bluuebunny/crossref_metadata_2025_split huggingface dataset:
XPS and SEM characterization of hydrated cerium oxide conversion coatings
Authors: Hughes A. E. , Taylor R. J. , Hinton B. R. W. , Wilson L. 
Published: December 2004

AbstractCerium‐rich conversion coatings have been deposited onto aluminium 2024‐T351 alloy by immersion into a solution containing 10 g L−1 CeCl3 and 1% H2O2 in a process described as ‘cerating’. Prior to deposition the alloy had been prepared either by using a standard chemical pretreatment used for aerospace alloys before conversion coating or by polishing. X‐ray photoelectron spectroscopy and scanning electron microscopy have been used to characterize these cerium‐containing conversion coatings. It was found that, during deposition, hydrated cerium oxide initially covered the intermetallics present in the alloy surface and then covered the surface generally. Deposition continued over the intermetallics throughout the conversion coating process, resulting in thick, heavily‐cracked regions considerably greater than the average thickness of the film (>0.3 μm). Elsewhere the coating was generally up to 0.2 μm thick, and appeared to comprised of deposited particles around 100 nm in size.
The effect of aromatic plasticisers on the photo‐dehydrochlorination of poly(vinyl chloride)
Authors: Biggin I. S. , Gerrard D. L. , Williams G. E. 
Published: December 2004

AbstractA comparison has been made of the effect of ultraviolet and solar radiation on plasticised and unplasticised PVC. It has been shown that, when the polymer, plasticised with either a phthalate or trimellitate ester, is exposed to short‐wavelength ultraviolet radiation (<292 nm), the photodehydrochlorination of the polymer is retarded by the plasticiser. It has also been shown that, when longer‐wavelength radiation is used, the dehydrochlorination is accelerated by the plasticiser. In each case, the effect of the trimellitate is greater than that of the phthalate. Possible mechanisms for the reactions at both long and short wavelengths are considered, and the role of the plasticiser is explained in terms of its electronic absorption spectrum.
PVC and other major plastics in the European economy
Authors: Claus P. G. 
Published: December 2004

AbstractFollowing a decade of strong development of plastics consumption, the European market and the production of European manufacturers have fallen back into stagnation since the oil crisis of 1973, followed by the second oil‐price explosior. of 1979. The author presents the reasons of the economic recession prevaling in the European plastics industry for a number of years, notwithstanding the temporary upsurge of 1979, in a review of aspects relative to internal economic government policies in Europe, relative to external trade and relative to the Community's policies towards Third World countries. Prospects for the European plastics industry are considered as a function of economic and industrial government policies in Europe, of development in third countries, and of new approaches by the European industry. The various aspects considered are illustrated in particular by the case of PVC, a typical representative of the major plastics reviewed.
Reasons for PVC bottle development in France
Authors: Decroly Pierre 
Published: December 2004

AbstractThe French PVC‐bottle market represents a consumption of 140,000 tons per year, much more than in other countries; in 1960, this consumption was practically nil. The technical ability to produce bottles suitable for the packaging of food products allowed the first general penetration of PVC in the bottle market. One may eventually observe bit differences from country to country in Europe. In the case of France, it clearly appears that it is the technical and legal possibility to use PVC to bottle mineral waters that had provoked the skyrocketing production of bottles from this material. We will analyze the technical, economical, and sociological reasons that have allowed this development to occur, and examine why other market sectors could not be reached by PVC bottles and why the evolutions were not the same in various countries; future trends will also be outlined.
Predicting heat buildup due to the sun's energy
Authors: Rabinovitch Elvira B. , Quisenberry Joseph G. , Summers James W. 
Published: December 2004

