bluuebunny/crossref_metadata_2025 huggingface dataset:
XPS study of amorphous As2S3 films deposited onto chromium layers
Authors: Petkov K. , Krastev V. , Marinova Ts.
Published: May 2005

This paper reports some XPS data on unexposed and exposed thin films of As2S3 deposited onto chromium‐coated glass substrates. We show the chemical changes on the surface and interface of As2S3 and chromium layers. The chromium layers are obtained by thermal evaporation, high‐frequency sputtering and electron beam evaporation. Chemical changes of the sample surface after laser irradiation are investigated. Exposure of As2S3 films results in photo‐induced oxidation of arsenic on the surface and formation of As2O3. It is established that the O 1s peak area on exposed samples decreases compared to the O 1s peak area on unexposed ones. This is related to desorption of As2O3 from the surface of exposed As2S3 layers. Another proof of desorption of As2O3 is the decrease of the As 3d/S 2p normalized peak area ratio on exposed As2S3 layers. The sulphur content on the surface remains unchanged after exposure of the samples, but its chemical surroundings change. An alteration of the chemical environment of As and Cr is observed at the As2S3/Cr interface, due to diffusion of chromium atoms through the interface into the As2S3 layer. This results in formation of an AsxCrySz compound at the As2S3/Cr interface, which dissolves with a lower rate. This hinders further etching of the metal coating during the photolithographic process employing Cr plates with inorganic photoresist based on vacuum deposited As2S3.
An XPS and SEMS study of silica sol‐gel/metal substrate interaction
Authors: Stoch A. , Stoch J. , Rakowska A.
Published: May 2005

Some applications of ceramic materials are difficult because of the markedly differing lattice bonding characteristics of ceramic and metals. This ‘affinity barrier’ can be overcome by the modifying of structure and composition in the interphase region. In our work the silica sublayer was deposited by the sol‐gel method on metal implants prior to electrophoretical deposition of hydroxyapatite coatings to improve the oxidation resistance of the metal surface and the adhesion of apatite to metal during the annealing. The aim of this study is to determine changes in chemical state and structure of the coatings caused by thermal treatment for the better understanding of a relation between their composition and properties. Plates of titanium, WT 1‐0, FeCrNi stainless steel and of low‐carbon steel were covered with silica layer by the sol‐gel method. The coating on low‐carbon steel was produced by the deposition of silica sol‐gel directly on the metal or, the silica–titania opacified porcelain enamel was obtained by electrophoresis. In the case of direct deposition, below 400 °C, an amorphous layer was formed while at 800–900 °C for only 2‐4 min the dense, fine crystalline structure was obtained including small amount of silicates and iron scales. The silica–titania enamel was electrophoretically applied on low‐carbon steel pre‐coated with nickel. During annealing nickel is alloyed with iron and decreases oxygen transport towards iron decreasing the rate of FeO formation. The silica from the enamel reacts with FeO producing a small amount of silicates. Titania partially precipitates at the metal boundary in the form of the needle‐like crystals of FeTiO3, growing from the steel surface into the enamel. When stainless steel was annealed at 700 °C in air, the surface oxide was enriched in chromium and manganese while the silica surface was enriched in iron and manganese.
The microchemistry of interfaces in fiber‐reinforced ceramics and glasses
Authors: Schneider R. , Woltersdorf J.
Published: May 2005

The mechanical properties and the high‐temperature behaviour of fibre‐reinforced composites are controlled by both the microstructure and the microchemistry of fibre/matrix interlayers. For a C‐fibre reinforced SiC composite and various SiC (Nicalon)‐fibre reinforced Duran glasses, the composition of the interfacial layers, which are rich in different carbon modifications—due to either fibre precoating or subsequent solid state reactions—has been investigated by different techniques of analytical electron microscopy (AEM).
The investigation of instrumental and sample parameters as potential sources for affecting the reproducibility of isotopic ratio measurements in secondary ion mass spectrometry
Authors: Adriaens A. , Adams F.
Published: May 2005

In this study a number of instrumental and sample parameters were investigated as potential sources for affecting the reproducibility of isotopic ratio measurements in secondary ion mass spectrometry. The study consisted of examining the energy distributions of the individual isotopes using different parameter settings. This way, 70% of the observed isotopic variation could be ascribed to the setting of certain instrumental parameters such as the field aperture, the contrast diaphragm and the energy window width. In addition, the effects of differing crystal orientations in the sample and macroscopic surface characteristics upon the reproducibility were evaluated using imaging techniques.
Surface composition of machined leaded brass
Authors: Wu J. X. , Ji M. R. , Galeotti M. , Giusti A. M. , Rovida G.
Published: May 2005

ESCA and RBS were used to obtain quantitative information on the thickness and nature of the surface layers formed on machined brasses containing 1–3% lead. The results show that the brass surface is strongly enriched in lead. The amount of this element accumulated on the surface increases with increasing bulk concentration. Lead appears to be present as islands partially covering the brass surface and having variable thicknesses up to several hundred Å. The outermost layer of the islands is mainly a Pb hydroxycarbonate, under which PbO and Pb metal can be detected. Between the islands, the brass surface is covered by a layer of zinc oxide covering the CuZn metallic phase. The accumulation of Pb at the surface is attributable to a smearing effect caused by the machining cool.
ESCA investigation of SnOx films used as gas sensors
Authors: Sanjinés R. , Rosenfeld D. , Gozzo F. , Alméras Ph. , Perez L. , Lévy F. , Margaritondo G. , Schreiner W. H.
Published: May 2005

