bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of calcium carbonate and paraffin wax levels on the performance of PVC pipe
Authors: Shaw Lane G. , Diluciano Albert R. 
Published: December 2004

AbstractPVC pipe compounds typically contain varying amounts and types of calcium carbonates, paraffin waxes, and other ingredients such as stabilizers, titanium dioxide, calcium stearate, and processing aids. The purpose of this paper is to study the effect of calcium carbonate particle size, coating, and usage level on the properties of PVC pipe. In addition, the effects of varying the paraffin wax level and melt temperature will be explored. The paper describes these effects as a function of both impact strength and stress‐rupture regression. Based on these results, a series of recommendations on type and usage level of the calcium carbonates and paraffin waxes, and processing conditions for the compound will be developed for use in guiding the pipe manufacturer towards producing PVC pipe that is both performance‐oriented and cost‐effective.
Temperature and shear history effects on fusion of PVC
Authors: Bower J. David , Heffner Malcolm H. 
Published: December 2004

AbstractStandard PVC compounds containing various lubricant systems were fused in a Haake Torque Rheometer equipped with a torque integrator, holding the shear stress time value constant. The total work put into the system to fuse the compound was therefore held constant. The fused material was compression molded into sheeting for physical testing. The data will characterize the compounds for both rheological and physical properties at several processing conditions. Plotted curves will depict the lubricant systems and processing temperatures necessary to obtain maximum physical strength.
PVC/styrene copolymer alloys for a balance of properties
Authors: Bourland Larry G. , Wambach Allen D. 
Published: December 2004

AbstractStyrene maleic anhydride copolymers blended with PVC result in alloys that exhibit elevated thermal properties and improved processability. These improvements will help PVC usage in electrical/electronic housings. The PVC component maintains flame retardance for the compound, without the need for further additives.
A semimicro brittleness test to monitor weathering of plasticized PVC
Authors: Sears J. Kern 
Published: December 2004

AbstractThis paper presents a test method, by modification of ASTM D 1790, to follow the changes in brittleness temperature Tb of plasticized PVC during weathering and to produce a profile of the changes in a composition. It may also be used to measure the change in brittleness temperature at the end of a specific weather test. Few and small specimens are used to avoid the exposure of prohibitively large sheets that otherwise would be required and to make short the unacceptably long time otherwise demanded. It therefore makes programs practical that involve many formulations aimed at superior performance. It gives greater confidence than mere visual and tactile observations that a given compounding ingredient or a total composition can or cannot do the job that is required of it.
Gamma radiation stabilization of PVC
Authors: Rakita P. E. , Fouré M. 
Published: December 2004

AbstractA new class of additives combining heat and radiation stabilization has been shown to prevent the discoloration and associated undesirable hydrogen chloride formation encountered when PVC is exposed to sterilizing doses of gamma radiation. Various mechanisms that lead to the decomposition are described and the free radical processes that cause changes in physical and mechanical properties are discussed. The performance of the new additives demonstrates that rigid PVC can be exposed to high (> 5MRad) radiation with little or no discoloration and loss of physical properties.
Testing for plateout using the torque rheometer
Authors: Leskovyansky Paul J. 
Published: December 2004

AbstractThe ability to predict the occurrence of plateout in PVC processing with a simple laboratory test which can be used to evaluate complete formulations before manufacture would be of significant benefit. Such a test is described and illustrated. A proposed mechanism for the induction of plateout based on attractive forces is advanced to supplement mechanisms based on solubiliity and phase equilibria. The test procedure can be extended to study other polymer systems and applied to the design of effective mold release systems for processes other than extrusion.
Process and material considerations in the industrial application of lubricants in rigid PVC extrusion
Authors: Pedersen Thomas C. 
Published: December 2004

