bluuebunny/crossref_metadata_2025_split huggingface dataset:
Report on the state of the art: Reactive processing using twin‐screw extruders
Authors: Sakai Tadamoto 
Published: April 2003

AbstractReactive processing technology is rapidly coming into widespread use in the plastic industry as a tool for both simplifying conventional polymerization processes and creating innovative polymers and their alloys. For a long time, we have been making great efforts to develop the technology and systems related to this field. In this report, we describe fundamental functions of twin‐screw extruders and introduce some applications of reactive processing using the twin‐screw extruder. Furthermore, we discuss the future trends of this technology.
Initiation of a solid‐state extrusion of a cross‐linked silicone rubber
Authors: Cohen A. , Burmester A. F. 
Published: April 2003

AbstractInitiation stage of a plunger‐driven extrusion of a cross‐linked silicone rubber material was investigated. The experiments were performed at room temperature with a series of capillaries of various diameters positioned in a conventional Instron rheometer. It was observed that the extrusion of the rubber started with a cylindrically shaped “plug” which was followed by an “apple peel” shape. This change in the shape of extrudates corresponds to changes in the load applied to the plunger. Analysis of this transition and its variation with the size of the capillary points to interesting physical mechanisms involved in this solid‐phase processing operation.
Metal injection molding: Freedom in design for sintered metal components
Authors: Bielzer Raffael , Michaeli Walter 
Published: April 2003

AbstractMetal injection molding represents a combination of sintering and injection molding technology. The shaping is performed by injection molding and the compaction into the definitive part by sintering. Shaping starts with the metal powders and binders being mixed, homogenized, and worked up to a granulate. The granulate is now processed to the so‐called green compact on an injection molding machine. Injection mold processing of powder metal is basically comparable to pure thermoplastics. After forming, the green compact must be compacted to the final, purely metallic component. To this end, the binder part must be removed from the body, which is subsequently sintered down to its final density. This article touches upon aspects of the problems and questions arising from powder–metal injection molding. The objective is to provide an insight into a promising production process.
Computer prediction of cycle times during rotational molding of plastics
Authors: Nugent P. J. , Crawford R. J. , Xu Liang 
Published: April 2003

AbstractA computer simulation program has been developed for the rotational molding of plastics. The predictions obtained from this program in terms of heating/cooling rates and overall cycle times have been compared with experimental molding trials with a range of plastics. It is shown that the computer model predicts accurately the real situation for a wide range of processing conditions. In particular, the program allows the effects of oven efficiency, mold material, mold wall thickness, and molded part thickness to be assessed quantitiatively. The article presents information on heat transfer coefficients that are applicable during rotational molding and typical cycle times for a wide range of process conditions. © 1992 John Wiley & Sons, Inc.
Thermoplastic polymer formulations: An approach through experimental design
Authors: Sell Joseph W. , Lepeniotis Stefanos S. 
Published: April 2003

AbstractAn approach to modify a thermoplastic polymer's cost–property profile is through polymer blends and glass reinforcement. An experimental design for a thermoplastic polymer formulation was done using RS/Discover® and EChip®. Here, two crystalline thermoplastic polymers have been compounded with fiber glass to reduce cost and maintain useful melt processing properties and physical properties. Using RS/Explore and EChip software, the results were analyzed by regression analysis and the results summarized in contour plots. The ease of use and resultant format of the data analysis from these software packages are compared. A total of 10 responses were measured and analyzed in this experiment and multivariate data analysis was incorporated where appropriate. © 1992 John Wiley & Sons, Inc.
Thermoplastic epoxies from n‐alkylamines
Authors: Huang Jan‐Chan , Gu Fan 
Published: April 2003

