Polymer Engineering and Science articles from March 2009

Polymer Engineering and Science archives from March 2009

Cavitation bubble dynamics in non-Newtonian fluids.(Technical report)
March 1, 2009... INTRODUCTION Cavitation phenomena play important roles in many areas of science and engineering, including acoustics, bio-medicine, botany, sonochemistry, and hydraulics. They occur in numerous industrial processes such as cleaning,...

Design of optimal extrusion die for a range of different materials.(Technical report)
March 1, 2009... INTRODUCTION The performance of extrusion dies depends, amongst other things, on the design of the flow channel, the rheological properties of the material, and on the operating conditions used during extrusion (1). To investigate the...

Planar aqueous electrode technique for polymer impedance spectroscopy.
March 1, 2009... INTRODUCTION The dielectric properties of polymers are known to be time-dependent because of polymer molecular motion in response to an externally applied electric field (1), (2). Impedance spectroscopy has been widely used for...

The stress relaxation behavior and mechanical properties of polypropylene and polypropylene/CaC[O.sub.3] in mechanical vibration injection molding.(calcium carbonate)(Technical report)
March 1, 2009... INTRODUCTION The vibration injection techniques have brought an important innovation since last century 80s in polymer processing field. Because of the new processing method, there are many different properties, comparing with the...

Effects of chlorinated polypropylene on the hydrogen-bond and electric property of polypropylene/chlorinated polypropylene/polyaniline composites: FTIR analysis.(fourier transform infrared spectroscopy)(Technical report)
March 1, 2009... In this article, the volume resistivity of polypropylene (PP)/chlorinated polypropylene (CPP)/polyaniline (PANI) composites was detected. The results show that the volume resistivity of PP/CPP/PANI composites decreases with increasing CPP...

An experimental study on shear stress characteristics of polymers in plasticating single-screw extruders.(Technical report)
March 1, 2009... INTRODUCTION Solids conveying and melting are two key processes in plasticating single-screw extruders. In order for the extruder to operate properly, the solids conveying section must have a rate high enough to supply material to the...

Determination of polymeric medium flow rate in extruders based on a new correlation.(Technical report)
March 1, 2009... INTRODUCTION Extrusion is a widespread practical method in polymer processing. It is based on pressing a polymeric melt through channels of molding tools which have different geometrical cross-sections. This processing method produces...

Scratch behavior of epoxy nanocomposites containing [alpha]-zirconium phosphate and core-shell rubber particles.(Technical report)
March 1, 2009... INTRODUCTION Scratch behavior of material surfaces has been extensively explored since the 1950s and has become an important area of research in the field of materials science and mechanics (1). Traditionally, most of the scratch research...

Crystallization behavior of poly(vinylidene fluoride)/montmorillonite nanocomposite.(Technical report)
March 1, 2009... INTRODUCTION In recent years, polymer/clay nanocomposites have been widely investigated because they usually exhibit remarkably improved physical and mechanical properties compared with pure polymers (1-4). For crystalline polymers, the...

Correlation of modified natural rubber properties by artificial neural networks.(Technical report)
March 1, 2009... INTRODUCTION Natural rubber (NR) is a polymer constituted by single units of isoprene, with degree of polymerizations in order of 5000 and high molecular weight distributed in a wide range (1). It presents a structure that makes possible...

Experimental study on multiaxial ratcheting behavior of vulcanized natural rubber.(Technical report)
March 1, 2009... INTRODUCTION Most of rubber components endure cyclic loading during their service, and a nonzero mean stress during cyclic loading may cause an accumulation of strain, which is known as ratcheting phenomenon and ratcheting strain is the...

Axial-Feed thermoforming of oriented polypropylene tubes.(Technical report)
March 1, 2009... INTRODUCTION The main objective of the manufacturing process is to produce parts that satisfy design specifications at the most economical cost possible. The mechanical properties of the final thermoplastic part can be improved by modified...

Warpage-crystallinity relations in rotational molding of polypropylene.(Technical report)
March 1, 2009... INTRODUCTION Rotational molding (RM) is a high temperature, low pressure, and shear-free process for production of hollow plastic articles. The process comprises a sintering phase followed by cooling and solidification. In Fig. 1, we show...

