bluuebunny/crossref_metadata_2025 huggingface dataset:
Compatibilizing effect of styrene–sodium methacrylate ionomers on nylon‐6–polystyrene blends
Authors: Lee Baek‐Hyun , Park Jung‐Ki , Song Hae‐Young
Published: April 2003

The compatibilizing effect of styrene–sodium methacrylate (S‐NaMA) ionomer on nylon‐6 (N6) and polystyrene (PS) blends was studied. The dispersed particle size of these blends containing the ionomers was significantly reduced compared with that of the blends without the ionomer. The reduction of the particle size was more pronounced when the ionomer with lower ionic content was added to the blend. The blends using ionomer with the lower ionic content showed higher tensile strength than the blends using ionomer with the higher ionic content. It is suggested that these results are caused by the proper combination of specific interactions and structural similarity between the component polymers and the ionomers. © 1994 John Wiley & Sons, Inc.
Graft copolymers and ionomeric associations from mixtures of phenoxy with acid functionalized polyolefins—Part II: Compatibilizers for HDPE/PET blends
Authors: Mascia L. , Bellahdeb F.
Published: April 2003

Graft copolymers and coionomeric mixtures produced by mixing a phenoxy polymer (polyhydroxyether of bisphenol A) respectively with ethylene–propylene copolymers, containing grafted maleic anhydride groups (EP‐g‐MA), and the sodium ionomers of the terpolymers of ethylene, an alkyl acrylate and a carboxylic acid, the ionomeric character of which being enhanced by the addition of either sodium benzoate (weak base) or sodium ethoxide (strong base), were used as compatibilizers for blends of PET and HDPE in different ratios and with varied molecular weight of the HDPE component. The preparation of the compatibilizer and the production of the blends were carried out on a twin‐screw extruder. Both types of compatibilizers acted as effective surfactants for the dispersion of the two polymers, at all weight ratios, and the blends exhibited a substantial increase in melt viscosity as a result of the addition of the compatibilizer. Only the coionomeric compatibilizers, however, produced substantial improvements in both tensile strength and elongation at break, irrespective of the ratio of the two polymers in the blends. This was attributed to the strong nucleating effects on the crystallization of the polymer components and to a strong interfacial adhesion between the two polymer phases. © 1994 John Wiley & Sons, Inc.
The use of generalized eulerian–lagrangian formulations in composite materials processing
Authors: Alexandrou Andreas N. , Ahmed Alauddin
Published: April 2003

The advantages of the Generalized Eulerian–Lagrangian (GEL) formulations in modeling and numerical solution of unsteady flow of fiber suspensions are discussed. This formulation offers the flexibility of selectively applying an Eulerian (Spatial), a Lagrangian (Material), and any combination of these two frames of reference in the same computational domain. This flexibility offered by the GEL formulation is exploited to exactly determine the shape and location of the free surfaces and moving boundaries in the numerical simulation of various manufacturing processes. The application of the GEL formulation to the solution for the flow field and fiber orientation in the unsteady flows of dilute and semiconcentrated fiber suspensions are presented. The flow field and fiber orientation predicted by this method agree well with the available theoretical and experimental results. © 1994 John Wiley & Sons, Inc.
Calorimetric and rheological analysis of the BMI based resins curing process
Authors: Greco R. , Laurienzo P. , Malinconico M. , Martuscelli E. , Perenze N. , Sorrentino A.
Published: April 2003

Rubber modified prepolymers were synthetized through a nucleophilic addition of diamines to aromatic bismaleimides, using N,N′bismaleimido‐4‐4′diphenylmethane (BMI), 1,4‐piperazine (PyP), and an amino‐terminated polydimethylsiloxane elastomer (PDMS). Thermal stability was investigated by thermogravimetric analysis (TGA) in order to elucidate the influence of diamines. Physical and rheological changes during the curing process were monitored by differential scanning calorimetry (DSC) and dynamic mechanical tests (DMA). The degree of cross‐linking of the sample with PDMS was higher than that of the sample without PDMS. This effect might be due to a larger chain mobility provided by the rubber during the cure. © 1994 John Wiley & Sons, Inc.
Advances in the technology of fiber reinforced thermoplastics during 1992
Authors: Kelleher Paul G.
Published: April 2003

This article is a review of developments published in the open literature during 1992 on subjects related to the injection molding of fiber reinforced thermoplastics. Topics discussed include high performance polymers, reinforcements, fiber–matrix adhesion, composite properties, data bases, factors involved in injection molding, product design, mold design and manufacture, product manufacture, and applications of fiber reinforced thermoplastic composites. The intent was to include information pertinent to improvements in the engineering, fabrication, and use of these materials. © 1994 John Wiley & Sons, Inc.
Comparison of calculated with measured flow fields in the gap between two rotating rolls
Authors: Klostermann Rainer , Von Bose Stefan , Mewes Dieter
Published: April 2003

