bluuebunny/crossref_metadata_2025 huggingface dataset:
In search of the ultimate experiment for quantitative depth profile analysis in glow discharge optical emission spectrometry. Part I: Calibration curves
Authors: Payling Richard , Jones Delwyn G. , Gower Stephen A.
Published: May 2005

This is the first part of our search for an experiment that will show definitively which is the best method for quantitative glow discharge optical emission spectrometry (GDOES). Three empirical methods for producing quantitative depth profiles from GDOES data are examined: the SIMR method, the IRSID method and the most recent BHP method. All three methods give worthwhile quantitative depth profiles of thin films and coated materials. The first two methods assume that pressure does not have a significant effect on emission yield, while the third method assumes that pressure is the only significant parameter affecting emission yield. The different approaches therefore imply very different physical processes inside the lamp and it is essential for further development of quantitative GDOES that the best approach be determined. Depth profiling in GDOES is, in principle, simply bulk analysis repeated over and over as a function of depth. The three methods are therefore tested here in their ability to do bulk calibration in a range of steels and zinc–aluminium alloy standards, all at constant current. All methods worked well for steel, while the best calibration curves in zinc–aluminium alloys were obtained with pressure‐corrected IRSID and SIMR methods or a voltage‐corrected BHP method. The results suggest that emission yields depend on both voltage and pressure (and presumably current, which was not tested here in Part I).
Characterization of plasma‐deposited styrene films by XPS and static SIMS
Authors: Leggett Graham J. , Ratner Buddy D. , Vickerman John C.
Published: May 2005

Plasma‐polymerized styrene films were studied by static secondary ion mass spectrometry (SIMS) and x‐ray photoelectron spectroscopy (XPS). The two techniques were found to yield complementary data regarding film chemical structure. Static SIMS proved to be highly sensitive to subtle changes in surface chemistry. For example, the static SIMS spectra exhibited features due to polymer cross‐linking and unsaturation. X‐ray photoelectron spectroscopy provided a good indication of the extent of oxygen incorporation into the plasma‐deposited films and characterization of time‐dependent changes in film composition.
X‐ray photoelectron and Auger electron spectroscopies and surface segregations in Pd–Rh and Pd–Ru membrane catalysts
Authors: Batirev I. G. , Karavanov A. N. , Leiro J. A. , Heinonen M. , Juhanoja J.
Published: May 2005

Auger electron and x‐ray photoelectron spectroscopies are used to estimate the segregation trends at the surface of Pd–Ru and Pd–Rh alloys. The measurements indicate Pd segregation in the studied systems that are in agreement with the Miedema criteria based on surface tensions of pure metals. Microscopic model calculations of the surface electronic structure of the relevant alloys show the same trend. Parameters associated with the electronic structure of the alloys are used in order to explain the experimental data for the hydrogenation reaction on a Pd–Ru alloy membrane catalyst.
Inelastic electron tunnelling spectroscopy and XPS study of the oxides grown on three aluminium alloys
Authors: Pritchard R. G. , Werrett C. R.
Published: May 2005

Three aluminium alloys, each with different major alloying components, have been studied using inelastic electron tunnelling spectroscopy (IETS) and XPS. The oxides grown on alloys containing magnesium and copper have IET spectra similar to that grown on pure aluminium and their IET spectra when doped with benzoic acid also show no differences. The alloy containing silicon gives a very different IET spectrum that has band positions similar to aluminosilicates. When doped with benzoinc acid the IET spectrum of this latter alloy also shows major differences to that of benzoic acid on pure aluminium (oxide), both in band intensities and particularly in the carboxylate stretching modes. X‐ray photoelectron spectroscopy analysis of the oxides on both the alloy thin films (IETS) and metal tokens confirms the results suggested by the IET spectra, showing that the magnesium and copper do not appear in the oxides of the first two alloys but that silicon is present in the oxide of the third and in quantities greater than that of the alloy composition.
Neural pattern recognition applied to AES depth profiling
Authors: Gatts C. , Zalar A. , Hofmann S. , Rühle M.
Published: May 2005

Neural pattern recognition was used to analyse the low‐energy Auger spectra of a thermally annealed Si/Ni/Si layered structure measured during the acquisition of a depth profile. The purpose was to gain information about the chemical state of the elements at the interfaces by processing the data in a way quite similar to conventional target factor analysis (TFA). The new approach, however, has some important advantages: no standards are required, it is extremely fast and it is fully automatic. In principle, there is only one arbitrary parameter, the vigilance parameter ρ, which sets a threshold for the level of similarity required for assuming two spectra as belonging to the same class of data. However, the requirement that the optimal value for ρ should correspond to the maximal correlation between the experimental data set and the recalculated spectra makes the system also robust against misconclusions based on subjective interpretation of the data set, which is not always the case in TFA.
Kinetics and mechanism of the thermal degradation of poly(vinyl chloride)
Authors: Fisch Michael H. , Bacaloglu Radu
Published: May 2005