AbstractThermoplastic epoxy resins have some special applications. In this study, the diglycidyl ether of bisphenol‐A and three different monoamines—butylamine, hexamine, and dodecylamine—at different epoxy–amine ratios were used to make epoxy resins. Relative viscosity, hardness, Vicat softing temperature, volume resistivity, and refractive index were investigated. As amine contents approach the equivalent value, these properties reach the maximum value except the refractive index, which decreases continously with increasing amine content. When the carbon number of amines increases, the properties decrease except volume resistivity. Refractive index values vary with composition, suggesting a possibility of producing epoxies with a desired refractive index for optical applications. © 1992 John Wiley & Sons, Inc.
Fundamentals of polymer compounding: The phase‐inversion mechanism during mixing of polymer blends
Authors: Shih Chi‐Kai 
Published: April 2003

AbstractDuring a routine extrusion compounding of a polymer blend of polyarylate resin and ethylene/acrylate rubber, an unexpected powdery product instead of a cohesive mixture was obtained. Also, the 20% rubber component was not well dispersed in the final product. This process problem was studied by simulation with a laboratory internal mixer following the procedure discussed by Shih. The powder formation was successfully reproduced. From the results of continuous video monitoring and analyses of the intermediate samples collected during the simulation experiments, we found that the progression of mixing from solid pellets to a cohesive mixture in a batch mixer or a twin‐screw extruder needs to “climb over” a prolonged transition state where the plastic polyarylate was dispersed in the 20% rubber. The finding led to two successful solutions to the powdering problem. A “phase‐inversion” mechanism is proposed to explain the observed morphological changes. This mechanism appears to have wider applicability in the processing of polymer blends. © 1992 John Wiley & Sons, Inc.
Compatibilization and toughening of PPE—PP blends with hydrogenated, styrene—diene block copolymers
Authors: Akkapeddi M. K. , Vanbuskirk B. 
Published: April 2003

AbstractSimple blends of poly(2,6 dimethyl 1,4‐phenylene ether) (PPE) and polypropylene (PP) are highly incompatible and consequently quite brittle regardless of the molecular weights and ductility of the individual components. Hydrogenated, styrene‐diene block copolymers, viz. S‐EB‐S triblock and S–EP diblock copolymers, can be used to compatibilize and toughen the blends. The ductility and impact toughness of the PPE–PP blends depend not only upon the nature of styrene block copolymers but also on the nature of PPE and PP used. It was found that lower‐molecular‐weight PPE was actually better in achieving a blend with desired combination of high‐impact toughness and high heat distortion temperature. Compatibilization efficiency and morphological considerations influencing the blend's properties are discussed. © 1992 John Wiley & Sons, Inc.
Modeling of membrane inflation in blow molding: Neural network prediction of initial dimensions from final part specifications
Authors: Diraddo R. W. , Garcia‐Rejon A. 
Published: April 2003

AbstractThe use of neural networks in the modeling of the inflation stage of the blow molding process is discussed. The simulation is enacted in the reverse process direction, predicting initial membrane dimension requirements from final part thickness distributions. This situation has practical implications because tooling costs and machine down times can be minimized with the information obtained. The optimal network topology entails simultaneous pre‐ and postprocessing of the data. An adaptive window is employed for modeling of the effects of adjacent segments. The optimal window length is 16 for both the input and output layers in the network topology. Simulations are run for bottles blown using various constant and pulsed die gaps. © 1993 John Wiley & Sons, Inc.
Blends of polypropylene and nylon 6: Influence of the compatibilizer, molecular weight, and processing conditions
Authors: La Mantia F. P. 
Published: April 2003

AbstractThe aim of this work is to study the influence of different types of compatibilizing agents, different processing conditions, and the molecular weight of the two components on the properties of immiscible blends of polypropylene and nylon 6. Increasing the content of the functional group of the modified polypropylene and the content of nylon in the blend, the effectiveness of the compatibilization improves. The same effect is observed by decreasing the molecular weight of the two components, in particular, that of the polyamide. The influence of the processing conditions is slight provided no degradation takes place during processing. © 1993 John Wiley & Sons, Inc.
Analysis of PVC blends by three‐dimensional solubility parameters
Authors: Huang Jan‐chan , Chang David C. , Deanin Rudolph D. 
Published: April 2003