AbstractThe proper lubrication of rigid PVC compounds often plays an important role in the successful operation of a rigid PVC extrusion plant. Changes in a particular lubricant system can have a substantial effect on the fusion rates of a rigid PVC compound and on the thermodynamics of the fusion process. Recently published research on the morphology of PVC resin and rigid PVC finished products has provided new insights into the morphological changes rigid PVC undergoes during processing. Lubricants can have a substantial impact on the rates and extent of morphological changes of rigid PVC during processing. Successful industrial optimization of a lubricant system involves balancing the rheological characteristics of the compound against the shearing and heating characteristics of the extruder and die tooling. Changes in the extruder and die tooling or lubricant system will result in changes in the work and energy balance. The impact of increases in fusion promoting lubricants, as well as increases in fusion delaying lubricants, on the work and energy balance for a twin screw extruder is explained.
Formulating for rigid PVC using multivariate analysis
Authors: Hatt Brian W. 
Published: December 2004

AbstractThe wide range of lubricants available for rigid PVC, and their complex interactions or synergisms, has meant that the formulator has often had to rely more on quantitative experience, however incomplete, rather than on quantitative data. Multivariate analysis offers the possibility of investigating lubricants and fillers with a relatively small number of rheological experiments and defining their role in a wide range of formulations. A computer program and associated methodology has been developed that allows up to five formulations or fusion parameters to be examined with a maximum of just thirty‐three torque rheometry experiments. The technique generates both first and second order coefficients for each parameter, coefficients that quantify all possible pair interactions, and applies statistical techniques to evaluate the significance of each coefficient. The levels of “internal” and “external” lubricants and fillers, as well as the charge volume and shear rate in the rheometer, have been correlated with fusion peak time and torque, equilibrium torque and melt temperature and other features of the fusion curve. The data are also presented in a series of graphs so that subsequent formulation can be done by interpolation, without further experimentation. The result have sometimes been unexpected and can help in understanding the role of the various additives in the extrusion of rigid PVC.
Development of light‐stable PVC stabilizer systems for rigid weatherable applications
Authors: Ho Ben Y. K. 
Published: December 2004

AbstractThere are technical, as well as economical, advantages to employ light‐stable polyvinyl chloride heat stabilizers for rigid weatherable applications. The desirable stabilizer systems should also be less or non‐toxic, without sulfur staining problem, with acceptable odor, with stable and competitive economics. Our research effort has been targeted towards worldwide applicability. Our earliest effort was to search for an active metal from the periodic table! Considerations were given to the fate of the metal chlorides formed in the PVC resin. Preliminary compounds were synthesized for screening. Subsequently, organic ligands were designed to control and to activate the molecule in the stabilization of polyvinyl chloride. Co‐additives, mostly conventional, were added to form stabilizer packages. Accelerated indoor light‐stability tests demonstrated the desired light‐stability against current stabilizer systems. Preliminary outdoor weathering data further supported the conclusion. The primary stabilizer has the following general structure:

The chemistry and stabilization mechanism will be discussed. The above patent pending technical innovation is revealed as a contribution of our research effort to the Vinyl Industry. The eventual product commercialization will be of interest to all, especially those involved in the rigid weatherable applications.
Limitations of using combustion toxicity testing for product selection
Authors: Hinderer Robert K. 
Published: December 2004

AbstractDuring the last two decades there has been considerable concern about the combustion toxicity of synthetic materials such as PVC, and about their impact on overall fire hazard. Studies using many different methodologies have shown that the combustion toxicity of PVC is not unusual, but is comparable to many natural and synthetic materials. Because of various limitations, these tests have not been considered useful for code setting or regulatory activities. Furthermore, it has been emphasized that combustion toxicity is only one of many factors which must be evaluated in determining the fire hazard of a material. Still, the fact remains that PVC has performed favorably under many different conditions.
Influence of the components in the flow properties and physical aging of spray coating PVC plastisols
Authors: Oregui X. , Santamaría A. , Hiriart J. M. , Etcheveste J. 
Published: December 2004