The kinetics of the thermal degradation of solid powdered poly(vinyl chloride) (PVC) under nitrogen was studied by thermogravimetry, rate of hydrogen chloride evolution, and rate of polyene sequence formation. These results are accommodated by a chain mechanism involving initiation by random dehydrochlorination at normal monomer residues of PVC, and a series of intermediates, each leaking to a stable conjugated polyene sequence. Structural irregularities such as allylic and tertiary chlorine are responsible for a fast initiation process at the very beginning of the degradation. Mean rate constants and activation parameters for random initiation, propagation, and termination reactions of the PVC degradation chain were calculated by simulation. Activation enthalpy/entropy correlations for the experimental data available for dehydrochlorination of chloroalkanes and chloroalkenes in the gas and in the liquid phase or nonpolar solvents and elementary reactions of PVC degradation show that initiation is an HCl elimination through a transition state of four centers requiring a synperiplanar conformation of the >CH–CCl< group, whereas propagation is a dehydrochlorination through a transition state of six centers requiring a cis configuration of the double bond.
Thermodynamic probe of intermolecular coupling in the interphase region of glass fiber reinforced polymer composites
Authors: Karian Harutun G.
Published: May 2005

Mechanical properties of polymer composites are enhanced by an interphase having a brush‐like structure, due to the entanglement of stretched compatibilizer chains and neighboring polymer molecules. Lipatov's model provides a calorimetric method for characterizing the fiber‐matrix interactions and determining the interfacial thickness, i.e., the heat capacity jump at Tg is sensitive to the combined effects of fiber glass content and intermolecular coupling in the interphase region. By a correlation between computed interfacial thickness from DSC methodology and measured tensile strength, we have a quantitative means to develop polypropylene composites having “mega coupled” tensile behavior.
Improved aging and UV resistance of TPEs derived from “diimide‐hydrogenated” emulsion SBRs containing a bound antioxidant
Authors: Parker Dane K.
Published: May 2005

In our continuing efforts to both (1) exploit the versatility of our unique emulsion based diimide hydrogenation technology and (2) expand the performance range of hydrogenated‐SBR TPEs derived from this technology, we have investigated some of the physical and chemical effects of incorporating a polymer‐bound antioxidant into HSBR. A polymerizable amine‐type antioxidant was incorporated into the SBR structure using a conventional type “cold” emulsion polymerization recipe. For comparative purposes, unmodified and AO‐modified SBRs were then “hydrogenated” in their latex forms by the diimide technique to approximately the same extent. Samples of the extracted, isolated polymers were evaluated by DSC techniques to ascertain any effects of the bound antioxidant. Additionally, latex cast films of the HSBRs were evaluated for their initial and aged physical properties. The results of these studies indicate that while hydrogenation of SBR into the 80–90% range does dramatically improve its resistance to oxidation compared with SBR (without antioxidant), a further substantial improvement in oxidation resistance can be obtained at the same hydrogenation level by the incorporation of a bound antioxidant. Furthermore, because the bound antioxidant molecule is too large to be incorporated into the polyethylene‐like crystallites, it resides in the TPE's amorphous phase, where antioxidant protection is needed most, and does not appear to affect crystallite size, distribution, or overall initial TPE physical properties compared with the unmodified HSBRs.
Optimization of antistatic additives in polypropylene
Authors: Williams J. B. , Geick K. S. , Falter J. A. , Hall L. K.
Published: May 2005

The antistatic behavior of glyceryl monoesters in polypropylene (PP) is measured at concentrations down to 0.30 wt%. Water contact angles and XPS analyses are used to explore the mechanism of internal antistats. Orientation of glyceryl monostearate (GMS) at the surface of PP is determined. Several new antistat compositions for PP are introduced.
PVC corrugated drainage pipe
Authors: Pazur A. S.
Published: May 2005

In the continuing struggle to obtain the most economical material for a given application, it is proposed that corrugated PVC can be quite competitive with corrugated PE. An advantage for PVC stems from a flexural modulus that is almost twice that of PE. Corrugated PVC pipe at 135 grams per foot competed with corrugated PE pipe at 140–150 grams per foot. PVC requires a different corrugation design than does PE. Proper attention to balancing flexural modulus and impact strength must be paid in formulation of PVC.
More meaningful measurement of plastisol properties
Authors: Dann Bill
Published: May 2005

The fundamentals of plastisol rheology must be understood in order to properly select and utilize plastisol property measurements. Useful evaluation should also be made of the rheological effects of formulation ingredients and their interrelationships. Other factors such as plastisol preparation, storage conditions, process shear rates, temperatures, dwell times, and finished product specifications will influence the design of effective test procedures. Once meaningful plastisol property measurements have been developed, better quality control assurance results, and in addition quality, productivity, and profitability improvements are effected.
SQC in PVC quality control testing
Authors: Hudak Victor J. , Hoffman David E. , Smith Carol J.
Published: May 2005

Quality control testing can be improved by applying statistical methods. For example, control testing of resins at different locations can identify idiosyncrasies in sites as well as in the testing itself. A program using standard and “control” resins in round‐robin testing between sites was designed to find the sources of variability and to develop procedures to reduce it. The test procedures were: inherent viscosity, bulk density, dry contamination, fisheyes, dry‐blend time, particle‐size distribution, and PVC resin color. Statistical quality control (SQC) charting with root‐cause analysis identified mechanical, environmental, and procedural sources of variability. Even further insight into sources comes from the reduction of variability discovered.
The biodeterioration of plasticized PVC and its prevention
Authors: Bessems Eugene
Published: May 2005

Plasticized polyvinyl chloride will be attacked by microorganisms. The microorganisms will use the plasticizer as a carbon source, whereas favorable growth conditions, like water and oxygen, promotes their growth.

