bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gloss control in rigid PVC—Part I. Techniques for gloss assessment of rigid PVC profiles
Authors: Rabinovitch Elvira , Harshbarger Deanna , Isner James 
Published: April 2004

AbstractThis paper describes various techniques for assessing the gloss of PVC extrudates. It discusses the effect of the incident light angle on measured gloss values and the test sensitivity. It also describes the relationship between surface gloss and extrudate roughness, as analyzed by scanning electron microscopy and optical microscopy. Finally, this paper provides recommendations on the most suitable methods for assessing the gloss of PVC extrudates.
Molecular weight distribution of PVC blends from resins with different K values
Authors: Pepperl G. 
Published: April 2004

AbstractThe molecular weight distribution (MWD) of blends of commercial suspension grade PVC resins with different molecular weights (MW) or K values is calculated. If the K‐value difference is not too high, the polydispersity of the blend is only slightly increased as compared to those of the components. It is not possible to get bimodal MWDs by blending. Additionally, a model calculation of mean molecular weights has been performed for temperature‐programmed polymerization. On the basis of the most realistic model, which takes into account the increasing polymerization reaction rate with increasing temperature and increasing conversion, it can be predicted that a linear temperature program will give a product corresponding to an isothermal resin polymerized at a temperature near the high end of the temperature program and showing only a slightly increased polydispersity.
High‐molecular‐weight flexibilizers in low‐smoke flame‐retardant PVC compounds
Authors: Griffin E. R. 
Published: April 2004

AbstractEthylene copolymer resin (ECR) modifiers play an important role in low‐smoke PVC. As high‐molecular‐weight flexibilizers, these resins reduce smoke and add strength and low temperature flexibility. This combination allows compounders to increase the amounts of flame‐retardant additives without compromising strength or flexibility or by adding liquids which increase smoke. This paper demonstrates these attributes versus liquid plasticizers used in PVC compounds.
Influence of various molding conditions on the uni‐, bi‐, and triaxial impact properties of poly(vinyl chloride) (PVC)
Authors: Elleithy Rabeh H. , Abu‐Ali Amjad , Harrell E. Ray , Summers James W. 
Published: April 2004

AbstractThis study discusses the influence of molecular weight, melt temperature, mold temperature, and aging on the impact characteristics of molded PVC. Tensile impact (uniaxial), instrumented drop‐dart impact (biaxial), and Izod impact (triaxial) methods were utilized to assess the impact properties of the material under investigation. It was found that the impact properties were affected by aging more than by the changes in the melt temperature or the mold temperature. Additionally, the molecular weight played a significant role in influencing the impact properties of PVC.
Effect of combining boron nitride with fluoroelastomer on the melt fracture of HDPE in extrusion blow molding
Authors: Yip Franky , Diraddo Robert , Hatzikiriakos Savvas G. 
Published: April 2004

AbstractBoron nitride (BN) is a new polymer processing aid which not only eliminates surface melt fracture in the extrusion of molten polymers, but also postpones the critical shear rate for the onset of gross melt fracture to significantly higher values that depend on resin type and additive concentration. In this work, the influence of BN as a polymer processing additive is first examined in the extrusion blow molding of high‐density polyethylene (HDPE) resins in order to evaluate its usefulness and performance in operations other than continuous extrusion. The equipment used includes both a Battenfeld/Fisher 50‐mm extrusion blow molding machine and a parallel‐plate rheometer. Two types of HDPE, which are blended with boron nitride at various concentration levels, are tested accordingly. It is found that the degree of BN dispersion, characteristics of the HDPE resins, extrusion temperature, and induction time play an important role in eliminating melt fracture. Finally, the influence of combining BN with fluoroelastomer, as an enhanced and potentially better processing aid on the melt fracture of a third HDPE is examined. It is found that such a combination is a superior processing aid that allows extrusion blow molding at very high shear rates.
Cross‐Linking of polystyrene by friedel‐crafts chemistry: Multifunctional additives
Authors: Yao Hongyang , Zhu Jin , McKinney Michael A. , Wilkie Charles A. 
Published: April 2004