The electronic properties of amorphous and ion‐implanted polycrystalline SnO2 films have been studied using x‐ray photoemission spectromicroscopy. First, we analysed the degree of oxidation and the homogeneity of as‐deposited films. The SnO and SnO2 phases were identified from their valence band spectra rather than from the Sn 3d core level spectra. Then we studied the damage effects due to the implantation of Pd+ and Ga+ ions in polycrystalline films. The ion bombardment of SnO2 films results in drastic changes of valence‐band spectra which is correlated to compositional changes. Annealing in air at 600 °C for 4 h leads to complete recovery of radiation damage. However, after such thermal annealings, the film surface still contains a relatively high amount of SnO (5–10%).
AES and SAM studies of oxide formation on Inconel 600 at high temperatures
Authors: Alstrup N. C. , Langvad N. , Chorkendorff I.
Published: May 2005

Characterization of the oxide formed on a Ni‐based alloy (Inconel 600) at high temperatures has been carried out using AES and SAM combined with ion‐etched depth profiling. The oxidation experiment was done at 1000 °C, in atmospheric air and under mild (H2/H2O) oxidation conditions. In air, the resulting surface is highly inhomogeneous, featuring large Ni‐rich islands on top of a continuous Cr‐rich oxide layer. When the oxygen partial pressure (H2/H2O) was lowered, the Ni‐rich layer was not formed.
In search of the ultimate experiment for quantitative depth profile analysis in glow discharge optical emission spectrometry. Part II: Generalized method
Authors: Payling Richard
Published: May 2005

The current and voltage terms of the SIMR approach are combined with the pressure approach of BHP to derive an empirical equation that describes the relationship between recorded emission signal and current, voltage and pressure in a model‐independent way. To test the equation, an emission line from each of five different elements in up to five different matrices recorded in all three operational modes of the glow discharge lamp for thirty different values of current, voltage and pressure were combined to give an average of 114 data points per line. The equation was then fitted to the data through multiple linear regression to derive a best estimate of the separate contributions of current, voltage and pressure to intensity and emission yield. The results show that current, voltage and pressure all contribute significantly to the recorded signals and emission yields. Typically, emission yield is proportional to current, decreases as the square root of over‐voltage and increases linearly with pressure at low pressures but decreases exponentially at higher pressures.
Reflection–absorption Fourier transform infrared spectroscopy (RAIRS) study of the conformation and orientation of poly(amino acid) Langmuir–Blodgett films
Authors: Auduc‐Boyer N. , Stevenson I. , Duc Tran Mihn , Linossier I. , Gaillard F.
Published: May 2005

A quantitative study by reflection–absorption infrared spectroscopy (RAIRS) on multilayer systems of Langmuir–Blodgett (LB) poly(amino acid) films has been carried out. Thickness measurements of monolayer and multilayer systems have been made and the results obtained by two well‐known equations have been compared. Evolution of the α‐helix conformation as a function of temperature in the case of polybenzyl aspartate (PBA) and polybenzyl glutamate LB systems has also been studied by RAIRS. Finally, a Fourier transform infrared transmission study on PBA LB multilayers as a function of temperature has allowed us to draw some conclusions on the orientation of the CO bonds (amide I) with respect to the dipping direction.
Caesium diffusion in sodium borosilicate glass studied by low‐energy ion scattering
Authors: Ceelen W. C. A. N. , Jacobs J.‐P. , Brongersma H. H. , Sengers E. G. F. , Janssen F. J. J. G.
Published: May 2005

A new, time‐saving method to determine the diffusion coefficient of caesium in sodium borosilicate glass is presented. With low‐energy ion scattering (LEIS) the diffusion coefficient of caesium in this glass, where the main components are the same as those in nuclear waste glass, is determined in a wide temperature range (723–849 K). Compared to the conventional concentration couple method where the diffusion has to be studied over large distances (105 nm), it is shown that by using LEIS accurate measurements can be performed when diffusion takes place over distances of the order of 10 nm. Diffusion coefficients for caesium as low as 2.6 × 10−22 m2 s−1 are extracted from the measurements. This is a factor of 106 smaller than that measured with the concentration couple method for the same system and more than a factor of 10 smaller than diffusion coefficients for caesium determined in nuclear waste glasses by other techniques. At high temperatures the results of the different methods are in absolute agreement.
XPS studies of NO selective reduction catalysts after SO2 poisoning
Authors: Grzybek Teresa , Klinik Jerzy , Buczek Bronisław
Published: May 2005

