with the Auger data. Fitting the SE‐data with a proper model makes it possible to determine the thickness accurately. A correlation is made between the thickness obtained with SE, FTIRS and AES. It is shown that for thin layers a good agreement is obtained.
Theoretical and experimental study of the infrared reflectance of multilayer oxide films on metals
Authors: Lefez B. , Lenglet M.
Published: May 2005

Theoretical calculations have been made for different single and duplex systems (Cr2O3/Fe, MnCr2O4/Fe, MnCr2O4/Cr2O3/Fe and Cr2O3/MnCr2O4/Fe) in order to study the initial stages of high temperature oxidation of AISI 304 and 316 stainless steels by FTIR specular reflectance spectroscopy at variable incidence. Used in conjunction with physical methods like SIMS or AES, the vibrational spectroscopy gives access to structural and compositional information in the analysis of multilayer systems with a high level of complication.
Analytical and electrochemical study of passive films formed on nickel—chromium alloys: Influence of the chromium bulk concentration
Authors: Boudin S. , Vignes J‐L. , Lorang G. , Da Cunha Belo M. , Blondiaux G. , Mikhailov S. M. , Jacobs J. P. , Brongersma H. H.
Published: May 2005

Depth composition and chemical states of elements constituting the overlayers of NixCr alloys (x = 0–30 at.%) passivated in borate buffer solutions (pH = 9.2) were determined as a function of the chromium bulk content of the alloy. Depth sputter profiling was performed using both Auger electron spectroscopy (AES) and low energy ion scattering spectroscopy (LEIS). Chemical bonding and (oxy‐hydroxy) structures of alloying elements in the passive films were investigated by x‐ray photoelectron spectroscopy (XPS). The electrochemical study mainly consists in establishing the cathodic reduction kinetics of the passive layers to characterize the resistance of the internal Cr2O3 barrier to reduction.

Very thin films (less than 2.5 nm) were obtained in those conditions showing duplex structures where minor external nickel oxy‐hydroxide layers are depicted covering an inner protective barrier mainly composed of chromium oxide Cr2O3. Only at high bulk chromium contents (> 15 at.%) are complete Cr2O3 layers built at the interface with the metallic alloy. Beneath the film, in the underlying matrix, a metallic nickel enrichment combined with a chromium depletion is observed, which seems to confirm, as for FeCr alloys, a mechanism by which Cr oxidizes preferentially in this medium during the first steps of the film growth.
AES investigations of local inhomogeneities in aluminium oxide films on Fe‐based alloys
Authors: Oswald S. , John A. , Quadakkers W. J.
Published: May 2005

Aluminium oxide layers grown during high‐temperature oxidation on Fe‐based alloys have been investigated by lateral high‐resolution Auger electron spectroscopy. Comparison of the results with depth profiles measured by secondary ion mass spectrometry shows that the distribution of minor elements is connected with the formation of local inhomogeneities in the oxide layers. These properties are different depending on minor element concentration and manufacturing conditions of the materials.
SIMS analysis of Al δ‐doped GaAs test structures using chemical bevelling as a sample preparation technique
Authors: Hsu C. M. , Sharma V. K. M. , Ashwin M. J. , McPhail D. S.
Published: May 2005

A chemical bevelling technique has been developed to synthesize high‐magnification bevels in gallium arsenide for SIMS linescanning and imaging. Bevels have been prepared in gallium arsenide substrate material, in gallium arsenide implanted with aluminium and in two delta‐doped (aluminium) GaAs test structures. The accuracy, sensitivity, dynamic range and depth resolution–depth characteristics of the bevel and linescan approach have been compared to conventional SIMS depth profiling. Images of the bevelled structures have been used to obtain a quick view of the features of interest. Linescans have yielded an aluminium profile from the aluminium implant that is very similar to that from a SIMS depth profile. Linescan results from the aluminium deltas in gallium arsenide indicate that depth resolutions of a few nanometers can be retained to depths of several microns. The depth resolution of the deltas has been measured as a function of bevel magnification and a theory has been developed to explain the results. A peak width (resolution) of 2.2 nm for an aluminium delta has been achieved at a bevel magnification of 6000 using a 15 keV 16O2+ ion beam, and a depth resolution limit of 1.3 nm has been deduced by extrapolation to infinite bevel magnification. The combined effects of beam‐induced mixing, microtopography and the escape depth of the secondary ions is a broadening of 2.0 nm for these conditions.
Static SIMS study of hydroxylation of low‐surface‐area silica
Authors: Wood B. J. , Lamb R. N. , Raston C. L.
Published: May 2005

