bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of cobalt promoter and glass fibers on the curing behavior of unsaturated polyester resin
Authors: Yousefi A. , Lafleur P. G. , Gauvin R. 
Published: April 2004

AbstractIn this study, a phenomenological autocatalytic kinetic model is used to describe the cure of a polyester system containing a cobalt‐based promoter. The effect of including the promoter in the cure system is discussed regarding the changes in the kinetic parameters. It was found that the cure characteristics of the unsaturated polyester system were affected by the presence of the promoter. This effect resulted in a temperature dependency of the reaction exponents as well as in a significant increase of the Arrhenius frequency factor at low temperatures. The changes in cure characteristics of promoted polyester system caused by incorporation of chopped glass fibers were also investigated. The results indicate that unlike the promoter, the presence of glass fibers does not appreciably affect the reaction exponents. However, the presence of glass fibers results in some changes in the overall reaction rate of the cure system. To take into account the unrecorded extent of reaction at high cure temperatures, a new procedure was implemented. This procedure estimates a correction factor related to the total isothermal heat of cure obtained from DSC experiments at different isothermal cure temperatures.
Developments in weatherable copolyester sheeting
Authors: Fagerburg D. R. , Donelson M. E. 
Published: April 2004

AbstractUntil recently, polyesters and copolyesters were not able to be seriously considered for use in an outdoor environment owing to rapid coloration upon exposure coupled with rapid loss of impact properties. Recent work at Eastman has resulted in a coextrusion technology with a high level of UV absorber that has now circumvented both of these problems. A caution on the use of accelerated device exposures will be discussed. Outdoor exposures in Florida, Arizona, and other locations will be presented and compared to the accelerated device exposures and each other. Some of the potential uses of this new technology will also be discussed.
Fourier transform infrared micro spectroscopy mapping. Applications to the vinyl siding industry
Authors: Garcia Dana , Black Janine 
Published: April 2004

AbstractFourier transform infrared (FT‐IR) micro spectroscopy is a powerful analytical technique capable of yielding high quality information with a spatial resolution as low as 10 microns. When coupled with an automated mapping stage it can offer unique evaluation capabilities. This paper describes a number of applications of FT‐IR micro spectroscopy mapping to the vinyl siding industry. Examples will focus on determining, in single sample mapping experiments, the compositional changes associated with capstock to substrate transition and evaluating the degradation species and level observed during weathering exposure throughout the thickness of the siding panel.
Functional copolymers of dibromostyrene as flame retardants for thermoplastic polyamides and polyesters
Authors: Fielding William R. , Elliott Jennifer L. 
Published: April 2004

AbstractAs resin requirements and environmental concerns have increased, the development of polymeric flame retardants has occurred. Brominated polystyrenes are widely used as flame retardants for thermoplastic polyesters and polyamides. The incorporation of comonomers at low levels has improved the compatibility of polybromostyrenes with each of these resin systems as evidenced by scanning electron micrographs. The improvement in physical properties and the reductionin flammability of PBT and polyamides as a function of the comonomer type and concentration are explored in this paper.
Evaluation of process aids for controlling surface roughness of extruded LLDPE
Authors: Hauenstein Dale E. , Cimbalik David J. , Pape Peter G. 
Published: April 2004

AbstractA method utilizing a single‐screw extrusion tape line, where each sample of tape was analyzed off‐line with a surface roughness tester, was used to screen the effectiveness of process aids in controlling the surface roughness characteristics of extruded LLDPE. The effectiveness of commercial process aids and new silicone process aid candidates was evaluated and compared as a function of addition level, mode of addition, as well as extrusion rate. A new silicone process aid was discovered that shows a significant reduction in surface roughness of both ethylene‐octene and ethylene‐hexene LLDPE copolymers. Beneficial effects on extruder parameters, such as reduction of pressure and current, were also observed.
The effect of low levels of plasticizer on the rheological and mechanical properties of polyvinyl chloride/newsprint‐fiber composites
Authors: Matuana Laurent M. , Park Chul B. , Balatinecz John J. 
Published: April 2004

