bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the receptivity of PVC articles toward water‐based inks, coatings, or adhesives
Authors: Napoleon Eugenia R.
Published: April 2004

Typically, the measure of hydrophobicity in PVC films and sheets is a surface energy measurement in dynes/cm in the low‐to‐mid thirties. More recently, the trend has been to lower the amounts of solvents used in inks, coatings, and adhesives, which, in turn, are used to coat or print the flexible PVC article. With the change in the makeup of coating systems, a modification in the surface energy of the flexible PVC film is needed to make an inherently hydrophobic material more hydrophilic. It has been found that the combination of a polymeric plasticizer and a monomeric plasticizer in conjunction with a metal oxide, unexpectedly increases the hydrophilicity of PVC sheets or films by factors of roughly 25% to 33%. This paper discusses the results of an investigation leading to an increase of surface tension from 33–36 dynes/cm to 40–43 dynes/cm.
Resorcinol bis(diphenyl phosphate), a non‐halogen flame‐retardant additive
Authors: Bright Danielle A. , Dashevsky Sophia , Moy Paul Y. , Williams Barbara
Published: April 2004

This paper is a review of Resorcinol bis(diphenyl phosphate) (RDP), a non‐halogen aromatic oligomeric phosphate flame‐retardant and flow modifier. Its high thermal stability and low volatility, compared with the triaryl phosphates, make it ideal for use in applications where high processing temperatures are requuired. Thermogravimetric data showing the effects of RDP on modified PPO and polycarbonate/ABS blends are presented. Current and potential end uses in thermoplastic resins and polyurethanes are discussed.
A new process aid for melt compounding of PVC with ethylene copolymer resins
Authors: Hofmann George H.
Published: April 2004

Ethylene copolymer resin (ECR) modifiers are solid, high molecular weight, permanent plasticizers for PVC. During the melt compounding step, the low melting ECR (m.p. ∼50°C) melts first forming a relatively low viscosity phase in which the higher melting (Tg ∼80°C) and more viscous PVC powder grains (∼150 μm in diameter) are suspended. Under these conditions, it is sometimes difficult to get enough shear energy into the system to break down, or flux, all of the PVC grains into unagglomerated primary particles (∼1 μm diameter). The remaining grains appear as gel‐like heterogeneities, in the final blend, that can produce rough, pimpled extrudates with reduced physical properties. This paper describes the use of a new experimental process aid that significantly improves homogenization, during the melt compounding process, leading to improved product quality and/or production rates.
New organic costabilizers for the stabilization of PVC
Authors: Burley Joseph W.
Published: April 2004

Organic costabilizers constitute a very important class of compounds where the replacement of heavy metals in PVC stabilizers is concerned. These materials are typically added at no more than 5% of the stabilizer formulation. They do, however, make a disproportionate contribution to performance based on addition level. This situation has spurred the search for new materials. Recent advances in this field are reviewed with particular emphasis on a new class of polyketones (pyrrolidine‐2,4‐diones) recently patented by Akcros Chemicals. The regulatory status, performance characteristics, and mechanism of action of this type of material are described.
Effect of extrusion conditions on rigid PVC foam
Authors: Rabinovitch Elvira B. , Isner James D. , Sidor James A. , Wiedl Daniel J.
Published: April 2004

There is a growing demand for rigid vinyl foam as a wood replacement in window frames, blinds, trimming and other applications. While rigid vinyl foam has existed for many years, additional understanding of its processability and required conditions for good quality extruded profile would be helpful. This paper examines the effect of extrusion conditions, such as melt temperature, screw speed, and drawdown on process morphology of rigid vinyl foam and the properties of the extruded profile, including density, cell structure, and surface appearance.
Structure/performance characteristics of bisamide lubricants in ABS
Authors: Williams J. B. , Geick K. S. , Falter J. A.
Published: April 2004

A number of bisamides were synthesized using fatty acid chain lengths varying from C4 to C22. Nonsymmetric as well as symmetric amides were prepared. The diamines from which these amides were prepared included ethylenediamine, butylenediamine, and 1,6 hexamethylenediamine. Properties of the pure bisamides and their effect in ABS polymers were measured. These properties included melting points, DTUL, impact, spiral flow, and color.
Migration of additives in polymers
Authors: Földes Enikö , Szigeti‐Erdei Andrea
Published: April 2004

The effects influencing the migration of different small molecular materials in polyethylene (PE) were studied. A decrease in weldability experienced after storage of the polymer at ambient and elevated temperatures was proved to be a result of migration of low molecular mass components of the polymer and some type of lubricants to the surface. Studies of different sorbitol fatty acid esters used as antifog agents in PE revealed that their mobility depends on the length of the hydrocarbon chain, while the antifog performance is influenced by the ratio of the OH groups to the hydrocarbon chain length.
Pigmentation evaluation of talc in polypropylene
Authors: Spano Joseph , Steen William
Published: April 2004

New automotive and appliance applications require increased use of color matched pigmentation. End uses for the colored compounds include automotive interior and exterior applications, home appliances, tools, and lawn and garden equipment. The effects of “Platyness,” “Fineness,” and “Whiteness” are studied to better understand the contribution of each variable to compound color development in the presence of a red organic pigment.
Increasing filler concentrations in PVC compounds using CPE
Authors: Ventresca Don A. , Berard Mark T.
Published: April 2004