The effect of an SO2–water vapour–air mixture on the structure of Fe3+‐, Cu2+‐, Co2+‐ or Ni2+‐active carbon catalysts used for selective catalytic reduction of NO with ammonia was studied by low‐temperature argon sorption and XPS. Active material reacted with oxidation products of SO2 to form appropriate sulphates. The reaction rate, expressed as surface sulphur‐to‐cation ratio, depended on the distribution of active material on the starting samples. The distribution of Fe3+, Cu2+, Ni2+ and Co2+ changed during the reaction as a result of movement of the cations into the porous system and was accompanied by some decrease in specific surface area and partial blocking of micropores.
On the role of molecular photofragmentation during depth profiling of tantalum oxide layers by laser SNMS
Authors: Wucher A. , Franzreb K. , Mathieu H.‐J. , Landolt D.
Published: May 2005

Depth profile analysis of an ultrathin native oxide layer grown on tantalum metal was performed by time‐of‐flight sputtered neutral mass spectrometry (SNMS) with laser post‐ionization and 11.6 keV Ga+ ion bombardment. Ionization of the sputtered neutral particles was achieved by non‐resonant multiphoton absorption from a pulsed excimer laser operated at 248nm. Particular emphasis was put on the signals of sputtered neutral Ta atoms and TaO molecules, which are interpreted quantitatively by means of a simple model proposed earlier describing the formation probability of sputtered oxide molecules. It is shown that the measured Ta signal contains a considerable fraction of fragmentation products produced by photodissociation of sputtered TaO. From the results, the time‐dependent surface stoichiometry as well as the relative probabilities for photoionization and photofragmentation of TaO are evaluated.
Quantitative surface analysis of styrene–butadiene copolymers using time‐of‐flight secondary ion mass spectrometry
Authors: Weng L. T. , Bertrand P. , Lauer W. , Zimmer R. , Busetti S.
Published: May 2005

The potential applicability of time‐of‐flight secondary ion mass spectrometry (ToF SIMS) as an independent quantitative technique has been studied using a more complicated copolymer system: styrene‐butadiene copolymer. The complication of this system is that the characteristic SIMS peaks are not unique to each monomer. It has been found that quantitative information can be obtained from the relative SIMS intensities of certain characteristic peaks, i.e. m/z = 63, 89, 103 and 115 for styrene and 53, 67 and 79 for butadiene. In particular, the intensity ratios A/(A + B), where A and B represent, respectively, the above characteristic peaks of styrene and butadiene, have been found to be linearly related to the bulk styrene molar concentration. These results suggest that a sensitivity factor that is constant and independent of the copolymer composition can be defined for these peaks. However, this conclusion cannot be generalized for other SIMS peaks, such as m/z = 77, 91 and 105.
Curve fitting of Cr 2p photoelectron spectra of Cr2O3 and CrF3
Authors: Grohmann I. , Kemnitz E. , Lippitz A. , Unger W. E. S.
Published: May 2005

Chromium (III) 2p photoelectron spectra show strong satellites on the high‐binding‐energy side of the main photoelectron peaks. In the case of Cr 2p spectra, the satellite of the Cr 2p3/2 peak strongly overlaps the Cr 2p1/2 peak. As a result, a virtual three‐peak spectrum is obtained. In order to analyse the spectral features of the Cr 2p photoelectron peaks, we propose a fitting formalism for Cr(III) 2p spectra that is consistent with a relaxation model. This model allows for the possibility of two different final‐state screening conditions of the photoinduced core hole. Considering these two final states, Cr 2p spectra basically can be interpreted by a superposition of two 2p doublets. X‐ray contributions arising from the Kα3,4 lines were also taken into account, as well as the existence of OH groups on the surface of Cr2O3 samples. Additionally, a rather pragmatic approach for fitting the Cr L3M23V Auger spectral region was used to obtain further spectral parameters (e.g. α′) that do not depend on charging.
The diffusion of gases and vapors in rigid PVC
Authors: Berens A. R.
Published: May 2005

Gravimetric sorption rate measurements have been carried out for (CO2, H2), and ten C1‐C6 organic vapors at low concentrations (≤ 0.2%) in PVC films and uniform‐particle powders at 30°C. The dominant transport process in all cases appears to be Fickian diffusion. A distinguishable contribution of relaxation‐controlled swelling was observed for the more soluble vapors, such as acetone and benzene. A significant contribution of surface adsorption to the total sorption process was detected only for the n‐alkanes, among the penetrants studied. Diffusion coefficients, determined from half‐sorption times and polymer dimensions, range from 4 × 10 −8 cm2/sec for H2O to 1.5 × 10 −15 cm2/sec for n‐hexane. Diffusivities determined in this study, in combination with those for gases reported by Tikhomorov, et al. (Makromol. Chem. 118 177 (1968)), define a continuous curve, covering more than nine orders of magnitude, when plotted as a function of the molar volume constant, b, of the van der Waals equation of state for gases and vapors.
MBS key variables and MBS/PVC alloy behavior
Authors: Purcell T. O.
Published: May 2005

This paper is another study of the use of graft polymerization onto synthetic rubber substrates. The mechanism of the grafting process and the resultant effects on impact strength are discussed. In addition, the effect of particle size on impact is presented.
Effect of phosphate esters on PVC flammability from a multi‐test viewpoint
Authors: Keeney C. N.
Published: May 2005

