bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyber security vulnerability analysis: An asset‐based approach
Authors: Baybutt Paul
Published: April 2004

This paper describes a method for identifying and analyzing threats and vulnerabilities of process plants to cyber system attacks by terrorists, saboteurs, and other criminals, and provides an example of its use. The approach considers how cyber assets can be exploited by assailants to cause harm. It defines threat events by pairing threats with cyber assets, and considers vulnerabilities to attack, existing countermeasures, and the need for new or improved countermeasures.

Previous security vulnerability analysis (SVA) methods have focused on physical and personnel security. Cyber security has not been explicitly addressed. Studies using the method described can be performed as adjuncts to existing SVAs, as part of future SVAs, or as stand‐alone cyber SVAs (CSVA). The method can also be used to consider all types of security issues in a single analysis, including physical, personnel, information and cyber security, or to study any of these areas individually.
Turning tragedy into triumph: How process accidents can benefit companies, employees, and, ultimately, customers
Authors: Lenz Douglas H. , Rovison John M. , Maser Michele A. , Hodgson Gerald M. , Pinsky Michael L. , Scott Paula , Mulholland Robert
Published: April 2004

In the mid‐1990s, FMC was challenged with a corporate goal of manufacturing the safest and highest quality persulfate product for our global customers. Successfully meeting this challenge required a systematic multi‐team approachutilizing both novel methods and standard tools in innovative ways to uncover the root causes of the accident. Novel and/or improved QC methods led to the creation of new product and process internal specifications, for routine QC laboratory monitoring of critical final product safety and quality specifications or parameters, and the quantification of a product parameter called “thermal stability,” an excellent indicator of product and process safety, product and process quality, and reliability. The use of this parameter as a predicator of product stability in storage, shipping, and handling was validated and benchmarked by full‐scale self‐accelerating decomposition temperature tests.

The FMC persulfate process and operating conditions were subsequently modified based on lessons learned. As a result, the packaged persulfate product has not undergone a decomposition in almost eight years. Addressing productsafety automatically led to process safety improvements, and these, in turn, led to better product and process quality. Quality improvements meant better process reliability, increased capacity, reduced process downtime and operating costs, and improved customer satisfaction. Ultimately, this case study shows how safety pays!
Shortstopping runaway reactions
Authors: Balasubramanian Santhana G. , Dakshinamoorthy Duraivelan , Louvar Joseph F.
Published: April 2004

Runaway reactions continue to be a problem in the chemical industry. A recent study showed that 26.5% of our major chemical plant accidents are due to runaways. This article reviews the (a) historical perspective of runaways, (b) state of our knowledge of how to detect potential runaways, since detection is a key element of a successful inhibition process, and (c) state of our knowledge on how to shortstop, or inhibit, reaction.

The objective of the research is to improve our plants safety performance in (a) identifying methods for successfully inhibiting runaway reactions under adverse conditions, and (b) highlighting future problems and limitations, as reactions are faster and reactors more complex. Computational Fluid Dynamics (Fluent) is the tool used in this study.
Informal reasoning regarding socioscientific issues: A critical review of research
Authors: Sadler Troy D.
Published: April 2004

Socioscientific issues encompass social dilemmas with conceptual or technological links to science. The process of resolving these issues is best characterized by informal reasoning which describes the generation and evaluation of positions in response to complex situations. This article presents a critical review of research related to informal reasoning regarding socioscientific issues. The findings reviewed address (a) socioscientific argumentation; (b) relationships between nature of science conceptualizations and socioscientific decision making; (c) the evaluation of information pertaining to socioscientific issues, including student ideas about what counts as evidence; and (d) the influence of an individual's conceptual understanding on his or her informal reasoning. This synthesis of the current state of socioscientific issue research provides a comprehensive framework from which future research can be motivated and decisions about the design and implementation of socioscientific curricula can be made. The implications for future research and classroom applications are discussed. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 513–536, 2004
Teachers' conceptions and misconceptions concerning three natural phenomena
Authors: Kikas Eve
Published: April 2004

This study focuses on the conceptions of trainee, primary, and subject teachers about three phenomena: the motion of objects, seasonal changes, and aggregate changes of matter. A total of 198 participants completed a questionnaire concerning two types of tasks. First, teachers evaluated the adequacy of a given explanation as compared to their knowledge of the contemporary scientific explanation. Four types of explanations were provided: a simple description, description with terms, an explanation with misconception, and a scientific explanation. Second, respondents answered multiple‐choice questions and substantiated their choices. The findings showed not only various misconceptions but also differences between the phenomena and the teacher groups. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 432–448, 2004
Using situated cognition theory in researching student experience of the workplace
Authors: Case Jennifer , Jawitz Jeff
Published: April 2004