During times of rising resin prices, the PVC processor is forced to optimize his operations in order to reduce manufacturing costs. One option the processor has is to increse the filler concentration in order to reduce formulation costs. Chlorinated polyethylene (CPE), an uncrosslinked rubber impact modifier for rigid PVC applications, allows the processor to significantly increase the filler concentration without suffering loss of impact strength or processing penalties. A mechanism is postulated, which is confirmed by Scanning Transmission Electron Microscopy (STEM), extrusion and impact measurements, that CPE domain breakup and dispersion are synergistic with the addition of calcium carbonate.
New process stabilization system for emulsion polymerized ABS
Authors: Earhart Neal J.
Published: April 2004

In emulsion polymerized acrylonitrile‐butadiene‐styrene (ABS), an antioxidant system is added to the latex prior to coagulation. The antioxidant protects the polymer against the high temperatures encountered during drying and processing. Traditionally, hindered phenols have been used in combination with a co‐stabilizer, such as tris‐nonylphenylphosphite (TNPP) or dilaurylthiodipropionate (DLTDP). This paper discusses an antioxidant stabilization system based entirely on hindered phenol chemistry. This system provides excellent performance compared to the traditional systems without the presence of a phosphite or sulfur based costabilizer. In addition, the new antioxidant system is a liquid allowing for ease of emulsification and handling.
Increasing pelletizing extruder output with fluoropolymer alloys
Authors: Priester D. E.
Published: April 2004

Fluoropolymer processing additives are used by many polyolefin processors. Typical benefits include the reduction of die build‐up and the elimination of shark‐skin melt fracture. Improvements in this technology have led to the fluoropolymer alloy, the most efficient fluoropolymer additive available. This same fluoropolymer additive can be used to increase the output in a pelletizing extruder. The improved efficiency of the fluoropolymer alloy makes the improvement cost effective. This paper will show how this is being done. Results will be shown from polyethylene plants where these improvements have been demonstrated.
Ultra‐high‐molecular‐weight functional siloxane additives in polymers. Effects on processing and properties
Authors: Ryan Kevin J. , Lupton Kevin E. , Pape Peter G. , John Vivian B.
Published: April 2004

Two new types of solid siloxane additives for plastics are described which give improved benefits compared to previous silicone additives. Ultra‐high‐molecular‐weight (UHMW) siloxanes are used in the new additives; traditional silicone plastic additives have used much lower molecular‐weight silicones. The siloxane is converted into solid forms, either masterbatch pellets or powders, that are easy to feed, or mix, into plastics during compounding, extrusion, or injection molding.

Ultra‐high‐molecular‐weight siloxanes can be compounded into masterbatch pellets at higher siloxane concentrations than previously possible, e. g., up to 50%. They impart improved processing and release, lower coefficient of friction, and broader performance latitude compared to conventional lower‐molecular‐weight silicones. These benefits can be delivered at reduced siloxane levels with increased concentration at the surface interface with a new functionalized UHMW siloxane which provides unique surface segregation characteristics.

Ultra‐high‐molecular‐weight siloxanes have been formulated into powders that can also act as processing aids and mechanical property modifiers for highly filled polymers such as fire‐retardant systems.

This paper uses polyolefins as a model. However, many of the effects shown in polyolefins have also been seen in other resin systems.
Moisture crosslinking process for foamed polymers
Authors: Pape Peter G.
Published: April 2004

Alkoxysilanes can be grafted onto an ethylene homopolymer or copolymer to give a moisture crosslinkable polymer. Moisture crosslinking has many benefits over peroxide‐ or irradiation‐induced crosslinking. Simple, conventional equipment allows processing with lower capital investment and less manufacturing space. The moisture crosslinking process permits conventional thermoplastic processing after the initial grafting process to give greater flexibility in the types of applications for this crosslinking technique. In foaming processes, silane crosslinking is compatible with most types of conventional blowing agents and other additives. The combination of silane crosslinking with metallocene polyethylene technology has given rise to a broad range of crosslinked polyolefin materials, including flexible, rigid, open, and closed cell foams. Good quality foams with very low densities, approaching 1 lb/ft3 (16 kg/m3), are possible. The advantages of silane crosslinking technology have opened many new markets for polyethylene foams.
Towards the prediction of pinking of PVC profiles in mild climatic conditions
Authors: Lemaire Jacques , Siampiringue Narcisse , Chaigneau Richard , Delprat Patrick , Parmeland Georges , Dabin Philippe , Spriet Christine
Published: April 2004

Pinking of TiO2‐pigmented PVC can be observed for profiles exposed to the mild environmental conditions of Northern European countries. In this paper, the pinking phenomenon is accounted for at the molecular level by the formation of polyene sequences which are not completely photooxidatively bleached under conditions of oxygen starvation. Photoreduction of TiO2 to give Ti(III) species accounts for greying which cannot be converted into pinking under mild thermooxidative conditions (65°C). The polyenic sequences which account for an initial greying after brief exposure in the SEPAP 12.24 apparatus can be converted into shorter, modified polyene sequences which explain the pinking. From the basic understanding gained, a predictive test has been designed and validated by comparison with results obtained under natural exposure conditions.
Impact strength of high density microcellular poly(vinyl chloride) foams
Authors: Juntunen Richard P. , Kumar Vipin , Weller John E. , Bezubic William P.
Published: April 2004

