bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure analysis of a PVC water pipe
Authors: Broutman Lawrence J. , Duvall Donald E. , So Paul K. 
Published: May 2005

AbstractTwo 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

AbstractProfitable 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

AbstractThe 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

AbstractMany 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

AbstractThis 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

AbstractDespite 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.
Functionalization of PVC by grafting of plasticizing group in a twin screw extruder
Authors: Cassagnau P. , Bert M. , Michel A. 
Published: May 2005

AbstractSubstitution reactions are an appropriate way to attach chemical functions to polymer chains for improving properties and to diversify the application of polymer materials. The stereoselective substitution of chlorine atoms affords a useful way to plasticize polyvinychloride (PVC) by attaching appropriate plasticizing functions (ester group) such as isooctylthiosalicylate. Thus, the substitution of chlorine atoms of PVC by reactant bearing plasticizing groups was carried out in a continuous mixing apparatus such as a twin screw extruder. This continuous chemical engineering process taking place in the extruder is studied as the function of the residence time distribution (RTD) measured by a UV method. This function combined with the kinetics of the chemical reaction allows to define a new function G as the distribution of the extent of conversion by analogy with the RTD function.
Optimizing the processing of rigid PVC compounds
Authors: Covas J. A. 
Published: May 2005

AbstractThe optimization of the extrusion of a simple rigid PVC compound in both single and twin screw machines is considered. Mass throughput, short term mechanical properties (tensile and impact). degree of mixing, and energy efficiency were selected as important parameters of the process. Using a statistically based experimental design, regression polynomials of the above variables were defined. The corresponding responses were superimposed and adequate processing windows were defined. Generally, processing rigid PVC at high screw speeds, small die resistances, and medium to high temperature profiles led to the most adequate values of the process parameters.
Polymeric plasticizers for higher performance flexible PVC applications
Authors: Svoboda Ronald D. 
Published: May 2005

AbstractFlexible PVC applications can be categorized as requiring either general or higher performance characteristics. In many application areas, specification requirements are becoming increasingly more severe requiring the use of polymeric polyester plasticizers in compounding. Polymeric plasticizers provide excellent migration, volatility, fluid chemical extraction, and/or weathering resistance in higher performance applications compared with that obtained from monomeric plasticizers alone.
Improved performance properties of PVC food wrap film
Authors: Falter J. A. 
Published: May 2005

AbstractA new complex ester additive has been developed for polyvinyl chloride (PVC) food wrap film. This material imparts significantly improved fog resistance and exhibits superior anti‐static characteristics compared to conventional systems. A “mushroom sensitivity” test shows that this new anti‐fog agent has no effect on color or consistency of mushrooms. Effects of conventional anti‐fog systems and this new proprietary product in PVC films are compared in: (a) fog tests at room temperature and at 2°C–5°C, (b) static decay measurements, and (c) thermal stability and optical properties.
Specialty low gloss PVC resin vs. traditional low gloss modifiers
Authors: Reichard Robert 
Published: May 2005

AbstractSpecialty low gloss PVC homopolymer resin effectively reduces gloss levels in flexible PVC compounds at replacement levels of 5 to 30 phr while having little effect on processing parameters. Compounds based on specialty low gloss homopolymers maintain their low gloss characteristics over a broad temperature range and during post heating. These compounds also out perform compounds based on other low gloss modifiers such as acrylics and silicas for physical properties.
Effect of plasticizer type on gelation and fusion of PVC plastisol, dialkyl phthalate series
Authors: Nakajima N. , Kwak S‐Y. 
Published: May 2005

AbstractDifferent grades of PVC resins and a variety of plasticizers are used to adjust processability and properties of plastisol. The plastisol, which is a dispersion of fine particles of PVC in plasticizer, is coated on a substrate and heated in an oven to gel and fuse. In the gelation stage the resin particles become swollen with plasticizer and then, in the fusion stage the entire system fuses to become one homogeneous phase. The finished products are flexible PVC such as coated fabrics and surgical globes. Different plasticizers, because of the difference in solvent power, affect the process of gelation and fusion, and hence, processability. This paper examines such an effect systematically by employing a homologous series of plasticizers, dialkyl phthalates. The progress of gelation and fusion are followed by the measurements of dynamic moduli and by the observation with a scanning electron microscope. As it may be expected, the shorter the alkyl chain, the higher the solvent power of the plasticizer.
Model simulation of radio frequency heatseal performance of flexible PVC and other materials
Authors: Ling Michael T. K. , Westphal Stanley , Woo Lecon 
Published: May 2005