AbstractPVC building products such as siding, windows, and roofings are exposed to the sun. Absorption of the sun's energy leads to a temperature rise, which may cause dimensional control problems, such as expansion and, in severe cases, distortion of the PVC products. The amount of heat buildup in the product depends on the color and/or pigment system of the PVC compound. Generally, the darker the color, the more the sun's energy is absorbed and the higher the temperature heat buildup. Because of the growing demand for darker colors of PVC building products, a test for measuring temperature rise to predict performance of the product in actual use is needed. A laboratory test method for predicting maximum heat buildup due to the sun is described in this paper. The effects of the sample thickness and gloss, carbon black and titanium dioxide levels, and the distance of an infrared heat source from the sample on the heat buildup are also presented in the paper.
A study of the variables affecting bubble stability in poly (vinyl chloride) plastisols
Authors: Harrell E. R. , Kim J. S. , Gall G. A. 
Published: December 2004

AbstractThe formation of stable air bubbles during processing is one of the most critical problems encountered in many PVC plastisol applications (often referred to as the “air release problem”). Stable bubbles can lead to both cosmetic and structural defects in finished products. Analysis of the air release problem has been difficult not only because air release is affected by many variables (some of which are interrelated), but also because no air release test has been universally accepted as being reliable. This paper presents a comparison of some of the more commonly used air release tests of the PVC plastisol industry, i.e., the Huff ring test, air injection by syringe, and air entrapment by stirring. Our investigation indicates that results obtained from these air release tests strongly depend upon test procedure, test environment, plastisol age, and even the amount of plastisol in the test container. Among the test methods which were examined, air entrapment by stirring was found to be the most convenient and reliable. Possible causes for the observed discrepancies among the tests and data scatter within each test are discussed in terms of variables which affect bubble stability, such as bubble size, rheology, film stress distribution, surface tension, and the Marangoni effect.
Rheology of poly(vinyl chloride) formulations from melt flow index measurements
Authors: Shenoy A. V. , Saini D. R. , Nadkarni V. M. 
Published: December 2004

AbstractA knowledge of the complete flow curve, or rheogram, of a PVC formulation depicting the variation of the melt viscosity over industrially relevant ranges of shear rate and temperature is essential in the design of polyer‐processing equipment, process optimization, and troubleshooting. These data are generated on sophisticated rheometers that are beyond the financial and technical means of most PVC processors. The only flow parameter that can be readily measured on an inexpensive apparatus is the melt flow index of the resin‐mix. In the present work, a method has been proposed to estimate the rheograms of a PVC formulation at temperatures relevant to its processing conditions with the use of a master curve, knowing the melt flow index and glass‐transition temperature of the formulation. A master curve that coalesces rheograms of different PVC formulations at various temperatures has been generated and proposed as a tool for estimating the flow curve.
The lubrication mechanism of calcium stearate/paraffin wax systems in PVC compounds
Authors: Rabinovitch Elvira B. , Lacatus Emilia , Summers James W. 
Published: December 2004

AbstractThe lubrication mechanism in PVC was studied using calcium stearate and paraffin wax lubricants. Based on the results of the differential thermal analyses, percent haze, microscopy, metal release, Brabender fusion, and extrusion studies we have developed a new theory of PVC lubrication based on molecular structure. Lubricants containing polar groups, which preferentially wet the metal surface in the presence of PVC, such as calcium stearate, are excellent metal lubricants. Non‐polar lubricants which do not wet the metal surface, such as paraffin wax, allow PVC to stick to the metal surface. However, these lubricants work in combination with the metal wetting lubricants to make the lubricant layer more fluid, providing a better lubricating system than either lubricant alone. Lubrication between PVC primary particle flow units is similar to that at the metal surface with the polar PVC surface acting in a similar manner as the metal surface. We find the common classification of lubricants as internal or external to be deficient in explaining performance.
Lubricant behavior in rigid PVC rheology
Authors: Vismara Hugo R. , Capiati Numa J. 
Published: December 2004

AbstractCapillary rheometry was carried out on lubricated suspension PVC resin at a temperature of 180°C and a shear rate range of 1.5 to 350 sec−1 to specify lubrication efficiency. Correction and discussion for the effects of pressure, non‐Newtonian behavior and viscous heating were done. An indication that the lubricant is localized in the resin free volume appears from pressure coefficient variation. Corrected capillary rheometry showed to be sensitive for low lubricant concentrations (0.3 to 2 Phr) similar to those used in commercial compounds.
Effect of processing on fracture toughness and fatigue crack propagation in unplasticized polyvinyl chloride (uPVC)
Authors: Mai Y. W. , Kerr P. R. 
Published: December 2004