It has been proposed that situated cognition theory, in which learning is conceptualized as induction into a community of practice through the activity of legitimate peripheral participation, offers an appropriate theoretical perspective for examining issues of gender in science education. This study critically engages with this proposal by means of an investigation of the vacation work experiences of a group of South African final‐year civil and chemical engineering students. Issues of race and gender appeared prominently and spontaneously in focus group and interview data. An analysis of these data using the situated cognition framework allowed for a deeper understanding of these issues and their impact on learning. It was found that access to legitimate peripheral participation was critical for good learning outcomes (associated with positive identity formation) while denial of this access (as sometimes experienced by black and female students) appeared to be related to less effective learning and poor feelings of self‐worth. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 415–431, 2004
Chemical removal of residual monomer from polyvinyl chloride latices and slurries
Authors: Marshall R. A. , Parker D. K.
Published: April 2004

Air quality standards are becoming increasingly stringent. Stripping and gas purging of the latex are no longer adequate to reduce dryer emissions of unreacted monomer below proposed limits. New technology has been developed in which the monomer is chemically removed from the latex before the drying step to reduce monomer emissions from the dryer and to lower monomer content in the product (1). Ozonation of vinyl latex is an effective technique because of its rapid reaction with double bonds. The short half life of ozone will result in no contamination of the product by unreacted ozone. Ozonation byproducts from the reaction with vinyl chloride are nontoxic and nonpolluting. Because the ozonation reaction is specific for double bonds, the polymer structure is left intact without affecting resin physical properties.
Shear effect on the devolatilization of filled polymers
Authors: Cheng Jianya , Bigio David I. , Briber Robert M.
Published: April 2004

This is the second part of a systematic program to investigate the onset and mechanisms of devolatilization of filled polymeric materials. The object of this work is to study the effect of shear flow on the devolatilization of filled polymers. It is found that shear flow enables abrupt foam growth at relatively high absolute pressure in comparison to the cases without shear flow. The shear flow also reduces the threshold pressure which distinguishes two regimes of gradual and abrupt foam. In addition, an oscillatory foam growth phenomena was observed. The foam growth and devolatilization efficiency are found to depend on the imposed shear rate.
State of dispersion: Polypropylene filled with calcium carbonate
Authors: Gendron Richard , Binet Danielle
Published: April 2004

The influence of mixing conditions on the state of dispersion of calcium carbonate filled polypropylene composite was studied. The polymer and the filler were compounded in a twin screw extruder under various controlled processing conditions. The variables studied were the screw speed, the feed rate, the filler concentration, the barrel temperature profile and the surface treatment of the filler. The state of dispersion of calcium carbonate filled polypropylene composites was characterized using a scanning electron microscope, and was correlated to the residence time and the shearing conditions that were prevailing within the extruder. Degradation of the polymer matrix was also observed.
The role of additives in PVC market opportunities
Authors: Johnson Richard W. , Oliveri Frank J. , Szamborski Eugene C.
Published: April 2004

Additives can be used to provide significant performance enhancements to plastics. For PVC, particular performance benefit can be gained from additives that raise HDT, increase impact, improve color fastness, and improve processing. This paper comments on what improvements are desired in these areas, and what benefits and market opportunities would then result.
Prospects and possibilities in the realm of vinyl research
Authors: Starnes William H.
Published: April 2004

In most of the academic laboratories throughout the world, basic research on vinyl polymers has been of little interest for several years. To many observers, this situation has seemed illogical in view of the great commercial importance of vinyl products. Be that as it may, specific areas now exist where technological progress might well result from additional basic understanding or simply from the utilization of basic facts that already are well‐known. This paper identifies some of those areas of opportunity and suggests ways in which they might be approached. The topics considered relate to the general subjects of polymerization, stabilization, smoke suppression, and fire retardance.
A review of commercially used chemical foaming agents for thermoplastic foams
Authors: Heck Rhomie L.
Published: April 2004

Literally hundreds of materials have been proposed and evaluated for use as foaming agents over the past 100 years. Only a relative handful of those materials are used commercially at the present time. An extensive review of physical and chemical foaming agents was written by Henry R. Lasman for the first edition of the Encyclopedia of Polymer Science and Technology published in 1965, and is one of the best historical and technical reviews available on chemical foaming agents (1). This paper will be limited to a review of chemical foaming agents that are currently used to produce thermoplastic foams.
Injection moldable FR‐HIPS formulations based on blends of chlorinated wax and non diphenyl oxide (DPO)‐brominated flame retardant in conjunction with metal oxide/metal sulfide synergists
Authors: Siddhamalli Sridhar K. , Lee Victor W.
Published: April 2004

A Response Surface Methodology (RSM) approach was used in performing a D‐Optimal mixture design of experiments of injection moldable fire retarded High Impact Polystyrene (FR‐HIPS) formulated with blends of Chlorez 700 SSNP (chlorinated paraffin wax) and FR‐1808 (octabromotrimethylphenyl indane, a non diphenyl oxide, brominated flame retardant that is considered more environmentally acceptable than decabromo diphenyl oxide flame retardant) in synergistic combination with antimony trioxide/zinc sulfide (white pigment) blends. An optimum processing region was identified from the viewpoint of product performance (burn time to meet UL‐94 V‐O @ 1.6 mm specification without affecting significantly other attractive physical properties) and economics that is dictated by the price of FR additives. This study has demonstrated that use of DOE offers an important benefit in formulation development and that a large number of factors can be evaluated in a relatively small number of experimental runs.
The effect of nucleating agents on glycerol monostearate antistat performance in three polypropylene resins
Authors: Dieckmann Dale
Published: April 2004