Many tests have been developed to provide relative flame/smoke data. In spite of the proliferation of such tests and test equipment, many chemical and polymer producers, as well as fabricators, use only one technique to evaluate the flame/smoke properties of a polymer system. This paper demonstrates the importance of multi‐method testing to rate the efect of phosphate esters and various fillers on PVC flammability and smoke generation.
Improving the stiffness of commingled thermoplastics
Authors: Schadler Linda S. , Gobran Riad , Park Sung Chul , Gleason Michael
Published: May 2005

One of the limitations of commingled recycled plastics is their low flexural modulus, resulting from both the linear nature of thermoplastics and the incompatibility of the polymer phases. The goal of this study was to increase the flexural modulus of commingled recycled plastics by the addition of small amounts of polyester that acted both as a compatibilizer and a crosslinking agent. It was found that the increase in flexural modulus was caused by the unsaturated polyester acting as a filler, the improvement in compatibility of the phases, and the crosslinking of the commingled plastics. The increase was offset somewhat by a decrease in crystallinity of the phases.
Use of molecular modeling to predict ligand efficiency in thermal stabilizers
Authors: Burchill Michael T. , Leste‐Lasserre Pierre
Published: May 2005

Molecular modeling software is employed to correlate the thermal stability of an organotin molecule in PVC and molecular structure. Synthesizing model organotin compounds, measuring dynamic properties in PVC, and calculating structural and electronic properties yield an empirical relationship between the stabilizing ability of the tin molecule and electron density of the heteroatom.
Heat stabilizers for poly (vinyl chloride). I. Synergistic systems based on calcium/zinc stearate
Authors: Abbås Kent B. , Sörvik Erling M.
Published: May 2005

Synergism in poly(vinyl chloride) stabilization was studied by the determination of the dynamic and static stability of 34 different formulations. Nine ratios of Ca/Zn stearate were tested. Both the static and the dynamic stability increased almost linearly with the calcium stearate content, but unfortunately the initial discoloration increased as well. Melt viscosity decreased with an increasing content of calcium stearate. This was mainly caused by the difference in lubrication effect between calcium stearate and zinc stearate. Several co‐stabilizers (synergists) for the Ca/Zn system were also evaluated. Among these, polyols were found to be the most effective. The addition of Polyol T 34, which was prepared through a coprecipitation of trimethylol propane and pentaerythritol, resulted in excellent initial color and improved transparency. Trimethylol propane and di‐trimethylol propane were also powerful in this respect. The best static stability was observed for compounds containing mannitol and sorbitol, although these formulations were slightly discolored. Pentaerythritol and di‐pentaerythritol were very effective in extending the static stability, but they were not useful for the improvement of initial color. Well‐known complexing agents like EDTA and dimethylglyoxime were surprisingly ineffective as synergists. The addition of tris(nonylphenyl) phosphite resulted in a somewhat higher thermal stability, but not in any significant color improvement.
Relationship of welding technology to degree of plasticization in the PVC films
Authors: Dodin M. G. , Kisanova N. N.
Published: May 2005

The influence of the degree of plasticization on the strength of the welded joints and technological parameters of high‐frequency heat‐sealing process is studied for PVC films with different quantities of di‐2‐ethylhexyl phthalate (DOP). The equation obtained relates the parameters of the welding process (time and specific anodic current) with the degree of plasticization of the plastic material. The equation allows calculation of the technological welding behavior to obtain maximum strength of welded joints.
Alumina trihydrate as a flame retardant filler for flexible vinyl compounds
Authors: Bonsignore Patrick V. , Claassen Pamela L.
Published: May 2005

In those flexible vinyl compounds which can accept fillers, alumina trihydrate can significantly improve flame resistance as measured by oxygen index

It should be appreciated that degrees of flammability as measured by small‐scale tests such as oxygen index may in no way reflect the relative hazard of these same materials when involved in a fully developed fire.

. Over a range of plasticizer concentrations, the lower the concentration of burnable plasticizer, the greater the contribution of hydrate to flame retardancy. Combinations of alumina trihydrate with antimony oxide are especially effective for improving the flame resistance of flexible vinyl compounds.
Investigations on the extrusion of rigid PVC on twin screw extruders
Authors: Lutterbeck J. , Menges G. , Potente H.
Published: May 2005

The processing of rigid‐PVC is mainly performed on twin screw extruders. For a thermal sensitive material, such as rigid PVC, this implies certain advantages. They consist primarily in the fact that intermeshing counter‐rotating twin screw extruders are axially closed pump systems, whereas single screw and co‐rotating twin screw extruders represent axially open mixing systems, conveying by means of friction forces. This fundamental difference leads to totally different flow rate and shearing force distributions of the axial flow, which in turn affects the residence time distribution and the thermal dynamics of the process. Investigations have been carried out to determine the influence of screw speed, die resistances, barrel wall temperatures and different compounds on the melt temperature and its homogeneity. It could be shown that the melt temperature can be essentially influenced by heating the barrel wall and the screw. This even applies to the most diverging degrees of mechanical power consumption resulting from different compounds. The homogeneity of the melt temperature thus depends on the relationship between the barrel wall temperature and the melt temperature within the respective heating zone. The possibility is shown to establish a model theory based on energetic and rheological similarities, which can be employed in the construction of machines of different diameters. For this purpose the geometrical and operational data of an optimal operating machine serve as a basis.
Impact modification of weatherable rigid PVC compounds
Authors: Gunson Dennis J.
Published: May 2005