AbstractVarious multifunctional aromatic compounds were synthesized and tested to ascertain if they were able to cross‐link polystyrene. Catalysis and inhibition at high temperature were studied to achieve control over the cross‐linking temperature, in order to develop suitable formulations which may function as flame retardants.
Thermoset/(Thermoplastic elastomer) blends: Epoxy/EVA
Authors: Siddhamalli Sridhar K. 
Published: April 2004

AbstractPhase separation behavior and phase morphology of mixtures of methylene dianiline (MDA)‐cured diglycidyl ether of Bisphenol A (DGEBA) epoxy oligomer and 0–30 wt % of ethylene‐(vinyl acetate) copolymer (70% vinyl acetate content) were investigated by means of small angle light scattering (SALS), optical microscopy, and scanning electron microscopy (SEM). Epoxies with EVA modified were also characterized by tensile, flexural, thermal, and hardness properties. Epoxy/EVA blend compositions, during isothermal curing, showed a ring pattern of light scattering, an increase of intensity, and a shift of peak angle to smaller scattering angle, all of which are hallmarks of spinodal decomposition. Optical microscopy studies revealed a two‐phase structure with unique periodicity and phase connectivity. Physical property measurements indicated that there was no toughening achieved by EVA modification of epoxy, and this result was explained with morphological information obtained by SEM.
Effect of curprous oxide in combination with molybdenum trioxide on smoke suppression in rigid poly(vinyl chloride)
Authors: Li Bin , Wang Jianqi 
Published: April 2004

AbstractFurther investigation of the synergistic effect of smoke suppression between cuprous oxide and molybdenum trioxide in rigid poly(vinyl chloride) (PVC) was carried out by using a cone calorimeter (cone) at a high incident heat flux of 50 kW m−2. Experimental data derived from the cone calorimeter indicated that binary mixtures of Cu2O and MoO3 clearly showed the synergistic effect in reducing smoke by decreasing total smoke production (TSP), average specific extinction area (av‐SEA), and smoke production rate (SPR). This result is in good agreement with that obtained from the NBS smoke chamber. However, the combustion process of rigid PVC could clearly be seen from the heat release rate (HRR), curve, SPR, and fire degradation obtained from the cone test, which could not be determined from the NBS smoke chamber. It was also found that the binary mixture showed the synergistic effect by increasing was also found that the binary mixture showed the synergistic effect by increasing char residue and reducing the fire degradation of the PVC backbone at a high incident heat flux of 50 kW.m−2. All experimental data well supported the early cross‐linking mechanism of the PVC backbone mentioned in the literature and were consistent with the fire degradation behavior obtained from the cone calorimeter.
Effect of various acid neutralizers on the crystallization temperature of nucleated polypropylene
Authors: Dieckmann Dale 
Published: April 2004

AbstractPolypropylene is often nucleated with sodium benzoate in order to raise its crystallization temperature (TOC). Conventional wisdom holds that calcium stearate is detrimental to TOC elevation because it chemically interacts with the sodium benzoate. This paper examines the effect of calcium stearate, sodium stearate, calcium lactate, and other substances on the TOC of nucleated polypropylene. We have found a definite effect on TOC elevation that correlates with neutralizer type. However, we find little evidence of chemistry occurring directly between neutralizer and nucleator.
Printing on vinyl—part II. FTIR and TOF‐SIMS studies
Authors: Burley Joseph W. 
Published: April 2004

AbstractEarlier surface analysis studies have suggested that, at least in some situations, the print adhesion properties of barium/zinc stabilized, stearic acid‐lubricated PVC are influenced by the migration (exudation) of a barium/zinc stearate complex. This paper expands the previous study in attempts to reproduce the effects observed on samples of commercially produced films, explain the origin of the migrating specie, and identify the variables that influence the extent to which the phenomenon occurs. The effects of different lubricants, stabilizers, and processing conditions are studied. Mechanistic work suggests that a revised hypothesis is appropriate and that the hydrolyzed complex is actually formed in the PVC matrix and not at the surface.
New opportunities with wood‐flour‐foamed PVC
Authors: Patterson John 
Published: April 2004