The effect of polypropylene nucleation on glycerol ester antistat performance is studied by measuring the electrostatic decay times of injection molded specimens. Behaviors in homopolymer, random copolymer, and block copolymer are compared. Antistat performance is related to crystallinity using DSC.
Macroscopic analysis of polyvinyl chloride (PVC) fracture modes under impact loads
Authors: Elleithy Rabeh H.
Published: April 2004

In this paper, the PVC impact fracture modes and processes were analyzed via the technique of successively increasing impact energies. Force‐displacement and microscopic analyses were employed at macroscopic level to study PVC fracture modes. The fracture modes were classified as: ductile, brittle, and mixed. The mixed mode was separated into: semi‐ductile and semi‐brittle. In the semi‐ductile mode, radial cracks were initiated and propagated, but were ultimatley arrested. For the semi‐brittle mode, the fracture was characterized by connected radial and circumferential cracks. It was verified that the primary elements which governed the fracture modes and impact resistance of PVC were the crack initiation and propagation processes.
Vitamin E based stabilizer components in HDPE polymer
Authors: Ho Y. C. , Young S. S. , Yam K. L.
Published: April 2004

The effects of individual components in a vitamin E based antioxidant formulation (CF‐120) on off‐odor release, melt flow property and yellow color property of HDPE resin pellets were investigated using a three‐phase study. The formulation consists of vitamin E, glycerol, polyethylene glycol‐400 (PEG‐400), and glyceryl monocaprylate/caprate (GMC). The resin pellets were extruded from HDPE resin powder using a laboratory scale single screw extruder. Off‐odor release from the resin pellets was evaluated using a sensory panel and GC/MS analysis. Melt flow indices and yellowness indices of the resin pellets were also measured. Screening experiment (Phase I) showed that GMC greatly contributed to off‐odor and MFI reduction; vitamin E greatly contributed to yellow color formation. Factorial experiment (Phase II) confirmed that GMC was the major off‐odor contributor. Response surface experiment (Phase III) showed that yellowness index and odor score reasonably correlated to vitamin E and GMC concentrations; MFI and nonanal concentration did not correlate well with vitamin E and GMC concentrations. The identification of octanoic acid by GC/MS from HDPE resin pellets suggested that possible thermal/mechanical degradation of GMC might occur in extrusion. The results are useful for designing a better vitamin E formulation for reducing the off‐odor, without significantly enhancing yellow color formation.
Approximate model for analyzing frozen‐in strains and shrinkage of extruded PVC lineal profiles
Authors: Ray Harrell E.
Published: April 2004

A mathematical model, based upon utilization of an “approximate” time‐temperature superposition for estimating stress‐strain properties of PVC, was derived for analyzing shrinkage of extruded PVC profiles. The model is composed of a single deformation, followed by a strain recovery (shrinkage) at the same or a different temperature. Profile shrinkage at any given time and temperature can be reduced by decreasing the magnitude of the imposed frozen‐in strain, increasing the temperature at which the strain is imposed, and/or increasing the time that is required to impose the strain. The model provides good estimates of the shrinkage of extruded profiles.
Effects of morphology on the fracture toughness of PVC‐U pipe
Authors: Kuriyama Takashi , Narisawa Ikuo , Shina Richi , Kotaki Masaya
Published: April 2004

The effects of processing conditions on the deformation and fracture behavior of PVC‐U pipe have been studied in terms of fracture toughness, following the BS 3505 standard. The processing conditions did not strongly affect the yield strength or elastic modulus, whereas FT (fracture toughness) values linearly increased with an increase of gelation levels. Microscopic observations of the damage zone ahead of the notch in C‐ring specimens, when loading was interrupted at half of creep life, showed that many voids and delaminations initiated from primary PVC particles in the higher gelated pipes, whereas multiple cracks between sub‐grains occurred in the lower gelated pipes.
Processing window in impact‐modified rigid PVC
Authors: Berard Mark T. , Ventresca Don A.
Published: April 2004

A method is described for quickly evaluating the processing window of impact‐modified rigid PVC formulations. This involves mixing the compound in a bowl mixer at various temperatures and to various levels of total work input. The impact properties are measured and plotted as a contour map versus melt temperature and work input. The melt temperature is the dominant factor in controlling the impact processing window. The total work input is a secondary effect, which mainly influences the system through shear heating effects on the melt temperature. This method was used to evaluate formulations with different impact modifiers and lubricant and filler levels. Impact modifier type, polyethylene wax, and filler concentrations are the dominant factors. The mechanisms involved are discussed.
The structure of lead stabilizers. 3: Reaction products with HCl
Authors: Grossman Richard F.
Published: April 2004