AbstractThe effect of processing on the fracture toughness and fatigue crack propagation rates in unplasticized PVC pipes, both along and perpendicular to the extrusion direction, is evaluated in this paper. The methylene chloride test is used to distinguish between well processed and poorly processed pipes. Well processed pipes have higher fracture toughness under monotonic loading test conditions. However, under impact conditions processing has no significant effects on notched Charpy fracture toughness. For the well processed pipes, there is no directional effect on the fatigue crack propagation rates. For the poorly processed pipes, fatigue crack growth is faster in the extrusion direction, but slight improvement in the processing level removes this difference. Generally, fatigue in the longitudinal direction is independent of the level of processing, but in the transverse (extrusion) direction it is quite sensitive to variations in processing.
Barium/cadmium for the stabilization of rigid vinyl for exterior applications
Authors: Bredereck Peter 
Published: December 2004

AbstractThe highly developed synergistic Ba/Cd stabilizer system for rigid vinyl use in exterior applications is the result of long lasting efforts in this field. By itself, cadmium carboxylate is ineffective because developing cadmium chloride acts as a strong Lewis acid and accelerates the decomposition of PVC. Barium carboxylate converts cadmium chloride formed back into the cadmium carboxylate. Addition of a chelating agent decidedly improves the stability of PVC. A certain ratio of Ba/Cd stabilizer must be retained; best ratio is 6 to 1. The addition of epoxidized soybean oil further improves both heat and light stability of these systems. More than 20 years performance of these formulations has been applied successfully. Increased stability of colored window profiles is effected with the addition of 0.5 parts of a UV absorber. Recommended pigmentations for masstone colored and tinted shades are provided in addition to formulations for white titanium dioxide pigmented profiles.
True stabilization: A mechanism for the behavior of lead compounds and other primary stabilizers against PVC thermal dehydrochlorination
Authors: Michell E. W. J. 
Published: December 2004

AbstractA free‐radical mechanism by which lead compounds are thought to inhibit thermal dehydrochlorination of polyvinyl chloride (PVC) is described. This mechanism is called “true stabilization” in order to distinguish it from simple hydrogen chloride (HCl) scavenging, which is a well‐known and sometimes important function of all primary stabilizers used in PVC. In true stabilization, it is thought that stearate or other aliphatic carboxylate groups (initially from lubricants) react with reservoirs of basic lead compound such as the carbonates, dibasic lead phosphite, the phthalates, or the sulfates, to give mobile carboxylates of lead. These latter salts then react with chlorine atoms released by the hot PVC, giving chlorides of lead and aliphatic carboxylate free‐radicals. Hence the chlorine atoms are trapped and unable to propagate free‐radical dehydrochlorination. Also it is thought that the aliphatic carboxylate free‐radicals esterify PVC molecules at methylenic carbon atoms (from which hydrogen atoms have been removed by chlorine atoms giving HCl and free‐radical sites in the polymer chain). Thus, unpaired electrons on the carboxylate free‐radicals and on these methylenic carbon atoms in the PVC molecules are paired, so that the neighboring chlorine atoms in polymer chloromethylenic groups are stabilized. Hence loss of chlorine atoms in the free‐radical dehydrochlorination of PVC is prevented. The pendant aliphatic carboxylate groups dissociate from the PVC molecules taking chloromethylenic hydrogen atoms to form acid molecules, and leaving chlorine atoms in relatively stable vinyl type groups. The aliphatic carboxylic acids react with more of the basic lead compound reservoir, giving mobile carboxylates of lead which can enter further reactions as just described. Thus, the true stabilizing mechanism is continuous and cyclic, while the reservoir of basic lead is available, and the PVC thermal dehydrochlorination will be retarded to almost negligible rates in favorable circumstances. It is thought that the behaviors of metal soaps and of organo‐tin stabilizers may be encompassed within the general true stabilization concepts of free‐radical exchanges and PVC esterifications described above. In these ways they also would retard PVC thermal dehydrochlorination. However, they are neutral compounds and have no basic reservoir which can react with carboxylic acids in the manner described above for lead stabilizers. Hence they are not able to confer long term stability on PVC in the way that basic lead stabilizing regimes do.
Role of organotin mercaptide stabilizer in heat and light stability of PVC
Authors: Rabinovitch Elvira B. , Dorsch John L. , Summers James W. , Quisenberry Joseph G. 
Published: December 2004