Rigid, weatherable PVC compounds used in the building products industry must have superior initial impact properties and maintain these when subjected to various environmental conditions. For instance the impact strength of a rigid PVC formulation changes when the temperature is lowered from ambient to sub‐zero, when it is exposed outdoors, and when different types and quantities of impact modifiers are used. To measure the aforementioned changes, instrumented as well as more conventional impact testing techniques are used.
Factors affecting the moisture barrier of vinylidene chloride‐vinyl chloride copolymer films
Authors: Delassus Phillip T. , Grieser Daniel J.
Published: May 2005

Copolymers of vinylidene chloride, SARAN* resins, can be fabricated into films which have excellent barrier to mass transport. They are useful for making packages which must keep oxygen out or prevent moisture from entering or leaving. The oxygen barrier properties of SARAN films have been recently published (8). The purpose of this paper is to describe the moisture barrier properties of SARAN films as functions of temperature, humidity, and film composition. This information will aid packaging engineers design better barrier packaging.
Melt rheology of semirigid PVC compounds
Authors: Tu Ching‐Fang
Published: May 2005

This paper describes a statistical experiment on the melt behavior of semirigid PVC compounds using a capillary rheometer. Three formulating variables, viz., PVC resin inherent viscosity, internal lubricant concentration, and external lubricant concentration, and two processing variables, viz., shear rate and temperature, were examined. The dependent variables tested were melt viscosity and critical shear rate. The regression equations relating the formulating variables with dependent variables were obtained at various temperatures. Melt distortion free formulations can thus be determined from the contour plots of the dependent variables. Depending on formulation and processing conditions, a discontinuity in the flow curves is observed Melt irregularity of extrudates was observed to occur not only at very high shear rates but also at very low shear rates and at the discontinuity of flow curve.
Plasticizer effects on vinyl extrusion efficiency
Authors: Cannon J. A. , Emge D. E. , Payne M. T.
Published: May 2005

The choice of plasticizer for extrusion of flexible vinyl profiles is usually made for product performance properties. This paper deals with plasticizer influence on the entire extrusion process from dry‐blend preparation to final extruded profile. Undestanding the effect of plasticizer throughout the extrusion line helps the compounder optimize for higher production rates, lower energy input, improved profile quality and better final physical properties. This study focused on the effect of low molecular weight, fast fusing plasticizers in the extrusion processing of general purpose formulations. Butyl benzyl phthalate was used as partial replacement for dialkyl phthalates. A positive influence of this replacement was observed in dry‐blend preparation, in the compound extrusion step, in the finished extrusion step and in final product quality.
Rheology of poly(vinyl chloride) blends
Authors: Baek T‐M. , Chung K‐H. , Salovey R.
Published: May 2005

PVC/EVA blends were studied with an extrusion plastometer in order to examine the effect of EVA on the processability of PVC. The melt flow of PVC/EVA blends containing from 4 to 30 weight percent EVA follows a simple power law between 160 and 180°C. EVA reduced the melt viscosity and enhanced processability. Blends of PVC and EVA were morphologically incompatible. The molecular weight of extruded PVC in the blends was unchanged.
Oriented PVC bottles: Process description and influence of biaxial orientation on selected properties
Authors: Presswood J. K.
Published: May 2005

Biaxial orientation of polyvinyl chloride bottles reduces haze development from pine oil exposure, suggesting that chemical attack may be reduced in other applications. Areas where PVC bottles are now marginally unacceptable may become markets for oriented PVC bottles. Orientation also improves bottle drop height, saves 15 to 20 percent in part weight, and saves 5 to 6 cents per pound of compound because less or no impact modifier or other compounds are required.
Applicability of linear elastic fracture mechanics to rigid PVC pipe materials
Authors: Darwish A. Y. , Mandell J. F. , Mcgarry F. J.
Published: May 2005

Linear elastic fracture mechanics (LEFM) has limitations for analyzing the fracture behavior of rigid polyvinyl chloride pipe materials. Fracture behavior shifts from notch‐insensitive, yield‐stress‐controlled to brittle, LEFM‐controlled as temperature decreases and displacement rate increases. Even under the most brittle conditions, the fracture toughness is sufficient to resist most anticipated flaws such as scratches.
Determination of lateral contraction of PVC compounds under axial stress by a microwave resonant technique
Authors: Bataille P. , Leduc P. , Nachman M.
Published: May 2005

A non‐contact microwave technique has been applied for measuring the change in the cross‐sectional area of rectangular rods made of polyvinyl‐chloride based plastics. It was found that, up to axial stresses of 20 kg/cm2, the relative change in the side of the rectangular cross‐section remains below 1%. Poisson's ratio was derived for PVC compounds with several concentrations of DOP. Good agreement with calculated values was obtained.
Improved falling weight impact test for poly(vinyl chloride) products
Authors: Rabinovitch Elvira B. , Summers James W.
Published: May 2005