The reaction of HCl with stabilizers such as dibasic lead phthalate, tribasic lead sulfate, and dibasic lead phosphite leads to a series of previously uncharacterized chlorinated derivatives. These compounds exhibit an interesting and hitherto unknown chemistry. Some are heat stabilizers in their own regard.
Ultraviolet light resistance of vinyl miniblinds. Part 2: Reaction products formed by lead in air
Authors: Grossman Richard F.
Published: April 2004

Accelerated ultraviolet light aging was carried out using lead stabilized commercial vinyl miniblinds as well as a vinyl composition designed for outdoor use. The levels of surface lead found after such exposure were compared to results obtained in the field by the North Carolina Department of Environment, Health, and Natural Resources (DEHNR).
The influence of rotational molding cycle on the morphology and physical properties of FR‐LLDPE
Authors: Siddhamalli Sridhar K. , Lee Victor W.
Published: April 2004

The major objective of the study was to develop formulations having maximum impact strength while maintaining a UL‐94 V‐0 flammability rating. Excellent impact strength and flammability performance were achieved in the modified FR‐LLDPE system at 20% impact modifier (ethylene copolymer), 22% flame retardant, 5.5% antimony trioxide, 0.25% PTFE, and 0.5% functionalized silicone additive. This paper further explores the performance of the aforesaid optimized FR‐LLDPE composition when rotomolded at various cycle times. Attempts were made to probe the influence of morphological characteristics on the physical properties of the rotomolded parts.
New soluble teflon for coating onto plastics
Authors: Stewart Charles W. , Wheland Robert C. , Anolick Colin , Tattersall Thomas L.
Published: April 2004

Teflon PTFE, FEP, and low melting HFP/TFE copolymers can be made to have excellent adhesion to substrates if residual stresses from large changes in temperature can be eliminated. PTFE and FEP can be adhered using a high boiling saturated perfluorinated oligomer to plasticize the fluoropolymer at the interface. Low melting HFP/TFE copolymers can be deposited as very thin films from solution in common perfluorinated solvents. Highly durable coatings can be prepared owing to the intimate degree of contact obtained between the substrate and the fluoropolymer chains. The use of low boiling solvents allow coatings on temperature sensitive substrates, such as plastics, rubber, and paper. Possible commercial applications range from mold release coatings, clear protective coatings on photographs, paintings, and documents and optical coatings on plastic and glass.
Stain resistance in resilient sheet flooring applications: The role of the plasticizer
Authors: Colletti T. A. , Renshaw J. T. , Schaefer R. E.
Published: April 2004

Stain resistance, or more properly, appearance retention, is a complex phenomenon in resilient sheet flooring applications. The process can be complex, involving the plasticizer, the overall toughness (or abrasion resistance) of the wear layer, and the thermoplastic nature of plasticized PVC. This paper explores the plasticizer related portions of the stain resistance phenomenon. Data are presented to illustrate relationships between stain resistance and plasticizer structure, concentration, extraction resistance, volatility, and solubility parameter.
New silicate‐based powders for fire protection of thermoplastics
Authors: Liu T. M. , Baker W. E. , Langille K. B. , Nguyen D. T. , Bernt J. O.
Published: April 2004

A new, intumescent powdered silicate additive for plastics (polyethylene and polyvinyl chloride) has been investigated that gives improved flame retardancy. Cone calorimeter evaluations of the compounds of polymer/powder show reduction in peak rate of heat release, total heat release, and rate of mass loss. The effects of various polymer/powder ratios and powder particle sizes on the fire protection performance are shown. The morphology of this powder and the polymer/powder compounds before and after combustion is observed. A fire‐protection mechanism is discussed that suggests the importance of an interpenetrating char structure.
Emerging technical and society trends—opportunities for vinyl: A look at the future and how the vinyl industry can respond for growth and profit
Authors: Summers James , Parsons Mark , Hawrylko Roman , Shakir Saleem , Jarus David , Kaminski Ronald , Bowler Peter , Rodriguez Ernesto
Published: April 2004

The vinyl industry has a rich history of providing solutions to society's needs. These include flame‐resistant wire insulation, piping systems for safe drinking water, and weatherable, flame‐resistant systems for siding, windows, auto interiors, floors, and pool liners. Also included are shatter‐resistant clear containers with handles, safe blood supplies and intravenous solutions, and flame‐resistant computer housings and electrical boxes. These are but a few of the things of which the vinyl industry can be proud.

The vinyl industry is mature, and as in many other mature industries, much of the technical and business effort goes into running the day‐to‐day businesses, putting out fires, reducing costs, and driving efficiencies. If poorly managed, this will be an all‐consuming effort, leaving no thought and no effort at all on longer‐term business opportunities. The future will look much different than today. Identifying future trends will allow well‐managed companies, looking for these future business opportunities, to seek out and set aside some efforts for developing future technologies and businesses. In this paper we discuss some future trends and needs, such as inexpensive and safe drinking water, personalized public transportation, prevention of resource depletion, high‐powered energy packages, nonpolluting energy sources, human genetic engineering, e‐bombs, and computers. The opportunities for the vinyl industry to participate in these changes also are discussed.
Photoluminescent properties of flexible PVC compounds and their interpretation for performance analysis of automotive exterior parts
Authors: Kann Yelena , Billingham Norman C.
Published: April 2004