Relative surface silanol (SiOH) concentration levels on low‐surface‐area crystalline silica (synthetic quartz crystal) have been determined using the static secondary ion mass spectroscopy (SIMS) technique. Various sample pretreatments, including water plasma (maximum silanol/hydroxylation), heating in a vacuum to ∼550°C, heating in a vacuum to > 1000°C (minimum silano/hydroxylation) and inert gas ion bombardment in ultrahigh vacuum (UHV), are examined. Both positive ion ration (SiOH+/SiO+, SiOH+/Si+) and a negative ion ratio (OH−/O−) were monitored as a function of temperature as the pretreated surface dehydroxylated (increasing temperature) and rehydroxylated (decreasing temperature) in the UHV analysis chamber. Plots of positive ion and negative ion ratios for all data at the various stages of hydroxylation indicated a linear relationship. Deviations from this were attributed to the presence of physisorbed water and/or surface hydrocarbon contamination.
Study of electron backscattering within the approximation of discrete flows
Authors: Borodyansky S. , Tougaard S.
Published: May 2005

The path length distribution function (PLDF) for backscattered electrons was calculated within the four‐flow approximation. The problem was solved by using the invariant‐embedding approach. It was shown that the PLDF is very sensitive to the variation of the parameter describing the elastic scattering cross‐section's anisotropy.

Methods of calculation of a probability of elastic electron backscattering and methods of reflection energy‐loss spectroscopy processing for calculating the electron differential inelastic scattering cross‐section are also discussed.
Analytical background correction in numerical Fourier transform procedures. Application to electron spectroscopy
Authors: Aminov K. L. , Pedersen J. Boiden
Published: May 2005

An analytical correction method is proposed to eliminate the problems resulting from numerical Fourier transformation of functions with a broad background. The method incorporates the analytically known or observed asymptotic behaviour into the numerical procedure. The applicability and high accuracy of the background correction method is illustrated by application to the analysis of reflected electron energy‐loss spectra.
Efficient calculation of photoelectron angular distribution
Authors: Werner Wolfgang S. M. , Tilinin Igor S. , Jablonski Aleksander
Published: May 2005

Different methods of calculating efficiently the angular distribution of photoelectrons escaping from uniform amorphous and polycrystalline targets are analysed in detail. Comparison has been made between the analytical results and Monte Carlo simulation data. The analytical approach is based on the solution of the kinetic equation in the transport approximation. The Monte Carlo codes comprise the conventional forward simulation algorithm and the reverse trajectory method. The reverse trajectory method employs the reciprocity theorem and allows same statistically significant results to be obtained with less computational effort. The angular distributions of photoelectrons leaving Al, Si, Cu, Ag, Ta and Au samples have been calculated as a function of polar and azimuthal angles for electron energies relevant in quantitative XPS analysis. It has been found that both Monte Carlo methods provide equivalent results. The discrepancies between the transport approximation and the Monte Carlo data do not exceed, as a rule, 5%. The largest deviations of the analytical results from those found by Monte Carlo codes are observed in the vicinity of the emission directions, where the photoelectric differential cross‐section has its minima, and are about 15%. The agreement between the results obtained by different approaches, corresponding to the magic angle geometry, is within 2% for all cases studied.
Effect of PVC resins on multi‐screw pipe extrusion
Authors: Weiler Robert G.
Published: May 2005

The increased use of multi‐screw (twin) extruders by pipe producers brought on this study of available PVC homopolymer “pipe grade” resins. Basic tests on resin were examined via a “Correlation Matrix” computer program. Highly significant test data were determined to be internal pore volume and centrifuge plasticizer adsorption. Additional compound evaluation proceeded via torque rheometer followed by twin‐screw extrusion. Significant resin test values affecting extrusion properties are inherent viscosity, apparent bulk density, porosity uniformity and melt viscosity. The work shows that the compounder should know resin properties in order to benefit from processing equipment developments.
Developing low temperature, impact‐resistant PVC—a new testing approach
Authors: Goldman Theodore D. , Lutz John T.
Published: May 2005

Concern over making end‐use predictions from milled/notched Izod test data for applications where product manufacturing techniques differ greatly from Izod test sample preparation brought on this study of the use of Gardner‐type impact tests on commercial and laboratory extruded PVC sheet. By notching the test sample, the standard Gardner and Izod impact tests at low temperatures could be predicted at room temperature in the Gardner test equipment.
Energy and material cost savings with polyester/monomeric plasticized PVC compounds
Authors: Bender M. H. , Lutz J. T.
Published: May 2005