A modified impact test using a 6.35 millimeter diameter tapered impacting tool has been developed to test profiles above 2.5 millimeters in thickness. The new method also helps to find the ductile‐brittle transition easily. It is even more important for the prediction of toughness, especially for exterior applications, than the minimum energy required for any type of failure.
Evaluation of permeation of organic solvents through PVC, asbestos/cement, and ductile iron pipes
Authors: Olson Alan J. , Goodman Donald , Pfau James P.
Published: May 2005

Buried potable waterpipes are susceptible to permeation by organic solvents. In studying piping made of PVC, asbestos/cement, and ductile iron, full‐pipe assemblies and laboratory bench techniques were employed. Elastomeric gaskets for all three systems become permeated, at least under exaggerated conditions. Results show that thermodynamic activity, as opposed to concentration, is the driving force. At solvent activities well above those encountered in typical soil, PVC is seen to be an effective barrier against permeation.
Which plastic package has the lowest contribution to taste and odor?
Authors: Solin Carrie F. , Fazey Anthony C. , McAllister Paul R.
Published: May 2005

Although plastics have made significant inroads in the packaging area, little work has been done in the U.S. to evaluate their effect on the taste and odor of the package contents. This is especially relevant for food, beverage, liquor, and bottled water.

Rohm and Haas contracted with an independent consulting firm, which uses a professional panel familiar with the effects of packaging, to assess the sensory impact of different plastics on the taste of water. Four types of plastics were tested: polyvinyl chloride (PVC), high‐density polyethylene (HDPE), polycarbonate (PC), and polyethylene terephthalate (PET).

Two forms of each polymer were evaluated, bottles and plaques, which were aged in water for four weeks at room and elevated temperature (120°F). The professional panel evaluated the taste and odor of the water on a numerical intensity scale and characterized any observed effect with words. The numerical rating permitted the effects of the plastic materials to be compared directly.

PVC had the lowest contribution to taste and odor of all of the plastics. PVC was followed by PET and then PC and HDPE. Therefore the two current packaging materials, HDPE and PC, were not the best! This implies that water and other taste‐sensitive products could be more appealing if packaged in appropriately formulated PVC.
The effect of shear on fusion and mechanical properties of rigid PVC pipes
Authors: Bystedt Jan , Flensjö Martin , Svensson Gunnar , Terselius Björn
Published: May 2005

The shear level was increased during twin screw extrusion of PVC at different melt temperatures by inserting a hole plate in front of the screw tips. The variation of shear level did not significantly affect the capillary pressure in capillary viscometry at 135°C. However, the falling weight impact strength was markedly influenced. In internal water pressure tests at 60°C premature failure was obtained for pipes extruded at 198°C at the highest shear level.
Kinetic modeling of generation and decay of HCl from burning PVC
Authors: Carroll W. F. , Hirschler M. M. , Smith G. F.
Published: May 2005

Assessing the fire hazard of a material has three facets: (a) the generation of heat and combustion products; (b) their transport to the vicinity of the building occupant; and (c) the response of each subject to specific exposures. In this study, interest has focused on the aspect of HCl decay. Two models for HCl generation, transport, and decay have been developed: an empirical and a rigorous model. Both have been applied to predict the behavior of HCl in small and large scale fire experiments. The rigorous model accounts for primary variables (humidity and type and extent of surface) in such a way that it is essentially independent of scale and specific geometry. The results show that the fire hazard of chlorinated materials is exaggerated unless HCl decay is considered.
Market development of PVC mineral water and wine bottles in western europe: Current status and projections for the future
Authors: Sahajpal V. K.
Published: May 2005

This paper will review the markets, business, technology, and future trends concerning the use of PVC bottles in various packaging segments such as mineral water—flat and low carbonated, wine, fruit juice, and edible oils in Western Europe. The market and business sections will include the major producers of mineral water bottles, capacity of PVC water bottle compounds, and bottles. Activities of major PVC bottle compound producers and bottlers to further improve quality of PVC premix and bottles produced will also be discussed. Also discussed will be the reasons for the success of PVC bottles for packaging mineral water and other food related items. The technology related to the production of PVC bottles for packaging mineral water such as manufacturing equipment, PVC compound systems, and bottle properties will be presented. In addition, future trends concerning PVC vs oriented PVC bottles for flat and carbonated mineral waters as well as new additives for PVC bottle compounds and technology under consideration will be discussed.
Odor and PVC: Identification and quantification of volatiles in clear polyvinyl chloride processing
Authors: Lemmen T. H. , Conroy G. M. , Bautista P. A.
Published: May 2005

Trapping experiments will be described in which standard workplace monitoring devices were used to collect samples over the dynamic mill, Brabender, and single screw laboratory extruder. Additionally, the results of static (unsheared) heating on clear PVC compound and finished goods with collection of emitted organic vapors are compared to the dynamic case. Identification and quantification of the possible contributors to process odor will be discussed.
Solubility and diffusion of small molecules in PVC
Authors: Berens Alan R.
Published: May 2005