A clear effect of the temperature of the water used in leaching experiments on the rate of fungal growth on the foil surface could be demonstrated. Studies also showed a difference in susceptibility of several types of plasticizers to fungal attack. The plasticizers can be divided into several classes based on their susceptibility to fungal attack.

Detailed studies on the microbiological population on foil surfaces showed the predominating position of fungi. This indicated a metabiotic system between fungi and bacteria on foil surface. Addition of biocides, during manufacturing of PVC, primarily must have fungistatic properties. The fungistatic activity of 10,10′‐oxybisphenoxyarsine (OBPA) is very high, and in consequence, very low concentration must be available on foil surfaces which will prevent fungal growth. These low amounts on foil surfaces are directly correlated to the amount of OBPA insite of the foil. The transport process of the insite OBPA to the surface of the foil will principally be determined by the recepe of the foil. Therefore the application concentration recommended to ensure to achieve the minimum inhibitory concentration for fungi on the foil surface will be determined from where the application actually manifests itself.
A new family of ester lubricants for PVC
Authors: Fahey T. E. , Falter J. A. , Rosen M.
Published: May 2005

A new class of complex esters offers the capability for tailoring lubrication characteristics to specific PVC applications. The lubricating performance of these esters can be varied from internal to external through changes in carboxylic chain length, polyol moiety, and degree of esterification. Changes in the degree of functionality of the polyol portion of the ester can be used to affect large variations in fusion time and mill stick time. Polyol functionality may also be used to control extrudate gloss without changes in other processing parameters. Dynamic stability is relatively independent of polyol type, with all of the esters providing excellent stability behavior. Carboxylic acid chain length has a pronounced effect on external lubricity, as demonstrated by large changes in mill stick time. Esters based on stearic or longer chain acids provide optimum extrusion processability and yield high gloss extrudates at low extrusion torques. Dynamic thermal stability also increases with acid chain length. The effect of degree of esterifications on lubrication is dependent upon the polyol portion of the ester. In low hydroxyl value esters, the degree of esterification can be used to vary external lubricity.
Strain‐induced crystallization kinetics of vinylidene chloride/vinyl chloride (VDC/VC) copolymers. Part III. Comparison of the effect of biaxial and uniaxial strain
Authors: Lund Monty , Steinbrunner Jim
Published: May 2005

Specimens of amorphous VDC/VC tube taken immediately after the water quench bath on the blown film process were stretched uniaxially and biaxially using a T. M. Long film stretcher. The stress and temperature responses were monitored. The crystalline content as a function of time was calculated based on an energy balance and the observed temperature response. It was found that SIC kinetics shows a similar dependence on extension ratio (ER) for the uniaxial and biaxial cases. The crystallization rate increases rapidly when an extension ratio of 3.5 is first reached in either the machine direction (MD) or transverse direction (TD). However, significantly greater engineering and true stress values are reached for biaxial stretching than for uniaxial stretching. This is due to the greater molecular alignment in the plane of the specimen versus the thickness direction and to the lesser specimen thickness for the biaxial case. The copolymer studied was an 88/12 wt/wt VDC/VC copolymer with a weight average molecular weight of 100,000 containing liquid additives that function as processing aids.
Poly(vinyl chloride)/plasticizer‐mixture interactions. Part I. Phthalate ester mixtures
Authors: Tomaselli F. , Gupta V. P. , Calderon H. S. , Brown G. R.
Published: May 2005

Flory‐Huggins interaction parameters, χ, have been determined as a function of plasticizer composition for poly(vinyl chloride) in various binary mixtures of phthalate ester plasticizers using a method involving the micro‐determination of the temperature at which PVC particles in excess plasticizer appear to melt. An optimum composition at which χ goes through a minimum was found to exist for some of the systems. A good correlation between the apparent melting temperature tm and χ for the neat plasticizers with PVC was also established.
Moderating the smoke produced by flexible and semi‐rigid PVC in fire tests
Authors: Coaker A. William
Published: May 2005

Flexible and semi‐rigid PVC formulations with high oxygen indexes and low smoke densities, as measured by the NBS Smoke Test (ASTM E662‐83) in both flaming and non‐flaming modes have been identified. The feasibility of a significant reduction of HCl emission from PVC compounds has been demonstrated in concept, and appears to be achievable when accompanied by increased oxygen index and/or significant reductions in rate of heat release and in smoke density, when measured in both the non‐flaming and flaming modes. PVC compounds, including those incorporating the kind of improvements outlined here for experimental prototypes, may be expected to compete in the future in both performance and price compared to other plastics materials.
TCLP and its impact on PVC
Authors: Grumbles Thomas G.
Published: May 2005