AbstractDespite the long history of the application of radio frequency energies for the joining and assembly of polymer films and articles, a comprehensive, quantitative understanding of all the factors has been lacking. In this article, a quantitative first principle type study is described for flexible PVC of various plasticizer contents and ethylene vinyl acetate (EVA) of different VA compositions. High frequency dielectric data of up to 10 MHz were collected over broad temperature ranges. Separate thermal properties of specific heat and thermal conductivity were determined. In addition, rheological functions over required temperatures and shear rates were applied. Comparisons of predicted heatseal behavior with experimental observations are presented.
Damage zone evolution of PVC/MBS blends
Authors: Bensason S. , Tse A. , Hiltner A. , Baer E. 
Published: May 2005

AbstractThe development of the stress‐whitened damage zone in poly(vinyl chloride) and its blends with methyl methacrylate‐butadiene‐styrene (MBS) core/shell rubber was investigated as a function of rubber content and temperature in a triaxial stress state obtained by slow tensile loading of specimens with a semicircular notch. The onset of stress‐whitening was characterized by a critical mean stress and a critical volume strain. Both of these criticality parameters were affected by temperature, where the blends exhibited a weaker temperature dependence in critical volume strain independent of the rubber content.
Prediction of the long‐term outdoor weathering of poly(vinyl chloride)
Authors: Gardette Jean‐Luc , Lemaire Jacques 
Published: May 2005

AbstractThe prediction of the long‐term durability of PVC polymeric material has been a controversial subject for a long time. Attempts to evaluate this durability have indeed largely preceded experiments on the basic mechanisms of PVC degradation, and they have been essentially empirical. The present paper reports on the general rules that have to be followed to avoid basic errors in predicting the performance of PVC compounds from accelerated weathering experiments.
RF welding of PVC and other thermoplastic compounds
Authors: Leighton J. , Brantley T. , Szabo E. 
Published: May 2005

AbstractMany of the acclaimed advances in medical sciences have been possible because of the improvements in material sciences, particularly plastic. Radio frequency (RF) sealing of plastics has adopted an increasingly important role as a means of manufacturing medical devices. A high intensity radio signal is used to impart increased molecular vibration in two similar or dissimilar polymers. RF sealing is one of the methods for fabrication that allows the designer to seal or connect different types of plastics. This study addresses the effectiveness of this welding method applied to various commercially significant medical grade polymers with emphasis on PVC of varying hardness. The study compares measured weld strength and weld quality (inspected microscopically) at ambient and elevated temperatures. Also, selected samples of polymeric compounds were exposed after RF welding to gamma radiation, a method of medical device sterilization, in order to study the effects on the weld strength and color shift in the weld area. Of prime interest is the determination of optimum welding parameters for various constructions of plastic compounds.
Changes in properties of rigid PVC during weathering
Authors: Rabinovitch Elvira B. , Summers James W. , Northcott William E. 
Published: May 2005

AbstractChanges in properties of PVC compounds upon weathering are categorized as due to physical aging or due to chemical change. PVC's tensile strength, flexural strength, tensile modulus, and flexural modulus generally rise slightly with weathering. DSC data on weathered samples show an annealing effect identical to physical aging. The impact strength of weathered PVC is substantially lower than expected from physical aging. Molecular weight of PVC on the weathered surface is lowered upon weathering. Thus the loss of impact strength of PVC upon weathering is mainly due to chemical change.
Effects of nozzle length on mold filling simulation accuracy
Authors: Weir Scott 
Published: May 2005

AbstractA common assumption in mold filling analysis is that the molding machine is capable of providing a fully pressurized uniform temperature melt to the rear orifice of the sprue. Based upon this assumption, the finite element model then only represents the geometry of the mold itself from the sprue rear orifice forward. This assumption, however, is acceptable only when the injection modeling machine nozzie extension is of such a length that the pressure drop in the nozzle is negligible. For large injection molded parts the exclusion of the molding machine nozzle in the design phase of the mold filling analysis may produce overly optimistic results. This study of an actual large (7.9 kg) injection molded thin wall (4 mm) vinyl part will show the effects of nozzle length on the accuracy of mold filling analysis software predictions. Analytical results with and without representation of the molding machine nozzle in the finite element model will be compared to production trial results.
Effect of plasticizer functionality on the performance properties of flexible PVC compounds
Authors: Ingram Jim E. , Hookanson Stephen H. 
Published: May 2005

AbstractThis paper is on the enhancement of physical properties achieved through utilization of linear plasticizers in flexible PVC compounds. This paper also emphasizes the use of statistical methods and designs of experiments. In a series of experimental designs, electrical, oven‐aging, and low temperature performance of commercially available phthalate plasticizers were evaluated. Test data will be given to show the effect of plasticizer functionality on the performance properties of flexible PVC compounds.
Additives for processing rigid PVDC copolymers
Authors: Patterson Michael C. , Dunkelberger David L. 
Published: May 2005