Velocity, pressure, temperature, and stress fields are calculated for the flow of a polymer between two counterdirectionally rotating rolls. The rheological behavior of the polymer is described by the Carreau equation, while elasticity is neglected. The results of the numerical calculations are compared with measurements. The stress field is measured by the birefringence method. The local principal stresses in the fluid are determined from the measured anisotropy of the sheared fluid for the penetrating monochromatic light by means of the stress optical law. The equations of motion and continuity are solved with a Finite Element Method (FEM) based on the Galerkin weighted residual method. The computer code is combined with a Boundary Element Method (BEM) algorithm using the Dual Reciprocity Method (DRM) to solve the coupled equation of energy. Results are shown for a shear‐thinning polyisobutene melt in a calender with totally submerged rolls. The calculated results for the principal stress differences are compared to the measured results and confirm fairly well. The influence of friction is discussed. © 1994 John Wiley & Sons, Inc.
MWD determination of ultra high MFR polypropylene by melt rheology
Authors: Yoo Hee Ju
Published: April 2003

A rheological technique of determining molecular weight distribution (MWD) of ultra high MFR polypropylene (PP) is presented. The development of this new technique was needed for two reasons. First, the advent of high activity catalyst made possible the direct polymerization and thus the commercialization of very high MFR PP. Secondly, the polydispersity index (PI) measurement based on crossover modulus from G′ and G″ curves, which was developed by Zeichner and Patel in 1981, was proven to be inapplicable to resins with MFR higher than about 40, due to instrument limitations. This new technique utilizes G′ and G″ data at low frequencies which are obtained from a dynamic frequency sweep test at 200°C. PI values, a measure of MWD, determined by this method are proven to have an excellent correlation with those obtained by gel permeation chromatography (GPC). This method has been very useful in determining MWD of melt brown fiber resins whose MFR is normally between 30 and 1000. It has also been used as a quality control tool during the resin production in a commercial plant. © 1994 John Wiley & Sons, Inc.
Solvent recycling of poly(methyl methacrylate) decorative sheets
Authors: Gouli S. , Poulakis J. G. , Papaspyrides C. D.
Published: April 2003

A model solvent technique for the recycling of poly(methyl methacrylate) (PMMA) decorative sheets is studied. The process comprises dissolution of the sheets in toluene, reprecipitation by n‐hexane, washing and drying. Moreover, the toluene‐hexane mixtures involved are separated by distillation for further reuse. Within our experimental conditions, the polymer was totally recovered in the form of grains with the solvents yields also being very satisfactory. The recycled grades proved to resemble closely the virgin material. © 1994 John Wiley & Sons, Inc.
Response surface modeling in compounding recycled polyolefinic blends
Authors: Adewole Akin , Dackson Keith , Wolkowicz Mike
Published: April 2003

Qualitative and quantitative response of recycled polyolefinic blend morphology and mechanical properties as a function of polymer component ratio, compatibilizer concentration, and mixing parameters were investigated using response surface methodology. Phase contrast optical microscopy (PCOM) and scanning electron microscopy (SEM) were used to characterize blend micromorphological phase structures for both dispersed and co‐continuous mixtures of HDPE in PP. Full polynomial models up to order 2(y = a0 + a1x1 + a2x2 + a3x3 + a11x12 + a22x22 + a33x32 + a12x1x2 + a13x1x3 + a23x2x3) were generated for each response as a function of the input factors using multiple linear regression (MLR). Optimization techniques were used to develop both processability windows and optimum blend conversions costs for a given balance of properties. © 1994 John Wiley & Sons, Inc.
Compatibilization of refined commingled post‐consumer plastics
Authors: Xanthos M. , Patel A. , Dey S. , Dagli S. S. , Jacob C. , Nosker T. J. , Renfree R. W.
Published: April 2003

In attempts to improve the properties of post‐consumer commingled plastics waste a variety of additives that could potentially act as compatibilizers/impact modifiers were evaluated. The feedstock was representative of a model curbside collection program and contained a variety of polymers, mostly polyethylenes with PET, PP, PVC, etc., in smaller amounts. The ground mixed plastics were first compounded and melt filtered in a counter‐rotating nonintermeshing twin‐screw extruder and then combined with different amounts of additives in a corotating intermeshing twin‐screw extruder. Additives included unmodified and maleated polyolefin elastomers and styrene/olefin block copolymers. Blends were analyzed for thermal and mechanical properties, and processability. The most effective modifier in terms of impact strength improvement was a styrenic block copolymer with very similar rheological characteristics to the commingled plastics matrix. The experimental observations were interpreted by considering the complex morphological features of the injection molded multicomponent, multiphase systems. © 1994 John Wiley & Sons, Inc.
Polycarbonate/ABS blends: A literature review
Authors: Greco Roberto , Sorrentino A.
Published: April 2003

A literature review concerning PC/ABS alloys is presented with the aim of providing a background suitable for a systematic investigation on the properties of such materials undertaken in our Institute. This is preceded by an additional survey on PC/SAN alloys. The purpose was to extend the above‐mentioned background furnishing literature information available on these systems (having two components out of three in common with PC/ABS alloys), particularly with respect to the phase compatibility. The articles here presented and discussed offer an almost exhaustive survey of the work done until now on these commercial materials. © 1994 John Wiley & Sons, Inc.
The extrusion and inflation of nonaxisymmetric parisons
Authors: DiRaddo R. W. , Garcia‐Rejon A. , Pecora L.
Published: April 2003

