Polymer Engineering and Science articles from December 2004

Polymer Engineering and Science archives from December 2004

Influences of hot stretch ratio on essential work of fracture of in-situ microfibrillar poly(ethylene terephthalate)/polyethylene blends.
December 1, 2004... INTRODUCTION The use of soft-drink bottles and textile fibers based on poly(ethylene terephthalate) (PET) is extensive. These one-way PET products require suitable approaches to their recycling. Melt-blending and alloying of PET with...

Morphology and mechanical properties of injection molded poly(ethylene terephthalate).
December 1, 2004... INTRODUCTION Poly(ethylene terephthalate), PET, a thermoplastic polyester widely used in packaging (e.g., containers for cosmetics, beverage bottles), is considered a high-consumption polymer of important commercial interest. PET is a...

Temporary networks in polymer-modified asphalts.
December 1, 2004... INTRODUCTION Bitumens and asphalts are mixtures of aliphatic, aromatic and naphthenic hydrocarbons and small quantities of organic acids, bases and heterocyclic components containing nitrogen, oxygen, sulfur and some metal atoms (e.g., Fe,...

Polymer crystallization kinetics, master quotients, master curves and Nakamura-Ozawa-equations of iPP and PTFE.
December 1, 2004... INTRODUCTION The kinetic crystallization model of Avrami (1-3) is generally accepted as a starting point for the analysis of isothermal polymer crystallization. However, in most cases, the experimental situation is complicated by an...

Investigation of solids transport in a single-screw extruder using a 3-D discrete particle simulation.
December 1, 2004... INTRODUCTION The granular mechanics of plastics within a single-screw extruder has, for the past five decades, remained a difficult phenomenon to model. It is generally understood that the solids are transported forward by the action of...

Design of calibrators for extruded profiles. Part I: modeling the thermal interchanges.
December 1, 2004... INTRODUCTION As shown in Fig. 1, a typical plastics extrusion line for the production of profiles comprises an extruder, a die, a calibration/cooling table (which can include several units), a haul-off and a saw (or, alternatively, a...

New experimental method for determination of effective diffusion coefficient of blowing agents in polyurethane foams.
December 1, 2004... INTRODUCTION Polyurethane cellular foams are widely used as thermal insulator materials as they are characterized by a very low thermal conductivity. One major drawback concerning the use of those materials is their thermal aging, that is,...

Cyclic deformation behavior of an epoxy polymer. Part I: experimental investigation.
December 1, 2004... INTRODUCTION Solid polymers are widely used in load-bearing applications, both in the homogeneous state or as a matrix phase in fiber-reinforced polymeric composites. Polymers and plastics are typical materials with viscoelastic...

Fate of erucamide in polyolefin films at elevated temperature.
December 1, 2004... INTRODUCTION Polyolefin plastomers (POP) are a relatively new family of polymers characterized by improved elasticity, high clarity, lower melting point, and lower modulus compared to conventional linear low-density polyethylene (LLDPE)...

A time-scale approach for analysis of coalescence in processing flows.
December 1, 2004... INTRODUCTION Blending of polymers is a common, economical practice in the polymer industry to meet the specific demands for new materials. Some polymer pairs are miscible, but a majority of the commercial blends are immiscible, and their...

Extrusion of broad-molecular-weight-distribution polyethylenes.
December 1, 2004... INTRODUCTION Extrusion is the most popular process for fabricating plastic parts. Product quality and production rate are the two most important aspects of the fabrication process. These not only are a function of the polymer and the...

Mathematical modeling and numerical simulation of cell growth in injection molding of microcellular plastics.
December 1, 2004... INTRODUCTION Microcellular injection molding blends atmospheric gas (usually nitrogen or carbon dioxide) in a supercritical state with a polymer melt inside the machine barrel to produce a single-phase polymer-gas solution. During the...

Isothermal and nonisothermal crystallization kinetics of syndiotactic polystyrene/clay nanocomposites.
December 1, 2004... INTRODUCTION Polymer nanocomposites--defined by the particle size of the dispersed phase containing at least one dimension in the range of 1-100 nm--are attracting much interest because of their excellent physical, mechanical, and thermal...

Experimental studies on radial extrudate swell and velocity profiles of flowing PS melt in an electro-magnetized die of an extrusion rheometer.
December 1, 2004... INTRODUCTION The coextrusion of polymer products involves two or more melt streams flowing together along a die. Knowledge of the flow properties of each melt stream is essential in terms of controlling the size and the quality of the melt...

Temperature control of injection molding. Part I: modeling and identification.
December 1, 2004... INTRODUCTION Injection molding is a cyclic and dynamic process (1), in which polymer melt temperature is a critical variable to be controlled. Melt temperature affects several other important process variables such as injection velocity,...

Temperature control in injection molding. Part II: controller design, simulation, and implementation.
December 1, 2004... INTRODUCTION Polymer melt temperature is widely known to be a critical variable to be controlled in the injection molding process (1). Final product quality indices such as part shrinkage, warpage, and weight and the controllability of...

The effect of molding conditions on mechanical and morphological properties at the interface of film insert injection molded polypropylene-film/polypropylene matrix.
December 1, 2004... INTRODUCTION Film-insert injection molding is a novel technique used to impart surface coatings or decorations on products that enhance both durability and aesthetic value. As today's manufacturers produce bigger and bulkier injection...

Preparation and characterization of poly(methyl methacrylate)-intercalated graphite oxide/poly(methyl methacrylate) nanocomposite.
December 1, 2004... INTRODUCTION Conducting polymer composites have been extensively studied because of their potential applications in batteries, antistatic, electromagnetic shielding, electrorheological fluids, and other applications (1-8). Since natural...

Studies on impact-modified nylon 6/ABS blends.
December 1, 2004... INTRODUCTION In 1987, Lavengood (1) reported that the impact strength of nylon/ABS blends could be improved by using MMA (methyl methacrylate) or AN (acrylonitrile) as a compatibilizer. He also mentioned that the size of the rubber...

Study of the miscibility and mechanical properties of NBR/HNBR blends.
December 1, 2004... INTRODUCTION Nitrile butadiene rubbers (NBRs) belong to the class of specialty elastomers that offer a broad range of thermal and oil resistance properties. These elastomers are extensively used in automobile and oil-drilling applications...