AbstractPlasticizers play a key role in the formulation of semirigid and flexible PVC and in determining their physical properties and processability. This study examines the effects of the low phr levels of plasticizer (DOP) on the rheological and mechanical properties of rigid and semi‐rigid PVC/newsprint‐fiber composites. Mechanical and rheological properties of unfilled PVC compounds and PVC/newsprint‐fiber composites at 45 phr were compared over the range of 0 to 15 phr of DOP plasticizer. Analyses of data using SAS procedures of ANOVA were also conducted to discern the effects of concentration of plasticizer on these properties. The following conclusions were reached: (1) DOP was relatively ineffective in improving melt flow index of the composites compared to unfilled PVC. (2) The composites were significantly inferior in tensile strength at yield and stiffer than unfilled PVC. The differences observed were roughly the same over the DOP range studied. (3) Elongation at break and toughness (break energy) were lower for the composites and were essentially independent of DOP level, whereas there was a significant improvement for unfilled PVC over the DOP range studied. (4) Impact strengths of the composites and unfilled PVC were essentially comparable up to about 11.25 phr of DOP. However, at 15 phr DOP, impact strength of the composite was far inferior to that of unfilled PVC. (5) The well‐known antiplasticization effect was noted for unfilled PVC, as well as to some extent for the filled PVC.
Accelerated test method for resistance of plastics to nitrogen dioxide
Authors: Brilliant Stuart Donald , Bacaloglu Ilze , Croce Michael 
Published: April 2004

AbstractThe discoloration produced by the exposure of plastics to a polluted atmosphere containing nitrogen oxides and other gases is well known. New formulations with increased resistance to such discoloration require reliable accelerated tests for characterization of additives and products. The new procedure is based on an exposure of plastics to an atmosphere with a controlled concentration of nitrogen dioxide and evaluation of subsequent discoloration by optical measurements.
The compression set of plasticized PVC
Authors: Rehm Torsten 
Published: April 2004

AbstractPlasticized PVC shows a surprising degree of elasticity. The reason is that during processing a gel structure is formed in which plasticizer‐stable PVC microcrystallites serve as nodes for the network. The formation of these microcrystallites and their effects on the flexibility of plasticized PVC are examined by means of differential scanning calorimetry (DSC) and measurement of compression set (C‐set). The C‐set of plasticized PVC below temperatures of roughly 130°C cannot be attributed to irreversible flow processes. It is explained by assuming the superimposition of a network formed during processing on a new network formed under deformation. This model allows a plausible description of the influence of temperature, time, plasticizer content, a quantitatively correct calculation of the C‐set of pre‐deformed specimens and an interpretation of annealing effects on the elastic behavior. It is shown that appropriate pre‐treatment can reduce the C‐set of plasticized PVC to below 50%, even for service temperatures of 70°C and above.
The influence of compositional variations in compounded thermoplastic olefins (TPOs) on the physical and mechanical attributes of injection molded plaques
Authors: Ryntz Rose A. 
Published: April 2004

AbstractCompounded TPO continues to make inroads into automotive applications because of the excellent price/performance balance reached in this thermoplastic substrate. Thermoplastic olefin (TPO), a blend of elastomer and poly(olefin), achieves its balance of properties through the choice of compounded ingredients. The injection molding conditions through which the desired plastic part is achieved are known to also influence the attained properties of the blend. In this paper, the influence of poly(olefin), namely poly(propylene) homopolymer, and elastomer utilized in the compounded blend, in conjunction with molding properties used to produce plaques, are studied as they relate to the physical and mechanical properties achieved. Paint adhesion and friction induced paint damage resistance of coated plaques are shown to be directly related to poly(propylene) molecular weight and elastomer crystallinity. Molding conditions, mainly influenced through the shear induced injection molding process, are also correlated.
Nontoxic replacement for Karl Fischer moisture analysis of plastics
Authors: Raisanen Walfred R. 
Published: April 2004