AbstractAn investigation was undertaken on the application of the three‐dimensional solubility parameter method to predict miscibility of polyblends. The three‐dimensional method attempts to account for the combined effects of dispersion, polar, and hydrogen bonding interactions between molecules. This study focused mainly on the miscibility of blends of poly(vinyl chloride) (PVC) with homopolymers as well as with copolymers. The three components of solubility parameters were calculated from the group contributions of the structural units of the polymers. By comparing the parameters of different PVC blends in two categories, PVC/homopolymer and PVC/copolymer blends, the miscibility trend of PVC blends was revealed. The three‐dimensional solubility parameter approach successfully predicted the miscibility of several homopolymers. For copolymers, the chance of miscibility was increased because of the ability to adjust the solubility parameter through composition. This was reflected in a smaller distance between the solubility parameter of copolymer and that of PVC. Experimental results reported in the literature confirmed this conclusion. © 1993 John Wiley & Sons, Inc.
Mechanochemical bonding of hard‐to‐bond materials
Authors: Vakula V. L. , Genel L. S. , Kestelman V. N. 
Published: April 2003

AbstractSome new aspects of mechanochemical treatment are reported. The method is developed to bond such specific materials as polytetrafluoroethylene, polyethylene, polypropylene, and others that are known as hard‐to‐bond materials. The new method possesses such advantages as low cost, simplicity, high strength of adhesive joints and stability of properties. © 1993 John Wiley & Sons, Inc.
Effect of solid–state modified polypropylene on the physical performance of sawdust–filled polypropylene composites
Authors: Sain M. M. , Kokta B. V. 
Published: April 2003

AbstractThe influence of solid‐state modified polypropylene on the physical performance of uncoated or thermoset‐resin coated sawdust‐filled polypropylene composites was studied. The effect of composition of the composites on tensile strength, Young's modulus, tensile toughness, elongation, and impact strength was determined through two 23 factorial rotatable designs. The results of this investigation show that both the m‐phenylene dismaleimide‐modified polypropylene precompounded sawdust as well as solid‐state modified maleated polypropylene can be successfully used to prepare sawdust‐filled polypropylene composites with good tensile strength. On the whole, this property improved compared to that of unfilled polypropylene. According to the analysis of factorial design, the optimum composition to prepare a composite with highest tensile strength within the experimental range was 30–40 wt% phenolic resin coated sawdust together with 4–6wt% solid‐state modified maleated polypropylene; while the product composition for the worst design was a combination of high amount of phenolic resin modified polypropylene with phenolic resin coated sawdust. The experimental design also concluded that effect of compositions on impact strength of composites was not significant in most of the cases. Overall, the empirical models constructed in this study provided a good approximation to actual experimental measurements; we are encouraged to extend this approach to processing conditions for manufacturing these composites. © 1993 John Wiley & Sons, Inc.
The microwave processing of polymeric materials
Authors: De Meuse M. T. , Ryan C. L. 
Published: April 2003

AbstractAn overview is presented of the currently studied microwave‐assisted chemical and physical processes, as they pertain to polymers. Furthermore, the features which affect the microwave heating of polymers are described. Finally, some of the factors which have limited more widespread acceptance of microwave processing of polymeric materials are highlighted. © 1993 by John Wiley & Sons, Inc.
Sheet coextrusion of polymer solutions and melts: Comparison between simulation and experiments
Authors: Hannachi A. , Mitsoulis E. 
Published: April 2003

AbstractCoextrusion flows of polymer solutions and melts to produce polymeric sheets are studied employing (a) the Lubrication Approximation Theory for a quick determination of interface development and pressure drops for each material; and (b) the Finite Element Method, which uses a u‐v‐p‐T‐h formulation for the velocities, pressures, temperatures, and interface location and solves in the flow domain the full conservation and constitutive equations. The determination of the interface is part of the solution process. Simulations have been carried out for several cases of two‐layer coextrusion of polymer solutions (Oppanols, i.e., polyisobutylenes) and compared with experimental data available in the literature. A three‐layer coextrusion case is also studied with a barrier ethylene vinyl alcohol and an adhesive layer tying a polystyrene layer, and the results are compared with experimental data. For low flow rates, the interface location agrees closely with experiments. For high flow rates, a tendency for encapsulation occurs, which cannot be captured by the present purely viscous two‐dimensional simulations. © 1993 John Wiley & Sons, Inc.
An integrated approach for modeling the injection, compression, and resin transfer molding processes for polymers
Authors: Liang Erwin W. , Wang H. P. , Perry Erin M. 
Published: April 2003

