Polymer Engineering and Science articles from September 2007

Polymer Engineering and Science archives from September 2007

Physical properties of epoxy resin self-reinforced with organic rigid-rod compounds.(Author abstract)
September 1, 2007... INTRODUCTION Polymer matrices based on epoxy resin (Diglycidyl ether of bisphenol A (DGEBA) exhibit excellent thermal and chemical resistance, good mechanical and dielectric properties, low shrinkage and high processability. Several...

Effect of montmorillonite on properties of styrene-butadiene-styrene copolymer modified bitumen.
September 1, 2007... INTRODUCTION High-temperature rutting and low temperature cracking of bitumen because of severe temperature susceptibility limits its further application. Therefore, it is necessary to modify bitumen [1]. The addition of polymers to...

Surface-graft hyperbranched polymer via self-condensing atom transfer radical polymerization from zinc oxide nanoparticles.
September 1, 2007... INTRODUCTION In recent years, much attention has been paid to the use of controlled/"living" polymerizations from flat [1] and nano [2] surfaces, because this allows better control over the target molecular weight and molecular weight...

Characterization and quality assessment of binding properties of the monocrotophos molecularly imprinted microspheres prepared by precipitation polymerization in toluene.
September 1, 2007... INTRODUCTION Polymers have played an important role as superabsorbents and water treatment chemicals in recent years, but lack of selectivity to the target substrates greatly limits the application of the polymers in many analytical fields...

Effect of a poly(dimethylsiloxane) modified polyolefin additive on the processing and surface properties of LLDPE.(linear low density polyethylene)
September 1, 2007... INTRODUCTION The processing of some commodity resins, like linear low density polyethylene (LLDPE) and high density polyethylene, in extrusion or film blowing operations is plagued by the occurrence of extrudate defects caused by flow...

Processability of LLDPE/LDPE blends: capillary extrusion studies.(linear low-density polyethylenes/low density polyethylene)
September 1, 2007... INTRODUCTION The processability of linear low-density polyethylenes (LLDPEs) can be improved by blending with a small amount of a low-density polyethylene [1-3]. However, because of structural differences between resins, many undesirable...

Application of essential work of fracture concept to toughness characterization of high-density polyethylene.
September 1, 2007... INTRODUCTION The essential work of fracture (EWF) [1-5] is a concept for material toughness evaluation. Its value represents the energy consumed within the fracture process zone (FPZ) where new surface is generated. For crack growth...

Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate.
September 1, 2007... INTRODUCTION Bisphenol-A polycarbonate (PC) is a semicrystalline polymer characterized by a very low crystallization rate, because of its chain rigidity and the difficulty in transforming into a crystalline structure. At the atmospheric...

Study of thermally poled and corona charged poly(vinylidene fluoride) films.
September 1, 2007... INTRODUCTION Electro-active polymers (EAPs) have been widely used in many fields, such as artificial muscles, vibration and noise control systems, actuators and sensors for robots, acoustic transducers, medical imaging systems, pumps, and...

Influence of nanofillers on thermal insulating properties of polyurethane nanocomposites foams.
September 1, 2007... INTRODUCTION Polyurethanes (PUs) are unique polymer materials with a wide range of physical and chemical properties. With well-designed combinations of monomeric materials, PUs can be tailored to meet diversified demands of various...

Identification of the possible defect states in poly(3-hexylthiophene) thin films.
September 1, 2007... INTRODUCTION The interplay between carrier charge mobility and photoemission final state screening has for decades attracted a lot of interest [1], but has only recently been applied to conjugated polymers [2-4]. From photoemission and...

Evaluation of the fracture behavior of multilayered polypropylene sheets obtained by coextrusion.
September 1, 2007... INTRODUCTION Polymer films and thin sheets present an important field in the plastic industry, with a share market estimation of at least 20% in weight, most of it for packaging purposes. In fact, over 50% of all Europe's goods are...