AbstractA newly developed automatic moisture analyzer for the plastic molding industry has a detection limit of 10 micrograms of water. Test results are available in three to six minutes. No reagents are used, and instrument setup and calibration takes less than ten minutes. Validation tests show moisture determination accuracy of better than 2% standard error, and precision (coefficient of variation) of 0.5 to 10%. The range of applicability is 10 ppm to 10% moisture.
Mode of action of surface active slip and antiblocking additives
Authors: Sharma Ashutosh H. , Beard Bruce C. 
Published: April 2004

AbstractThe surface concentration and structure of oleamide slip additive and stearamide antiblocking additive commonly used in polyolefins has been investigated by X‐ray photoelectron spectroscopy. The oleamide has been found to form a complete continuous thick layer on the surface of the polymer, whereas the stearamide results in an incomplete discontinuous layer of lesser thickness. Such surface structures are intuitively consistent with the observed action of these molecules in practice. Migration rates of the two long chain amides were found to differ, with the oleamide appearing at the surface at a rate about three time greater than the stearamide. Time dependent surface oxidation of the oleamide additive was observed. It is speculated that the unsaturation within the oleamide molecule is the site of oxidation.
Mechanical properties and dispersion behavior of composite materials compounded with surface treated titanium dioxides
Authors: Hamamoto A. , Tanaka T. , Kinoshita M. 
Published: April 2004

AbstractThe mechanical properties of polycarbonate compounded with titanium dioxide are investigated. Titanium dioxide treated with methyl polysiloxane on alumina silica coating is compounded into the polymer by using a twin screw extruder. Izod impact strength of this composite material is higher than that of the composite material compounded with untreated titanium dioxide. The dispersibility of this treated filler is evaluated by fracture surface and turbidity of the solution of the composite materials. The results suggest that the composite material compounded with titanium dioxide treated with methyl polysiloxane and alumina silica has higher dispersibility. Also, the melt viscosity of the composite material shows the same behavior as that of neat polycarbonate. This result suggests that the melt viscosity is affected by the dispersibility of the particles.
Production of electrically conducting plastic composites by three‐dimensional chaotic mixing of melts and powder additives
Authors: Danescu R. I. , Zumbrunnen D. A. 
Published: April 2004

AbstractExtended micron‐scale structures were produced in thermoplastic melts from initially large clusters of conducting carbon black particles transported by three‐dimensional chaotic mixing. The structures formed extensive networks that were captured by solidification and rendered the materials electrically conducting. In essence, percolating structures were constructed in situ in lieu of being the result of chance associations among particles. A systematic study was carried out to assess the influence of key parameters and to relate the electrical properties to the microstructures. Micrographs showed complex structures exhibiting patterns characteristic of chaotic advection. Electrical measurements indicated that conductivity was achieved at carbon black concentrations significantly lower than those achievable by common mixing methods and lower than those reported recently for two‐dimensional chaotic mixing.
Aging modifiers for extruded LDPE foam
Authors: Dieckmann Dale , Holtz Ben 
Published: April 2004

AbstractAging modifiers help to regulate the isobutane/air interchange in LDPE foams. In the absence of sufficient modifier, the foam will shrivel and collapse. Several glycerol esters are evaluated at four use‐levels for dimensional stability of the foam, antistatic properties, and additive “rub‐off.” Stearamide is compared at one‐use level. Only the glycerides provided antistatic protection, and a distilled monoglyceride made from fully hydrogenated tallow had the best overall performance.
Challenge to fortyfold expansion of biodegradable polyester foams by using carbon dioxide as a blowing agent
Authors: Park Chul B. , Liu Yuejian , Naguib Hani E. 
Published: April 2004

AbstractThis paper presents a new foaming technology using supercritical carbon dioxide as a blowing agent to obtain large volume expansions of biodegradable polyester foams of over fortyfold. The basic approach for the promotion of a large volume expansion ratio with carbon dioxide was to prevent cell coalescence by using a branched material, to dissolve carbon dioxide completely in the melt by promoting convective diffusion under a high processing pressure, to reduce the diffusivity of gas by lowering the melt temperature, and to optimize the processing conditions in the die to maximize volume expansion. The desirable composition of the materials includes dehydrated branched biodegradable polyester (polybutylene succinate), CO2(blowing agent), and tale (nucleating agent). A single‐screw extrusion system was used for foam processing. A large volume expansion ratio of up to forty‐fivefold was achieved from the biodegradable polyester foams. The morphologies and volume expansion ratios of biodegradable polyester foams at various processing temperatures and pressures were studied.
New light stabilizer for coextruded polycarbonate sheet
Authors: Botkin James H. , Schmitter Andre 
Published: April 2004