AbstractComposites of wood with polyethylene, polypropylene, and poly(vinyl chloride) represent an emerging class of materials that combine the favorable performance and cost attributes of both wood and thermoplastics. One of the major disadvantages, however, of these materials is a relatively high specific gravity compared with those of many natural wood products. A PVC‐wood composite, for example, has a specific gravity of about 1.3 g/cc. This paper looks at producing cellular PVC‐based wood composites and the properties that are achieved as the foam density is reduced. Overall, even with densities as low as 0.6 g/cc, the physical properties should be adequate for many wood replacement applications. The composites also offer the aesthetics of wood and economics that are favorable compared to those of both rigid and cellular PVC.
Study of PVC degradation using a fast computer scanning procedure
Authors: Bacaloglu Radu , Stewen Ulrich 
Published: April 2004

AbstractA computer scanning procedure for the determination of total double‐bond concentration resulting from PVC degradation is described. It is fast, fully automated, and has a very high sensitivity (5 ppm of degraded monomer units). This high sensitivity makes possible the monitoring of discoloration on a very small surface and generates very large amounts of experimental data allowing corrections for inhomogeneities and surface irregularities. The measured extinctions (Ergb) correlate with the concentrations of double bonds and allow the estimation of degradation rates. The measuring of stabilization times and the reaction rates of stabilizers with allylic chlorides and HCI offers the capability to optimize the PVC stabilization.
Computational simulation of poly(vinyl chloride) reduction with tri‐n‐butyltin hydride. The use of revised rate constants
Authors: Knudson S. K. , Starnes W. H. 
Published: April 2004

AbstractThe computer simulation of the reductive dechlorination of poly(vinyl chloride) (PVC) with Bu3SnH is reexamined by using a new set of rate constants that has been corrected (a) statistically for the presence of different numbers of chloro substituents and (b) for a triad reactivity factor used to determine the constants for rr‐and mm‐VVV triads from that for mr‐VVV triads. The simulation method is verified by comparison with analytic kinetic results for the reduction of 2,4‐dichloropentane and 2,4,6‐trichloroheptane model compounds. The revised rate constants should and do lead to a smaller ratio of racemic to meso diads in PVC as reaction nears completion, compared to the ratio obtained from the original set of rate constants that had been proposed by previous workers. Experimental data are not sufficiently accurate to distinguish between the two sets of simulation results.
Identification, quantitation, and qualification of PVC multifunctional systems with near‐infrared spectroscopy and chemometrics
Authors: Garcia Dana , Borden Farrel , Bouveresse Eric 
Published: April 2004

AbstractMultifunctional systems (MFS) comprising impact modifiers, processing aids, lubricants, stablizers, and fillers are utilized throughout the PVC industry to impart greater consistency, obtain faster and easier blending cycles, reduce inventory, and minimize cross‐contamination. Qualitative and quantitative product analysis, to ensure adherence to performance specifications, is an integral part of any quality control function. Near‐Infrared (NIR) spectroscopy coupled with chemometrics techniques enables one to distinguish clearly among different MFS formulations (product identification) and to detect changes in product composition for each formulation (product qualification). Additionally, models can be developed to provide a completed compositional analysis.
Photostabilization of poly(vinyl chloride) by protective coatings
Authors: Decker Christian 
Published: April 2004

AbstractThe light stability of poly(vinyl chloride) plates has been substantially increased by protecting their surface with a UV‐cured acrylic clearcoat containing both a UV absorber and a HALS radical scavenger. To ensure a long‐lasting adhesion, the coating was photochemically grafted onto the PVC substrate. The coated PVC sample remained transparent, non‐colored, and glossy upon accelerated QUV‐B weathering for up to 3000 hours. An additional advantage of this method of photostabilization is to improve some of the surface properties of the coated polymer, such as its resistance to solvents, abrasion, and scratching. The method was also successfully used to recover highly photodegraded PVC and make it even more weathering‐resistant than the original polymer.
Gamma‐radiation‐induced graft copolymerization of N‐[4‐(N′‐substituted amino carbonyl)phenyl] maleimide onto poly(vinlyl chloride) films
Authors: Abdel‐Naby Abir S. 
Published: April 2004