The impact strength of microcellular poly(vinyl chloride) (PVC) produced from an industrial formulation was investigated. The solid‐state process with carbon dioxide as the blowing agent was used to prepare the specimens. Processing conditions were explored to produce microcellular PVC with a relative density of 0.6 and higher. These foams were impact tested by using a falling‐weight impact tester. Impact strength of microcellular PVC was found to decrease linearly with relative density. The gas saturation pressure did not significantly affect the impact strength of microcellular PVC foams. Microcellular PVC foams with up to 40% reduction in density possessed a normalized mean failure energy of 3.8 J/mm (0.85 in.‐lb/0.001 in.).
New developments in fire retardant non‐halogen aromatic phosphates
Authors: Levchik Sergei V. , Bright Danielle A. , Moy Paul , Dashevsky Sophia
Published: April 2004

Akzo Nobel Chemicals has recently introduced on the market an aromatic oligomeric phosphate (BDP) based on Bisphenol A. This product shows higher thermal and hydrolytic stability than other aryl phosphates. It provides similar or better fire retardant performance than an oligomeric phosphate (RDP) based on resorcinol. Fire retardant formulations with BDP based on polycarbonate/ABS plastic (PC/ABS) blend, polyphenylene oxide/high impact polystyrene (PPO/HIPS) blend, and HIPS alone show similar or better physical properties than those obtained with RDP. Upon thermal decomposition of the fire retarded polymers containing BDP, phosphorus tends to accumulate in the solid residue, a result which indicates that the primary fire retardant action of BDP is likely to occur in the condensed phase.
Effects of impact modifiers on the properties of rigid PVC/wood‐fiber composites
Authors: Mengeloglu Fatih , Matuana Laurent M. , King Julia A.
Published: April 2004

This study examined the effects of impact modifier types and addition levels on the mechanical properties of rigid PVC/wood‐fiber composites. The impact resistance of rigid PVC/wood‐fiber composites depends strongly on the type and content of impact modifier. With the proper choice of modifier type and concentration, the impact strength of rigid PVC/wood‐fiber composites can be significantly improved without degrading the tensile properties. Methacrylate‐butadiene‐styrene and all‐acrylic modifiers performed in a similar manner and were more effective and efficient in improving the impact resistance of rigid PVC/wood‐fiber composites than the chlorinated polyethylene modifier.
Gloss control in rigid PVC—Part II. Effect of processing variables on the gloss of rigid PVC profiles
Authors: Rabinovitch Elvira , Harshbarger Deanna
Published: April 2004

This paper describes the results of a study of the effect of extrusion conditions on the gloss of rigid PVC profiles. Extrusion variables investigated are extrusion melt temperature, extruder temperature settings, extrusion rate, and the die/sizer metal surface condition. It is hoped that this information will help PVC profile manufacturers to optimize their process for achieving desirable gloss.
Microcellular foaming of impact‐modified rigid PVC/wood‐flour composites
Authors: Matuana Laurent M. , Mengeloglu Fatih
Published: April 2004

Solid state microcellular foaming technology was employed to investigate the influence of impact modification on the foamability of neat rigid PVC and rigid PVC/wood‐flour composite samples. The effects of impact modifier types (crosslinked versus uncrosslinked) and concentrations on the void fraction of foamed samples were examined. The influence of impact modification on the sorption behavior of CO2in the samples was also studied. The experimental results indicate that impact modification accelerates the rate of gas loss during the foaming process, which impedes the growth of nucleated cells, independent of modifier type. Because of this accelerated gas loss, impact modification inhibits the potential of producing foamed samples with void fractions similar to those achieved in unmodified samples.
Combining boron nitride with a fluoroelastomer: An enhanced polymer processing additive
Authors: Seth Manish , Hatzikiriakos Savvas G.
Published: April 2004

The effect of a new processing additive (boron nitride powder in combination with a fluoroelastomer) on the rheology and processability of molten polymers is studied. The equipment used includes an Instron capillary rheometer equipped with a special annular die (Nokia Maillefer wire coating cross‐head) and a parallel‐plate rheometer. Metallocene polyethylenes with and without boron nitride (BN) and fluoroelastomer are tested in extrusion. First, it is demonstrated that BN is a superior processing aid compared to conventional fluoropolymer ones. Second, it is found that the combination of BN powders with a small amount of a fluorelastomer improves even further the processability of molten polymers (melt fracture performance).
Flexible vinyl resiliency property enhancement with hollow thermoplastic microspheres
Authors: Ahmad Maf
Published: April 2004

This paper demonstrates an enhancement in resiliency and rebound properties of vinyl plastisol based materials incorporating hollow thermoplastic microspheres; and their characterization using Dynamic Mechanical Analysis involving the time‐temperature superposition technique. These materials have a wide range of applications, including automotive underbody coatings, gaskets, sealants, and recreational and athletic articles.
Polymerization of vinyl chloride with butyllithiums and metallocene catalysts
Authors: Endo Kiyoshi , Kaneda Noriyasu , Waku Hidenori , Saitoh Makoto , Emori Nobuyoshi
Published: April 2004