AbstractWeatherable polycarbonate sheet can be produced by coextruding a cap layer containing a UV absorber over a minimally stabilized bulk layer. A new UV absorber based on hydroxyphenyltriazine chemistry has been developed that is especially suited to this application. The product provides superior long term weatherability because of its strong UV absorbance and its excellent photostability. It is also relatively nonvolatile and has only a minimal effect on melt viscosity.
TiO2 pigment structure and kinetics of PVC weathering
Authors: Gesenhues Ulrich , Hocken Jörg 
Published: April 2004

AbstractThe influences of doping the core of TiO2 pigments with Al2O3 and of various inorganic surface modifications on the rate of poly(vinyl chloride) (PVC) weathering are investigated. The kinetics of loss of gloss are transformed into photooxidation rates by using Weibull statistics of failure, and a scheme of two consecutive reactions is fitted to the intermediate losses of brightness observed for the most photoactive pigments. When Ca/Zn stabilizers in PVC are exchanged for Pb stabilizers, gloss degradation rate doubles, and the energetic spread of irradiation defects broadens. No indications for specific interactions between pigment and stabilizer are found.
Increasing PVC suspension polymerization productivity by using temperature‐programmed reactions
Authors: Longeway George D. , Witenhafer Donald E. 
Published: April 2004

AbstractVinyl chloride polymerizations are known to be autoaccelerating. The reaction rate increases with conversion. Because of this phenomenon, substantial reactor productivity at early conversion can be lost because the heat‐removal capacity of the reactor is not fully utilized until near the end of the polymerization. For this reason it is desirable to speed up the polymerization at the beginning and slow it down near the end. This rate adjustment can be achieved by running the polymerization hotter in the beginning and then cooling. We have written a scientifically based computer model of the polymerization designed specifically to simulate such temperature‐programmed reactions. The model does a complete heat balance on the polymerization, has a molecular weight predictor, and will be described and demonstrated for a polymerization at 50°C using sec‐butyl peroxydicarbonate (SBP) as initiator. By using this single initiator and a very simple straight‐line temperature‐programmed reaction, the time to 80% conversion can be reduced from 335 minutes to 240 minutes. This is a substantial increase in productivity.
Improved organotin stabilizers: Continuing health and environmental research
Authors: Murphy Sandra R. , Bertelo C. , Ringwood R. , Cochran M. 
Published: April 2004

AbstractYears of experience and significant research support the use of organotin mercaptides as PVC stabilizers. Safe use of organotin stabilizers involves following Material Safety Data sheet instructions and using adequate engineering controls and/or personal protective equipment. Modifications of stabilizers to develop more efficient formulations continue, Product stewardship includes continued development of data to improve our understanding of the effects of materials. An overview of stabilizer trends in the industry, existing data, and planned health/environmental research is presented.
A new processing aid for the extrusion of polyolefins
Authors: Yip Franky , Hatzikiriakos Savvas G. , Clere Thomas M. 
Published: April 2004

AbstractThe influence of a new processing additive (a composition of fine particles of boron nitride) on the rheology and processability of molten polymers is studied. The equipment used includes both an Instron capillary rheometer with special annular dies (Nokia Maillefer wire coating crosshead) attached to the rheometer and a parallelplate rheometer. Two metallocene polyethylenes with several types of boron nitride powders varying in particle size distribution are tested at various concentration levels. The powder having the finest particle size was found to have the greatest influence in the processing of polyolefins using crosshead dies and tips. As a result, its use eliminates surface melt fracture and postpones the critical shear rate for the onset of gross melt fracture to significantly higher values depending on the additive concentration. The performance of the boron nitride in eliminating melt fracture is compared with that of a typical fluoroelastomer. It is shown that boron nitride is a superior processing aid.
High‐performance phosphite stabilizer
Authors: Stein Daryl , Stevenson Don 
Published: April 2004