Many plasticized PVC articles are exposed to harsh environments that cause loss of plasticizer through extraction, volatility, or migration. In order to survive in these applications, the PVC must contain plasticizers that have a reasonable degree of permanence. Two approaches are the use of low molecular weight polyester plasticizers, or higher molecular weight polyester/monomeric plasticizer blends. The blend approach can give better cost‐performance and, due to faster fusion, reduced energy/manufacturing costs. The blends maintain their advantages even upon further dilution with monomeric plasticizers and in permanence tests of long duration. Although better than monomeric plasticizers, neither the low molecular weight polyester nor the blend system is recommended for applications requiring the ultimate in migration resistance.
Electrical behavior of poly(vinyl chloride): Wien‐Onsager effect deviations from Ohm's law
Authors: Wingrave James A.
Published: May 2005

An examination of electrolyte conduction in solid PVC plaques shows an enhancement in equivalent conductance in excess of that predicted by Onsager's theory of electrolyte conduction even when ion activity effects are considered. Although Onsager's theory includes Wien effect behavior, the experimental equivalent conductances were significantly in excess of the predicted values. From an examination of electrolyte conduction theory, several unique features of electrolyte flow in PVC are found which are not observed for liquid dielectrics. Based on these concepts, a qualitative explanation based on Onsager's original theory is proposed. The observed behavior is referred to as a Wien‐Onsager effect.
Ways of poly (vinyl chloride) stabilization
Authors: Minsker K. S. , Kolesov S. V. , Zaikov G. E.
Published: May 2005

Main results of research on poly (vinyl chloride) (PVC) stabilization are discussed. Stabilization is viewed from the standpoint of the modern notions of the reasons for PVC low thermal stability, the complicated nature of its dehydrochlorination, and the kinetics of its degradation. The internal unsaturated oxygen‐containing groups of ∼C(O)CHCHCHCl∼ type are regarded as the main source of the polymer instability. Typical processes resulting in PVC stabilization, such as the substitution of labile chlorine atoms and the destruction of initial active sites during reactions with various chemical agents, as well as the kinetic aspects of stabilizers' effect on HCl elimination and PVC macromolecules crosslinkage are considered. The influence of additives on the polymer coloration is estimated.
Flow behavior of PVC in hot‐die‐face pelletizing: Die hole pattern optimization
Authors: Campbell Gary A.
Published: May 2005

Die hole pattern optimization can minimize the pressure loss across the die plate for a given set of products, while maintaining sufficient steel strength. Data will be presented from a high‐pressure capillary rheometer to establish flow behavior and investigate the effects of die geometry on flow resistance. The influence of formulation parameters, degree of gelation and shear gradient will be considered. Finally a model will be developed for the optimization of the die hole pattern. Using this procedure, it will be possible to establish the data needed for optimal die hole pattern design by calculation and graphic presentation.
Behavior of plasticizers in poly (vinyl chloride) resins. I. A method for measuring dynamic plasticizer absorption in suspension resin grains
Authors: Wingrave James A.
Published: May 2005

An instrument which measures the absorption of plasticizer in resin grains as a function of time is described. From a single experiment, one is able to determine directly the capacity of the resin for a desired plasticizer and the time and temperature required for complete absorption or “drying‐up” of the plasticizer by the resin. Based on data for a series of resins with different polymerization histories, observations regarding the effects of grain morphology on plasticizer absorption are discussed.
Air release in PVC plastisols
Authors: Defife J. R.
Published: May 2005

The ability of a PVC plastisol to liberate entrapped air during mixing and processing is an important factor to the processors. This property, known as air release, is affected by several variables such as resin, plastisol viscosity, surface tension, surfactant system and plasticizer type. A study was conducted to obtain a more fundamental understanding of the effects of these variables on air release. Complicating the accurate study of a plastisol's air release properties is the fact that current test procedures such as the vacuum rise, syringe test and Huff or ring test each have limitations imposed by either plastisol properties or by testing technique. Any one of these procedures alone may not adequately measure air release. This paper, in addition to studying the factors affecting air release, discusses these testing limitations and makes recommendations as to the best methods for evaluating air release properties in the laboratory.
Low smoke, non‐contaminating speciality compounds
Authors: Varenelli Andrew D. , Weintraub Lester , Pearson Stanley
Published: May 2005

A proprietary polymer has been used to create a variety of compounds. Of particular interest are a series of compounds which are flame resistant, generate low smoke, are non‐contaminating, and which exhibit excellent oven aging characteristics without impairment of low temperature flexibility. The paper will discuss the properties of the polymer and the properties of the various compositions which make them suitable for many applications such as wire and cable, film and sheet, medical, automotive, shoe soles and appliances.
Injection molding of PVC—today and tomorrow
Authors: McNally William J.
Published: May 2005