AbstractA study of the rheological properties and aging characteristics of 15 poly(vinyl chloride) (PVC) plastisols formulated for spray coating is made. The influence of the PVC type, plasticizer, filler, diluent, and thixotropic agent is analyzed and discussed in terms of the yield stress value, a shear thinning index, and an aging characterizing parameter.
Blends of rigid PVC and polystyrene
Authors: Rudin Alfred , Bloembergen Steven , Cork Stephen 
Published: December 2004

AbstractSeveral compatibilizing agents were investigated to stabilize blends of rigid poly(vinyl chloride) and polystyrene. Copolymers of alpha‐methyl‐sytrene and methacrylonitrile were made by emulsion polymerization. These products, with alpha‐methylstyrene contents varying between 50 and 75 weight percent, could be blended with the two primary polymers to produce alloys with good processability and strength. Styrene‐acrylonitrile copolymers with 70 and 75 percent styrene content were also found to provide useful polyblends. All mixtures were opaque. Compositions containing at least 30 weight percent PVC were self‐extingushing. Polystyrene‐poly(vinyl chloride) mixtures with as little as 7.5 weight percent styrene‐acrylonitrile copolymer appear to have adequate mechanical strength and processability for commercial applications. Some end‐uses for variations of these polyblends are suggested.
The effect of aromatic plasticizers on the photodehydrochlorination of poly(vinyl chloride). Part II: Dialkyl phthalates
Authors: Gerrard D. L. , Bowley H. J. , Williams K. P. J. , Biggin I. S. 
Published: December 2004

AbstractSamples of PVC, plasticized with a range of dialkyl phthalates, linear and branched, have been naturally weathered by exposure for one year in Arizona. The results confirm previous findings, that aromatic plasticizers can act to accelerate the photodehydrochlorination of PVC and that the low photostability of phthalates with long, branched side chains results in a greater level of dehydrochlorination than that produced by either linear or branched shorter alkyl chains. For alkyl groups of the same carbon number, the branched chains produce a greater level of dehydrochlorination than the straight chains. Possible explanations for these observations are considered.
A monomeric plasticizer for high temperature applications
Authors: Payne Marc T. , Renshaw James T. 
Published: December 2004

AbstractThe results of this study demonstrate that high molecular weight and predominantly linear diundecyl phthalate (DUP) provide improved performance properties and cost savings when used as a partial or total replacement for trimellitate plasticizers in critical applications such as vinyl electrical insulations and crashpad covers. DUP is shown to be a permanent and stable plasticizer with a high efficiency in improving low‐temperature flexibility of formulated vinyls.
Thermal transitions of ethylene‐vinyl chloride copolymers and their blends
Authors: Bowmer Trevor N. , Tonelli A. E. 
Published: December 2004

AbstractDifferential Scanning Calorimetry (DSC) measurements were performed on a series of ethylene‐vinyl chloride copolymers (E‐V) prepared via reductive dechlorination of poly(vinyl chloride) with tributyltin hydride. The copolymers were identical in chain length and branching distribution; differing only in comonomer content, sequence distribution, and stereoregularity of adjacent —V— units. Extrapolation of glass transition temperatures, Tg, measured for our E‐V copolymers to pure polyethylene (PE) predicted a Tg = −85 ± 10°C for amorphous PE. E‐V copolymers with greater than 60 mol percent —E— units exhibited melting endotherms from 20 to 128°C and degrees of crystallinity from 12 to 63 percent. The melting point depressions observed for our E‐V copolymers were in agreement with Flory's theory, if the CH2CH2 moiety is considered to be the crystallizable unit and the moiety is assumed to prevent the CH2CH2 units attached on either side from being incorporated into the crystal. In general, the E‐V copolymer blends with PE were incompatible, while those with PVC were compatible only for E‐V copolymers with high V contents (>80 mol percent). Blends of the amorphous E‐V copolymers were found compatible if their V contents differed by less than 15 mol percent, while blends where one or both E‐V copolymers are crystalline were found to be incompatible. The properties of these copolymers will be discussed in terms of their microstructure.
Melt rheology of vinylidene chloride‐vinyl chloride copolymers
Authors: Hyun Kun Sup 
Published: December 2004