AbstractInfrared analysis can be used to study the conversion of organotin mercaptide stabilizers in PVC from dialkyltin dimercaptide to dialkyltin monochloride monomercaptide to dialkyltin dichloride. This technique is used to study the effects of the stabilizer level and thermal heat history on the light stability of PVC.
Synthetic magnesium silicate: A single‐component/multi‐functional modifier
Authors: Varela Manuel A. , Driscoll Stephen Burke , Grolman Cory Peter , Mehta Naresh R. 
Published: December 2004

AbstractRecent laboratory and in‐production tests have indicated the attractive commercial properties of synthetic magnesium silicate in plastics processing. In addition to its enhancing the flow behavior/materials handling of the base powdered resin, such as PVC, it has also proved to be a valuable, yet inexpensive polymer modifier. This non‐abrasive single‐component additive has demonstrated clearly its multi‐functional capabilities. For example, when compounded (at 0.5 to 1.5 phr) in a standard rigid vinyl formulation, the synthetic magnesium silicate contributed to improved compaction in the extruder feed section, initiated a faster fusion time, reduced melt viscosity, and enhanced thermal stability. Laboratory torque rheometer numbers and ASTM D 4440 Rheometrics Dynamic Spectrometer viscoelastic behavior is included along with typical extrusion and physical property test data. The significance of the co‐stabilization was complemented by the enhancement of physical properties, reduction of the necessary amount of lubricant, and did not affect sample color and appearance.
The effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride): A resonance Raman spectroscopic study
Authors: Gerrard D. L. , Bowley H. J. , Biggin I. S. 
Published: December 2004

AbstractA laser Raman spectroscopic study has been made of the effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride) (PVC). The results obtained indicate that, in terms of the total level of dehydrochlorination, cadmium stearate is not as superior to barium stearate as the visual appearance of the polymer suggests. Also, the level of dehydrochlorination produced in the presence of a mixed stabilizer is not significantly lower than that produced in the presence of barium stearate alone, while samples of the latter exhibit much stronger color. It has also been shown that cadmium stearate can reduce the length of long polyene sequences, presumably by a reaction near the center of such a sequence.
The effect of fillers on the impact properties of oxytuf high impact PVC
Authors: Schwartz Willis T. 
Published: December 2004

AbstractOxytuf® mass polymerized PVC (IIP) contains grafted rubber moieties which provide for excellent impact resistance. The addition of a particulate filler to this resin with preservation of impact properties can be accomplished providing the particles are submicron and can be readily dispersed in the resin. Small particle size, surface treated, precipitated CaCO3, when added to IIP provided impact retention superior to that of a homopolymer control containing an added, non‐grafted impact modifier.
An examination of DSC as a method of characterization of PVC lubricants
Authors: Holsopple Peggy S. 
Published: December 2004

AbstractDifferential Scanning Calorimetry (DSC) has been used to characterize various lubricant additives for PVC in order to determine effectiveness. Depending on the processing period, and therefore the temperature profile, each lubricant undergoes a change in the internal vs. external nature of its behavior. In the process described, monitoring of the glass‐transition temperature produces evidence for the effectiveness of additives as internal lubricants.
Study of the preparation of plasticized PVC with a surface with barrier properties
Authors: Aboutaybi A. , Bouzon J. , Vergnaud J. M. 
Published: December 2004