Optimization of resin usage in blow molding necessitates the use of nonround or nonaxisymmetric die tooling. These die geometries are referred to as “ovalized.” The extrusion and inflation of parisons formed from nonaxisymmetric dies are complex because of the radial thickness dependency. Four die geometries are considered in this work; one axisymmetric and three nonaxisymmetric. The three nonaxisymmetric dies have one side set at a constant die gap (1.5 mm) and the side rotated 90° from it, set at progressively increasing die gaps (2.0, 2.5, 3.5 mm). A methodology is presented for the measurement of the radial parison diameter and thickness swell profile for ovalized parisons. The methodology employs a simple mass balance approach between an axisymmetric part and the parison it was blown from. Experimental results are obtained for the radial parison diameter and thickness swell at two radial locations. © 1994 John Wiley & Sons, Inc.
Computer aided design of wire coating dies
Authors: Lafleur P. G. , Arpin B. , Lenir V.
Published: April 2003

A nonisothermal analysis of wire coating using the lubrication approximation is presented. The flow problem is solved with the broken section method where the extrusion die is broken perpendicularly to the wire axis. The flow variables (velocity, stresses, and temperature) are computed with a finite difference scheme. Any generalized Newtonian constitutive equation can be used and the energy balance includes convection in the flow direction, viscous dissipation, and conduction through the die and wire. Experimental data for inlet pressure and wire tension, obtained on an industrial line, were compared to simulated results. The predictions were satisfactory and the trends predicted by the model were relatively accurate. The main problem comes from the difficulty of measuring viscosity at high shear rates, corresponding to high processing velocity, with standard techniques. © 1994 John Wiley & Sons, Inc.
Prediction of shrinkage by dual kriging for injection molded polypropylene plaques
Authors: Kamanayo G. , Trochu F. , Sanschagrin B.
Published: April 2003

The shrinkage of thermoplastic products has become an important theme of investigation for many researchers during the last two decades. Two approaches have been followed. The first one consists of solving the balance equations (mass, momentum, and energy) that govern the polymer flow and cooling. The shrinkage and warpage of the part are then deduced from this solution. The second approach is empirical and consists of fitting a model to experimental data. In this article, a new empirical method of prediction, based on dual kriging interpolation, is proposed. A theoretical validation is performed on a set of experimental measurements. The results are compared with previous models based on regression, which can be obtained as limit cases of dual kriging. © 1994 John Wiley & Sons, Inc.
Morphology and property relationships in ternary blends of polyethylene/polyamide‐6/compatibilizing agents
Authors: Chandramouli K. , Jabarin S. A.
Published: April 2003

The effects of compatibilizing agents on the morphology and properties of high density polyethylene (HDPE) and polyamide‐6 blends were investigated. The ternary blends were studied with the objective of understanding and optimizing the compatibilization of HDPE and polyamide‐6. The blends were prepared by melt mixing the individual components in a twin‐screw extruder. Mechanical property, rheological property, differential scanning calorimetry, and scanning electron microscopy results are discussed. The addition of compatibilizing agents results in a greatly reduced dispersed phase particle size. The properties of the blends level out after a compatibilizer level of 3 wt% has been reached. The rheological, mechanical, and thermal property results indicate the presence of the compatibilizing agent along the interfacial boundary regions between the other two phases. © 1995 John Wiley & Sons, Inc.
Effects of molecular weights and compatibilizing agents on the morphology and properties of blends containing polypropylene and nylon‐6
Authors: Wu Jeng‐Yue , Lee Wan‐Chung , Kuo Wen‐Faa , Kao Hsin‐Ching , Lee Mao‐Song , Lin Jen‐Lien
Published: April 2003

Polymer blends containing nylon‐6 of different molecular weights (MW) and polypropylene (PP) were prepared by using a twin screw extruder in order to examine the effects of molecular weights of nylon and the influences of different types of compatibilizing agents on the phase morphology and the properties. The morphology of the resulting blends was characterized by using both scanning electron microscope (SEM) and optical microscope and the properties measured included Izod impact strength, melt flow index (MI), flexural modulus, and heat distortion temperature (HDT). It was found that the molecular weights of the nylon matrix had a significant effect on the phase morphology. The fracture surface of the low MW nylon blend demonstrated a uniformed phase morphology with the dispersed PP particles of dimensions in the range of 1 μm in diameter embedded in the nylon matrix, suggesting an improved compatibility as compared with the high MW nylon system, even though these two constituents were incompatible in nature. Three different types of compatibilizers, including maleic anhydride modified PP (MA‐g‐PP), acrylic acid modified PP (AA‐g‐PP), and ethylene glycidyl methacrylate copolymer (EGMA), were used to examine their effects. It seemed that blends compatibilized with MA‐g‐PP exhibited the most homogeneous phase morphology and superior mechanical properties among the three. In the blends containing low MW nylon as the matrix phase, the Izod impact strength was shown to have increased by about 40% as compared with the noncompatibilized blend, while a 20% increase of the impact strength was measured in the high MW nylon system. The effects of nylon's molecular weights and the compatibilizers were also studied in systems of PP/nylon blends reinforced with silane‐treated glass fibers. It was shown that the properties of the composites relied on the phase morphology which, in turn, was affected by both the molecular weight of nylon and the compatibilizing agents. © 1995 John Wiley & Sons, Inc.
In‐situ compatibilization of thermoplastic polyurethane and polydimethyl siloxane rubber by using ethylene methyl acrylate copolymer as a reactive polymeric compatibilizer
Authors: Santra Robin N. , Roy Sanjoy , Tikku V. K. , Nando Golok B.
Published: April 2003