Injection molding of PVC has been considered quite difficult because of the apparent low thermal stability with a high viscosity. While other materials were benefited by improved molding technology, technology applied to the molding of PVC received little attention. Whereas injection molding of PVC has been limited to general purpose pipe fittings, new resin technology and formulations provide compounds with excellent flow, easy molding characteristics and a good balance of physical properties.
Factors affecting the carbon dioxide barrier of vinylidene chloride‐vinyl chloride copolymer films
Authors: Delassus Phillip T.
Published: May 2005

Copolymers of vinylidene chloride can be fabricated into films that have excellent barriers to carbon‐dioxide transparent. To retain the maximum barrier, liquid additives should not be used. Since the carbon dioxide barrier properties of different polymers have different temperature sensitivities, you must compare properties at the temperature of intended use.
Gel phenomena in flexible PVC resin
Authors: Zabrecky Judy E.
Published: May 2005

The existence of fisheyes or gels in PVC final products has been a problem which the PVC industry has coped with for many years. The classical gel is a non‐porous PVC particle which cannot absorb plasticizer. Other finished product defects which may be classified as gels by a customer are unfused particles of higher molecular weight resin or resin gels and agglomerates caused by improper mixing procedures called compound gels. Although this paper will define and cite examples of resin gels and compound gels, it will deal primarily with classical gel. Over the years, many different gel tests have been used by PVC suppliers and consumers in order to define the gel level of a particular sample of resin. The most common of these tests is the test using a two roll mill to produce a colored mill sheet which is examined and the number of gels reported. This paper will use statistical methods to the factors which can introduce variability into the test results, including mill roll gap, mill speed, milling time, and temperature. In addition, the nature of the distribution of gels in a sample of PVC resin will be discussed. Finally, the paper will delve into new laboratory techniques which may lead to eventual automation of counting and reporting of gel levels in a resin sample.
PVC compounds for photochemical crosslinking
Authors: Drexler Jiří , Maláč Jiří , Rektoříková Libuše , Šimoník Josef
Published: May 2005

The best of all photoinitiator systems for crosslinking PVC compounds, according to tests made with a Tesla RVIM discharge tube, is the combination of chlorthioxanthone and triethanolamine. Pentaerithroltriacrylate is the most effective crosslinking agent. Lead stabilizers give the best heat stability and a higher rate of photochemical crosslinking than tin and antimony stabilizers.
Effects of plasticizer desorption, temperature, and pressure on the permeability of saran
Authors: Chen J. S. , McCarthy S. P.
Published: May 2005

Work has shown that (1) the permeability of saran film increases exponentially with increasing temperature due to activation energy, (2) permeability of saran film decreases slightly with increasing pressure–but to only a very slight extent, (3) microwave radiation does not affect permeability as long as the film is not heated during treatment, and (4) low amounts of liquid additives correlate with lower permeability. It is suggested that the barrier property of saran film can be improved without sacrificing the processing ability.
Rigid PVC: New developments for improving weatherability
Authors: Conroy Gary M. , Wursthorn K. R.
Published: May 2005

Polyvinyl chloride is rapidly becoming recognized as a versatile polymer. It has a unique ability to accept additives, and the properties of the finished article often depend more on formulation than the resin itself.

A wide variety of chemical may function similary in PVC, yet processors often have to compromise in selecting one additive over another. For example, both tin mercaptides and metal carboxylates function as thermal stabilizers. The mercaptide is superior as a thermal stabilizer while the carboxylate offers better weathering stability. Today's market tends to compromise at the expense of weathering. To compensate, high levels of reflective pigments (TiO2) are used.

Recently, we initiated a research program and discovered a class of compounds which provide excellent weatherability with processability comparable to the highly‐efficient tin mercaptide. This cost‐effective development allows reduction of TiO2 levels by 25–50%. In addition, dark pigmented profiles remain relatively undeveloped because of serious weathering problems. Accelerated weathering and outdoor exposure tests demonstrate this technology is quite effective for UV stabilization of dark brown systems.
Strain‐induced crystallization kinetics of vinylidene chloride/vinyl chloride (VDC/VC) copolymers
Authors: Lund Monty , Remenar Richard , Burt Ed
Published: May 2005

The strain‐induced crystallization (SIC) behavior of VDC/VC copolymers has a significant effect on processibility on the blown film process. However, data on SIC of VCD/VC copolymers has been very limited due to the difficulty of measuring the rapid crystallization rates induced by strain; whereas, crystallization under quiescent conditions has been studied extensively. In this work, SIC of VDC/VC copolymers has been calculated from measurements of the adiabatic temperature rise upon stretching of amorphous specimens. The effect of stretching conditions such as strain rate, total strain, and initial temperature and the effect of polymer variables such as copolymer composition, molecular weight, and plasticizer content are determined. It is found that the performance of different VDC/VC copolymers on the film‐blowing process correlates much better with measurements of SIC than with quiescent crystallization behavior.
Application of the UNIFAC‐FV group contribution method to the prediction of relative compatibility of plasticizers with PVC
Authors: Boo Hwee‐Khim , Shaw Montgomery T.
Published: May 2005