AbstractThree types of N[4‐(N‐substituted amino carbonyl)phenyl] maleimide (RPhMI:N‐substituent (R) = phenyl, cyclohexyl, p‐chlorophenyl) were grafted onto poly(vinyl chloride) (PVC) films by using gamma irradiation. The effects of different parameters on the graft yield were investigated. These parameters included radiation dose and monomer concentration. Thermal properties of the grafted polymer were investigated by the determination of dehydrochlorination rate, thermal gravimetric behavior, and UV stability.
Thermal stabilization of PVC by “plasticizer thiols”
Authors: Starnes W. H. , Du B. , Zaikov V. G. 
Published: April 2004

AbstractVarious new carboxylate esters containing one or more sulfhydryl groups are shown to be remarkably effective as both thermal stabilizers and plasticizers for poly(vinyl chloride) (PVC). These “plasticizer thiols” function well as primary stabilizers in the absence of metal‐containing additives when they are introduced at either a typical plasticizer level or a conventional stabilizer level. Their syntheses are straightforward and, in some cases, require only an acid‐catalyzed esterification performed with commercially available starting materials. Unlike typical thiols, the purified plasticizer thiols do not have offensive odors when their molecular weights are relatively high.
Zinc stannate–coated fillers: Novel flame retardants and smoke suppressants for polymeric materials
Authors: Cusack P. A. , Hornsby P. R. 
Published: April 2004

AbstractNovel zinc hydroxystannate‐ or zinc stannate‐coated hydrated fillers are shown to be highly effective flame‐retardant and smoke‐suppressant additives for chlorinated polymers. The performance of these systems is discussed, with reference to PVC, polychloroprene, halogenated polyester resin and polypropylene formulations. Relative to unmodified magnesium hydroxide and alumina trihydrate, coated variants of these fillers can achieve similar fire‐retardant properties at significantly lower additive levels.
Study of the processability of commercial PVC plastisols by rheology
Authors: García‐Quesada J. C. , Marcilla A. , Beltrán M. 
Published: April 2004

AbstractA qualitative model that satisfactorily explains the rheological behavior of PVC plastisols during gelation and fusion is shown. Several industrial production cases have been analyzed, and the rheological characterization of the corresponding plastisols during gelation and fusion processes has proved to be a valuable technique to improve the knowledge and understanding of the industrial rotomolding process.
Mechanism of organotin stabilization of poly(vinyl chloride). 1: The structure and equilibria of alkyltin thioqlycolates and their compatibility with PVC
Authors: Fisch Michael H. , Bacaloglu Radu , Biesiada Keith , Brecker Lawrence R. 
Published: April 2004

AbstractA series of alkyltin thioglycolates was synthesized and their structure and equilibria with alkyltin chlorides studied by infrared analysis. Dynamic mechanical analysis was used to determine their compatibility with PVC. The implications of these results on PVC stabilization were discussed
Effects of formulation variables on rheology of rigid PVC
Authors: Hayes Virginia Odle 
Published: April 2004

AbstractThe effects of lubricants, impact modifier, and process aid on the processing and physical properties of a rigid PVC compound have been modeled using a central composite designed experiment. Capillary rheology was used to evaluate the flow properties of the various formulations in the study. By modeling the rheological properties it is possible to optimize simultaneously the flow, extruder conditions, and final part properties.
Phenomenon of color change in colored poly(vinyl chloride) compound
Authors: Kann Yelena 
Published: April 2004

AbstractThis paper addresses a phenomenon of color shift found during the development of a colored poly(vinyl chloride) (PVC) compound for exterior automotive application containing, among other pigments, red anthraquinone (C.I. Pigment Red 177) and titanium dioxide (TiO2). Color was found to shift about 2 points delta b* on a CIELAB scale from yellow to blue during the first one month and a half since the compound had been processed. The shift took place at the regular conditions: room temperature with no exposure to sunlight or heat.
Performance of Di‐n‐Hexyl phthalate in flexible vinyl formulations
Authors: Kozlowski Richard R. , Gallagher Thomas K. 
Published: April 2004

AbstractLow‐molecular‐weight esters have been available to the PVC compounder for many years. They have found a significant niche in the performance vs. permanence compromise as a compound ingredient that provides manufacturing efficiency or some special property with adequate permanence for many vinyl applications. In many respects, low‐molecular‐weight esters are the processing aids of the plasticizer family. This group of plasticizers may be said to include C4 to C7 dialkyl phthalates, the benzyl phthalates and the benzoic acid esters. This paper will introduce and compare di‐n‐hexyl phthalate (DNHP) to other phthalates against which it will directly compete.
Prediction of plasticizer solvency using hansen solubility parameters
Authors: Krauskopf Leonard G. 
Published: April 2004