Study of fluorescence emission from flexible PVC‐based formulations, colored by exposure to road asphalt or degraded thermally or by UV aging, shows that fluorescent species are formed during the interaction of PVC with road asphalt. For the conditions found in exterior automotive applications, no other known degradation causes development of fluorescence. Flexible PVC‐based formulations discolored by asphalt staining or degraded thermally at moderate temperatures bleach completely under conditions of natural or artificial weathering. A simple technique, using visually observed photoluminescence and photobleaching, can thus identify photoactive groups formed during the interaction of PVC with road asphalt. Application of this test method will allow selective improvement of failed asphalt resistance without treating the “overall” stability of a compound.
Enhanced impact modifier for rigid PVC formulations
Authors: Effler Lawrence J. , Berard Mark T.
Published: April 2004

A new chlorinated polyethylene has been developed for the impact modification of rigid PVC. In addition to imparting excellent impact, the modifier promotes faster PVC fusion and enhances the melt strength of the formulation. Faster fusion allows for economic savings by reducing fusion‐promoting ingredients and via higher output. The enhanced melt strength results in better part quality, especially for complex profiles.
Environmental degradation of highly loaded polypropylene
Authors: Benavides R. , Ponce‐Ibarra V. H. , Reyes‐Vielma B. , Billingham N. C.
Published: April 2004

Six formulations of polypropylene (PP) containing combinations of calcium carbonate (CaCO3), stearic acid, and a light stabilizer were prepared and placed in the environment for their degradation. Samples were taken at proper time intervals for following the consequences of the outdoor conditions. Impact resistance and elongation at rupture were evaluated as mechanical properties. On the other hand, size exclusion chromatography, chemiluminescence, and infrared spectroscopy (FTIR) were used to follow chemical changes. Polypropylene by itself showed a slow but stable aging, while PP + CaCO3 had improved initial mechanical properties but was more sensitive to degradation. The treatment of CaCO3 with stearic acid before its addition to PP resulted in an improved material but with an induction time to degradation greatly reduced to 2 weeks of environmental exposure. The addition of the UV stabilizer reduced the negative effect of the stearic acid to some extent but did not compensate for it completely.
Effect of extrusion melt temperature on properties of flexible PVC
Authors: Rabinovitch Elvira B.
Published: April 2004

This paper provides an insight on the relationship between the physical properties of profiles extruded from flexible PVC compounds and the extrusion melt temperature. The properties include tear resistance, tensile properties, brittleness temperature, and compression set. The effect of heat history on surface characteristics of the extrudate, such as surface roughness and gloss, and their relationship with the processing morphology are also discussed.
Fundamental aspects of wood as a component of thermoplastic composites
Authors: Stokke Douglas D. , Gardner Douglas J.
Published: April 2004

In order to utilize wood‐based particles and fibers effectively as fillers or reinforcements in thermoplastic composites, a fundamental understanding of the structural and chemical characteristics of wood is required. Wood is the secondary xylem of trees, shrubs, and woody lianas (vines). Although the physiological function of wood is similar among different groupings of trees, significant differences are found in the basic anatomical structure of the broadest groupings of gymnosperms (coniferous trees or “softwoods”) and angiosperms (broad‐leaved trees or “hardwoods”). In addition, there are anatomical differences in wood structure among the various species of trees. These structural differences may have effects on the use of these materials in composites. Wood cell walls comprise three major organic constituents, namely, cellulose hemicelluloses, and lignin. In addition to these structural polymers, numerous other organic materials (“extractives”) may be present within the wood. The chemical composition of wood varies between species. The basic characteristics of anatomy and structure combine to impart variations in permeability, bulk chemistry, and surface chemistry. Characterization of particle size and shape, as well as surface tension characteristics as indicators of wettability, becomes important as we try to understand how these biopolymeric materials will behave when introduced into synthetic polymer systems.
Thermal decomposition of chlorinated poly(vinyl chloride) (CPVC)
Authors: Elakesh Esmail O. , Richard Hull T. , Price Dennis , Carty Peter
Published: April 2004

Chlorinated poly(vinyl chloride) (CPVC) shows reductions in flammability and smoke production over PVC. The thermal decomposition of pure CPVC (without stabilizer or lubricant) was studied by dynamic thermogravimetric analysis (TGA) at heating rates from 5 to 100°C/min in atmospheres of nitrogen, air, and oxygen. In each case, a two‐step decomposition was observed similar to that for PVC where dehydrochlorination is followed by pyrolysis/oxidation of the carbonaceous residue. The rate of dehydrochlorination was dependent on atmosphere, occurring slightly slower in nitrogen than in air, and slightly more quickly in oxygen than in air. The decomposition of the residual char was clearly dependent on the conditions in which it was formed. Under dynamic conditions, chars formed at high heating rates appeared more resilient to oxidative degradation than those formed more slowly. However, when chars were formed by heating at different rates and then held at 500°C, the char formed at the slowest heating rate was the slowest to be oxidized. The uptake of oxygen by the char appears to be rate‐limiting. At low heating rates char oxidation is similar in both air and oxygen. As the heating rate is raised, the rate of mass loss of char in air becomes progressively closer to that in nitrogen until at 100°C/min they are almost identical. This work is important to the understanding of the decomposition and flammability of CPVC and flame‐retarded CPVC, where the char formation is one of the flame‐retardant mechanisms.
Mechanism of organotin stabilization of poly(vinyl chloride). 6. Compatibility of organotin stabilizers with PVC
Authors: Safronov A. , Somova T. , Suvorova A. , Fisch M. H. , Stewen U. , Bacaloglu R. , Dooley T.
Published: April 2004