The applicability of a modified version of UNIFAC group contribution method, UNIFAC‐FV, is explored for use in predicting liquid‐liquid equilibrium behavior of plasticizer/PVC systems. A Fortran program for the UNIFAC‐FV model has been written to calculate the activities and changes in the Gibbs free energy for multicomponent systems. By this means, the interaction parameter X for a polymer‐solvent system is defined using the well known Flory‐Huggins equation. The concentration dependent Gibbs free energy of mixing is used as a criterion for the relative compatibility of the PVC‐plasticizer system. The method indicates that, for the plasticizers examined, DOS is the least compatible and DBP is the most compatible with PVC. This confirms the results of the glass transition width measured by dynamic mechanical analysis previously reported.
Multiphase PVC/styrenic copolymer alloys: Internally reinforced by partial miscibility
Authors: Bourland L. G.
Published: May 2005

Although polymer/polymer miscibility is considered the exception to the general rule, in polymer thermodynamics specific interactions between active sites on two polymers can be a driving force for polymer/polymer miscibility. Both the intermolecular interactions of the alpha hydrogen of PVC with carbonyl groups in various polyesters and the polarity of the chlorine bond have been claimed to promote miscibility. Both of these interactions are potential in PVC/styrene maleic anhydride (SMAnh) polymer blends. These specific interactions promoting miscibility and the resulting mechanical properties of these systems is the subject of this report. SMAnh (12.5% MA) copolymer was melt compounded with a stabilized PVC compound using a Haake Rheocord twin screw extruder. Test data generated for these blends were analyzed for miscibility and effects of SMAnh copolymers on heat resistance, fire retardance, impact strength, and processability of PVC.
Shrinkage in rigid PVC profile extrusions
Authors: Rabinovitch E. B. , Quisenberry J. G.
Published: May 2005

Shrinkage in PVC profile extrusions may have an effect on the end use performance (dimensional stability, mechanical properties) of the building products such as house siding and windows when they are heated by the sun. This paper examines the heat shrinkage tests being used in the industry, and most importantly, describes effects of the extrusion conditions such as melt temperature, shear rate, percent drawdown, and other variables on shrinkage in PVC profiles.
Effect of degree of ethoxilation on the viscosity depressancy properties of fatty acid ethoxilates used in PVC paste formulations
Authors: Düzgören M. , Bilgic T. , Savaşçi Ö. Tunç;
Published: May 2005

Plastisols of poly (vinylchloride) (PVC) are important commercial products. The rheological properties especially the viscosity of the paste plays an important role in PVC paste applications. Viscosity depressants are usually added to paste formulations in order to obtain desired paste viscosities. In this work, viscosity depressant effects of various fatty acid/ethylene oxide condensates containing 2 to 12 moles ethylene oxide per mole are investigated by Brookfield rotational viscometric method. The effectivenesses of the viscosity depressants are determined at 1.3 sec−1 shear rates and a relationship between ethylene oxide content and viscosity reduction is found. This relationship between effectiveness and degree of ethoxilation gives way to prediction of viscosity reduction of paste by simply determining the ethylene oxide content. The effect on 24 h aging is also studied. The results showed improvements in short term aging properties of the PVC paste.
Composites of polyvinyl chloride—wood fibers: IV. Effect of the nature of fibers
Authors: Maldas D. , Kokta B. V. , Daneault C.
Published: May 2005

The suitability of different pulps (e.g. chemithermomechanical, kraft, tempure, temalfa, cotton, and sawdust) as well as various wood species (e.g. softwood, spruce; hardwood, aspen and birch) as the reinforcing filler for thermoplastic composites of PVC (two different grades) have been evaluated on the basis of mechanical properties. Mechanical properties of the non‐treated composites were improved by the addition of a coupling agent [poly (methylene (polyphenyl isocyanate))] either in pure state or in solution, and by the pre‐treatment of the fibers by encapsulation. The order of reactivity of the pulps varies widely with the change in the grades of thermoplastics and the quality of treatment. Due to the interference of properties of the pulps in the composites, the relative reactivity changes.
Comparative effect of plasticizer interchange on flexible PVC processing as measured by a torque rheometer
Authors: Bergado Simo T.
Published: May 2005

Present testing methods of comparing dryblend and fusion characteristics of poly (vinyl chloride) address resin interchange, but not plasticizer interchange. The wide range of available plasticizers requires methodology to predict plasticizer performance from a processing viewpoint. Modification of the test parameters reported in this study makes it possible to predict how plasticizer interchange affects processing under dynamic conditions.
Use of regrind in the PVC extrusion process
Authors: Rabinovitch E. B. , Booth Patrick C.
Published: May 2005