Toxicity Characteristic Leaching Procedure (TCLP) is the revised original EPA test method “Extraction Procedure” (EP) designed to eliminate its recognized shortcomings. TCLP, like its predecessor EP, is used to identify those wastes which pose a hazard to human health and the environment if improperly managed. The objective of both procedures is to identify wastes which pose hazards due to their potential to leach significant levels of specific toxic chemicals. The new test is designed to improve the leaching of organic constituents and expands the toxicity characteristic list to include 38 additional chemicals. The expanded criteria list of hazardous constituents includes vinyl chloride monomer. This means if a PVC sample does not pass the TCLP test it becomes a hazardous waste when discarded The regulatory burden and disposal costs then increase significantly, perhaps exponentially, Adoption of TCLP now may require PVC users to obtain Federal or State permits to install facilities to comply with regulatory standards. Indications are that EPA may promulgate the final rule in 1988, but exclude waste water.
Computerized PVC formulating for optimized cost/performance
Authors: Brofman C. M. , Caillault J. J. , Krauskopf L. G.
Published: May 2005

The versatility of poly(vinyl chloride) is largely a result of its capability to be modified by a wide variety of formulating additives, especially plasticizers and fillers. These additives vary widely with respect to their chemical composition, and the concentrations used in PVC, which impart significant effects on costs and performance properties. Computerized formulating programs have begun to replace laboratory testing directed at developing cost effective PVC formulations. A broad data base is required to capitalize on the many cost effective options posed to the PVC formulator. The Marketing Technical Service function of Exxon Chemical Co. utilizes COPPCO, COmputerized Profit/Performance COnsulting, to evaluate the options. The coherent data base contains 34 different plasticizers ranging from 25 to 90 phr, and can accommodate filler effects over a range of zero to 100 phr. COPPCO performs the following functions: cost and performance properties are predicted for specific formulations; lowest cost formula is defined to satisfy a specified set of performance properties; cost and performance properties are predicted for blends of plasticizers in unfilled and filled PVC compositions; performance properties are graphically presented as a function of PHR of plasticizer and plasticizer blends; graphic contours define constant property values as a function of plasticizer and of filler levels; and three dimensional response surfaces reflect the coincidental variation of both plasticizer and filler levels. COPPCO utilizes SAS (Statistical Analysis System) and Telegraph graphics, combined with sophisticated mainframe programs developed specifically to provide the desired output. Unlimited cost and performance options of the PVC formulator can be evaluated in milliseconds, vs. the traditional laboratory exercises which result in limited data after one to two weeks of sample preparation and testing.
PVC packaging recycling
Authors: Pazur A. S.
Published: May 2005

This study examines the recyclability of PVC bottles into other PVC products. Post consumer bottles can potentially be granulated and used, without further treatment, in the production of these products. Washing will allow the granulate to recover most of the properties of the original bottle compound, by removing paper labels and residual product contamination. Plastic contaminants, such as those from caps and other plastic bottles, show little effect on several physical properties at levels up to 3%. This granulate can thus be used as a significant portion of the raw material feed for a number of PVC products including DWV (drain/waste/vent) pipe, pipe fittings, rigid sheet, bottles, etc. Post consumer PVC bottle granulate thus constitutes a valuable resource; the recyclability of PVC packaging thus is a question of collection.
Improved CPVC compounds: Miscible alloying with styrenic copolymers
Authors: Bourland L. G.
Published: May 2005

Previous studies of PVC with styrene/maleic anhydride (SMAnh) copolymers showed miscibility or single phase morphology, but only at very low blended proportions of 10:1. At higher blend proportions this alloy system separated into two altered phases, neither being a pure component. Unlike PVC/SMAnh alloys, chlorinated poly(vinyl chloride) (CPVC) SMAnh systems show total miscibility for all blended proportions. The effects of alloying CPVC resins with SMAnh copolymers is the subject of this report. Using DSC and DMA miscibility of these systems are examined. Effects of SMAnh levels in these alloys on heat resistance, melt viscosity, processability, and flame retardance are assessed.
Failure analysis of rigid vinyl
Authors: Woo L. , Ling T. K. , Cheung Y. W.
Published: May 2005

In an attempt to better understand factors that govern the fracture resistance of rigid vinyl components, a multifaceted study was undertaken. Fracture toughness was determined by a high rate servohydraulic tester. Failure morphologies were analyzed by Scanning Electron Microscopy (SEM). In many cases, very abrupt ductile to brittle transitions were observed at moderate strain rates. In addition, since the glass transition temperature for these materials are relatively low, being of the order of 70°C to 80°C, considerable free volume relaxation or physical aging are observed at conditions near or slightly above ambient. Differential Scanning Calorimetry (DSC) was used to quantify the degree of aging. Results correlated with observed failure properties.
PVC Stabilizers of the past, present, and future
Authors: Doworkin R. D.
Published: May 2005