AbstractPlasticized PVC sheets are often used in packaging for blood or liquid foods, as well as cosmetics or solvents. Two matter transfers may take place: the liquid entering the PVC, and the plasticizer leaving the solid. These transfers are detrimental to the polymer, which becomes less flexible, and to the liquid, which is polluted. A two‐step process for preparing plasticized PVC samples with low matter transfers is studied. The polymer is immersed into a liquid for a short time and then dried. At the end of the process, a steep gradient of concentration is obtained next to the PVC surface both for the plasticizer and the liquid, with a low concentration on the surface. As the process of transport is controlled by diffusion with concentration‐dependent diffusivities, very low initial rate of transport is obtained for the final PVC. Models based on numerical methods with finite differences are used in order to describe the process and provide a fuller insight of its mechanism.
Heat distortion temperature modification of rigid PVC and chlorinated PVC: A method to produce low smoke compositions
Authors: Termine Enrico J. 
Published: December 2004

AbstractThe use of a new low smoke, heat distortion temperature modifier for rigid PVC and chlorinated PVC is discussed. This material, CN‐1427, is a tetrabromobisphenol A carbonate oligomer which is compatible with vinyl compositions. The carbonate oligomer can be compounded into PVC resin to improve heat distortion temperature of PVC and CPVC by 20–30°C. Unlike conventional HDT modifiers, brominated carbonate oligomers do not increase smoke evolution during flammability testing. Thus, using carbonate oligomer technology, it is possible to achieve low smoke, Class I (ASTM E‐84) and V‐O flammability (UL‐94) performance. Vinyl compositions, modified with the carbonate oligomer described in this work, can be utilized as an alternative to expensive engineering thermoplastics. This paper reports recent studies on the use of carbonate oligomers as heat distortion temperature modifiers for low smoke vinyl applications. Formulation information addressing flammability and physical property performance is presented in detail.
Characterizing the quality of PVC by melt flow testing
Authors: Pinette Roger G. 
Published: December 2004

AbstractTraditionally, PVC compounds are identified by reference to bulk properties such as hardness, specific gravity, tensile, elongation. While these are useful and descriptive notations, they do not serve effectively to define compound quality. Melt flow is broadly used to great advantage in testing most commerical thermo‐plastics as described in ASTM D‐1238. These procedures utilize the dual advantages that a plastometer is a very expedient instrument to use in a given processing facility, and that a MF test is highly sensitive, capable of detecting relatively small differences in polymer structure and composition. However, PVC's are not considered within D‐1238 for several important reasons. The thermal and rheological instabilities of PVC create special considerations in testing as well as in processing. Furthermore, the polymer is always used in a highly varied compounding‐ingredient‐environment which further complicates the problem.
Filler tolerance of dispersion resins: An analysis of oil absorption and particle size effects
Authors: Harvey W. Wallace 
Published: December 2004

AbstractPlastisol rheological characteristics are of prime importance to the formulator and processor. As the formulas become more complicated, interactions can occur between ingredients that have significant effects on rheology. This paper explores aspects of the resin‐CaCO3filler interaction. Experiments investigating some of the effects of resin‐filler interaction on rheological behavior have been performed. The experiments indicate that particle size distributions of the resin and filler, as they relate to packing efficiency, have a significant effect on rheological behavior, especially at high filler concentrations. The effects of particle packing vs. oil absorption are also investigated and discussed.
The use of statistical process control in batch processed PVC compounding. Part II
Authors: Brown David J. 
Published: December 2004

AbstractThis paper describes various SPC methods that can be used to promote quality improvement, resulting in increased productivity and lower costs. By concentrating on preventative systems rather than detective systems, the operation has increased productivity by 5.0% over a period of two years with relatively little capital investment. This has resulted in an additional capacity of 650,000 kg per year.
Examples of recycled vinyl products
Authors: Summers James W. , Mikofalvy Bela K. , Boo H. Khim , Krogstie James M. , Sell W. Alan , Rodriguez Juan C. 
Published: December 2004

AbstractWe describe examples in which we have demonstrated the feasibility of collection, separation, cleaning, and manufacture of several recycled products. We show that vinyl in municipal solid waste can be recycled into bottles, drainage pipe, and drainage pipe fittings with good appearance and properties. We also demonstrate the feasibility that vinyl wire and cable can be recycled into a variety of applications, including wire and cable traffic cones and drainage pipe with good appearance and properties.