Controlled drug release through carboxymethyl-chitosan/poly(vinyl alcohol) blend films.
September 1, 2007... INTRODUCTION Polymer coating is increasingly important in the controlled delivery of drug in recent years. Drugs and excipients (polymer) are usually manufactured into various film configurations for conveniently controlling drug release...

Effects of a tert-butylphenylene substituent on the structure and optical, fluorescent and thermal properties of the poly(p-phenylenevinylene) derivatives.
September 1, 2007... INTRODUCTION Since the report of poly(p-phenylenevinylene) (PPV) as a light-emitting material for light-emitting diodes (LEDs) in 1990 [1], great research interest was focused on the electro-optical properties of PPV derivatives by...

Carrageena-g-poly(acrylamide)/poly(vinylsulfonic acid, sodium salt) as a novel semi-IPN hydrogel: synthesis, characterization, and swelling behavior.
September 1, 2007... INTRODUCTION Superabsorbent hydrogels are hydrophilic crosslinked polymer networks that are capable of absorbing and retaining large quantities of water, saline, or physiological solutions [1]. They are widely used in many fields such as...

Mechanical, dielectric, and magnetic properties of the silicone elastomer with multi-walled carbon nanotubes as a nanofiller.
September 1, 2007... INTRODUCTION The elastomers, as an intelligent material, are widely used--from the small-scale biomaterials to the large-scale earthquake damping devices--because of their good biocompatibility and highly reversible deformation properties...

Rotational molding cycle time reduction through surface enhanced molds: Part A--theoretical study.
September 1, 2007... INTRODUCTION Rotational molding is a low-pressure process that uses heat and biaxial rotation to produce hollow plastic products such as containers, tanks, road barriers, toys, and playground equipment with a relatively low financial...

Rotational molding cycle time reduction through surface-enhanced molds, Part B: experimental study.
September 1, 2007... INTRODUCTION The rotational molding industry has recognized that long production cycle times often hinder the overall process efficiency and further progress. This issue may be due to both manufacturing scheme design and processing...

Correlation between different microstructural parameters and tensile modulus of various polyethylene blown films.
September 1, 2007... INTRODUCTION For many years, the dependence of mechanical properties on the morphological structure of the polymer has been the subject of research works. Many investigations have been reported concerning complex relationships among...

Structure and properties of injection-molded polypropylene with sorbitol-based clarifier.
September 1, 2007... INTRODUCTION Various nucleating agents for isotactic polypropylene (PP) have been widely studied and developed for a long time [1-4]. These agents include alkaline-earth metals, salts of organic carboxylic acids, phosphoric acids, sulfonic...

Melt compounding of polypropylene-based clay nanocomposites.
September 1, 2007... INTRODUCTION Clay-containing polymeric nanocomposites (CPNC) are composed of polymer matrix and clay with nanoscale dimension [1]. When well dispersed, small amount of clay dramatically improves properties of the CPNC, such as mechanical...

The effect of density profile on the flexural properties of structural foams.
September 1, 2007... INTRODUCTION Sandwich structures are important for engineering purposes because of their high mechanical performance. Although foamed core sandwich materials have lower mechanical properties than compact samples of equal thickness, they...

Sheet molding compound resins from soybean oil: thickening behavior and mechanical properties.
September 1, 2007... INTRODUCTION Unsaturated polyesters (UPE) are formed by the reaction of petroleum-based acids, such as iso-phthalic, orthophthalic, and maleic acid with diols such as ethylene glycol. The C=C double bonds remaining after the ester...

Influence of UV absorber on photodegradation processes of poly(vinyl chloride) with different average degrees of polymerization.
September 1, 2007... INTRODUCTION Poly (vinyl chloride) (PVC), which remains one of the most useful, economical, and versatile commodity polymers, has become an essential material in almost every aspect of modern day life [1]. Nowadays, because of its...

Real-time diagnosis of co-injection molding using ultrasound.
September 1, 2007... INTRODUCTION Plastic injection molding is widely used in mass production and prototyping for various kinds of polymeric products including automotive components and housings for consumer electronics. This technology has a number of process...