When chemical additives were found that could minimize the loss of chemical and physical properties of a thermally‐processable but heat‐sensitive polymer called poly(vinyl chloride) (PVC), an industry was born. And with it grew the world of plastics additives. Stabilizers for PVC became and industry itself, feeding into and off of this versatile polymer industry, in an almost symbiotic relationship. There have been so many types of stabilizers in use throughout the past fifty years: inorganics, leads, organics, barium/cadmiums, calcium/zincs, organotins, and antimony. And so very many more have been conceived but not commercialized: organoleads, organoantimonys, bismuths, indiums, and a myriad of organic chemicals. What are the merits and deficiencies of these stabilizers? What of yesterday's products are still with us? What are the newer types? What might be tomorrow's products? This paper will attempt to review and discuss the past, present, and future of PVC stabilizers; the factors that are responsible for their variety, for influencing their research, development, and commercialization, and how these factors change with time.
Influence of physical aging on medical plastics properties
Authors: Woo L. , Cheung Y. W.
Published: May 2005

Proper design of medical devices requires a thorough understanding of material properties throughout the manufacturing, distribution, and end‐use conditions. Widely used amorphous polymers deserve special attention. In this article, we will focus on the physical aging phenomenon. This process affects many important properties of materials. An improved Differential Scanning Calorimetry (DSC) technique was developed to quantify the extent and the kinetics of aging. Consequences of aging were also studied with physical testing and Scanning Electron Microscopy (SEM).
A comparison of oven sag temperature and heat deflection temperature for measuring heat resistance
Authors: Balasko Michael M. , Summers James W. , Dickerson James L. , Rodriguez Ernesto L.
Published: May 2005

The plastics industry places great emphasis on heat deflection temperature (HDT) as a measure of heat resistance when designing a plastic product. However, many manufacturers will evaluate a material's heat resistance by exposing a finished part to meximum use temperature under gravity load rather than the high loadings associated with the heat deflection test. The oven sag test is an alternate method which looks at the sag of a molded bar under gravity load. One end of the bar is clamped while the other end is free to sag. By employing a range of temperatures, the temperature at which gross sag takes place can be found. This study investigated how well the heat deflection temperature test and the oven sag test correlate to the performance of an injection molded box subjected to high temperatures using one and two phase PVC blends. The oven sag test was found to provide a more practical and more accurate measure of a material's performance under high temperatures and no external load. It is particularly well suited for evaluating two phase polymer blends.
Molecular weight viscosity relationships for PVC
Authors: Perkins George , Haehn James
Published: May 2005

The inherent viscosity of PVC resin in compounds containing fillers and additives can be calculated accurately and conveniently from the weight average molecular weight or the peak molecular weight as measured by High Performance‐Size Exclusion Chromatography (HP‐SEC). Molecular weight/inherent viscosity relationships are shown for typical production PVC resins. The utility of HP‐SEC instrumentation for the determination of IV for samples of commercial interest is demonstrated. Mark‐Houwink coefficients from the literature were used to calculate a convenient conversion factor of 0.612, which can be used to convert the molecular weight measured relative to polystyrene by HP‐SEC to the actual molecular weight for PVC.
Component interactions and properties of crosslinked vinyl systems
Authors: Schreiber H. P. , Degrendele C. , Bataille Crasp P.
Published: May 2005

Compositions based on PVC, containing DIDP or TOTM plasticizers, and in several cases also containing chlorinated polyethylene (CPE) as property modifier, have been crosslinked by irradiation, using di‐ and tri‐functional acrylic crosslinking agents. Crosslinking effectiveness has been analyzed by solvent swelling data, and the effects of irradiation up to dosages of about 10 Mrad on the mechanical properties of the systems have been recorded. The interaction potential of components used in these systems has been determined by recently‐developed methods of inverse gas chromatography (IGC). These classify PVC and CPE as electron acceptors, and the plasticizers as donors. Expectedly, increased moduli and decreased elongational properties follow exposure to gamma‐rays. The plasticizers reduce the effectiveness of crosslinking, the magnitude of the reduction being related to the degree of acid/base interaction between PVC and plasticizing fluids. When present, CPE competes with PVC for plasticizer so that for given quantities of DIDP or TOTM, the fraction available to solubilize the host polymer is reduced. In compounds with CPE, therefore, the crosslinking effectiveness of irradiation is raised, consistent with the acid/base balance of interactions, as given by the IGC results. Twin yield points have been observed in the stress‐strain curves of compounds containing CPE. It is postulated that distinct, interpenetrating crosslink networks are formed when these polymers are subjected to gamma irradiation.
Cadmium‐free stabilizer systems for flexible vinyl
Authors: Baker Paulette
Published: May 2005

Recently, cadmium‐containing additives for plastics have been designated as undesirable environmentally. Prior to this adverse characterization of cadmium derivatives most flexible vinyl in the United States involving severe stabilizer demand during processing or service utilized metal blends based on cadmium salts. As a result many vinyl formulators have been forced to find suitable alternatives. Replacement of a stabilizer composed of specific levels of barium/cadmium salts in flexible vinyl with another containing the same levels of barium/zinc has been found to give dramatically reduced performance in heat stability tests. Results of this study has shown that satisfactory replacement of barium/cadmium/zinc or barium/cadmium systems in flexible vinyl is possible with barium/zinc stabilizers. This replacement appears to depend on higher barium‐to‐zinc ratios than those utilized in barium/cadmium analogs, use of special ligands that compensate for the smaller sized zinc cation; and prevention of their destruction by inadvertent addition of competitors.
Properties of poly(vinyl chloride) fibers crosslinked by 2‐dibutylamino‐4,6‐dimercapto‐1,3,5‐triazine
Authors: Jandó Tamás , Mori Kunio
Published: May 2005