AbstractThe initial rates of air oxidation of eight aromatic phosphites were measured at 200°C in hydrocarbon solvents. The phosphites were oxidized to the corresponding phosphates, and, in every case, a small amount of the corresponding substituted phenol was also detected. The phenolic compounds likely arose from hydrolysis of the phosphites by water generated during oxidation. In general, alkyl substitution caused a decrease in the rate of oxidation. Phosphite 7 [bis(2,4‐dicumylphenyl) pentaerythritol diphosphite] and, to a lesser extent, phosphite 6 [bis(2,6‐di‐t‐butyl‐4‐methylphenyl) pentaerythritol diphosphite] had a combination of high rate of oxidation and good resistance towards hydrolysis in the bulk state, a combination that is not usual with most commercially available phosphites (1).
Combustion products of lead stabilizers: Dibasic lead phthalate
Authors: Grossman Richard F. 
Published: April 2004

AbstractThe volatile products of combustion of dibasic lead phthalate in air were found to be complex and unanticipated. In addition to phthalic anhydride and water, decomposition products anticipated from TGA studies, actual combustion yields salicylic acid, apparently from decarbonylation. The presence of basic lead acetate, from acetic acid catalysis in the preparation of dibasic lead phthalate, leads to minor amounts of dehydroacetic acid and 2‐hydroxyacetophenone.
Viscosity effects in rigid PVC
Authors: Berard Mark T. 
Published: April 2004

AbstractThe viscosity of PVC is better understood if the material is treated as a fluid which contains filler. Anomalous effects such as die swell increasing with increasing melt temperature and melting history causing changes to the viscosity can be explained if the PVC primary particles are viewed as filler which disappears during melting. The fusion torque peak is well‐described by this approach. The compaction minimum is a free‐flowing powder which changes to a filler‐containing viscous liquid. If another viscous liquid is added to a PVC compound, then the fusion peak will be at a lower torque, because the effective level of filler is reduced. This reduction helps to explain the fusion curve of PVC compounds that contain chlorinated polyethylene (CPE) impact modifier.
Unique benzoate plasticizer for reducing viscosity and fusion temperature
Authors: Bohnert T. , Stanhope B. , Gruszecki K. , Pitman S. , Elsworth V. 
Published: April 2004

AbstractPlastisol viscosity reduction and control is an important property specification in many vinyl plastisol formulations. A unique benzoate plasticizer is under development that functions as a viscosity reducer. It also is a highly solvating plasticizer in standard plastisol systems. Data are presented on the effects of the new benzoate plasticizer on the properties of phthalate‐ and benzoate‐containing plastisols and vinyl sheet.
New generation of high‐performance PVC alloys
Authors: Weng Dexi , Andries John , Saunders Keith , Macaluso John , Brookman Robert 
Published: April 2004

AbstractNewly developed alloys of flexible poly(vinyl chloride) (PVC) and polyolefin elastomers have been shown to exhibit improved physical properties compared to those of conventional flexible PVC control compounds. In particular, the new alloys display enhanced electrical properties, better high temperature stability, greater low temperature flexibility, and superior gas barrier properties. In addition, this study demonstrated that PVC/polyolefin rubber alloys have potential utility in many applications where conventional flexible vinyl compounds do not meet certain end‐use performance requirements.
Hot‐tool and vibration welding of poly(vinyl chloride)
Authors: Stokes Vijay K. 
Published: April 2004

AbstractThe weldability of poly(vinyl chloride) (PVC) is assessed through hot‐tool and 120‐Hz vibration welds. Equivalent strengths have been demonstrated for welds made by both of these welding techniques. For two grades of PVC, relative weld strengths of 85 and 97%, with corresponding failure strains of about 2.5 and 3.3%, respectively, have been demonstrated.