Compatibility of PVC with liquid alkyltin alkylthioglycolate stabilizers was studied by thermal methods, including isothermal calorimetry of mixing, DSC, DMA, and dielectric relaxation. The enthalpy of mixing of PVC with the series of alkyltin alkyl thioglycolates was measured over the entire concentration range at ambient conditions. It was found that all tested compounds are compatible with PVC in a broad concentration range and form homogeneous mixtures. The results are discussed in terms of the superposition of glassy state and molecular interaction contributions to the enthalpy of mixing of the glassy polymer with liquid additives. The influence of organotin stabilizers on the glassy structure of PVC films was studied by means of DSC and the dielectric relaxation spectrum. The enhancement of the glassy structure of PVC by alkyltin alkyl thioglycolates is interpreted as the result of strong multi‐site molecular complexes between organotin molecules and PVC chains, which act as additional clips in the entanglement network of polymer chains.
Mechanical properties of poly(vinyl chloride)/wood flour/glass fiber hybrid composites
Authors: Jiang Haihong , Pascal Kamdem D. , Bezubic Bill , Ruede Paul
Published: April 2004

Short glass fibers were added to poly(vinyl chloride) (PVC)/wood flour composites as reinforcement agents. Unnotched and notched impact strength of PVC/wood flour/glass fiber hybrid composites could be increased significantly without losing flexural properties by adding type L glass fibers and over 40% of PVC. There was no such improvement when using type S glass fiber. The impact strength of hybrid composites increased along with the increment of the type L glass fiber content at a 50% PVC content. At high PVC contents, impact fracture surfaces were characterized by wood particle, glass fiber breakage and pullout, whereas interfacial debonding was the dominant fracture mode at higher filler concentrations. The significant improvement in impact strength of hybrid composites was attributed to the formation of the three‐dimensional network glass fiber architecture between type L glass fibers and wood flour.
Review of PVC dispersion and blending resin products
Authors: Shah Ashok C. , Poledna David J.
Published: April 2004

The world consumption of PVC (2001) was around 25 MM MT (55 billion pounds), second only to low density polyethylene. Total PVC consumption in North America (2001) was 15 billion pounds. This represents almost 17% of all domestic plastics sales of 88 billion pounds. Dispersion and blending (extender) PVC resins are truly specialty resins, and they represent no more than 5% of the total PVC sales. This paper reviews the manufacturing processes, markets, plastisol/organosol compounding, applications, and technical challenges for the dispersion and blending resin industry. It also discusses some guidelines to help the formulator select the most cost‐effective resin package.
An innovative plasticizer for sensitive applications
Authors: Wadey Brian L.
Published: April 2004

Di(isononyl) cyclohexane‐1,2‐dicarboxylate (HEXAMOLL® DINCH) is a new plasticizer for PVC. In the tests used, it has no indication of toxicity or genotoxicity; it is biodegradable; and it has low sensitizing properties. Its properties in PVC compare favorably to those of other plasticizers having well‐balanced properties. This plasticizer should be well‐suited for sensitive applications.
A dual slit in‐line die for measuring the flow properties of S‐PVC formulations
Authors: Thorsteinsen P. , Hinrichsen E. L. , Glomsaker T.
Published: April 2004

We have developed an instrumented dual slit die mounted on a twin‐screw extruder. This device allows us to distinguish the predominant flow pattern and calculate the shear viscosity, Cogswell elongational viscosity, and a Mooney wall‐slip velocity. The melt‐down process is also monitored by measuring the screw torque together with temperatures and pressures along the screw barrel. So far, we have seen that many pipe and profile formulations have a predominant plug or slip‐dominated flow behavior in the die, while others can be more sticky. Generally, the sticky highly viscous formulations will be more affected by shear heating effects when exposed to high rates during processing. We also give a detailed discussion, with examples, of how data from the device are to be analyzed and how the correct flow boundary condition is to be identified.
New developments in melt rheology aid formulating rigid vinyl compounds with improved extrusion processing
Authors: Shah Pravin L.
Published: April 2004