PVC fibers, fastened to a needle frame, were crosslinked by 2‐dibutylamino‐4, 6‐dimercapto‐1,3,5‐trizine in the presence of tetra‐n‐butylammonium bromide and alkali in water at 96°C. Solvent resistance, characterized by the gel fraction of THF, improves markedly. Mechanical properties of the fibers investigated by tensile tests at 20°C show that both the modulus and tensile strength at break increase, while elongation at break decreases over 40% gel content. Creep tests indicate that the resistance to heat deformation improves by crosslinking. The heat distortion temperature increases by 12°C at 75% gel content. Results of dynamic tests show that the Tg of PVC fibers determined by a peak in the loss modulus (E'') increases from 40% gel content. Dynamic modulus (E') increases by 74% at 23°C and the Tg by 37°C in the case of crosslinked PVC fibers having a 92% gel content. The shrinkage of PVC fibers in hot water at 94°C for 30 min decreases more than 50% over 75–80% gel content indicating the improved resistance to heat deformation.
Variations occurring in the light scattering film test
Authors: Duncan Carolyn B. , Chiasson Percy J.
Published: May 2005

Variation in the results obtained in the Light Scattering Film (LSF) Test, also referred to as the Fog Test, presents problems both for the investigator as well as the formulator. The results are often confusing (two similar formulas will produce widely different results) and seldom repeatable. In the Fog Test high fog values are desired because high fog values mean less fog. The results of this study demonstrate that the standard deviation for multiple tests on the same sample decreases with increasing fog value. The values obtained when little LSF is produced (high fog values) vary only slightly while the values obtained for heavy LSF (low fog values) fluctuate as much as 30 points. Several explanations are offered for this lack of repeatability, but they condense down to the fact that all of the variables which affect the results are not presently controlled.

The tests cited in this report were conducted using Di‐2‐ethylhexyl phthalate, Diisodecyl phthalate, and Di‐(1‐heptyl, nonyl, undecyl) phthalate as neat plasticizers from commerical suppliers. DOP was used because it is currently used by the SAE as an industry standard. The remaining two plasticizers were used because they are typically used in flexible PVC for automotive interiors. Results of this study confirm that the variations encountered in the LSF Test are inherent in the test itself and not due to the material being evaluated. Fluctuations which occur around a given LSF value occur to the same degree irrespective of the material producing the light scattering film.
Blowing agent decomposition in vinyl foams
Authors: Marshall R. A.
Published: May 2005

Azodicarbonamide has been widely used for many years as the blowing agent of choice for expansion of vinyl foams. It has been especially useful in chemically embossed flooring because the sensitivity of the blowing agent to various factors affecting its decomposition temperature permits control of the degree of expansion of the foam. Considerable work has been done by a number of investigators to elucidate these factors. Mechanisms for the decomposition of azodicarbonamide have been proposed in the literature to explain the activating or retarding effect of many compounds on the decomposition temperature. The use of Differential Scanning Calorimetry with an active reference is shown to be an extremely useful tool in determining small effects of various additives on the decomposition temperature of the blowing agent.
The fusion characteristics of PVC‐plasticizer mixtures
Authors: Gonzalez‐Roa C. , Ramos‐Devalle L. F. , Sanchez‐Adame M.
Published: May 2005

Dry blends of a PVC resin with various plasticizer mixtures were processed at different temperatures to produce samples of different degrees of fusion. The ease of fusion increased with decreasing the solid‐gel transition temperature (Tm) of the plasticizer mixture. Nevertheless. Tm was not necessarily a linear function of the individual concentration of plasticizers in the mixture. Therefore, the ease of fusion showed in some cases an optimum at a given concentration of the plasticizer mixture.
Impact of the presence of amines on the degradation of vinylidene chloride copolymers
Authors: Howell B. A. , Liu H.
Published: May 2005

Because of the prominence of vinylidene chloride/methyl acrylate copolymers in barrier plastic packing applications, the degradation of these materials continues to be the focus of much interest. The prominent degradation process at moderate temperature (<200°C) is dehydrochlorination. This reaction is a typical radical chain process with distinct initiation, propagation, and termination phases. A principal defect structure responsible for the initiation of degradation is unsaturation along the polymer backbone. Although most stabilization packages for these polymers contain basic components to absorb hydrogen chloride as it is generated, materials sufficiently basic to abstract hydrogen chloride might actually enhance the rate of degradation by introducing double bonds into the polymer structure. That this is the case has been established by the thermogravimetric examination of the degradation of a methyl acrylate (5 mol%)/ vinylidene chloride copolymer in the presence of amines of varying base strengths. In general, the initiation rate constant, kt, for the degradation process is enhanced in the presence of amine.
Environmental concerns with vinyl medical devices
Authors: Rakus J. , Brantley T. , Szabo E.
Published: May 2005

