Polymer Engineering and Science articles from August 2003

Polymer Engineering and Science archives from August 2003

Production of barrier films by chaotic mixing of plastics.
August 1, 2003... INTRODUCTION In recent years, chaotic mixing has been employed as a tool for controllably generating a variety of fine-scale internal structures among two or more polymers and additives (1-3). Initially large component bodies (e.g.,...

Hyperbranched polymers in cationic photopolymerization of epoxy systems.
August 1, 2003... INTRODUCTION Hyperbranched polymers (HBP) have attracted a great interest for their peculiar structure and interesting properties, reminiscent of dendrimers with the advantage of easier synthesis. In the past 15 years, different HBP...

Behavior of fully filled regions in a non-intermeshing twin-screw extruder.
August 1, 2003... INTRODUCTION Twin-screw extruders (TSE) are high intensity mixers capable of compounding a wide variety of materials. Specific throughput is the ratio of throughput to the maximum throughput achievable for a given screw speed. Almost all...

Tribological behavior of pure and graphite-filled polyimides under atmospheric conditions.
August 1, 2003... INTRODUCTION From both scientific and practical points of view, knowledge about wear and friction of polymer materials is important, since metal sliding components in machine elements have been more and more frequently replaced by polymer...

Pressure drop and die surface changes in unplasticized PVC extrusion.
August 1, 2003... INTRODUCTION In the processing of PVC, the phenomena occurring at the interface between the PVC and the metal tooling are of crucial importance. Here, the existence of wall slip is essential to limit residence times in extrusion and avoid...

Enhancing slit die performance by optimization of restrictor profiles.
August 1, 2003... INTRODUCTION An important requirement in the design of slit dies is to achieve a uniform flow rate across the die exit, to give a sheet or film of uniform thickness. Although it is theoretically possible to design dies where the flow...

Enhanced apparent Payne effect in a gum vulcanizate at low temperature approaching glass transition.
August 1, 2003... INTRODUCTION Dynamic performance characteristics of pneumatic tires such as sliding friction related to driving safety and rolling resistance related to vehicle fuel consumption depend critically on the nonlinear dynamic viscoelastic...