This paper describes a new approach to the rheological characterization of PVC compounds using a capillary rheometer. Since the control of the thermal degradation rate of rigid PVC is very critical in extrusion, a new quantitative method of measuring the true degradation rate of PVC is proposed for formulating rigid vinyl compounds. The usefulness of this new technique is demonstrated in formulating PVC compounds with the lowest rate of degradation measured on the Kayeness capillary rheometer. This study shows a very good correlation between the capillary rheometer data and the extrusion melt temperature, melt viscosity, and the rate of degradation of PVC. The ideal melt temperature for extrusion is determined from the rheology data of each PVC compound to attain the longest run time. The study also shows how to measure the true melt temperature in extrusion, an important variable, to control the rate of degradation in processing. The results of this study show how the new rheology technique can be used as a practical tool for product development, quality control of the PVC compounds, and the development of optimum extrusion parameters.
Contributions to fogging from phthalate plasticizers
Authors: Jachowski D. , Poppe A. C.
Published: April 2004

The minimization of fogging in cars is an ongoing subject of discussion. Among many substances, plasticizers have been identified to contribute to fogging. Differences in their fogging performance are discussed and it is shown that present by‐products have a significant impact. Long chain branched phthalates (C11) can compete with currently widely used linear specialities.
Study on poly(vinyl chloride) paste blending resins
Authors: Zhang Liucheng , Tai Huiwen , Zhang Jinwei , Liu Yudi
Published: April 2004

Polyvinyl chloride paste blending resins were prepared by a suspension polymerization process, and the optimum ingredients and technological conditions were studied experimentally. The effect of dispersant, surfactant, and agitator design on the particle morphology was discussed. In order to improve the thermal stability of the blending resin, stabilizer was added to the polymerization system, and a special after‐treatment was adopted. The effect of blending resins on the rheological and gelation characteristics of the plastisols formed and on mechanical properties, thermal stability, and foamability of the finished articles is demonstrated.
Analysis of the main parameters affecting the change of color and physical properties of weathered PVC profiles
Authors: Gervat L. , Morel P.
Published: April 2004

A review of good weatherability requirements for PVC profiles is presented. Analytical tools to assess these requirements are recalled and justified. Detailed analysis of the various parameters that may affect PVC weatherability show that except for a few additives, the key point is the level of thermal degradation undergone by PVC during its processing.
The technology of halogen‐free flame retardant phosphorus additives for polymeric systems
Authors: Davis John , Huggard Mark
Published: April 2004

Halogen‐free flame retardant additives based on phosphorus function by developing a protective char. A variety of additives are available, ranging from the element itself, in the form of amorphous red phosphorus, to specialty organophosphorus compounds, and examples of their use in a range of thermoplastics are given. Intumescent formulations based on phosphates are especially designed for polyolefins. The behavior of a typical intumescent system is described with respect to flame retardant performance, thermal stability, water sensitivity, and filler compatibility.
Lubricated, high heat polycarbonate
Authors: Harding Jeff A.
Published: April 2004

A polycarbonate resin based on a copolymer of bisphenol‐A and bisphenol‐trimethyl‐cyclohexanone was modified with a dispersion of PTFE powder and compared to a standard PTFE lubricated, general purpose BPA‐polycarbonate, PTFE is used to lower friction and wear rates in thermoplastics. Mechanicals, thermal properties, limiting PV behavior, and wear rate were measured and compared.
Finding the information that you need
Authors: Coleman Ernest A.
Published: April 2004

Technical libraries have been and continue to be the place where the most information about plastics and polymer additives is to be found. Information specialists who work with these libraries are generally the best informed in the broad areas of information and data acquisition and retrieval. Technical libraries with their access to electronic databases (some in disc form and some over the various networks) are essential sources of technical information. In libraries and on data‐bases, technical journals along with patents are valuable for at least three reasons: (a) cutting edge technology is often presented first in these formats, (b) reading reviewed journals and patents will provide unexpected insight into other technology that may be currently important to you or your company, and (c) peer‐reviewed journals and patents are the basis of all the modern databases. Independent information experts can help greatly in suggesting which database to use and in cost effective retrieval of that information and data. In addition, several low cost and quite valuable data sources such as your professional colleagues, professional society publications, technical salespersons, trade magazines and newspapers, and information hot lines are all available at low cost to members of the Society of Plastics Engineers and others at the same or slightly higher prices.
Comparison of glass transition measurements between carrimed rheometer and differential scanning calorimetry using methylacrylate‐vinylidene chloride copolymer
Authors: Rakesh L. , Howell B. , Rajaram C. V.
Published: April 2004

The potential of the Carrimed CSL 500 rheometer for the thermal analysis of methylacrylate‐vinylidene chloride (MA‐VDC) random copolymer was evaluated by comparing the glass transition temperature (Tg) of the copolymers with the value obtained from the differential scanning calorimeter. The major relaxation phenomenon in amorphous polymers, namely the glass transition temperature, could be identified clearly using the Carrimed rheometer. Samples of varius contents of methylacrylate in methylacrylate‐vinylidene chloride copolymer were prepared as solvent cast films. Small amplitude oscillatory measurements showed as a function of temperature, that methylacrylate‐vinylidene chloride copolymer between 12% and 70% methylacrylate (MA) content showed glass transition temperatures between 48°C and 63°C. For the methylacrylate content ranging from 4% to 70%, the saran copolymers had glass transition temperatures between 12°C and 56°C. Both techniques showed the Tg of the methylacrylate‐vinylidene chloride copolymer first increased and then decreased with increasing methylacrylate content. Both methods show a peak in the Tg vs. percent methylacrylate content of the copolymer at around 50% methylacrylate content. Small angle amplitude measurements also showed that it is very sensitive to the frequency. The Tg obtained using the Carrimed CSL 500 rheometer is very reproducible and is comparable with that obtained using the standard DSC.
Extrusion‐rotomolding of plasticized PVC formulations
Authors: Mendizábal Eduardo , Candia Juan M. , Jasso Carlos F. , Cruz Luis
Published: April 2004