AbstractAn integrated finite element process simulator has been developed for modeling the injection, compression, and resin transfer molding processes for polymeric materials. The similarities among the three processes permit consolidation of the models into an integrated software package with low maintenance and ease of future extension. An introduction to the integration algorithm embedded in the process simulator is followed by models for injection, compression, and resin transfer molding. The validation of the injection molding portion of the integrated simulator is then addressed by comparing pressure history and filling patterns between the simulator predictions and experimental data. Tooling, processing, and quality issues—such as gating and venting design, weldline locations, and pressure and closing force requirements—are illustrated by two examples, a 3‐D fan blade and a ribbed box. © 1993 John Wiley & Sons, Inc.
Cross‐Linking of polypropylene by peroxide and multifunctional monomer during reactive extrusion
Authors: Kim B. K. , Kim K. J. 
Published: April 2003

AbstractPolypropylene (PP) powder was extruded in the presence of peroxide and multifunctional monomers at varying concentrations. With increasing peroxide concentration, MFI increased almost linearly, whereas hardness, modulus, and impact strength decreased, and the results were interpreted in terms of decreased molecular weight and its distribution by chain scission. On the other hand, triacrylate type multifunctional monomers (PETA and TMPTA) reduced the MFI of PP upon extrusion, and led to increase of Tm and Tc followed by increased modulus, yield strength, and elongation as well. TAIC and PBQ exerted effects smaller than triacrylate type. When the multifunctional monomers were added to the 0.01 phr peroxide containing system, MFI decreased below that of peroxide, and increased above that of multifunctional monomer of the same concentration, and synergistic physical properties were generally obtained, especially at low content of coagent. However, at higher peroxide concentration (0.05 and 0.1 phr) MFI increased with PETA and TMPTA, and decreased with PBQ. In general, increase and decrease of MFI were respectively followed by the decrease and increase of modules, strength, and impact strength as well. © 1993 John Wiley & Sons, Inc.
Solid state processing of polymers: A review
Authors: Jog J. P. 
Published: April 2003

AbstractThe solid state processing technique is used for processing of a variety of polymers such as ultra high molecular weight polyethylene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyether etherketone, and polyphenylene sulfide. The solid state processing involves cold compaction of polymeric powders followed by sintering at temperatures above their melting point. The properties of such products are influenced by the powder characteristics and a number of process parameters encountered during the compaction and sintering processes such as compaction pressure, rate of compaction, sintering temperature, and time. The understanding of the physical processes involved in solid state processing of polymers is essential for defining the parameters to obtain the product with desired properties. In this review, the various aspects of solid state processing are discussed with reference to the physical processes. © 1993 John Wiley & Sons, Inc.
Advances in injection molding of fiber‐reinforced thermoplastics during 1991—Part II: Processing, design, and manufacture
Authors: Kelleher Paul G. 
Published: April 2003

AbstractThis article is the second part of a survey of developments in the open literature during 1991 on subjects related to the injection molding of fiber‐reinforced thermoplastics. Topics discussed include injection molding machines, screw design, process control systems, modeling, product design, mold design and manufacture, characterization techniques, and applications of composites. Although these technological advances are broadly applicable to the processing, design, and manufacture of thermoplastics generally, they are essential to the enhanced engineering, fabrication, and utilization of fiber‐reinforced thermoplastics. © 1993 John Wiley & Sons, Inc.
Pressure‐related driving forces in the fully filled nonintermeshing twin screw extruder
Authors: Bigio David I. , Ramanthan Mohan R. , Herman Paul 
Published: April 2003