Polymerizations of vinyl chloride (VC) with butyllithium (BuLi) and metallocene catalysts were investigated. In the polymerization of VC with BuLi, the activity for polymerization decreased in the following order; t‐BuLi > n‐BuLi > s‐BuLi. A polymer controlled structurally in the main chain was found to be synthesized from the polymerization of VC with BuLi. The molecular weights of polymers obtained in bulk polymerization were higher than those of polymers obtained in solution. A linear relationship of the Mn of the polymer and the polymer yields was observed. The Mw/Mn of the polymer did not change significantly during polymerization, although the Mw/Mn was around 2. Thermal stability of the polymer obtained with BuLi was higher than that of polymer obtained with radical initiators, as determined by TGA measurements. In the polymerization of VC with Cp*TiX3/MAO (X: Cl and OCH3) catalysts, polymers were obtained with both catalysts, although the rate of polymerization was slow. The Cp*Ti(OCH3)3//MAO catalyst in CH2Cl2 gave higher‐molecular‐weight polymers in a better yield than in toluene. From elemental analysis and the NMR spectra of the polymers, the Cp*Ti(OCH3)3/MAO catalyst gave polymers consisting of repeating regular head‐to‐tail units, in contrast to the Cp*TiCl3/MAO catalyst, which gave polymers having anomalous units.
Stereochemical microstructure dependence of physical properties of poly(vinylchloride) (PVC). Principles and some recent correlations
Authors: Guarrotxena N.
Published: April 2004

As described in earlier work and surveyed herein, stereospecific substitution reactions on PVC produce controlled changes in stereochemical microstructure. The corresponding changes in Tg are analyzed for each of the reactants utilized. A linear correlation is found between Tg and the ratio between the mmr tetrad reacting through its central mm triad and the mmmr pentad reacting through its mr triad plus the rrmr pentad reacting through its mr triad. The proposed explanation lies in the nature of the conformational changes which each of these reactions involves. Interestingly, the absolute value of the microstructure/Tg correlation is independent of the nucleophile, the nature of which can, however, determine the sign of that correlation. In addition, the evolution of both the amount and nature of the space charges that originate when applying an electrical field to the polymer films has been systematically studied by the thermal step method. The correlations obtained justify the mmr tetrad as being the main trap of either heterocharges or homocharges, depending upon whether mmr takes the GTTG TT or the GTGTTT conformation, respectively. This result agrees with the results of a tentative attempt with the stretched films. Some novel approaches toward understanding the physical behavior are proposed.
PVC‐clay nanocomposites: Preparation, thermal and mechanical properties
Authors: Wang Dongyan , Parlow Daniel , Yao Qiang , Wilkie Charles A.
Published: April 2004

PVC‐clay nanocomposites were prepared by melt blending of the polymer with an organically modified clay, both in the presence and in the absence of di(2‐ethylhexyl) phthalate (DOP). The clay can serve as a plasticizer for PVC in the absence of DOP. The nanocomposites were characterized by using X‐ray diffraction and transmission electron microscopy, and the materials were found to be largely intercalated. Thermal properties were evaluated by using thermogravimetric analysis, and the thermal stability was determined to be variable, depending upon the amounts of clay and DOP that were present. The fraction of polymer that remained at 600°C was significantly reduced in the presence of the clay, a result indicating that the clay had an effect on the course of the degradation of the PVC. The tensile strength of the nanocomposites increased as the fraction of clay increased, and the addition of a small amount of clay increased the elongation, but when additional clay was added, the elongation decreased.
Achievements and research tasks for poly(vinyl chloride) aging and stabilization
Authors: Minsker K. S. , Zaikov G. E.
Published: April 2004

Perspectives for the manufacture of PVC that does not contain liable groups in the backbone are considered. If achieved, such manufacture will provide a drastic increase in the intrinsic stability of the polymeric products, the possibility of processing PVC with minimal contents or in the total absence of stabilizers and other chemical additives, and the opportunity of creating materials and products based on PVC with increased service lifetimes. The data presented allow creation of rigid, semirigid, and flexible (plasticized) materials and products with minimal contents of chemical additives and increased service lifetimes under natural and special conditions.
PVC‐Based TPEs for year 2000 and beyond
Authors: Weng Dexi , Morin Phil , Saunders Keith , Andries John
Published: April 2004

Soft, low‐compression‐set and chemically resistant TPEs have been developed from advanced PVC blend technology. These blends have low‐temperature flexibility comparable to that of commonly used TPEs and can be made flame‐retardant. These new TPEs are suitable for applications in consumer products, automotive, wire and cable insulation, and jacketing. This new class of TPEs, suitable for injection and extrusion operations, represents a significant advance in PVC compounding technology.
Fourier transform infrared micro spectroscopy mapping studies of weathered PVC capstock type formulations. II: Outdoor weathering in pennsylvania
Authors: Garcia Dana , Black Janine
Published: April 2004

FTIR micro spectroscopy coupled with mapping techniques is a powerful methodology to evaluate dimensionally dependent changes such as those encountered in PVC weathering processes. It is based on the complexity and specificity of the infrared spctrum and the dimensional resolution of the microscope. This paper will outline a systematic FTIR study of changes observed during outdoor photo degradation of PVC siding capstock formulations, as a function of exposure time and TiO2 level. The results are compared with previously obtained accelerated QUV data. Profiles through the thickness dimension were analyzed to identify degradation species and depth distribution.
Surface analysis of poor printability PVC films
Authors: Burley Joseph W. , Beard Bruce C.
Published: April 2004

Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS) were employed to analyze the surfaces of PVC films with poor printability. FTIR indicated that, independent of formulation, the migrating species were metal carboxylates. Different techniques penetrate the surface to different depths allowing examination of a range of surface layers. XPS indicated that, in the worst case, the upper surface layer was comprised almost exclusively of a mixed metal carboxylate. Atom percentages obtained by XPS indicated hydrolysis of the mixed metal carboxylate at the vinyl surface.
Rigid PVC formulation optimization using sequential simplex
Authors: Berard Mark T.
Published: April 2004

A rigid PVC formulation was optimized for processing window and cost using sequential simplex techniques in combination with desirability functions. This optimization was performed on seven of the ten ingredients from a ‘standard’ siding compound with a relatively limited number of experiments. The processing window contour mapping technique was used to evaluate the effects of formulation changes. This was combined with the formulation cost by using desirability functions to give an overall response for the simplex to optimize. The basic mechanics of sequential simplex and desirability functions are described along with the results of the optimization.
The NMR spectra of lead stabilizers
Authors: Grossman Richard F.
Published: April 2004

High resolution proton and 13C NMR spectra of lead‐based heat stabilizers and their reaction products, obtained using the magic angle spinning technique, support structural assignments inferred from IR spectra. These demonstrate that lead stabilizers are unique compounds, rather than the double salts of lead oxide found in textbooks.
Stabilization of rigid poly(vinyl chloride) by 5,6,7,8‐Tetrahydro‐2‐mercapto‐4‐(p‐methoxyphenyl)‐3‐quinolinecarbonitrile
Authors: Andel‐Naby Abir S.
Published: April 2004

The chemical 5,6,7,8‐Tetrahydro‐2‐mercapto‐4‐(p‐methoxyphenyl)‐3‐quinolinecarbonitrile (TMQC) has been investigated as a thermal stabilizer for rigid poly(vinyl chloride) (PVC) at 180°C in air. The results reveal the higher stabilizing efficiency of the investigated material, as shown by the longer induction period obtained in its presence relative to those produced by commonly used industrial stabilizers. Ultraviolet irradiation of the polymer stabilized by TMQC gives a lower extent of discoloration compared to that of unstabilized PVC. Reaction of TMQC with the polymer in solution also has been studied in order to investigate the mechanism of stabilization.
Adventures in fire retardancy
Authors: Wilkie Charles A.
Published: April 2004

The work of the author's research group on fire retardancy over the past twenty years is reviewed.
Designing with glass fiber reinforced vinyl composites. II: Long term creep considerations
Authors: Woods Martin E. , Elleithy Rabeh H.
Published: April 2004

Seven years ago we initiated a long‐term study on the effect of time and temperature on the data sheet modulus values for glass fiber reinforced vinyl composites. Results after the first year showed that the measured creep modulii were higher than those predicted by time‐temperature superposition of dynamic mechanical data. This paper presents five years of additional creep data and examines the effect of sample aging on the creep predictions.
Effect of thermal degradation on the impact properties of PVC compounds
Authors: Ryan Sullivan F. , Elleithy Rabeh H. , Abu‐Ali Amjad
Published: April 2004

An instrumented drop weight impact test was used to study the effect of thermal degradation on the impact properties of PVC compounds. The impact resistance of the aged compounds related well with their weight loss and hence, with thermal degradation. Each compound showed a specific weight loss percentage that correlated with a 50% loss in its impact properties (failure point), irrespective of the aging temperature. The results were also used to estimate a thermal index (TI) of each compound in a rapid and reliable way.
Degradation and stabilization of poly(vinyl chloride). 6: Model studies on dehydrochlorination of 6(4)‐chloro‐4(5)‐tetradecenes in the presence of alkyl phosphites and zinc di(dialkyl phosphites)
Authors: Fisch Michael H. , Bacaloglu Radu
Published: April 2004

Thermal dehydrochlorination of trans‐6(4)‐chloro‐4(5)‐tetradecenes, models for PVC degradation, was studied by NMR spectroscopy both alone and in the presence of alkyl and zinc phosphites. The implications of these results on PVC degradation and stabilization are discussed.
Retrostructural analysis of poly(vinyl chloride) particles
Authors: Lukas Rudolf
Published: April 2004

A poly(vinyl chloride) (PVC) matrix of final particles is investigated by means of quasi‐elastic light scattering (QELS) and high resolution porosimetry (HRP). It is demonstrated that the QELS method is a powerful tool for the detection of various higher organized structures in particle interiors, which in all likelihood will be a difficult‐to‐process fraction of the resin. Measurements of common PVC grades revealed that the QELS records are usually composed of three distinctly separated size distributions, which were assigned to the size distribution of single macromolecules dissolved (maximum at ca. 10 nm), associates of macromolecules (primary particles, the maximum at ca. 100–200 nm), and microglobules (the maximum at ca. 0.8–1 (μm)). The properties of primary particles are presented, as well as the correlation between QELS and HRP records. Based on this correlation, it can be suggested that the pore size distribution is in fact a morphological fingerprint of individual PVC resins. Some consequences of the results obtained for the evaluation of the processsing properties of PVC are discussed.
Optimization of additive packages for processing and long‐term thermal stabilization of film grade high‐density polyethelene
Authors: Parrondo Aitor , Allen Norman S. , Edge Michele , Liauw Christopher M. , Fontán Eusebio
Published: April 2004