In this work, we present a novel process to produce plasticized PVC articles. Plasticized PVC dispersion resin (dry blend) was extruded and poured into a hot mold. The mold was transferred to a rotomolding machine, where the final geometry was obtained. Formulations using commercial PVC suspension resin and three different types of plasticizers were prepared under different processing conditions. The physical appearance of the articles and the tensile properties of the materials were evaluated.
EP(D)M structural and thermal property effects in polypropylene compounds
Authors: Brignac Stephen D.
Published: April 2004

EPDM rubber is an important ingredient in thermoplastic polyolefin elastomers (TPOs). Such key properties as impact strength, flexibility, and flow are significantly affected by EPDM polymer properties. In this work, a set of EPM and EPDM polymer is used to produce via melt processing a series of TPOs, consisting of simple binary blends of rubber and polypropylene of varying composition. Various structural and thermal properties of the EPDM are correlated with the TPO compound properties. Significant property relationships are explored.
Process emissions for vinyl pipe industry
Authors: Ernes D. A. , Griffin J. P.
Published: April 2004

The vinyl pipe industry consumed approximately 1.9 million metric tons of polyvinyl chloride (PVC) in 1994. This resulted in 2.1 million metric tons of extruded pipe in the same time interval. If one uses an emission factor contained in the 1978 USEPA contractors report, this industry would result in 117,000 metric tons of emissions. This factor was acknowledged to be too high, however; no data was available to indicate a more realistic factor. The current work involves a study commissioned by the Vinyl Institute and UNI‐BELL to establish a more realistic factor using accepted EPA protocols as well as newly developed laboratory techniques. The results of this work has yielded an emission factor that is 1000 times lower than that appearing in the 1978 report. Laboratory procedures have also been shown to accurately reflect the results obtained from the plant monitoring study.
The performance of ultrafine talc in rigid PVC
Authors: Wiebking Henry E.
Published: April 2004

This paper demonstrates how ultrafine talc can be used in a rigid PVC formulation to design a compound with increased stiffness and high impact strength. The talc's shape and particle size, combined with the affects of increased levels of impact modifier, produce a PVC material with an outstanding impact stiffness balance. Although more expensive than conventional PVC formulations, it can compete with other resins, such as ABS, in high performance applications.
Poly(vinyl chloride) in medical device and packaging applications
Authors: Hong K. Z.
Published: April 2004

Poly(vinyl chloride) (PVC) is the leading polymeric material used in medical device and packaging applications in terms of total volume consumed. It offers a uniquely broad range of properties for a wide variety of applications in the medical and health care industry. It fulfills an extensive range of performance and processing requirements such as gloss, transparency, chemical resistance, scuff resistance, flexibility, bondability, sterilizability by steam, ETO, or high energy irradiation. This paper examines fundamental chemsitry and physical structure of PVC to provide a clear insight and a better understanding on how versatile properties and performance are rendered. The paper also illustrates how specific mechanical and thermal properties can be tailored via compounding and fabrication processes to serve specific purposes in medical applications.
Ambient mechanical properties of impact‐modified polyvinyl chloride and methyl methacrylate copolymer blends
Authors: Burke Dennis Mechael
Published: April 2004

The objectives of this study were to determine the compatibility of various blends of commercially available rigid, unplasticized, impact‐modified polyvinyl chloride (UPVC) and methyl methacrylate (MMA) copolymers. The effects of acrylic type and loading level on compatibility were investigated. The resultant alloys or blends were subsequently evaluated for compatibility through examination of the following properties: processability, rigidity, strength, impact resistance, heat resistance, clarity, and ultra‐violet aging. This report limits itself to the discussion of the ambient mechanical properties of rigidity, strength, and impact behavior.
Processability and optical properties of impact‐modified polyvinyl chloride and methyl methacrylate copolymer blends
Authors: Burke Dennis Michael
Published: April 2004

The objectives of this study were to determine the compatibility of various blends of commercially available rigid, unplasticized polyvinyl chloride (UPVC) and methyl methacrylate (MMA) copolymers. The effects of acrylic type and loading level on compatibility were investigated. The resultant alloys or blends were subsequently evaluated for compatibility through examination of the following properties: processability, rigidity, strength, impact resistance, heat resistance, clarity, and ultraviolet aging. This report limits itself to the discussion of processability and the optical properties of clarity and UV color stability.