Extrusion products that to not meet specification are generally reground for extrusion reprocessing. This paper describes the effect of heat history of regrind materials on extrusion quality, including surface appearance (melt fracture), toughness, edge tear, and heat stability. It is hoped that the information presented in this paper will help processors optimize use of regrind for best performance.
Recent developments in plasticized flame retardant polyvinyl chloride (PVC)
Authors: Green Joseph
Published: May 2005

Triaryl and alkylaryl phosphates are plasticizers/flame retardants for polyvinyl chloride. The former are more effective flame retardants and the latter are better plasticizers. The latter also gives less smoke. A new phosphate ester blend with good plasticizer properties and low smoke is reported. A brominated triaryl phosphate ester is shown to be a highly effective flame retardant giving plasticized polyvinyl chloride compositions with oxygen index values up to 36. These compositions are suitable for high temperature wire and cable products.
Comparison of QUV accelerated weathering to outdoor exposure for PVC compounds
Authors: Rabinovitch Elvira B. , Butler Robert S.
Published: May 2005

Weathering characteristics of the PVC compounds used for exterior applications, such as house siding, window and door frames, must be determined in order to predict their performance in actual use. In this study color weatherability of various PVC compounds, determined in the QUV accelerated weatherometer, was compared to the outdoor exposure in Arizona, Ohio, and Florida. The effect of the compound base formulation and color on correlation of the QUV to the outdoor weathering has been also analyzed.
A review of the relationship of tin content and ligand structure on stability of rigid PVC compositions
Authors: Kugele Thomas G. , Conroy Gary M.
Published: May 2005

Histrorically, the measure of thermal performance on given PVC compositions has been approximated by the metal content of the chosen heat stabilizer. However, advances in tin and ligand chemistry necessitate the evaluation of thermal stabilizers on criteria other than metal content. Many factors including the nature of the metallic species and relative activity of the organic ligands must be considered. A discussion will be given on the facets of heat stabilizer compositions and their effects upon PVC formulations and processing. Performance criteria for organotin stabilizers. The take‐home point will be that tin content alone, in most formulations, is not the most important determinant in PVC heat stabilizer effectiveness.
Hazardous waste: The toxicity characteristic
Authors: Ledvina Joseph C.
Published: May 2005

On March 29, 1990, EPA promulgated the Toxicity Characteristic (TC) greatly expanding the amount of waste considered hazardous. The rule became effective six months later on September 25, 1990. Under the TC, wastes are evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) to determine if the waste is hazardous. Regulatory levels were established for an additional 25 organic compounds expanding the TC constituents list to 39 substances. The regulatory level for vinyl chloride was set at 0.2 mg/1, a sufficiently high level to assure that most PVC wastes will not be hazardous because of VCM.
Effect of co‐additives on the flame/smoke suppression properties of zinc borates
Authors: Moore Fred W. , Kennelly William J.
Published: May 2005

Two zinc borates are useful partial replacements for the antimony oxide flame retardant normally used to flame retard flexible PVC products. The effect of using various co‐additives with zinc borates on the flame retardancy and smoke formation of a model flexible PVC cable jacket was evaluated in an attempt to further improve the properties of the formulation. The use of ammonium octamolybdate with the borates yields products with improved properties. Highly flame retarded formulations that yield low levels of smoke can be prepared by using alumina trihydrate or magnesium compounds as replacements for the usual calcium carbonate filler. Replacement of part of the phthalate ester plasticizer with brominated ester, a phosphate ester, or a brominated phosphate ester also results in formulations with oxygen values as high as 39.5 which produce lower levels of smoke.
Medical grade tubing: Criteria for catheter applications
Authors: Lambert James M. , Lee Min‐Shiu , Taller Robert A. , Solomon Donald D.
Published: May 2005

In 1990 there were approximately 710 million catheter units produced world‐wide from a variety of materials. This number is expected to increase 5–7% in 1991. Intravenous catheters are currently being produced from a myriad of materials including polyurethanes, polyvinylchloride, silicone rubber, and Teflon®, to name a few. Along with the ultimate end usage of a catheter, many other performance characteristics must be evaluated. Some of these characteristics are mechanical and physical properties, surface properties, hemocompatibility, biostability, and processability. The Vialon® biomaterial has a tensile strength of 520 kg/cm2 which is over 50% higher than the other materials studied. This bioengineered material, which is a member of the broad class of polyurethanes, also gave better hemocompatibility properties, as measured by in vivo platelet deposition. In addition Vialon® is engineered such that the material softens in the body's moisture and heat rendering it biocompatible. The thermoplastic nature of this polymer also allows its ease of processing by such conventional means as thermal extrusion. A comparison of the aforementioned materials against these and other performance criteria was undertaken and will be presented.
Carrier resin for a multi‐polymer solid color concentrate
Authors: Popli R. , Mauer D. H. , Witenhafer D. E.
Published: May 2005