Analysis and optimization of the simultaneous effects within different additive packages for stabilization during melt processing and long‐term thermal stabilization of high‐density polyethylene were carried out by using a carefully constructed statistical experimental design involving response surface methodology (RSM). The packages consisted of blends of phenolic antioxidants, phosphites, and zinc stearate. The degree of melt processing stabilization was assessed by using melt flow rate (MFR) and yellowness index (YI) measurements conducted on samples that had varying degrees of processing history imposed by varying the number of passes through a twin‐screw extruder. The long‐term thermal stabilization was assessed by YI measurement after oven aging at 110°C. The RSM approach utilized in this study enabled the contribtion of each additive to the stabilization and interactions between the additives to be observed. Furthermore, the concentration and ratio of each additive could be optimized.
Evaluation of surface concentration of erucamide in LLDPE films
Authors: Rawls Amy S. , Hirt Douglas E. , Havens Marvin R. , Roberts William P.
Published: April 2004

Additives are often blended into polymers to improve specific performance features of the finished film. Erucamide is a common slip agent used to reduce a film's coefficient of friction (COF), which is a good attribute for high speed packaging operations. Because such additives must migrate to the surface to be effective, this study focuses on erucamide blooming to the surface of linear low‐density polyethylene (LLDPE) films. Both the surface and bulk concentrations of erucamide were measured over time to determine the equilibrium additive partitioning. The surface concentration was determined by surface washing for different time intervals and extrapolated back to a “zero” time to offset the solvent extraction of additive from the bulk film. The bulk concentration was determined by a deep microwave extraction. Initial experiments with forced aging at 60°C showed significant evaporative losses of erucamide. The final work focused on room temperature, at whcih additive evaporation was negligible. The room temperature blooming results showed that the erucamide surface and bulk concentrations reached equilibrium within 24 hours. The data also showed that erucamide surface concentration increased with initial additive loading for a fixed film thickness and with increased film thickness for a fixed additive concentration.
Mechanical properties and rheological behavior of PVC blended with terpolymers containing N‐phenylmaleimide
Authors: Yang Liting , Liu Guodong , Sun Donghai , Wang Weina , Gao Jungang , Zhang Liucheng , Jin Riguang
Published: April 2004

Three kinds of terpolymers containing N‐phenylmaleimide (PhMI) were synthesized by emulsion polymerization. The terpolymers were used as heat‐resistant modifiers, and acrylic‐core/shell (ACR) was used as an impact modifier in blends with PVC. The mechanical properties and rheological behavior of the blended systems were determined. The results showed that the mechanical properties of the blends improved with increasing terpolymer content and that the apparent melt viscosity of the blends decreased with increasing terpolymer content. When 8 phr of ACR was added to the blended system, the mechanical properties and the apparent melt viscosity were greatly improved.
Rheological and mechanical performance of ethyl‐vinyl acetate/poly(vinyl chloride) formulations
Authors: McConnell D. C. , McNally G. M. , Murphy W. R.
Published: April 2004

A range of powdered ethyl‐vinyl acetate (EVA) copolymers and poly(vinyl chloride) (PVC) formulations were compounded at PVC:EVA ratios of 100:0, 60:40, 50:50, 40:60, and 0:100. Two grades of EVA with 20% and 27% of vinyl acetate (VAc) (EVA I and EVA II) and two grades of PVC with K values of 56 and 71 (PVC I and PVC II) were used in the investigation. Mechanical analysis was performed on injection molded samples of these blends, and the results showed that the tensile and flexural moduli decreased significantly with increasing EVA concentration. Rheological analysis was performed by using dual capillary rheometry, and the results showed only slight changes in shear viscosity with increasing EVA content, even at lower shear rates. Dynamic mechanical thermal analysis showed partial miscib lity of the PVC and EVA over the range of concentrations studied.
Review of specialty PVC resins
Authors: Shah Ashok C. , Poledna David J.
Published: April 2004

World consumption of PVC was around 25 MM MT (55 billion pounds) in year 2001, second only to that of low density polyethylene. Only 10% of the PVC produced is classified as specialty PVC resins, while the other 90% is referred to as general purpose (GP) commodity resins. This paper tries to define what specialty PVC resins are, how they are produced, and their markets, applications, fabrication processes, and compounding as compared to those of GP resins.
Chlorinated poly(vinyl chloride) and plasticized chlorinated poly(vinyl chloride)—thermal decomposition studies
Authors: Carty Peter , Price Dennis , John Milnes G.
Published: April 2004

The thermal decomposition of chlorinated poly(vinyl chloride) and three plasticized chlorinated poly(vinyl chloride) systems has been investigated. The routes of decomposition of these systems have been elucidated by investigating char formation and by using a combination of thermogravimetric analysis (TGA) and prolysis/gas chromatography/mass spectroscopy methods (Py/GC/MS). The effects of the charforming/smoke‐suppressing iron(III) compound FeOOH in these polymer systems has also been investigated. The structure of both CPVC polymer and plasticzer determine the path of thermal decomposition and also the quantity and nature of the decomposition compunds formed. Changes in oxygen index and the formation of smoke during burning in these systems have been related to the char that is formed and also to the chemical nature of the decomposition products.
Fusion mechanism in rigid PVC
Authors: Berard Mark T.
Published: April 2004