The effect of Ethylene Methyl Acrylate (EMA) copolymer as a reactive polymeric compatibilizer in a blend of 50:50 Thermoplastic Polyurethane (TPU)‐Polydimethylsiloxane (PDMS) rubber has been studied. The compatibility was proved by mechanical property measurements and phase morphology studies. EMA reacted with PDMS rubber at 180°C at 100 rpm rotor speed during melt mixing to produce EMA‐g‐PDMS rubber in situ, which acted as the compatibilizer for the binary system of TPU and PDMS rubber. EMA‐g‐PDMS rubber is believed to undergo specific interaction via hydrogen bonding with the TPU matrix through the CO group of EMA and the unassociated NH group of TPU, whereas the PDMS rubber in the EMA‐g‐PDMS disperses well with the bulk PDMS matrix. The phase morphology studies showed a drastic reduction in the size of the dispersed phase at the optimum concentration of EMA. © 1995 John Wiley & Sons, Inc.
The role of the compatibilizer on morphologies and mechanical properties of polyamide 6/(styrene–[ethylene–butylene]–styrene) triblock copolymer blends
Authors: Wu Chung‐Jen , Kuo Jen‐Feng , Chen Chuh‐Yung
Published: April 2003

In this study, the morphologies and the mechanical properties of the ternary blend of PA (polyamide)6/SEBS(styrene–[ethylene–butylene]–styrene triblock copolymer)/maleated SEBS were investigated. Maleated SEBS compatibilizers of various maleic anhydride (MA) content were prepared in the laboratory. The compatibilizer significantly influenced the dispersion of the rubber as well as the crystalline form and spherulites of the polyamide. The effects of the compatibilizer on mechanical properties were correlated with the observations of morphology and stress–strain behavior. The toughness of the blends was found to be increased for those undergoing additional yielding during cold drawing. Finally, a compatibilization mechanism of maleated SEBS for the blends was proposed. © 1995 John Wiley & Sons, Inc.
EMI shielding plastics: A review
Authors: Huang Jan‐Chan
Published: April 2003

The objective of this article is to review the use of conductive plastics in the shielding of electromagnetic interference (EMI). The theory of EMI shielding and evaluation methods of EMI materials are discussed. Different approaches in achieving high conductivity of plastics are reviewed. Emphasis is placed on filled plastics which are a promising way for shielding and do not require a secondary process. Literature on properties and processing of several common conducting plastics is reviewed. Design and processing requirements of such filled plastics are also given. © 1995 John Wiley & Sons, Inc.
Development of moldability diagrams for gas‐assisted injection molding
Authors: Yang S. Y. , Liou S. J.
Published: April 2003

Gas‐assisted injection molding (GAIM) has proven itself to be a breakthrough in molding technology. However, the process involves additional gas‐related parameters to control the molding process. The interaction between melt and gas makes the gas‐assisted process complicated. To make satisfactory parts, the material, the mold, and process parameters determine the “moldability” of a specific system. The concept of “molding areas” on the critical plane can be extended from thermoplastic injection molding to GAIM. This research is devoted to the development of a proper moldability diagram for GAIM. The first part of this study employs gas‐related parameters to define the molding area. The second part is devoted to identifying the relative importance of process parameters. The results show that melt temperature and short shot are the two factors which most significantly affect the GAIM process. The third part of this study defines the moldability based on critical parameters. The application of the moldability concept is demonstrated in selecting the optimum rib geometry. These moldability studies are intended to give first guidelines for system optimization. © 1995 John Wiley & Sons, Inc.
Neural‐network‐based model approach for density of high‐molecular‐weight esters used as plasticizers
Authors: Keshavaraj Ramesh , Tock Richard W. , Narayan Raghu S. , Bartsch Richard A.
Published: April 2003

High–molecular‐weight esters are frequently used to plasticize commercial polymers. Because the physical properties of the polymer matrix can be significantly modified by the type of the plasticizer that is used, these high–molecular‐weight esters have been extensively investigated during the last decade. Liquid density, for example, has been found to be a useful bulk property of these liquid plasticizers, since density helps define the internal molecular flexibility. Most of the time, however, experimental difficulties prevent the accurate determination of density. Moreover, the existing empirical models are tedious because of many ill‐defined parameters. In this study a simple artificial neural‐network–based model was utilized for the density of these esters as a function of their chemical structure and temperature. The sum of squared error for densities predicted by this proposed model was within 0.0009. In this study, the density of a series of five different esters was investigated. These were DSEs, DDEs, TGEs, TTEs, and PTEs. © 1995 John Wiley & Sons, Inc.
The development of on‐line techniques and novel processing systems for the monitoring and handling of the evolution of microstructure in nonreactive and reactive polymer systems
Authors: Sakai Tadamoto
Published: April 2003

The use of newly developed polymer processing technologies to enable the microstructure control of nonreactive and reactive polymer systems, which up to now have been manufactured with conventional chemical polymerization processes, has been rapidly becoming popular, particularly in the field of polymer alloy systems. In this article the mechanisms of morphological development and its control for polymer alloys used mostly in a twin‐screw extruder have been reviewed mainly from our studies. And furthermore, on‐line monitoring and handling techniques developed at The Japan Steel Works are described in relation to the evolution of microstructure of polymer systems in a twin‐screw extruder. © 1995 John Wiley & Sons, Inc.
Progress in numerical modeling of the thermoforming process
Authors: D'oria Francesco , Bourgin Pierre , Coincenot Ludovic
Published: April 2003

