Polymer Engineering and Science articles from September 2004

Polymer Engineering and Science archives from September 2004

A model-based virtual sensing approach for the injection molding process.
September 1, 2004... INTRODUCTION The injection molding industry has continuously sought precision and quality molding. Many efforts have been devoted to understanding how process variables determine part qualities, notably pvT data for part quality (1-4)....

Surface texture characterization of injection-molded pigmented plastics.(Editorial)
September 1, 2004... INTRODUCTION Whether or not a complete car interior gives an aesthetic impression is dependent on the satisfactory combination of many different plastic components. The appearance of each component is mainly described in terms of color and...

Impact fracture toughness of polyethylene/polypropylene multilayers.
September 1, 2004... INTRODUCTION In an increasing number of components, two thermoplastics are co-processed to form a multilayer structure. Two component polymers may be co-injected successively into a single cavity, or into a cavity that changes geometry to...

Removal of ungrafted monomer from polypropylene-graft-maleic anhydride via supercritical carbon dioxide extraction.
September 1, 2004... INTRODUCTION The use of supercritical fluids as an extraction medium has been successful in many applications as a replacement for liquid solvents and as a means of performing difficult separations. Supercritical carbon dioxide has...

Three-dimensional polymer flow in the calender bank.
September 1, 2004... INTRODUCTION Counter-rotating rolls are used in calenders to produce sheets and foils from polymeric materials. Usually, the applied calenders consist of several coaxial counter-rotating rolls in order to meet the quality requirements for...

Rheo-kinetic measurement of thermoplastic polyurethane polymerization in a measurement kneader.
September 1, 2004... INTRODUCTION Thermoplastic polyurethane (TPU) is a versatile elastomer that is used in automotive products, electronics, glazing, footwear and for industrial machinery. A common production method for thermoplastic polyurethane is reactive...

Flow-induced morphology of cast polypropylene.
September 1, 2004... INTRODUCTION In many packaging applications, there is an increasing use of polypropylene, easily extrudable in film form, commonly known as cast polypropylene (CPP). In film casting, the melt is forced through a slit die, forming a...

Rotational molding of polypropylene/ultra-low-density ethylene-[alpha]-olefin copolymer blends.
September 1, 2004... INTRODUCTION Polymer blends can address the growing needs of the rotational molding industry by providing new tailored materials with good balances of properties. Although blends are widespread in most polymer processing operations, they...

Hot-fillable containers containing PET/PEN copolymers and blends.
September 1, 2004... INTRODUCTION Polyethylene terephthalate (PET) containers are widely used for packaging of carbonated and noncarbonated beverages, oils and other liquid drinks as well as for packaging of various solid foods. Its high clarity, good...

Spectroscopic, transport, and morphological studies of polyaniline doped with inorganic acids.
September 1, 2004... INTRODUCTION Conducting polymers have attracted significant attention in recent decades because of their potential applications in various fields (1-4). Among these polymers, polyaniline (Pani) is unique because of its high electrical...

Synthesis and non-isothermal crystallization behavior of poly(ethylene phthalate-co-terephthalate)s.
September 1, 2004... INTRODUCTION Poly(ethylene terephthalate) (PET) has excellent thermal and mechanical properties, high chemical resistance, and low gas permeability (1-3). Because of these advantageous properties, this polyester is widely used in synthetic...

Investigation of phase behavior during melt processing of novel inorganic-organic polymer hybrid material.
September 1, 2004... INTRODUCTION Key factors affecting the final properties of immiscible polymer blends, organic-inorganic polymer hybrids, and multiphase systems are the phase inversion and continuity, because of their inherent control of the overall...

Effects of ZnO nano particles on thermal stabilization of polymers.
September 1, 2004... INTRODUCTION Hong et al. (1) reported a new finding that a nanocrystal ZnO retarded gelation of branched low-density polyethylene (BLDPE). It has been reported that nanocrystals of inorganic materials exhibit many properties unexpected...

Essential work of fracture of rubber-modified polyamide 6 in impact.
September 1, 2004... INTRODUCTION The growing use of polymeric materials in engineering applications demands new methodologies for assessing the material capability to withstand loads. More specifically, it is well known that thermoplastics, even toughened...

Stress relaxation in low-shrink-force polyolefin films.
September 1, 2004... INTRODUCTION Polyolefin shrink films are widely used in the packaging industry. In recent years they have been replacing PVC (polyvinyl chloride) films, which degrade with HCl formation, and which are sometimes not approved for food...

Influence of ionomeric compatibilizers on the morphology and properties of amorphous polyester/polyamide blends.
September 1, 2004... INTRODUCTION Extensive research has been employed in enlarging the scope of applications for polyesters and polyamides in the form of blends and composites to control and improve their properties. While early research focused on the...

Injection moldability and properties of compatibilized PA6/LDPE blends.
September 1, 2004... INTRODUCTION Immiscible polymers are usually expected to give rise, upon melt blending, to materials characterized by coarse and unstable morphology and poor mechanical properties. These drawbacks can generally be overcome by incorporation...

Scratch deformation characteristics of micrometric wollastonite-reinforced ethylene-propylene copolymer composites.
September 1, 2004... INTRODUCTION Polymers are being increasingly considered for structural applications in view of good combination of mechanical strength, processability, and ready availability. They are the ultimate materials in the materials substitution...

Relating the molecular structure and crystallization behavior of polypropylene.
September 1, 2004... INTRODUCTION Biaxially oriented polypropylene (BOPP) film, one major type of biaxially oriented film, has been developed since the 1960s through the mass production of polypropylene. This film is today widely used in commercial packaging...

Electrically conductive thermoplastic blends for injection and compression molding of bipolar plates in the fuel cell application.
September 1, 2004... INTRODUCTION Fuel cells constitute one of the most promising sources of clean energy for the future. These devices produce electrical energy and heat by converting the chemical energy stored in a fuel, such as hydrogen or methanol, through...

A low-cost, low-fiber-breakage, injection molding process for long sisal fiber reinforced polypropylene.
September 1, 2004... INTRODUCTION Cellulosic natural fibers are being incorporated into polymeric matrices to reduce cost and to improve mechanical properties, this trend being driven mainly by government regulations that promote the use of renewable and...

Exfoliation and dispersion enhancement in polypropylene nanocomposites by in-situ melt phase ultrasonication.
September 1, 2004... INTRODUCTION The class of materials known as nanocomposites has enjoyed increased interest since the initial development of a nylon-based material by Usuki et al. at Toyota in 1993 (1). In general, polymer nanocomposites combine an organic...

Pre-necking and post-necking relaxation and creep behavior of polycarbonate: a phenomenological study.
September 1, 2004... INTRODUCTION As solid polymers continue to gain favor in applications traditionally fulfilled by metals, such as automobile inlet manifolds and even high-pressure fuel rails, there is no question that accurate analysis of polymer...

Rheological aspects of blends of metallocene-catalyzed atactic polypropylenes with bitumen.
September 1, 2004... INTRODUCTION Metallocene-type catalytic systems are well known as catalysts of single centers, in contrast to conventional Ziegler-Natta multiple-center catalysts. The performance of these catalysts to polymerize industrial polyethylenes...

Impact strength and elongation-to-break of compatibilized ternary blends of polypropylene, nylon 66, and polystyrene.
September 1, 2004... INTRODUCTION The scrap or waste plastics available for recycling often contain a number of different polymers. To obtain useful mechanical and physical properties from such mixtures, the various pairs of polymers usually need to be...

SI metric units.
September 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...