Finite element modeling of polymer hot embossing using a glass-rubber finite strain constitutive model.(Technical report)
March 1, 2009... A hyperelastic-viscoplastic constitutive model for amorphous polymers was used in finite element simulations of micro-hot embossing across the glass transition. The model was selected for its ability to capture finite strain temperature and...

Properties and strain hardening character of polyethylene terephthalate containing Isosorbide.(Technical report)
March 1, 2009... INTRODUCTION There is an increasing interest in preparing polymers utilizing monomers derived from renewable sources like corn (1). Figure 1 shows the steps to make Isosorbide monomer from glucose. It involves two steps: hydrogenation of...

Effect of cellulose concentration in NMMO * [H.sub.2]O solution on prediction of MW and MWD of cellulose using a rheology-based method.(N-methlymorpholine-N-oxide monohydrate)(molecular weight distribution)(Technical report)
March 1, 2009... INTRODUCTION Cellulose is the most common organic compound on Earth. It is tasteless, odorless, hydrophilic, insoluble in water and most organic solvents, and biodegradable. It is mainly used to produce cardboard and paper. It can be...

The effect of hyperbranched polymers on processing and thermal stability of biodegradable polyesters.(Technical report)
March 1, 2009... INTRODUCTION Biodegradable polymers and polymers from renewable resources are a relatively new class of materials and as a result lack of comprehensive understanding of their processing characteristics. Some of the well-established...

Strategies for improving graft degree of urethane derivative of 2-hydroxymethyl methacrylate grafted onto LDPE.(low density polyethylene)(Technical report)
March 1, 2009... INTRODUCTION Functionalization of olefin polymers by grafting unsaturated monomers is highly important for processing polymer blends, preparing of polyolefin with improved adhesion towards solid surfaces (1-3). As one of the most widely...

Development of epoxy/hyperbranched blends for resin transfer molding and vacuum assisted resin transfer molding applications: effect of a reactive diluent.(Technical report)
March 1, 2009... INTRODUCTION Epoxy resins are widely used due to their thermal, mechanical, chemical, and corrosion resistances. The low viscosity in the uncured state is a favorable property that enables processing without the use of high pressure...

Ethylene vinyl acetate/ethylene propylene diene terpolymer-blend-layered double hydroxide nanocomposites.(Technical report)
March 1, 2009... INTRODUCTION Polymer nanocomposites are a new class of composite materials that can impart tremendous improvements in properties over pure polymer or that of conventional composites (1). These improvements include mechanical properties,...

New smart conducting elastomer blends of bi-based superconductor ceramics nanoparticles reinforced natural rubber/low-density polyethylene for double thermistors, antistatic protectors, and electromagnetic interference shielding effectiveness applications.(Technical report)
March 1, 2009... INTRODUCTION Incorporation of conductive fillers such as carbon black, graphite, metals, and others into a hosting polymer matrix constitutes a good approach for the development of special materials, which combine electronic conductivity...

Dissolution mechanism of polymers in high pressure--high temperature n-alkanes--application to blends separation.(Technical report)
March 1, 2009... The use of a high temperature-high pressure near critical solvent is an interesting alternative to dissolve high-molecular-weight polyolefins with alkanes. This characteristic allows their separation from the blends with other polymers. In the...

([Eta]6-N-alkylcarbazole) ([eta]5-cyclopentadienyl) iron hexafluorophosphate salts in photoinitiated and thermal epoxy polymerization.(Technical report)
March 1, 2009... INTRODUCTION UV curable systems are categorized as either radical or ionic polymerizations. Photoinitiated radical polymerizations have been investigated for a considerable period of time, but photoinitiated cationic and anionic...

The rheological modification of talc-filled polypropylene by epoxy-polyester hybrid resin and its effect on morphology, crystallinity, and mechanical properties.(Technical report)
March 1, 2009... INTRODUCTION Polypropylene (PP) is an attractive candidate for many engineering applications because of its excellent chemical resistance, acceptable range of tensile strength and modulus, good impact strength and processability, and low...