A multi‐polymer color concentrate has the advantage of reducing the inventory cost for the user and the manufacturer. In this paper, we present results on a carrier polymer which has been used to color a wide‐variety of non‐olefin polymers, such as PC, ABS, SAN, PMMA, PET, PS, POM, and nylons. The carrier polymer is miscible with the plastic to be colored, has excellent pigment wetting character and possesses thermal stability for processing. Data demonstrating miscibility, mechanical properties, and multi‐polymer coloring ability for many of the polymer is presented.
Polymer lifetime studies in hostile environments
Authors: Hamid S. H. , Amin M. B. , Maadhah A. G. , Al‐Jarallah A. M.
Published: May 2005

Photo‐oxidative degradation reactions are mainly responsible for reduced lifetime in polymers. These reactions are responsible for the decay in useful physical and chemical properties of polymers. In addition to high ultraviolet radiation doses, hostile environments have increased temperature, high humidity, and air‐borne sand. In this work white pigmented polyvinyl chloride (PVC) pipe sections were exposed to natural weather at seven different locations. Characterization studies were made on exposed samples using Fourier transform infrared (FTIR) spectroscopic, gel permeation chromatographic (GPC), and scanning electron microscopic (SEM) studies. Performance characteristics were determined by testing changes in the mechanical properties. Functional groups introduced during the processing of PVC and irregularities in the polymer chain can be held responsible for the initiation and propagation of photo‐oxidative degradation reactions catalyzed by high surface temperature and increased humidity.
Microcellular PVC
Authors: Kumar Vipin , Weller John E. , Montecillo Romano
Published: May 2005

Novel microcellular PVC foams with a very homogenous cell distribution and cell densities ranging from 107 to 109 cells/cm3 have been created using carbon dioxide as the nucleating gas. Microcellular foams with relative densities (density of foam divided by the density of unfoamed polymer) ranging from 0.15 to 0.94 have been produced. It was found that the bubble nucleation density has and Arrhenius‐type dependence on temperature, while the average bubble diameter is relatively independent of the foaming temperature. A majority of the cell growth was found to occur in the early stages of foaming.
Selecting the proper process aid for the application
Authors: Kitai Kiyokazu , Holsopple Peggy , Okano Kenji
Published: May 2005

With the advent of new and demanding applications such as foam core pipe and coextruded siding and profile, coupled with the demand for more highly efficient cost/performance products in older PVC applications resulting from the desire to increase output, and with the push towards recycling, there is a strong need for efficient and effective processing aids. Process aids have been used for many years to improve the appearance and properties of PVC. In the past they were limited to low and high molecular weight products (0.3 to 0.5 reduced viscosity value), lubricating type acrylics, and some lower‐efficiency styrenics. This paper will describe a much broader range of process aids that are designed to fit the requirements of specific formulation and processing techniques. Rather than force fitting the few older processing aids into all applications, the PVC processor now has the luxury of optimizing his formulation by choosing from a wide molecular weight range of products (0.1 to 0.9 reduced viscosity value). The different structures and molecular weights of currently commercial process aids are discussed, as well as their “fit” in today's formulations.
Investigation of multiphase polymeric systems of poly(vinyl chloride)/ethylene‐propylene‐diene‐gp‐(styrene‐CO‐acrylonitrile) blends
Authors: Sudhakar K. , Singh R. P.
Published: May 2005

The graft copolymer, ethylene‐propylene‐diene rubber (EPDM)‐gp‐(styrene‐co‐acrylonitrile) has been synthesized by solution precipitation polymerization using benzoyl perixide as initiator. The graft copolymer has been characterized after separation through soxhlet extraction by IR, NMR, and elemental analysis techniques. The graft copolymer of EPDM is melt blended with PVC. The nature of compatibility of the graft copolymers with PVC has been studied by means of morphological analysis and by thermal analysis. The mechanical properties, Izod impact strength, tensile strength, and flexural modulus of the blends are extensively studied over the wide range of concentrations. The results of both compatibility and mechanical properties are compared with those of PVC/EPDM blends. The nature of compatibility obtained shows that PVC/EPDM blends are incompatible and the PVC/EPDM‐gp‐SAN system is semicompatible. Also, these results indicate that the PVC/EPDM‐gp‐SAN system has its highest impact strength at 14 wt% of EPDM/gp‐SAN graft copolymer. The fractured surface analysis of the impact fractured samples is also undertaken by an SEM technique. The results of the mechanical properties are discussed in view of existing theories of impact modification, along with the morphological feature of fractographs.
Processing aids for poly(vinyl chloride)
Authors: Parker Hsing‐Yeh , Dunkelberger David L.
Published: May 2005