AbstractA continuous extruder slit‐die rheometer system determines the rheological properties of thermally sensitive copolymers of vinylidene chloride and vinyl chloride to aid the design of processing screws, melt dies, and coextrusion feed blocks for the production of barrier film. The flow of VDC‐VC copolymers was dependent on molecular weight, temperature, and shear rate. Increased chain mobility causes low‐melting‐temperature copolymers to flow more easily. Liquid additives also reduce viscosity.
Rectangular torsion of thin polymeric materials: A modification of the rheometrics system four
Authors: Foss Peter H. 
Published: December 2004

AbstractDynamic mechanical analysis is a common and important method for rheological characterization of polymeric materials. By adapting the sensitive fluids load cell and motor set on the Rheometrics System Four to a rectangular torsion geometry, one is able to measure dynamic shear modulus of thin strips as a funciton of frequency and temperature over a wide modulus range. In studies on plasticized poly vinyl chloride, we were able to characterize samples over the entire primary transition region—from glassy through the leathery and into the rubbery plateau.
The effect of fusion and physical aging on the toughness of poly(vinyl chloride)
Authors: Lacatus Emilia E. , Rogers Charles E. 
Published: December 2004

AbstractIt is well known that during aging or annealing, materials become stiffer and more brittle, and creep and stress relaxation rates decrease. Research in this area is very important because physical aging (annealing) plays a large role in the production of products, and it also occurs during the use of the objects or products. The decrease of free volume with time is unavoidable even at ambient temperatures. The influence of fusion and physical aging on the toughness of extruded PVC profiles was investigated. It is known that the toughness of PVC is influenced by secondary crystallization—after primary particles of PVC are partially melted. Recrystallization upon cooling or annealing forms a three‐dimensional structure tying together the primary particles. This three‐dimensional structure normally produces a tougher PVC product. The density of glassy PVC can be changed by changing the quenching rate. The density can be further changed by annealing below Tg. The densification of a glassy polymer normally leads to a less tough PVC product. This study uses density measurements and differential scanning calorimetry scans to measure the amount of enthalpy relaxation (related to densification) and crystalline melting energy (related to the amount of crystallinity) for various annealed samples. These are related to toughness as measured by notched Izod and droppeddart impact tests.
Studies on morphology, mechanical properties and failure mode of blends of plasticized poly(vinyl chloride) and thermoplastic copolyester elastomer
Authors: Thomas Sabu , Gupta B. R. , De S. K. 
Published: December 2004

AbstractMorphology and mechanical properties of blends of plasticized poly(vinyl chloride) (PVC) and thermoplastic copolyester elastomer (Hytrel 40D) have been studied with special reference to the effect of blend ratios. Morphology of the blends indicates that the Hytrel phase is dispersed as domains in the continuous PVC phase up to 75 percent of its concentration. Dynamic mechanical analysis of the blends shows marginal level of compatibility between the two phases. The mechanical properties depend on the proportion of thermoplastic rubber in the blend. Attempts have been made to correlate the blend morphology with properties. Failure surfaces were examined by scanning electron microscope and it was found that the fractographs depend on the type of failure (tensile or tear) and on the blend composition.
Effect of fillers on the apparent hot melt viscosity of plasticized poly (vinyl chloride)
Authors: Ramos‐Devalle Luis , Avalos Felipe 
Published: December 2004

AbstractCapillary rheometry is used to study the effect of fillers (carbon black, calcium carbonate, talc, and titanium dioxide) on the apparent viscosity of plasticized poly(vinyl chloride). It was found that viscosity shows a minimum at about 5 percent filler volume content, for CaCO3, Talc, and TiO2. An assumption is presented relating this phenomenon with the ability of filler for plasticizer absorption, i.e., with filler surface area.
Miscible polymer blends containing poly(vinyl chloride)
Authors: Robeson Lloyd M. 
Published: December 2004