A finite element code to simulate the thermoforming process was developed. A dynamic approach, a membrane hypothesis, and a second order explicit integration method were considered in developing the code. Tensile tests were carried out on a servohydraulic Instron device to validate hyperelastic and memory integral constitutive laws. An original experimental approach was designed and built to measure the displacement of the surface of the sheet at several points during the forming stage. A validation mold was instrumented to measure the in‐mold pressure profile during the forming process. Some preliminary attempts were carried out to consider the transient sheet heating stage and to evaluate its influence on the subsequent forming step. © 1995 John Wiley & Sons, Inc.
An expert system for injection mold cost estimation
Authors: Chin Kwai‐Sang , Wong T. N.
Published: April 2003

In recent years, the notion of the expert system (ES) has become very popular, and its enormous potential to industry and ways in which it could improve decision‐making have been recognized. This article presents the research work of an expert system (ESIMCOST) the authors developed to assist the manufacturers in the injection mold cost estimation at the early product design stage. The system domain is concerned with the concurrent decision‐making of the plastic part design, injection mold design, and mold‐making process planning during the cost estimation process. Numerous interrelated variables and technical data for estimating the injection mold cost are well organized. With the inputs of the features of a plastic part, the ESIMCOST will generate an estimated cost of the injection mold required to produce the part. Some of the projected benefits from the system implementation are addressed in the article. © 1995 John Wiley & Sons, Inc.
Injection molding, mechanical properties, and morphology of a compatibilized polycarbonate blend in the presence of weld lines
Authors: Mekhilef N. , Ait‐Kadi A. , Ajji A.
Published: April 2003

Weld lines are known to present serious problems, especially in injection molding processes. They usually represent the weakest region in a molded part in terms of mechanical properties. They are also known to be even weaker in the case of blends. In this work, the mechanical properties and the morphology of injection molded polycarbonate (PC), high‐density polyethylene (HDPE), and their blends (PC/PE) were investigated. This typically immiscible blend was compatibilized by the addition of small amounts (<5% by weight) of ethylene vinyl acetate copolymer (EVA) containing 60% by weight vinyl acetate. The modified and nonmodified blends were injection molded in the presence of weld lines using a double‐gate dogbone‐shaped tensile bar mold. The weld line strength and its morphology were investigated as a function of injection temperature. In the case of pure polycarbonate, the weld line strength was found to be very sensitive to injection temperature whereas for polyethylene no difference was observed between the strength of the nonwelded and the welded specimens. For the 80/20 PC/PE blend, the weld line strength is lower compared to that of the blend components. The addition of less than 1% of EVA increased the strength of the weld line above that of the neat blend. The morphology of the nonmodified blend was similar to that of a typical immiscible blend (i.e., PE spheres dispersed in a rigid matrix of PC). However, addition of the copolymer to the blend resulted in a better phase dispersion and finer PE particles. In addition, the V‐notch in the middle of the sample was greatly reduced by the addition of the copolymer. This was experimentally investigated by scanning electron microscopy in the region of the weld line. © 1995 John Wiley & Sons, Inc.
Reactive dual‐component compatibilizers for polycarbonate/high‐density polyethylene blends
Authors: Mascia L. , Valenza A.
Published: April 2003

Enhanced compatibility for blends of polycarbonate with high‐density polyethylene has been achieved with the addition of 5 wt% compatibilizers composed of 1 : 1 mixtures of phenoxy and the sodium ionomer of an ethylene methacrylic acid copolymer at two different levels of neutralization. Both components of the compatibilizer have been found to be capable of reacting with the polycarbonate phase to produce branched polymer chains. These impart a degree of compatibilization in polycarbonate/high‐density polyethylene blends, however at higher levels of sodium in the compatibilizer the polycarbonate phase undergoes crosslinking reactions, causing severe embrittlement. Compatibilization effects are confirmed by morphological examinations, dynamic rheological data, and dielectric loss spectra. © 1995 John Wiley & Sons, Inc.
Marketing research and new product development success in Thai food processing
Authors: Suwannaporn Prisana , Speece Mark
Published: April 2003

Marketing plays an important role in new product development (NPD) through several mechanisms. One is crossfunctional communication and collaboration so that marketing issues are integrated into the NPD process. Another is the strategic orientation of NPD, which includes marketing strategy issues such as customer orientation and market fit. Third, marketing research plays a specific role, as it provides the information and knowledge which marketing brings into its NPD roles. We show that use of marketing research is the most important determinant of higher NPD success in Thailand's food processing industry. Crossfunctional communication is also an important success factor, but strategy and planning elements are not very critical in this industry in Thailand. [EconLit classification: M310; Q130.] © 2003 Wiley Periodicals, Inc. Agribusiness 19: 169–188, 2003.
Modeling coupon values for ready‐to‐eat breakfast cereals
Authors: Price Gregory K. , Connor John M.
Published: April 2003