Processing aids are an important class of additives for poly(vinyl chloride) (PVC). At relatively low concentration, processing aids enable the melt processing of rigid PVC and enlarge its processing windows. Discussed in this presentation are some major functions of processing aids, such as promoting PVC fusion, modifying PVC's melt rheology, and lubricating to prevent adherence of PVC melt to the processing equipment. Some examples are given to show the effects of processing aids on PVC die swell, melt fracture, melt viscosity, and PVC fusion. Commercial sources of various processing aids and typical PVC formulations for various applications are also discussed.
The coloring of PVC
Authors: Sarvis Harrey E.
Published: May 2005

Polyvinyl chloride—PVC—has been commercial since the mid‐1930s. It is one of the most versatile of all thermoplastic resins. By the end of this year, United States consumption of PVC resin could reach 4.2 million metric tons. Some of the key markets for PVC are pipe, siding, windows, floor coverings, wire and cable insulation, and protective coatings, to name just a few. As you would expect, color plays an integral part in many of these applications. The purpose of this paper is to review the major colorant types and families that are used to color PVC, with special emphasis placed on end‐use applications. Within the context of coloring PVC, the continued use or replacement of lead and cadmium bearing colorants is discussed.
Antistatic agents
Authors: Grossman Richard F.
Published: May 2005

The different types of antistatic agents used in vinyl compounds are reviewed. Although each type functions generally in the same way, by formation of a two‐dimensional, hydrogen‐bonded, hygroscopic network on the surface of the finished article, there are noticeable differences in performance and suitability for various applications. Test methods are compared and working formulations for a range of applications discussed.
Improved method for detection of organotins in food simulants
Authors: Dominic Mary Rita , Koch Charles P. , Mills Jerry K.
Published: May 2005

An improved method for detection of organotin compounds in fatty food‐simulants has been developed. It offers improved sensitivity and specificity over complexation‐colorimetric and other methods. This method has been used to test for leaching of tin from PVC bottles stabilized with methyltin stabilizers. The results of this testing at various temperatures demonstrated safe levels for consumers.
Rigid cellular PVC—the next house siding material?
Authors: Szamborski E. C. , Buterbaugh T. E.
Published: May 2005

The technology for extruding rigid cellular PVC has grown substantially over the past decade. Formulation additives, tooling, and processing expertise have made possible a variety of applications—relatively complex profiles, foam‐core pipe, thermoformable foam sheet, and house siding. In the U.S. market, vinyl house siding is typically a relatively thin extrusion that is folded into a final shape that resembles wood cladding in appearance. An alternative to conventional form vinyl siding could be a foam structure that is thicker and stiffer than the solid form, and with a density similar to that of wood. This paper presents several performance advantages of rigid cellular PVC cladding in comparison to the current solid product, in addition to mentioning certain limitations that exist in the foam product that is produced with the technology available today.
Factors influencing PVC resin apparent bulk density
Authors: Kauffman Mark A. , Guise Richard S.
Published: May 2005

Bulk density is one of the easiest measured and most practical physical properties of PVC resins and compounds, especially those used in rigid applications. The paper addresses the importance of bulk density of rigid PVC resins, both regular and antistat, and their compounds. The negative influence of static electricity on bulk density measurement of PVC resins is studied and discussed. Effective static removal and accurate, consistent bulk density measurement is explored through various methods such as compacted bulk density and conditioned bulk density (either by addition of silica, methanol or carbon black, or by treatment with an ionizer).
Concentration and temperature dependence of plasticizer diffusion into plasticized PVC
Authors: Audouin L. , Andre A. , Verdu J.
Published: May 2005

The diffusion of a plasticizer S1 from a source made of PVC containing 25 wt% of S1 into a medium made of PVC film containing another plasticizer S2 in 15, 20, 25 and 30 wt%, was studied at temperatures ranging from 70 to 108°C. S1 was generally diphenyl‐iso‐octyl phosphate (DPIP) and S2 was dioctyl phthalate (DOP) but the reciprocal system was also studied in some cases. Starting from a reference point corresponding to a temperature of 70°C and a DOP concentration of 25 wt%, it was found experimentally that an increase Δv of the DOP volume fraction (v) or an increase ΔT of the temperature, led to the same variation of the diffusion coefficient of DPIP if ΔT/Δv ∼ 139K. A reasonably close value can be obtained from a simple free‐volume approach, using the literature data on the plasticizer action of DOP on PVC.