A classic approach for studying network effects in carbon‐black‐containing rubber was applied to PVC with stabilizer. This approach involves measuring the shear modulus with increasing strain. In carbon‐black‐containing rubber, the modulus drops dramatically at a critical strain level. This is known as the Payne effect and is associated with the breakup of the carbon black network. Rigid PVC that is fused to different levels in a bowl mixer shows exactly the same behavior, and the drop point correlates very well with the fusion peak in the mixing bowl. The relationship between network effects and fusion in PVC is discussed.
Conservative vs. surgical management of septic abortion with renal failure
Authors: Singhal Pravin C. , Kher Vijay K. , Dhall Gian I. , Mehta Ravindera L. , Visweswaran R. Kasi , Nampoory M.R. Narayanan , Chugh Kirpal S.
Published: April 2004

The role of surgery in the management of postabortum renal failure complicated with extensive uterine sepsis, perforation or peritonitis is controversial. This study compares the course and final outcome of 14 patients (66.6%) conservatively managed with appropriate antibiotics, fluid or blood replacement and dialysis, with seven patients (33.3%) for whom hysterectomy or laparotomy was undertaken in addition. Whereas all 14 patients treated conservatively died as the result of uncontrolled septicemia, three of the seven surgical patients recovered completely. Extensive necrosis with perforation of the uterine wall was confirmed either at laparotomy or at autopsy in all 21 women. To reduce mortality, the authors recommend early surgical intervention for patients suffering from post‐abortum renal failure complicated with uterine sepsis or perforation.
Outcome of labor following previous cesarean section
Authors: Wadhawan S. , Narone J.N.
Published: April 2004

Four hundred fifty‐one patients who had had previous lower segment cesarean section were studied for subsequent pregnancy outcome at the University Teaching Hospital, Lusaka, Zambia. Of 319 who were allowed to go into labor, 63% succeeded in delivering vaginally, while 37% had to undergo repeat intrapartum cesarean delivery. No maternal death occurred. Scar dehiscence occurred in one case only. Parturition in otherwise obstetrically normal patients seems to be safe, and the trial of labor approach is desirable as it results in a lower number of repeat cesarean deliveries.
Ovarian pregnancy in association with an intrauterine device
Authors: de Vries K. , Shapiro I. , Degani S. , Levitan Z. , Mitrani A. , Sharf M.
Published: April 2004

Within a 1‐year period, two cases of primary ovarian pregnancy associated with an intrauterine device (IUD) occurred in our institution. The clinical signs and symptoms were similar to those in any other ectopic pregnancy. Both cases satisfied the criteria of Spiegelberg. The final diagnosis was based on the histopathological findings. A review of the literature is presented summarizing the 53 cases reported until now. The association between IUD, ectopic pregnancy in general, and ovarian pregnancy in particular is discussed.
Mortality in relation to method of delivery in breech infants
Authors: Petitti Diana B. , Golditch Ira M.
Published: April 2004

To study the relation of method of delivery to perinatal mortality, we examined information from the deliveries of 1593 breech infants weighing 1000 g or more born in 1976 and 1977. In none of the birthweight groups 1000 g or more was neonatal mortality significantly different between infants delivered vaginally compared with those delivered by cesarean section, although the number of deaths was small. In all the birthweight groups, perinatal mortality was higher in breeches delivered vaginally, but the differences were because all of the infants who died before labor were delivered vaginally. Total mortality (intrapartum plus neonatal deaths) in infants who survived to labor was not significantly different in breech infants delivered by one or the other method at any birthweight. These data suggest that routine cesarean delivery for infants 1000 g or more who are in the breech presentation may not be justified from the standpoint of mortality.
Prevention of postoperative infection in cesarean section after rupture of the membranes
Authors: Schedvins K. , Moberg P.J.
Published: April 2004

Patients having a cesarean section more than 6 h after rupture of the membranes constitute a high risk group for postoperative infections. Two such groups were studied. Patients were given either cefuroxim 1.5 g every 8th hour for 24 h followed by cefadroxil 0.5 g twice daily for 6 days or received no medication. The infection rate was significantly reduced in the treatment group as compared to the control group (15% vs. 48%). Non‐infected patients had a significantly shorter stay in hospital (8 days vs. 12 days).

Combined use of these drugs for prevention of postcesarean infection has not previously been reported. No side effects of the antibiotic prophylaxis were reported.
How Chinese clinicians contribute to the improvement of maternity care
Authors: Yan R.Y.
Published: April 2004

Clinicians in China are deeply involved in efforts to improve maternity care throughout the country. A Women's Health section has been established in the Chinese Society of Obstetrics and Gynecology. Staff of tertiary hospitals participate in perinatal surveillance of cities, including regular maternal and perinatal mortality meetings and comparative inter‐hospital evaluations of service and clinical statistics. Clinicians from larger urban centers visit rural hospitals to provide guidance in management of high risk patients.
Ethnic and other factors affecting birthweight in Singapore
Authors: Viegas O.A.C. , Ratnam S.S. , Cole T.J.
Published: April 2004