More and more jurisdictions generate increasingly strict air quality regulations that, almost without exception, include limitations on vinyl chloride. Processors frequently express concerns about their ability to meet environmental and occupational safety VCM limits. To address these concerns, the paper traces residual VCM levels through various stages of conversion from raw PVC resin to finished product storage. Another environmental concern often raised involves the reusability of molded or extruded vinyl devices. While plant regrind is routinely fed back into virgin production and its effect on physical properties is well known, solid waste management considerations increasingly involve postsale reuse of devices, an area not well explored. This paper looks at the reprocessing following long‐time storage of devices, not only on physical performance but also on thermal and radiolytic (gamma sterilization) stability.
Extrudate swelling and viscoelasticity of rigid PVC compounds
Authors: Huneault Michael A. , Carreau Pierre J. , Lafleur Pierre G. , Gupta Ved P.
Published: May 2005

In this paper, we investigate the effects of processing aids, impact modifiers, inorganic fillers, and resin molecular weight on the postextrusion swelling of rigid PVC compounds. Rotational rheometry measurements of the loss tangent in dynamic mode and of the recoverable shear in creep mode are made to evaluate PVC's elasticity. Long elastic relaxation times are found for rigid PVC. This apparent contradiction, i.e., relatively low swell but very high elastic relaxation time, is explained by taking into account the two‐phase flow behavior of PVC.
Electrical conductivity of carbon black filled polymers—effects of morphology and processing
Authors: Lee Biing‐Lin
Published: May 2005

This paper discusses the relation of the morphology of conductive carbon black and its critical volume fraction, ϕc, required to achieve semiconductor property. We also discuss the influence of processing on the electrical conductivity of polymer composites. An equation based on the crowding factor of concentrated suspension rheology and Janzen's particle contacts percolation is proposed to describe the relationship between ϕc, and the maximum packing fraction of conductive fillers. The relationship could explain the influence of particle morphology on conductivity and the conductivity difference in the high shear and low shear region of a processed polymer composite part.
Effect of thermal aging on physical properties of impact‐modified vinyl
Authors: Einhorn Richard A. , Stevenson Janis C.
Published: May 2005

Maintenance of physical properties after thermal aging is becoming more and more important for vinyl as the polymer makes further inroads into engineered applications. Many OEMs and regulatory agencies are now requiring that polymers used in business machine, appliance, and consumer electronic applications maintain both tensile and impact properties for long periods of time at high temperatures. The choice of impact modifier and other formulation ingredients appears critical to developing a successful compound that will maintain both tensile and impact properties after thermal aging. In this paper, we discuss the effects of different impact modifier types and other formulation variables on property retention.
Use of reflectance spectra to predict heat buildup of pigmented PVC panels
Authors: Sullivan T. , Peake G.
Published: May 2005

We present a method for predicting the heat buildup of pigmented PVC panels. Vinyl panels prepared for use in the ASTM D4803‐89 heat buildup test are scanned for percent reflectance from 200 to 2500 nm. For each sample an intensity factor is calculated according to:

where

IF = intensity factor,

Rλ = fractional reflectance of the sample at 20 nm intervals, and

Lλ = relative intensity of the heat lamp at 20 nm intervals.

A plot of the IF for each sample vs. its measured heat buildup (ASTM D4803‐89) for more than 50 sample panels containing a wide variety of pigments shows a linear relationship. Thus, the result in the ASTM D4803‐89 heat buildup test can be predicted based on the sample's reflectance spectrum and the intensity factor calculation. This method makes running the heat buildup test unnecessary and is very useful in evaluating pigments and pigmented systems for relative coolness.
SPC and the measurement process
Authors: Zuilhof John D.
Published: May 2005

This paper presents the basic principles of SPC charts and how to employ SPC techniques in performing simple measurement accuracy and precision studies. Information on the concepts of variation, basic statistics, the normal distribution, and the central limit theorem are presented to set the foundation for SPC. With these concepts in place, it is possible to introduce the two SPC charts on which accuracy and precision studies can be based—individuals charts and X‐bar charts. Many other types of control charts exist that are not described in this paper, specifically, control charts for attributes data. These are generally not applicable to measurement accuracy and precision studies, and numerous texts are available that sufficiently detail control charts for attributes data.
Processing conditions optimization for PVC plastisol rotational molding
Authors: Mendizabal E. , Candia J. M. , Gonzalez‐Alvarez V. , Jasso‐Gastinel C. F. , Cruz L.
Published: May 2005

In this work we present the optimization of the processing conditions for PVC plastisol rotational molding. The effects of oven temperature, processing time, rotational, speed and amount of plastisol over the degree of curing, physical appearance, and mechanical properties of the molded articles were studied. Also, using a simple mathematical model to simulate the temperature profiles of the plastisol inside of the spherical mold as a function of time, the viscosity change of the plastisol with time is reported. A rotational molding machine laboratory size was used for the experiments. The oven (at different points) as well as the mold (at the inside and outside of the cavity) temperatures were measured as a function of time in order to get a better understanding of the curing process. Such data in conjunction with the model gives the support for process optimization and control.
Particle size effects in X‐Ray emission analysis: Simplified formulae for certain practical cases
Authors: Rhodes J. R. , Hunter C. B.
Published: May 2005