AbstractThe solvating strength of a plasticizer for poly(vinyl chloride) resin is a measure of the interactive forces between these two materials. Hansen's three‐dimensional solubility parameters provide a quantitative measure of these interactive forces. By using CO‐ACTSM service, a computer program designed for solvent systems with various resins, plasticizers were found to lie near the edge of the solvency “sphere” of PVC. The relative positions of various plasticizer structures are in the expected order, while known solvents show strong association and lubricating additives fall outside the solvency sphere of PVC.
Initial mechanisms of dispersion of core‐shell impact modifiers in a polymer matrix
Authors: Scott Chris E. , Rockford Lee D. 
Published: April 2004

AbstractCore‐shell impact modifiers are effective toughening agents for many thermoplastics. In order to achieve optimum performance, agglomerates of these particles must be dispersed and the individual submicron particles well distributed within the polymer matrix. The focus of this paper is a description of the initial mechanisms of dispersion during compounding of core‐shell impact modifiers into polymer matrices. Model experiments were conducted with acrylic‐based modifiers in a poly(methyl methacrylate) matrix by using a batch intensive mixer. Based on the observed morphologies at numerous mixing times, a qualitative description of the mechanism is developed. Significant structural changes occur in all three of the classical processing regimes: solids conveying, melting, and melt flow. Differences in the form of modifier addition, pellet or powder, are explored. The degree of fill of the mixer is found to have a critical effect on the dispersion mechanism.
The effect of lubricants on processing—part I. detection by PVC melt flow
Authors: Riley David W. 
Published: April 2004

AbstractFor decades it has been recognized that one can detect molecular structural changes in the processing of PVC by using ASTM D 3364 [PVC Melt Flow Test]. In the course of this work, we also realized that this Melt Flow Test could detect small changes in the ingredients as well. Through a special design of experiment, the effect of three lubricants on extrusion of dry blends of PVC (with and without calcium stearate) has now been investigated. The effects of extrusion on extruded pellets have also been studied as part of this design. To detect the changes in lubricity, the techniques of ASTM D 3364 have been modified to include new higher pressures on the ram as well as other revisions. This report shows how the various lubricants at differing concentrations and types can alter the PVC Melt Flow Test results and imply differences in processing.
Recent developments: Benzoate esters in polyvinyl resilient flooring
Authors: Bohnert T. , Izadi R. , Pitman S. , Stanhope B. 
Published: April 2004

AbstractBenzoate plasticizers provide excellent foam quality, stain resistance, and UV light stability. They are used as primary plasticizers in resilient flooring applications but are limited in use because of viscosity. New benzoate‐based blends have been developed that result in reduced‐viscosity plastisols and lower VOC emissions than for existing benzoate products. A variety of European and North American formulations have been used to evaluate the processing and performance properties of these benzoate‐based blends and are highlighted in this paper.
Effect of iron compounds (oxide, salt, or complexes) on poly(vinyl chloride) thermal and photochemical stability
Authors: Girois Stephane 
Published: April 2004

AbstractThe color requirements for vinyl siding have drastically evolved over the last decade and have moved toward medium to dark colors. Therefore, manufacturers are exploring new ways to modify their formulations in order to improve weather‐ability of these challenging colors. Examination of some of the PVC additives typically used in these formulations has led to some interesting revelations about the performance of iron‐containing pigments, which are extensively used in darker colors. A quick weathering test was designed to evaluate the effect of iron in PVC formulations, and this test clearly demonstrates the correlation between iron content and PVC photodegradation.
Chemical coupling of polypropylene systems containing nonglass fillers
Authors: Roberts Darilyn H. 
Published: April 2004

AbstractMaleic anhydride (MAH) modified polypropylene (PP) was demonstrated to be a chemical coupling agent in filled PP compounds. Improved properties were shown for talc and wollastonite filled PP compounds with MAH modified PP as a coupling agent. Partial replacement of glass fiber with wollastonite showed no reduction in properties.