AbstractPolyvinylidene chloride (PVDC) copolymers are highly crystalline materials used in packaging applications because of their strength and excellent barrier properties. The crystalline moiety (∼40 to 50%) generally melts from 160 to 170°C and the amorphous phase Tg is between 0 and 35°C depending on the comonomer type and level. PVDC is much less thermally stable than PVC and degrades very rapidly in the same temperature range (i.e. above the Tm) required to process the material. Added plasticizers are utilized to reduce processing temperatures but at the expense of barrier properties. There is a need to process PVDC sans plasticizer to achieve maximum possible barrier properties in multilayer composite sheet and films. Additives will be discussed that have been shown (in laboratory tests) to delay the fusion of the amorphous phase of unplasticized PVDC until the material temperature nears the crystalline melting point, thus reducing the overall heat history with a minimal effect on other important properties.
Trimethylpentanediol dibenzoate: New plasticizer for plastisol screen ink
Authors: Arendt William D. , Beitsch Harry O. 
Published: May 2005

AbstractTrimethylpentane diol (TMPD) dibenzoate use in vinyl as a plasticizer is not well recognized, and little has been published on vinyl performance characteristics. To assess new applications for vinyl, a basic evaluation was conducted. Based on the results of the screen and other considerations an evaluation for utility in plastisol silk screen ink was conducted. The results indicated that the TMPD dibenzoate performed very well in white ink, requiring good fabric dye bleed resistance compared to polymeric and phthalates currently being used for non‐bleed ink. Non‐bleed characteristics are important for colored tee shirt printing. The benzoate is a good solvator and has excellent extraction resistance.
Lubricant systems for rigid PVC applications
Authors: Falter J. A. , Geick K. S. 
Published: May 2005

AbstractLubricants are used in extrusion processing of rigid polyvinyl chloride (PVC) compounds to control fusion and reduce shear heating. Without lubricants, conversion to the melt state results in excessive shear heating and degradation of the compound. The present work compares new lubricant systems containing complex esters with conventional systems based on ethylene bisstearamide (EBS) and paraffin. These new systems provide improved compound stability, weatherability, and physical properties. In addition, use of these systems results in lower compound viscosity compared with the conventional lubricant packages. The effects of other characteristics of these systems, such as the degree of esterification on compound properties, are also discussed.
Characterization of PVC/CPE blends by thermally stimulated current
Authors: Gray R. L. , Ibar J. P. 
Published: May 2005

AbstractIn recent years, the use of polymer blends and alloys has become increasingly important in the development of advanced engineering materials. Through the combination of existing polymers, new and improved properties such as impact strength, chemical resistance, and increased temperature use range have been achieved. An important challenge has been to develop new analytical methods capable of properly evaluating these increasingly complex polymer systems. Careful examination of the blend morphology and degree of internal stress between phases is often critical to the success of the development of new blends and alloys. Blends of grafted and crosslinked PVC and CPE were evaluated by Thermally Stimulated Current (TSC). The extent of crosslinking and degree of interpenetration between the two phases were evaluated by examination of the glass transition peaks generated during the TSC experiments. The unique sensitivity of this technique provided excellent insight, which may allow prediction of long term stability and impact strength based on the degree of internal stress that exists at the phase boundaries. This paper explores the application of TSC as a development tool in the study of impact‐modified PVC.
Recycling postconsumer PVC bottles: Technology and market development
Authors: Carroll William F. 
Published: May 2005

AbstractThe drive to recycle individual polymers in a “closed‐loop”—that is, bottles‐to‐bottles—began in the late 1980s. Technology and market streams for high‐volume packaging plastics like HDPE and PET evolved first. Smaller‐volume packaging plastics have followed. This article describes technology development and the state of the market, including general economics for vinyl recycling. Recycling of PVC packaging, to say nothing of recycling of other plastics, continues to evolve and should be viewed as a work‐in‐progress; still, closed‐loop recycling of PVC bottles is a commercial reality.
Aspects of miscibility in poly(vinyl chloride)/epoxidized natural rubber blends. Part I: Mechanical and morphological properties
Authors: Ishiaku U. S. , Nasir M. , Ishak Z. A. Mohd 
Published: May 2005

AbstractMiscibility in poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends was studied by examining evidence from tensile, impact, and physical properties. The observation of synergism in tensile strength, percent elongation at break, hardness, and relative density has reaffirmed PVC/ENR blends as miscible systems. Studies of impact properties, however, revealed that the blends are microheterogeneous in nature. This could be attributed to the large sizes of polymer molecules involved and the microgel content of ENR‐50. Results from Fourier transform infrared spectroscopy (FTIR) revealed that hydrogen bonding is extensively involved in PVC/ENR systems. This evidence unveiled the exact nature of the specific interactions responsible for miscibility and hence the enhanced mechanical properties of PVC/ENR blends.