The Berry—Furuta—Rhodes model is used to derive formulae for the characteristic X‐ray intensity in specimens of ‘non‐infinite’ thickness, as a function of particle size both for discrete values and for continuous distributions, including the Junge distribution for aerosols. Significant simplifications in otherwise complex for mulae are obtained for a number of cases of practical importance, namely, thin specimens, monolayers and low or high packing fractions. The simplified working formulae consist of the equation for a thin, homogeneous specimen, multiplied by a grain size dependent factor. This factor is a function of fluorescent grain size only, so eliminating most inter‐element effects. Practical applications of these cussed, with special reference to energy dispersive X‐ray fluorescence analysis of thin briquetted specimens and of aerosols collected on filters.
LII,III emission and LIII absorption spectra of vanadium with the electron microprobe
Authors: Romand M. , Solomon J. S. , Baun W. L.
Published: May 2005

The characteristic LII,III X‐ray emission bands of vanadium in pure metal and nitrides VN0.82 and VN are investigated with an electron microprobe. Results are discussed in relation to the theories proposed in the literature. Also presented is the vanadium LIII absorption spectrum from the pure metal; this spectrum is processed by the self‐absorption method.
The deterioration in counting efficiency of a scintillation detector
Authors: Kerrigan G. C. , O'Connor B. H. , Thomas W. W.
Published: May 2005

A description is given of the decrease in counting efficiency of a scintillation detector with time. The attenuation of an incident beam for various wavelengths was shown to be consistent with the observation that an amorphous layer had formed on the NaI crystal.
Quantitative electron microprobe analysis using a lithium drifted silicon detector
Authors: Reed S. J. B. , Ware N. G.
Published: May 2005

Pulse pile‐up, dead time, escape peaks, background, and peak overlap in Si(Li) spectra are discussed in relation to microprobe analysis, and procedures for carrying out the necessary corrections for quantitative analysis of elements of atomic number 11 to 30 are described. The accuracy is generally comparable with that obtained with crystal spectrometers, though the limit of detection (about 0.1%) is higher.
Hazards in the use of X‐ray analytical instrumentation
Authors: Jenkins R. , Haas D. J.
Published: May 2005

This paper outlines the potential hazards in the use of X‐ray analytical instrumentation and is composed of two major sections. The first section defines the terminology employed and outlines the causes and effects of radiation damage. Also covered is the national recognition of the problem which has led to present day legislation of dose levels. The second part is a verbatim copy of the report MORP 68‐14 Radiation Safety Recommendations for X‐ray Diffraction and Spectrographic Equipment by Moore and McDonald, and is reproduced by kind permission of the United States Department of Health, Education and Welfare, Bureau of Radiological Health.
The effect of crystal absorption on the instrument smearing function of a two‐crystal X‐ray spectrometer
Authors: Suoninen E. J. , Gregory T. K.
Published: May 2005

The instrument smearing function of a two‐crystal spectrometer in the (n, n) position having negligible vertical divergence has been calculated for an unpolarized incident beam assuming the crystals to be centro‐symmetric and to reflect according to the Prins‐Darwin theory. The results are given in terms of the parameters g and s̀ which describe the ‘overall absorption’ and the imaginary part of the structure factor, respectively. In the region g, s̀ σ ≤ 0.5 asymmetries of up to 60% are found in the smearing function. Variations of several tens of per cent occur in the half‐breadth as compared with the breadth obtained for a σ polarized beam with no absorption.

In order to avoid the undesirable effects of absorption, silicon (111) crystals should not be used above wavelengths 3 to 4 Å. Suitable wavelengths for calcite (211) crystals are 3.07 to 6 Å.
A correction for interelemental background contributions in energy‐dispersive X‐ray (EDX) spectroscopy
Authors: De Jesus A. S. M.
Published: May 2005

Various ore fractions (and mixtures thereof), of which the main metallic components are iron, copper and zinc, were analysed by means of radioisotope X‐ray fluorescence spectroscopy using a Si(Li) detector. As a result existing equations which deal with interelement effects (selective attenuation and enhancement of characteristic radiation) were further developed, and a new set of general equations, which accounts for the important interelemental background contribution, has been formulated. Its validity has been experimentally tested over a wide range of concentrations which, in some cases, varied by as much as a factor of 200. Satisfactory results were obtained.
Utilisation du Cristal de Phtalate de Thallium pour l'Analyse en Fluorescence X dans le Domaine des Grandes Longueurs d'onde
Authors: le Sage R. Vié , Grubis B.
Published: May 2005

Les cristaux de phtalate ont pour formule générale HOOCPhCOOX où X = TI+, Rb+, NH4+, K+ ou Na+ et leur structure est orthorhombique. Ils permettent d'explorer un domaine de longueurs d'onde allant jusqu' à 25 Å.

Le cristal de phtalate de thallium récemment élaboré par la Société Quartz et Silice présente des performances qui, si elles étaient confirmées, lui permettraient d'entrer dans la gamme des cristaux analyseurs de base équipant la majorité des spectromètres.