AbstractResearch in understanding the mechanisms behind driving forces in the fully filled nonintermeshing twin screw extruder concentrated on experimental analysis of the relation between stagger, screw speed, and cross‐channel flow due to measured pressure differential in the nip region. A new measure of the pressure driving force was also sought out, to correlate new data to previous findings from visual studies. The first part of the study was to obtain the values for the dynamic pressure on both sides of the nip region. Further refinements to the equipment used in previous studies allowed closer placement of the transducers in the nip region. After the data were stored, analysis started by determining the δp values from the trace of the pressure differential. By plotting these values, we obtain a highly repeatable curve confirming that the greatest pressure flow occurs at small staggers. A simple 2‐D model for pressure flow in the nip region was used to estimate the effect of the cross‐channel pressure differential. Values for the cross‐channel pressure flow were calculated and compared with the drag flow and found to be significant. © 1993 by John Wiley & Sons, Inc.
Intelligent processing of polymer sheets for calendering
Authors: Tseng A. A. , Shih W. H. , Thomas C. L. , Chen S. J. 
Published: April 2003

AbstractThe Intelligent Processing of Materials (IMP) concept has been applied to the calendering process with the goal of improving shape quality and process efficiency. All four basic features of the IPM, including modeling, data processing, sensing, and controlling, are considered. In the process modeling, bending and thermal models are developed. With these models, the relationship between the process parameters and quality of the calendered sheets has been established. A material data bank has been established to couple with the process modeling and real‐time sensing data. In sensing, ultrasonic and temperature sensors have been implemented to measure critical quality and process parameters in situ. The sensing data have been used not only to verify the modeling prediction but also to establish information needed to diagnose the causes of the layflat problem. Based on the model prediction as well as sensing information, a better control system to alleviate layflatness problems has been developed. Finally, a control strategy for future improvement of the calendering system is proposed. © 1993 by John Wiley & Sons, Inc.
The precise determination of polydispersity index (PI) in rheological testing of polypropylene
Authors: Shang S. W. 
Published: April 2003

AbstractThe polydispersity index (PI) of polypropylene (PP) obtained from plotting the crossover point of shear storage modulus (G′) and loss modulus (G″) was comparable to that using gel permeation chromatography (GPC). The precise PI determination was dependent upon the material properties of PP and rheological measurement technique. The effect of testing percent strain on PI was determined over a wide range of melt flow rate (MFR). The employed percent strain could affect PI of this percent strain was not independent of the frequency at the crossover frequency of the resin. To measure PI precisely, a 5% strain was recommended for MFR ≥ 30, while a 15% strain was suitable for MFR < 30. © 1993 by John Wiley & Sons, Inc.
Structure and properties of nucleated random and block copolymers of propylene
Authors: Sterzynski Tomasz , Lambla Morand , Crozier Hervé , Thomas Michel 
Published: April 2003

AbstractThe addition of various nucleating agents to a polymer leads to the modification of its crystalline structure, i.e., the formation of small spherulites with consequent changes in mechanical and optical properties. The aim of our research was to determine the role of nucleating agents on the crystallization of propylene copolymers. Random and block copolymers containing propylene and low amounts of ethylene were used in formulations with nucleating agents based on derivatives of sorbitol such as dibenzylidene sorbitol (DBS) and para‐methyldibenzylidene sorbitol (MDBS). The introduction of low concentrations of DBS and MDBS leads to significant changes in the crystalline structure with respect to α and β phases, as well as in the kinetics of crystallization. Using WAXS, DSC, optical microscopy, and tensile testing, the following changes of nucleated propylene copolymers were observed: (a) an increase in the crystallization temperature; (b) an increase of the level of crystallinity; (c) a considerable decrease of the size of spherulites (i.e., an improvement of the transparency of the random copolymers); (d) a decrease of the amount of the β phase in block copolymers; (e) an increase in tensile strength at yield; and (f) an increase in secant modulus. In most cases we found that the most efficient nucleating agent was the MDBS. © 1994 John Wiley & Sons, Inc.