Polymer Engineering and Science articles from October 2005

Polymer Engineering and Science archives from October 2005

Thermodynamic approach of inflation process of K-BKZ polymer sheet with respect to thermoforming.
October 1, 2005... INTRODUCTION Thermoforming of cut sheets is extensively used in the industry for various commercial applications. In this process the sheet is heated to a softened state and subsequently deformed into a mold by an applied pressure, vacuum,...

Influence of the cross-linking density on the main dielectric relaxation of poly(methyl acrylate) networks.
October 1, 2005... INTRODUCTION The dielectric relaxation spectra of poly(n-alkyl methacrylates) and poly(n-alkyl acrylates) has been extensively studied. The merging of the main [alpha] relaxation and the secondary [beta] relaxation, at temperatures above...

On the relation between surface texture and gloss of injection-molded pigmented Plastics.
October 1, 2005... INTRODUCTION The appearance of any object is usually described in terms of color and surface features such as gloss and texture. Nevertheless, the concept of appearance also contains significant subjective elements and there is in a broad...

Effects of length distribution on the steady shear viscosity of semiconcentrated polymer-fiber suspensions.
October 1, 2005... INTRODUCTION Fiber polymer composite materials are widely used in industry because of their low cost and high performance. Such materials are obtained by adding rigid fillers to a polymer matrix to achieve enhanced mechanical and thermal...

A comparison of the thermoformability of a PPE/PP blend with thermoformable ABS. Part I: small deformation methods.
October 1, 2005... INTRODUCTION Thermoforming is a method widely used for processing of polymers into desired shapes from extruded sheets. It is a process typically suited for low volume large parts where injection molding is more costly due to its high...

Comparison of the thermoformability of a PPE/PP blend with thermoformable ABS. Part II: large deformation methods.
October 1, 2005... INTRODUCTION In Part I of the series [1], small deformation rheological methods were used to understand and compare the thermoforming behaviors of a blend of polyphenylene ether (PPE) and polypropylene (PP) with thermoformable...

Rheological and mechanical properties of PEO/block copolymer blends.
October 1, 2005... INTRODUCTION Polyethylene oxide (PEO) is a soft semi-crystalline thermoplastic that displays a lot of interesting properties and finds many applications due to the wide range of molecular weight in which it is commercially available...

Studies on proton conductivity of acid doped polybenzimidazole/polyimide and polybenzimidazole/polyvinylpyrrolidone blends.
October 1, 2005... INTRODUCTION Nowadays, hydrated perfluorosulfonic acid membranes, such as Dupont's Nafion, are typically used as the polymer electrolytes in hydrogen/oxygen polymer electrolyte membrane (PEM) fuel cells because of their excellent chemical...

Description of the dynamic moduli of poly(trimethylene terephthalate)/polyamide-12 blends in molten state.
October 1, 2005... INTRODUCTION The ultimate properties of a polymer blend are directly associated with the state of its morphology, which in turn depends on the rheological properties of the phases, on the composition of the blend, on the processing...

Quantitative study of shrinkage and warpage behavior for microcellular and conventional injection molding.
October 1, 2005... INTRODUCTION Injection molding with microcellular plastics (MCPs) is capable of producing parts with excellent dimensional stability while using less material, lower injection pressure, and achieving a shorter cycle time. This process...

Thermal strategy for the separation of a polymer mixture.
October 1, 2005... INTRODUCTION Reuse and recycling of waste polymer materials is one of the most important environmental issues [1, 2]. Using these materials as fuel has been proposed because their main components are hydrocarbons [3-5]. Such thermal...

Mechanical improvement of concrete by irradiated polypropylene fibers.
October 1, 2005... INTRODUCTION As argued by Castano and his colleagues [1, 2], ceramics were the first engineering materials known to mankind and they still constitute the most used class of materials in terms of weight. Hydraulic cements and cement-based...

Effect of polypropylene on the rheology of co-continuous PS/SEBS blends.
October 1, 2005... INTRODUCTION Block copolymers have gained significant research interest in recent decades. SBS (styrene-butadiene-styrene) type tri-block copolymers, containing two styrene end-blocks and a butadiene mid-block, are of particular importance...

Increase of open-cell content by plasticizing soft regions with secondary blowing agent.
October 1, 2005... INTRODUCTION Until recently, open-cell foams have been almost exclusively manufactured with polyurethane thermoset materials [1]. Because the manufacturing technologies for open-cell thermoplastic foams have not been developed extensively,...

Viscoelastic properties of extrusion cast sheets of natural and synthetic aliphatic polyesters.
October 1, 2005... INTRODUCTION Naturally occurring polymer-based plastic composites have received much interest in recent years as possible alternatives to petroleum. However, the inherent sensitivity of starch to moisture has necessitated the need for...