Recent studies have shown that the amount and rate of absorption of gases and organic liquids and vapors in rigid and plasticized PVC can be correlated with their molecular dimensions, solvent power, and thermodynamic activity. The amount absorbed at equilibrium depends upon the solvent power of the diffusant, expressed in the Flory‐Huggins interaction parameter, x, and upon the vapor pressure or activity of the diffusant in the environment of the PVC. The rate and kinetic form of the approach to equilibrium vary with the ratio of the final uptake to Cg, the diffusant concentration which produces the glass‐rubber transition at the experimental temperature. At concentrations far below Cg, absorption follows ideal Fickian kinetics with diffusion coefficients steeply dependent upon the diffusant molecular size and shape. When the concentration approaches or exceeds Cg, absorption is faster, kinetics are non‐Fickian, and the dependence upon molecular size is diminished. Carbon dioxide at high pressure strongly accelerates the absorption of other substances because it uniquely combines the high diffusivity of a small gas molecule with the solubility and plasticizing action of an organic swelling agent.
Gelation and interaction in plasticizer/PVC solutions
Authors: Boo Hwee‐Khim , Shaw M. T.
Published: May 2005

Gelation of PVC solutions is generally agreed to result from network formation. The proposed network linkages include crystallites, hydrogen‐bonds, and entanglements brought about by spinodal decomposition. The objective of this work is to relate the phase behavior or compatibility of PVC/plasticizer solutions to their gelation behavior. The thermoreversible sol‐gel transition of plasticized PVC was studied using a simultaneous light scattering and dynamic viscoelastic analysis technique, in parallel with a thermal optical analysis (TOA). PVC solutions of 1% to 15% in different types of phthalate and sebecate plasticizers were used. Preliminary results suggest phase separation in the less compatible plasticizer during gelation process while more compatible plasticizer/PVC solutions gel without phase separation. This suggests that the gelation process can be relatively independent of the liquid‐liquid phase equilibria in the system.
Prediction of residual stress distribution in plastic pipe extrusion
Authors: Doshi Shailesh R.
Published: May 2005

In thermoplastic pipe extrusion, the extrudate emerging from the die is typically sized and cooled from outside in a quench tank. This process causes quick solidification of the external layer, while the inner mass of molten material cools only gradually. The slow cooling and crystallization, and the associated shrinkage of this material, can lead to build‐up of severe stresses in the final part that can affect the long term service performance. In this paper, a simple theoretical analysis of this process of residual stress build‐up is presented. The pipe undergoing quenching is modeled as an annular cylinder of molten polymer being cooled at a controlled rate from outside. The overall stresses are derived numerically by adding up the stress contributions due to incremental advance of the solidification boundary. The results of the analysis are found to be in qualitative accord with the experimentally measured stress profiles in thermoplastic pipe.
Weatherable rigid PVC: The effect of light and thermal stabilizers
Authors: Capocci Gerald
Published: May 2005

Rigid PVC compositions used in outdoor applications such as siding, profiles, windows, and soffit predominantly contain a tin mercaptide thermal stabilizer. It is well known that tin mercaptides impart outstanding thermal stability to vinyl compounds, however, it is also well known that they provide only marginal light stability. Mercaptides can be used in these applications primarily because they are combined with high levels of titanium dioxide. They are not well suited for dark colored PVC and compositions without titanium dioxide. These require a more weatherable thermal stabilizer, such as a tin carboxylate. In this paper, principles for formulating rigid weatherable vinyl will be discussed. The influence of thermal stabilizers and the interdependence of light stabilizers and thermal stabilizers on PVC photostability will be emphasized. Data will be presented showing how one can formulate weatherable dark brown and pastel PVC through the use of tin carboxylate thermal stabilizers, the appropriate light stabilizers, and pigments. Traditional approaches to achieving weatherability will be compared to what can be attained by capitalizing on the latest advances in stabilization technology. Finally, methods for reducing TiO2 concentration will be shown.
Vinyl chloride suspension polymerization with constant rate. A numerical study of batch reactors
Authors: Pinto J. C.
Published: May 2005

Based on the analysis of a simple mathematical model, different temperature profiles are generated in order to provide vinyl chloride (VCM) suspension polymerization with constant reaction rates in batch reactors. In order to reproduce these temperature profiles in industrial‐scale reactors, some process variables, such as coolant temperature, initiator concentration, and rate of water and monomer condensation, have to be manipulated. It is shown that those temperature practices can almost never be applied to large‐scale reactors if the jacket temperature is the only variable that can be manipulated. It is also shown that developing an initiator feed procedure or using a reflux condenser may be advantageous.
Gloss control additives for PVC
Authors: Dunkelberger D. L. , Fitzwater S. J.
Published: May 2005

Matte finishes are characterized by a lack of specular (mirror‐like) reflectance. Using equations from the literature which relate surface roughness to specular reflectance, surface roughness values were calculated for various particle size inclusions assuming that the particles protruded half in half out of the surface and that 20% of the surface area is covered by the particles. Specular reflectance values at 85 deg illumination were calculated from the surface roughness calculated data. Based on these calculations, a series of large particle size monodispersed emulsion polymers was prepared using Ugelatad polymerization techniques and evaluated for their surface altering effects in PVC. Considering that the model contained many approximations, excellent agreement was found between the predicted and measured particle size effect on the surface gloss.
Failure analysis of a PVC water pipe
Authors: Broutman Lawrence J. , Duvall Donald E. , So Paul K.
Published: May 2005

Two fractured 8″ IPS SDR 26 PVC 1120 water pipe specimens were analyzed to determine the causes of failure. The pipes were part of a water distribution system in a condominium apartment complex. The analysis included evaluation of material properties, examination of the fracture surfaces, and fracture stress calculations utilizing linear elastic fracture mechanics. It was concluded from these studies that both pipe specimens failed due to excessive bending of the pipeline sections during the after installation.
Highly filled potable water pipe
Authors: Mesch Keith A. , Wursthorn Karl R. , Hyde Jeffrey R. , Goose Miller H. , Prezzavento Bruce A.
Published: May 2005

Profitable production and sale of rigid PVC water pipe is difficult even in the best of economic times. The industry is intensively cost driven. The development of lower cost formulations is, therefore, of great interest.