This study identifies the determinants of coupon values at the brand level within the context of a complex marketing program. A two‐equation, fixed‐effects, panel‐data model accounts for the bidirectional causality between brand prices and discount levels. The empirical model is fitted with data on household purchases of ready‐to‐eat (RTE) breakfast cereals and captures the industry's 1996 price cuts and discount reductions. Higher brand prices cause coupon values to rise, supporting the price discrimination hypothesis. Coupon values fall with in‐store displays and more intense advertising but rise when couponed products are featured in store flyers. Discount levels are positively related to brand market share and the size of discounts redeemed for rival cereals. Coupon values fall with increasing brand loyalty among RTE cereal purchasers. Cereal prices are positively affected by coupon values, advertising expenditures, input costs, and the prices of competing brands. Inventory levels are negatively correlated with brand price. [EconLit citations: Q130, D120, L130]. © 2003 Wiley Periodicals, Inc. Agribusiness 19: 223–243, 2003.*
Analyses of consumers' dietary behavior: An application of the AIDS model to supermarket scanner data
Authors: Jones Eugene , Akbay Cuma , Roe Brian , Chern Wen S.
Published: April 2003

Nationwide food consumption surveys often find no difference in the diets of lower and higher income Americans, while studies of particular food commodities find major differences. These contrasting results represent a consumption paradox. We attempt to gain an understanding of this paradox by using supermarket scanner data to examine food purchases and, by extension, consumption patterns for consumers in two, geographically distinct, income areas. These areas are part of the larger Columbus, OH, metropolitan area (CMA) and six stores are selected for purchase and consumption analyses—three from the lowest income areas of the CMA and three from the highest income areas. Seven product categories are analyzed in this study and these categories are subdivided into meaningful nutritional classes. An Almost Ideal Demand System is employed and the empirical results reveal major differences in consumption behavior for the two groups. [EconLit citations: D120 and D190.] © 2003 Wiley Periodicals, Inc. Agribusiness 19: 203–221, 2003.
The effect of trust on public support for biotechnology: Evidence from the U.S. Biotechnology Study, 1997–1998
Authors: James Harvey S.
Published: April 2003

The purpose of this article is to examine the extent to which trust directly affects public support for biotechnology, particularly in applications to food production and genetic modification of crop plants. Unlike previous research in which trust is assumed to be exogenous, this article posits that trust is endogenously determined. An econometric model is developed that controls for the endogeneiy of trust using instrumental variable and selection correction techniques. Using data from the U.S. Biotechnology Study, this study finds that the effect of trust on public support is substantially stronger than previous estimates. [JEL Codes: Q13, Q16, Q18.] © 2003 Wiley Periodicals, Inc. Agribusiness 19: 155–168, 2003.
An economic analysis of California raisin export promotion
Authors: Kaiser Harry M. , Liu Donald J. , Consignado Ted
Published: April 2003

The effectiveness of the California raisin industry's export promotion programs in Japan and in the United Kingdom is addressed in this article. An econometric import demand equation was estimated for each of the two foreign markets. The results indicate that the export promotion programs have increased the demand for California raisins in both Japan and the United Kingdom. The benefit‐cost ratios for the Japanese and the United Kingdom markets were computed to be 5:1 and 15:1, respectively; indicating that the benefit of export promotion in terms of expanding export revenue was greater than the cost of the programs. Optimality analysis suggest that, while the current export promotion spending level in Japan is about optimal, the industry should explore the option of investing more money in its export promotion activities in the United Kingdom. [EconLit citations: Q130: Agricultural Markets and Marketing; Cooperatives; Agribusiness; Q170: Agriculture in International Trade; Q180: Agricultural Policy; Food Policy.] © 2003 Wiley Periodicals, Inc. Agribusiness 19: 189–201, 2003.
Closed‐loop recycling of postused PP‐filled garden chairs using the restabilization technique. Part 2: Material performance during accelerated heat aging
Authors: Kartalis C. N. , Papaspyrides C. D. , Pfaendner R.
Published: April 2003

The long‐term thermal stability of postused CaCO3‐filled Polypropylene was evaluated through accelerated heat aging tests for about 2000 h. The material from old garden chairs was recycled by applying the remelting‐restabilization technique while using different stabilization systems in selected concentrations. To study the effect of heat aging on the material properties, crystallinity content, tensile strength, and tensile impact strength together with time to embrittlement were monitored. The results illustrate that the restabilization recipe is of crucial importance for improving the long‐term thermal stability of the postused chair material, ensuring its reuse in the original application. Best long‐term performance is achieved by combining a filler deactivator with appropriate heat and light stabilizer systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3033–3044, 2003
Empirical viscosity model for polymers with power‐law flow behavior
Authors: Chen Zwea‐Long , Chao Ping‐Yi , Chiu Shih‐Hsuan
Published: April 2003

The aim of this study is the creation of an empirical model that can be used to predict the viscosity of a semicrystalline polymer melt for polymer process control. We have developed an empirical viscosity equation from both analysis and experimentation that takes into consideration the effect of temperature on both the flow behavior and the consistency index in the power law. The analysis is based on previously published literature, whereas the experimental data have been obtained from both the literature and laboratory investigations. The coefficients of the empirical model for low‐density polyethylene and polypropylene have been obtained from the experimental data derived from capillary rheometer measurements in the laboratory. This empirical model is able to produce results matching the experimental data with remarkable accuracy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3045–3057, 2003
Poly(propylene)–poly(propylene)‐grafted maleic anhydride–organic montmorillonite (PP–PP‐g‐MAH–Org‐MMT) nanocomposites. II. Nonisothermal crystallization kinetics
Authors: Xu Weibing , Liang Guodong , Wang Wei , Tang Shupei , He Pingsheng , Pan Wei‐Ping
Published: April 2003

