Polymer Engineering and Science articles from January 2003

Polymer Engineering and Science archives from January 2003

The thickness profile of ultra-high molecular weight polyethylene films during sequential biaxial drawing.
January 1, 2003... INTRODUCTION The geltrusion process is used to produce thin ceramic-filled and unfilled ultra-high molecular weight polyethylene (UHMW-PE) films. In this paper we will consider only unfilled films. The process is based on the phenomenon of...

Modification of recycled high-density polyethylene by low-density and linear-low-density polyethylenes +.
January 1, 2003... INTRODUCTION In Australia. post-consumer polyolefins represent the largest waste stream of polymers, 330,000 tons per annum. The fraction of HDPE blow molded bottles is approximately 50,000 tons p.a., with half still ending up in landfill....

The importance of timely polymer sintering while processing polypropylene foams in rotational molding.
January 1, 2003... INTRODUCTION In response to the increasingly growing need for reinforced rotational moldings that can satisfy severe service requirements and/or demonstrate improved insulation properties, in the last decade, the conventional rotational...

Analysis of closed-discharge single-screw extrusion of power-law fluids.
January 1, 2003... INTRODUCTION Todd et al. (1) have developed a new instrument known as the helical barrel rheometer or HBR. The HBR is essentially a single-screw extruder instrumented to measure pressure buildup ([DELTA]P), control rpm (N) and temperature....

Residual birefringence in modified polycarbonates.
January 1, 2003... INTRODUCTION Residual Birefringence It is well known that the properties of polymers depend on the processing history. For precision applications it is necessary to have a good understanding of how the processing affects the state of...

Effect of reactive compatibilization on the interfacial slip in nylon-6/EPR blends.
January 1, 2003... INTRODUCTION Blending of immiscible polymers provides an economical and versatile way to develop new polymeric materials with tailor-made properties. An essential step in controlling the microstructure, and hence the performance of such...

A study of the stick-slip phenomenon in single-screw extrusion of linear polyethylene.
January 1, 2003... INTRODUCTION Flow instabilities are encountered during the extrusion process of polymers above critical conditions. Many publications in the last five decades have been devoted to the understanding of these phenomena and the following...

Novel ultrasonic process for in-situ copolymer formation and compatibilization of immiscible polymers.
January 1, 2003... INTRODUCTION Blending and reactive extrusion of mixtures of polymers are useful approaches for the manufacture of new materials with specially tailored performance characteristics that are often not exhibited by the corresponding single...

Application of ultrasound in the determination of fundamental extrusion performance: residence time distribution measurement.
January 1, 2003... INTRODUCTION Residence time distribution (RTD) is one of the most important performance indicators during polymer extrusion process. It governs the back-mixing characteristics important to all practical applications. Many in-line...

Impact behavior and modeling of engineering polymers.
January 1, 2003... INTRODUCTION Engineering polymers have increasingly been applied in applications such as housings for electronic appliances, lenses, goggles, and windows, which have to sustain accidental impact without showing signs of damage. In these...

Properties of rapid prototype injection mold tooling materials.
January 1, 2003... INTRODUCTION Injection molding is a method to fabricate plastic parts by utilizing a mold or cavity with a shape and size identical to the part being produced. Molten polymer is injected into the cavity and yields the desired part upon...

Dynamic mechanical signatures of Viton A and plastic bonded explosives based on this polymer *.
January 1, 2003... INTRODUCTION Viton A is a fluoroelastomer manufactured by DuPont Dow Elastomers and used by Lawrence Livermore National Laboratory (LLNL) as a binder in the formulation of HMX based explosives LX-10, LX07, LX-04 and LX-11. Viton A is a...

Effect of process conditions on the weld-line strength and microstructure of microcellular injection molded parts.
January 1, 2003... INTRODUCTION Injection molding with microcellular plastics (MCPs) is capable of producing parts with excellent dimensional stability while using lower injection pressure, shorter cycle time, and less material. This process (also known as...

Primary structure and physical properties of poly(ethylene terephthalate)/poly(ethylene naphthalate) resin blends.(Brief Article)
January 1, 2003... INTRODUCTION Poly(ethylene terephthalate) (PET) is used in a wide variety of fields, including fiber products, household appliances, and medical supplies. In particular, PET is used in large quantities in the container industry as a...

Industrial solidification processes in polybutene-1. Part I-quiescent melts.
January 1, 2003... INTRODUCTION. SOLIDIFICATION IN A QUIESCENT SAMPLE For the description of the process of solidification of a crystallizable sample, several theories have been proposed. The first classical theory on this subject was published by Stefan in...

Industrial solidification processes in polybutene-1. Part II-influence of shear flow.
January 1, 2003... INTRODUCTION Basic Results From Previous Studies During polymer processing, the polymeric melt is exposed to shearing and stretching, and undergoes a cooling process simultaneously with or shortly after these operations. These events...

Nylon 10 10--montmorillonite nanocomposite made by intercalating polymerization.
January 1, 2003... INTRODUCTION In the last decade, there has been increasing interest polymer-clay nanocomposites because of their unexpected hybrid properties synergistically derived from the two components, including improved tensile strength and moduli...

A study of the effect of surfactants on the properties of polystyrene-montmorillonite nanocomposites.
January 1, 2003... INTRODUCTION Polymer composites have been widely used in various areas of transportation, construction and electronics products. They offer unusual combinations of stiffness and strength, which are difficult to attain separately from the...

Essential work of fracture of polypropylene and polypropylene blends over a wide range of test speeds.
January 1, 2003... INTRODUCTION Improvements in the impact properties of engineering polymers such as isotactic polypropylene (iPP) are usually achieved by incorporating dispersed second phase domains during either polymerization or melt processing (1, 2)....

Selectivity of peroxide-initiated graft modification of ethylene copolymers.
January 1, 2003... INTRODUCTION Free radical--mediated graft modification of commodity polymers is an important commercial technology and an active field of polymer research (1). These synthetic techniques employ relatively inexpensive reagents, require...

Investigation of the rheological and mechanical properties of a polystyrene-polyisobutylene-polystyrene triblock copolymer and its blends with polystyrene.
January 1, 2003... INTRODUCTION Block copolymers represent an interesting class of materials in which each molecule consists of two or more segments of simple polymer blocks joined in various arrangements (1, 2). They are unique phase-separated materials...

Numerical simulation of the flow in an Extensional Flow Mixer. Effect of fluid elasticity on the flow.
January 1, 2003... INTRODUCTION The quality of polymer blends and alloys depends on the mixing state. Most blends are prepared in either a single or a twin screw extruder, where a shear flow is dominant over an extensional flow. However, it is difficult to...