AbstractPolymer blends have received particular interest in the past several decades in both industrial and academic research. An initial survey of miscible polymer pairs (1) (1968) revealed 12 combinations. A later survey (2) (1979) noted approximately 180 miscible pairs. Today possibly over 500 miscible combinations have been noted in the open and patent literature (3). However, the vast majority of possible polymer blend combinations are not miscible (thus phase separated). A significant number of diverse polymer structures have been shown to exhibit miscibility with PVC. Several of these blends have been studied in detail and have shown specific interactions primarily involving the α‐hydrogen and PVC (considered the proton donor in proton donor‐proton acceptor hydrogen bonding type interactions). The blend of poly(ϵ‐caprolactone) with PVC illustrates this interaction and has been reported in many published papers. While polymer miscibility in PVC blends offers significant academic interest, industrial utility is also of considerable importance. The addition of low Tg, miscible polymers to PVC offers permanent plasticization. The addition of high Tg, miscible polymers to PVC yields the desired heat distortion temperature enhancement of rigid PVC. A specific example of permanent plasticization involves nitrile rubber blends which have been commercial since the early 1940's. This presentation will review the growing number of polymers noted to be miscible with PVC. The importance of specific interactions will be discussed.
ULTRASONIC IMAGING SYSTEM USING A 2D ENVELOPE BEAMFORMING TECHNIQUE: IN-HOMOGENEITIES LOCATION
Authors: MEDINA L. , MORENO E. 
Published: December 2004

An algorithm has been developed to implement synthetic aperture focusing technique for B-scan. This is made at a several transmitter/receiver locations to form a map of ultrasonic reflectivity on the insonified region, considering the path travelled by the ultrasonic pulse from the transducer to the target and back again. To reconstruct the image, a time domain beam-former is applied to the envelope of the detected signals. This method minimizes the side-lobe amplitude and the restriction of λ/2 distance between two adjacent transducer positions can be neglected without loosing image resolution. The present work is focused on the location of the in-homogeneities, caused by the presence of a phantom immersed in a water tank. The results are presented when the distance between two adjacent transducer positions are varied from 0.5λ to 2.5λ showing that the longitudinal resolution is not affected but the lateral resolution becomes poorer when the distance is about 2λ. The error in the longitudinal location of in-homogeneities is within the minimum detectable distance of the system, while the lateral location error is increased when the distance between any two adjacent transducer positions is larger than 1.5λ.
The Relation between the North Atlantic Oscillation and SSTs in the North Atlantic Basin
Authors: Wang Weile , Anderson Bruce T. , Kaufmann Robert K. , Myneni Ranga B. 
Published: December 2004

Abstract
The authors use the notion of Granger causality to investigate the relationship between the North Atlantic Oscillation (NAO) index and the sea surface temperatures (SSTs) over the Northern Hemisphere. The Granger causality analysis ensures that any apparent oceanic influence upon the atmosphere (as measured by the NAO) is provided by the ocean and is not related to preexisting conditions within the NAO itself (and vice versa when looking at the atmospheric influence upon the ocean). Although this statistical technique does not imply physical forcing of one field on the other, it is generally more reliable compared to the simple lead/lagged correlation. Using this technique, the authors find that on seasonal time scales, the preceding NAO anomalies' influence on the wintertime SST field is rather restricted. Conversely, preceding SST anomalies have a statistically significant causal effect on the wintertime NAO. However, the causal relation between preceding SSTs and the wintertime NAO is limited to the Gulf Stream extension; in contrast to the canonical tripole SST pattern typically associated with the NAO, the authors do not find that SST anomalies in either the Greenland or subtropical regions have a significant causal effect on the NAO. These results suggest that the Gulf Stream SSTs have an important influence in initiating disturbances of the atmospheric circulation over the wintertime North Atlantic.