The nonisothermal crystallization kinetics of poly(propylene) (PP), PP–organic‐montmorillonite (Org‐MMT) composite, and PP–PP‐grafted maleic anhydride (PP‐g‐MAH)–Org‐MMT nanocomposites were investigated by differential scanning calorimetry (DSC) at various cooling rates. Avrami analysis modified by Jeziorny and a method developed by Mo well‐described the nonisothermal crystallization process of these samples. The difference in the exponent n between PP and composite (either PP–Org‐MMT or PP–PP‐g‐MAH–Org‐MMT) indicated that nonisothermal kinetic crystallization corresponded to tridimensional growth with heterogeneous nucleation. The values of half‐time, Zc; and F(T) showed that the crystallization rate increased with the increasing of cooling rates for PP and composites, but the crystallization rate of composites was faster than that of PP at a given cooling rate. The method developed by Ozawa can also be applied to describe the nonisothermal crystallization process of PP, but did not describe that of composites. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. The results showed that the activation energy of PP–Org‐MMT was much greater than that of PP, but the activation energy of PP–PP‐g‐MAH–Org‐MMT was close to that of pure PP. Overall, the results indicate that the addition of Org‐MMT and PP‐g‐MAH may accelerate the overall nonisothermal crystallization process of PP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3093–3099, 2003
Structure and properties of hybrid poly(2‐hydroxyethyl methacrylate)/SiO2 monoliths
Authors: Ji Xiang‐Ling , Jiang Shi‐Chun , Qiu Xue‐Peng , Dong De‐Wen , Yu Dong‐Hong , Jiang Bing‐Zheng
Published: April 2003

Hybrid poly(2‐hydroxyethyl methacrylate) (PHEMA)/SiO2 monoliths were synthesized via a sol–gel process of the precursor tetraethyl orthosilicate (TEOS) and the in situ free‐radical polymerization of 2‐hydroxyethyl methacrylate (HEMA). The weight ratio of the starting chemicals, TEOS to HEMA, was varied between 100/0 and 0/100. Structural analysis was performed by IR and NMR. The NMR results indicated that the introduction of PHEMA in the silica networks gave rise to a lower degree of condensation of TEOS. The resulting monoliths showed more than 75% transmittance in the visible region, that is, good transparency. Mechanical properties were studied with an Instron tester, and the monoliths exhibited better compressive strength and modulus than did bulk PHEMA. Surprisingly, thermogravimetric analysis (TGA) data showed greater than 50 wt % solid residue up to 700°C, possibly related to some degree of chemical crosslinking between the polymer and the silica moiety, which would greatly improve the thermal stability of such hybrid monoliths compared with a pure PHEMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3168–3175, 2003
Synthesis and gelation of novel fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide copolymers containing triol segments—Interaction of these fluorinated gels with various hydrophilic compounds
Authors: Sawada Hideo , Fujisawa Akiko , Kawase Tokuzo
Published: April 2003

Fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide (DOBAA) copolymers containing triol segments were prepared by the reactions of fluoroalkanoyl peroxide with the corresponding monomer and N‐tris(hydroxymethyl)methylacrylamide (NAT). These obtained fluorinated copolymers [RF‐(DOBAA)x‐(NAT)y‐RF] were found to cause gelation in water, dimethyl sulfoxide, and N,N‐dimethylformamide under the non‐crosslinked conditions, although the corresponding nonfluorinated DOBAA–NAT copolymer [‐(DOBAA)x‐(NAT)y‐] could cause no gelation in these solvents. This gelation is governed by the synergistic interaction of strong aggregations of end‐capped fluoroalkyl segments and intermolecular hydrogen bonding between triol segments. We also studied the uptake and release of a variety of hydrophilic compounds such as methylene blue, methyl orange, 4‐hydroxyazobenzene‐4′‐sulfonic acid sodium salt, 2,4‐dihydroxyazobenzene‐4′‐sulfonic acid sodium salt, acriflavine hydrochloride, acridine hydrochloride, lucigenin, and fluorescein by this fluorinated copolymer gel and fluoroalkyl end‐capped NAT homopolymer gel [RF‐(NAT)n‐RF] for comparison. It was demonstrated that the uptake and release ratios of these hydrophilic compounds by RF‐(DOBAA)x‐(NAT)y‐RF gel become generally lower than those of RF‐(NAT)n‐RF gel. Interestingly, RF‐(DOBAA)x‐(NAT)y‐RF gel has no releasing power toward methylene blue, acridine hydrochloride, lucigenin, and fluorescein, although RF‐(NAT)n‐RF gel has a good releasing power toward these compounds. Additionally, RF‐(DOBAA)x‐(NAT)y‐RF gel was applied to the controlled release of anticancer drugs such as methotrexate (MTX), and the releasing ratios of MTX became higher with increasing pH values (from pH 4.3 to 9.1). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88:3212–3217, 2003
Changes in orientation caused by UV irradiation of nylon 6 fibers
Authors: Fouda I. M. , Shabana H. M. , El‐Sharkawy F. M.
Published: April 2003