Conventional pressure pipe formulas do not provide sufficient hydrostatic strength when calcium carbonate filler levels exceed 5 parts per hundred resin (phr). This paper will describe the development of a pressure pipe formulation which contains up to 10 phr filler while maintaining physical properties exceeding all of the required minimum standards.

The presentation will include the physical property testing required to develop the formulation including cell classification and long‐term hydrostatic design stress tests. These will be contrasted with data obtained from conventional formulas containing 10 phr of fillers.

The quality of commercially extruded pressure pipe made with the new formula will be discussed as a function of raw material selection, blending, and extrusion conditions.
The effects of polyvinyl chloride hierarchical structure on processing and properties
Authors: Summers James W. , Rabinovitch Elvira B.
Published: May 2005

The hierarchical structures in PVC are such that the larger structures formed during polymerization are broken down to smaller structures during processing. These smaller structures have properties dependent on their microstructure. While PVC's microstructure is mostly amorphous, it contains crystallites that act as physical crosslinks connected together by tie molecules. The microstructure is extended to a larger three dimensional structure by melting during processing followed by recrystallization upon cooling. The strength of this larger three dimensional structure is interpreted from the roughness of extrudate from a zero land length die. This visual method is more sensitive for detecting large three dimensional network structure than measuring capillary entrance pressures, especially for very weak three dimensional structures. Both higher processing temperatures and higher molecular weight PVCs contribute strength to this three dimensional structure which plays a large role in determining lzod impact and stress rupture. Plasticized PVC has a structure similar to rigid PVC as judged by the roughness characteristics of its extrudate. In this case, the plasticizer is soluble in the amorphous phase leaving the crystallites intact.
Gamma radiation resistant rigid poly(vinyl chloride) for the medical device industry
Authors: Steiniger J. L. , Benderly D. , Rajagopalan M.
Published: May 2005

Many varied articles for the health care industry are produced by extrusion and injection molding processes using poly(vinyl‐chloride). Until recently, a mixture of 12% ethylene oxide/88% dichlorodifluormethane (Freon 12) was used to sterilize PVC based components and sets by chemical fumigation. In 1978 EPA reported ethylene oxide to be carcinogenic and mutagenic and established a 50 ppm exposure which was later lowered to 1 ppm. Likewise, Freon 12 came under regulation and is currently being taxed. These developments resulted in an industry need to be furnished with a viable replacement for ethylene oxide sterilization. Gamma irradiation was selected for this purpose as an economical and effective method. This study shows that a rigid PVC compound can be commercially produced that satisfies the critical balance of properties required for the medical device market and also can be sterilized by gamma irradiation without adversely affecting critical properties.
More than speculation: The current and future regulatory climate for the vinyl industry
Authors: De La Cruz Peter L.
Published: May 2005

This discussion of the past regulatory trends and current developments for the vinyl industry will provide an overview of the regulatory world that producers and fabricators of poly(vinyl‐chloride) face today, with some projections of what the future may hold. By considering past regulatory trends and current developments, projecting future developments can be more than mere speculation. Because environmental issues are very complex and challenging, the overview begins and concentrates there. The focus will also discuss OSHA regulations, pending actions of EPA, California's Proposition 65, and Consumer Product Safety Commission's regulation of phthalates. The overview will conclude with an analysis of projected specific regulatory actions including: reducing VCC emissions, additional restrictions on land disposal, demands that vinyl products demonstrate that they fit the general solution to the solid waste crisis, and coping with state and local regulations that pose conflicting or unreasonable requirements.
Vinyl recycling: An update
Authors: Carroll William F.
Published: May 2005

Despite industry protests to the contrary, in September, 1989, few people believed that PVC bottles were recyclable in the same sense that PET soft drink bottles and HDPE milk bottles were. At that time, however, OxyChem announced its post‐consumer recycling initiative, offering to buy bottles back from anywhere in the United States. By paying prices comparable to that of PET ($0.06–$0.10/1b) and paying the freight from the recycler's dock, recycled PVC has begun to appear. Collection is handled by existing waste haulers and recyclers as an addon to their overall program. Promotional materials were generated to aid in visual separation of PVC from other plastics; in addition, automated sortation is being engineered by two laboratories with financial assistance from the Vinyl Institute. In general, PVC is reprocessed in the same fashion as other plastics: it must be ground, washed, and pulverized or repelletized. Care must be taken to minimize heat history and in some cases to boost stability and lubricity before pelletization. Material is resold into permanent, semi‐permanent and packaging applications.