bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of molecular modeling to predict ligand efficiency in thermal stabilizers
Authors: Burchill Michael T. , Leste‐Lasserre Pierre 
Published: May 2005

AbstractMolecular 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

AbstractSynergism 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

AbstractThe 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

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

AbstractThe 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

AbstractRigid, 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

AbstractCopolymers 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

AbstractThis 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

AbstractThe 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

AbstractPVC/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

AbstractBiaxial 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

AbstractLinear 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

AbstractA 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

AbstractA 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

AbstractBuried 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

AbstractAlthough 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

AbstractThe 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

AbstractAssessing 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

AbstractThis 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

AbstractTrapping 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

AbstractRecent 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

AbstractGelation 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

AbstractIn 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

AbstractRigid 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

AbstractBased 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

AbstractMatte 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.