Polymer Engineering and Science articles from July 2004

Polymer Engineering and Science archives from July 2004

Preface.(Editorial)
July 1, 2004... This issue of Polymer Engineering and Science (PES) contains six selected papers presented during the Second International Symposium on Polymeric Nanocomposites (PNCs), held at the Industrial Materials Institute (IMI) of the National Research...

Characteristics of polystyrene/polyethylene/clay nanocomposites prepared by ultrasound-assisted mixing process.
July 1, 2004... INTRODUCTION Recently, polymer-clay nanocomposites have opened new horizons for composite materials. Nanocomposites, in which at least one dimension of the dispersed particles is in the nanometer range, have become a new class of...

Development of a new production method for a polypropylene-clay nanocomposite.
July 1, 2004... INTRODUCTION The clay mineral is a potential nanoscale additive because it is composed of silicate layers in which the fundamental unit is a 1-nm-thick planar structure. If a dispersion of these nanometer-scale silicate layers could be...

Polyolefin nanocomposites: formulation and development.
July 1, 2004... INTRODUCTION There is much interest in polymer nanocomposites, which consist of a polymer matrix reinforced by nano-reinforcement, because of their improved properties compared with neat polymers. The most interesting nano-reinforcements...

Morphology of EVA based nanocomposites under shear and extensional flow.
July 1, 2004... INTRODUCTION Polymer-layered silicate nanocomposites (PLSN) have gained tremendous interest in both the academic and research fields because of their unique structure as well as physical and chemical properties (1). The mere addition of a...

Influence of the initiation rate on the polymerization kinetics of hydroxy ethyl methacrylate (HEMA) filled with HEMA-grafted silica preformed nanoparticles.
July 1, 2004... INTRODUCTION Inorganic glasses are generally formed in a two-step route (hydrolysis and condensation of precursors) by the sol-gel process at low temperature (1-5). A similar method was extended to hybrid materials to incorporate inorganic...

Hybrid organic inorganic nylon-6/Si[O.sub.2] nanocomposites: transport properties.
July 1, 2004... INTRODUCTION Over the past decade, the incorporation of fillers into a polymer matrix has produced a wide range of multifunctional properties such as increasing polymer backbone stiffness (1), catalytic activity (2), optical applications...

Dispersion, temperature and torque models for an internal mixer.
July 1, 2004... INTRODUCTION A fundamental understanding of mixing is important for optimizing the operation of internal mixers, which typically represents the first step in the production of many consumer items, including tires. Mixing operations affect...

Modeling of polymer melting, drop deformation, and breakup under shear flow.
July 1, 2004... INTRODUCTION The polymer melting mechanism in extruders has attracted much attention (1-6), especially as experimental investigations have shown that the main morphology change occurs during the melting process (7-10). Comparable to...

Comparison of the dynamic thin shell and quasi-cylindrical models for blown film extrusion.
July 1, 2004... INTRODUCTION The thin shell model is the most heavily studied steady-state description for blown film extrusion (1, 2) (see Fig. 1). During an extensive experimental and modeling effort, Liu and co-workers (3-5) reported that the thin...

Photo polymerization of acrylamide onto calcium carbonate particle surfaces and filled nylon-6.
July 1, 2004... INTRODUCTION Inorganic fillers have always played an important role in the polymer industry for improvement in properties of materials (1-3). Of these fillers, CaC[O.sub.3] is the mostly widely used. An important factor that determines the...

Shear field induced diffusion and molecular weight fractionation during polymer processing.
July 1, 2004... INTRODUCTION Polymer processing generally involves flow at high shear rates. Examples include flow through strand or spinnerette dies, film dies, injection molding gates, etc. These processes are usually characterized by a maximum shear...

Computational prediction of PVC degradation during injection molding in a rectangular channel.
July 1, 2004... INTRODUCTION One of the most common problems encountered when polyvinyl chloride (PVC) is not molded properly is the appearance of burn (degradation) marks. These burn marks are easily visible in materials that are translucent or of light...

An experimental study of solid-bed break-up in plasticization of a reciprocating-screw injection molding.
July 1, 2004... INTRODUCTION Plasticization in a reciprocating-screw injection molding machine has been commonly assumed to be similar to that of a single-screw extruder. That is, the screw can be divided into three functional zones of solid-conveying,...

Environmental stress cracking of a chemical nature in a PBT/PBA copoly(ester ester).
July 1, 2004... INTRODUCTION Environmental Stress Cracking (ESC) of polymer materials can result in the sudden and unpredicted failure of structures. The chance of ESC occurring can easily be overlooked because neither loading nor the environment in...

On the effect of pressure on the shear and elongational viscosities of polymer melts.
July 1, 2004... INTRODUCTION Increasingly, computer simulations for the design of tools and setting of process parameters employ precise specification of materials. For polymers, viscosity is the crucial characteristic. The dependence of viscosity on...

Rubber plasticizers from degraded/devulcanized scrap rubber: a method of recycling waste rubber.
July 1, 2004... INTRODUCTION In previous research (1-3), 100% vulcanized rubber powders were successfully remolded employing a newly developed technique called "High-Pressure High-Temperature Sintering" (HPHTS), without incorporating any virgin rubber or...

Free volume changes in mechanically milled PS and PC studied by positron annihilation lifetime spectroscopy (PALS).
July 1, 2004... INTRODUCTION Mechanical milling is a long-known technique for refining particles in various kinds of solid materials. The first systematic experiment for advanced applications was carried out in 1960. Research in this field is still...

Uniaxial stretching of poly(keto-ether-imide) films.
July 1, 2004... INTRODUCTION Polymer films are useful as vapor barriers, as flexible structural elements and windows, as electrical substrates, and as piezoelectric and photorefractive materials. Their mechanical, optical, electrical and barrier...

Simulation of PTFE sintering: thermal stresses and deformation behavior.
July 1, 2004... INTRODUCTION Polytetrafluoroethylene (PTFE) is a polymer with outstanding features, mainly due to its characteristic chemical structure: it shows excellent thermal and chemical resistance, and also very good anti-friction and dielectric...

A non-isothermal finite element model for injection stretch-blow molding of PET bottles with parametric studies.
July 1, 2004... INTRODUCTION Injection stretch-blow molding (ISBM) is one of the most popular blow-molding processes for making thin-walled polyethylene terephthalate (PET) bottles. In this process, the PET resin is first injected into a tube-shaped mold...

Experiments and flow analysis of a micropelletizing die.
July 1, 2004... INTRODUCTION Micropelletization is a relatively new technology for producing resin particulate that exhibits many of the advantages of a pellet yet possesses a size closer to that of a powder. The reason for manufacturing these...

Erratum.(Correction Notice)
July 1, 2004... "A Study on The Effects of Chaotic Mixer Design and Operating Conditions on Morphology Development in Immiscible Polymer Systems," by Madhusudan Sau and Sadhan C. Jana, Polym. Eng. Sci., 44, 407-22 (March 2004). The relationship given on...

SI metric units.
July 1, 2004... The following list shows the names, symbols, and equivalence of the more common quantities allowed in the SI metric system. The prefixes and symbols for the more common multiple units are also shown. Neither list is complete. Full details are...