The effect of UV radiation on the structural parameters that relate to the optical properties of nylon 6 fibers are investigated using interferometry. When the optical parameters are known, we can use them to calculate various orientation functions given by Hermans and de Vries. The properties of concern are the surface reflectivity, transparency, stress optical coefficient, stress due to UV irradiation, optical configuration parameter, segment anisotropy, dielectric constant, and susceptibility. The number of molecules per unit volume, isotropic refractive index, polarizability of a monomer unit, specific refractivity of the dielectric (along and across the fiber axis) and the form birefringence were obtained. The results are established by relationships designed to relate the calculated structural parameters to the time of exposure. The study demonstrates how the structural parameters change during exposure to UV radiation. Illustrations are given using graphs and microinterferograms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3202–3211, 2003
Mechanical and dielectric properties of polymer composites containing tubules
Authors: Chiou Bor‐Sen , Lankford Andrew R. , Schoen Paul E.
Published: April 2003

The thermal, dynamic mechanical, and dielectric properties of copper‐coated lipid tubules incorporated into three polyurethane matrices with varying surface tensions have been examined. The tubules did not affect the glass‐transition temperature of the polymer matrices, indicating that the tubule–polymer interactions may not be strong enough to restrict the mobility of polymer chains near the filler surface. The composite's elastic modulus can also be adequately modeled using the Nielsen equation. In addition, the real part of the permittivity for the composites increased monotonically over the tubule concentration range. All samples had a small imaginary part of the permittivity, indicating the tubule concentrations were below the percolation threshold concentration. Also, the three types of matrices had comparable permittivity values at each tubule concentration, suggesting the polymer surface tension did not affect the tubule distribution in the composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3218–3224, 2003
Investigation of microstructure of 4‐vinyl pyridine–methacylonitrile copolymers by NMR spectroscopy
Authors: Hooda Sunita , Brar A. S.
Published: April 2003

4‐Vinyl pyridine–methacrylonitrile (V/M) copolymers of different composition were prepared by bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition was determined from quantitative 13C{1H}‐NMR spectra. The reactivity ratios for V/M copolymer obtained from a linear Kelen‐Tudos method (KT) and nonlinear error‐in‐variables method (EVM) are rV = 0.79 ± 0.12, rM = 0.38 ± 0.09 and rV = 0.79 ± 0.13, rM = 0.38 ± 0.07, respectively. The complete spectral assignment in term of compositional and configurational sequences of these copolymers were done with the help of distortionless enhancement by polarization transfer (DEPT), two‐dimensional heteronuclear single quantum coherence spectroscopy (HSQC). Total correlated spectroscopy (TOCSY) experiment was used to assign the various three‐bond 1H‐1H couplings in the V/M copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3232–3238, 2003
Synthesis and characterization of degradable copoly(trans‐4‐hydroxy‐L‐proline/ϵ‐caprolactone)
Authors: Lee Ren‐Shen , Yang Jen‐Ming
Published: April 2003

The melt polycondensation reaction of N‐protected trans‐4‐hydroxy‐L‐proline (N‐Z‐Hpr) and ϵ‐caprolactone (ϵ‐CL) over a wide range of molar fractions in the feed produced new and degradable poly(N‐Z‐Hpr‐co‐ϵ‐CL)s with stannous octoate as a catalyst. The optimal reaction conditions for the synthesis of the copolymers were obtained with 1.5 wt % stannous octoate at 140°C for 24 h. The synthesized copolymers were characterized by IR spectrophotometry, 1H NMR, differential scanning calorimetry, and Ubbelohde viscometry. The values of the inherent viscosity (ηinh) and glass‐transition temperature (Tg) of the copolymers depended on the molar fractions of N‐Z‐Hpr. With an increase in the trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L‐proline (N‐CBz‐Hpr) feed from 10 to 90 mol %, a decrease in ηinh from 2.47 to 1.05 dL/g, and an increase in Tg from −48 to 49°C were observed. The in vitro degradation of these poly(N‐CBz‐Hpr‐co‐ϵ‐CL)s was evaluated from weight‐loss measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3176–3182, 2003
Small‐angle X‐ray scattering analysis of nanophase titanium dioxide, poly[N‐(4‐sulfophenyl)aniline], and their composite
Authors: Narsimlu Nachagoni , Kuo Yen‐Ding , Wu Chun‐Guey
Published: April 2003

Small‐angle X‐ray scattering and spectroscopic (infrared and ultraviolet–visible) techniques were used to investigate the interactions between titanium dioxide (TiO2) and the semiconductor polymer poly[N‐(4‐sulfophenyl)aniline] (PSA) in a poly[N‐(4‐sulfophenyl)aniline]/TiO2 composite (TPSA). The radius of gyration of the cross section, the radius and length of the rodlike particle, the persistence length, the surface fractal dimension, and the PSA layer thickness on TiO2 in aqueous solutions and in powder form were calculated. The results indicated that the aggregation of TiO2 particles on drying was reduced by the formation of the composite with the semiconductor polymer. Only the particle length of the TPSA particle (which had a rodlike shape) increased on drying, probably because of increasing void sizes and the formation of aggregation. The persistence length of the TPSA particles decreased with respect to its individual components. The PSA layer thickness on TiO2 was about 3.6 nm and decreased (to 2.6 nm) on dehydration because of the expulsions of water molecules from the TiO2/PSA composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3183–3187, 2003