Data on 1800 term babies, 600 from each of the Chinese, Malay and Indian racial groups, were used to identify the factors affecting birthweight in Singapore. After adjustment for gestation, maternal height and other variables, the mean Indian birthweight was 100 g less than for the Chinese (P < 0.001), while the Malays averaged 33 g less than the Chinese. The shortfall in Indian birthweight is thought to be due, at least partly, to environmental factors.
Placental site trophoblastic tumor associated with immature ovarian teratoma
Authors: Stetler‐Stevenson W. , Lurain J.R. , Murad T.
Published: April 2004

This paper describes a woman who developed three malignancies within a very short time. Two of these, immature teratoma and placental site trophoblastic tumor, were rare gynecological neoplasms. The third was a breast carcinoma. This is the first report of an association of placental site trophoblastic tumor with a primary germ cell tumor of the ovary.
Vaginal birth after cesarean section in rural Tanzania
Authors: van Roosmalen J.
Published: April 2004

Eighty‐seven of 134 women with a history of previous cesarean section in two rural hospitals in Tanzania had a vaginal delivery after a trial of labor. The incidence of scar‐rupture was high; in 9 of 134 cases (6.7%). Maternal death, however, did not occur. It is concluded that a trial of labor is justified, and that the risk of scar‐rupture should be balanced with the risk of repeat operations.
Pregnancy‐associated hypertension in Maputo. A study on maternal characteristics and perinatal outcome in 1275 consecutive cases
Authors: Merz R. , Said A. , Bergström S. , Bugalho A. , Samucidine M.
Published: April 2004

A total of 1275 consecutive cases of pregnancy‐associated hypertension were registered in the Maputo Central Hospital (corresponding to 2.9% of a total of 43 794 city parturients). In the hypertensive and in the reference populations the following prevalence figures were registered, respectively: age below 25 years, 52% and 23% (P < 0.0005); nulliparity, 33% and 19% (P < 0.0005); twin pregnancies, 3.9% and 1.7% (P < 0.0005); stillbirths, 5.7% and 2.3% (P < 0.0005); and low birthweight (LBW), 22.9% and 10.7% (P < 0.0005). In the hypertensive population the prevalence of LBW newborns was 20.1% in the liveborn group, while it was 68.4% in the stillborn group (P < 0.0005). In the ongoing perinatal audit it was found useful to review hypertensive women separately, in order to assess current routines in cases of pregnancy hypertension.
Counselling the Mafia: The Sopranos Regina Barreca, ed., A Sitdown with the Sopranos: Watching Italian American Culture on TV's Most Talked-About Series (New York: Palgrave Macmillan, 2002). 0 312 29528 6 David Bishop, Bright Lights, Baked Ziti: The Unofficial, Unauthorised Guide to The Sopranos (London: Virgin Books, 2001). 0 7535 0584 3 David Chase, The Sopranos Scriptbook (London: Channel 4 Books, 2001). 0 7522 6157 6 Glen O. Gabbard, The Psychology of the Sopranos: Love, Death, and Betrayal in America's Favorite Gangster Family (New York: Basic Books, 2002). 0 465 02735 0 The New York Times, The New York Times on the Sopranos, introduction by Stephen Holden (New York: ibooks, 2000). 0 7434 4467 1 Allen Rucker, The Sopranos: A Family History (London: Channel 4 Books, 2000). 0 752 26177 0 Allen Rucker (Recipes by Michele Scicolone), The Sopranos Family Cook Book As Compiled by Artie Bucco (London: Hodder and Stoughton, 2002). 0 340 82724 6 David R. Simon, Tony Soprano's America: The Criminal Side of the American Dream (Boulder, CO, and Oxford: Westview, 2002). 0 8133 4036 5 David Lavery, ed., This Thing of Ours: Investigating the Sopranos (New York: Columbia University Press, 2002). 0 231 12781 2
Authors: WYNN NEIL A.
Published: April 2004

The HBO television series The Sopranos, produced by David Chase, achieved unprecedented critical acclaim and quickly established itself on both sides of the Atlantic as cult viewing. The fourth series, shown in the UK on Channel 4 in spring 2003, had already attracted record audiences in America and received 13 Emmy Award nominations. Not surprisingly, The Sopranos has generated several web sites and a considerable amount of literature, ranging from the usual spin-offs of television series, cds, scripts, collected reviews, and a number of more academic studies ranging from cultural studies through to explorations of the psychological aspects of the programme. At least one MA has been written dealing with the portrayal of psychotherapy in this series and in films. This is not as remarkable as it might seem given that therapy is central to the whole story. The main character, Tony Soprano (played by James Gandolfini), is the head of an Italian–American family living in New Jersey. However, like his name itself, “family” has a double meaning. Tony is also the head of a Mafia-style gang of mobsters, operating a “waste management company” and night club (The Bada Bing!). The two roles of family head are explored when Tony talks (or “sings”) to a psychiatrist (in addition to his gang-land counsellors) as a result of his anxiety attacks and depression. Thus, Tony Soprano, mobster, is presented as a troubled family man – troubled by his relationships with his wife, daughter, and son, and their futures, but also troubled by business rivalries and problems that arise from the nature of his “work” and colleagues. As one commentator writes, Tony is the subject of “profound moral ambiguity” and it is his struggle to come to terms with this that makes it possible for viewers to identify with him. It is also the focus of his sessions with the therapist, Dr Melfi (played by Lorraine Bracco).