Polymer Engineering and Science articles from January 2004

Polymer Engineering and Science archives from January 2004

Analysis of gate freeze-off time in injection molding.
January 1, 2004... INTRODUCTION Injection molding is commonly schematized into three main phases: the filling step, during which a molten resin is injected into a cavity colder than the resin solidification temperature; the packing/holding step, when further...

Measurement of interfacial tension in PS/LDPE melts saturated with supercritical C[O.sub.2].
January 1, 2004... INTRODUCTION Interfacial tension between two polymer melts is an important factor that, together with the composition, rheological properties of components and processing conditions, influences the morphology of polymer blends (1)....

Polyaniline/carbon nanotube composite Schottky contacts.
January 1, 2004... INTRODUCTION Schottky diodes fabricated from solvent casting (1-3), electropolymerization (4), (5), Langmuir-Blodgett deposition (6), (7), vacuum deposition (8), and pellets (9) of polyaniline (PANI) have been investigated by several...

Effect of erucamide and silica loadings on COF behavior of POP multilayer films in repetitive testing.
January 1, 2004... INTRODUCTION The use of multilayer polyolefin films has been increasing because of the advantages they offer over conventional single-layer polymer films. These advantages include excellent moisture- and oxygen-barrier properties, superior...

Compression behavior of pulp fiber networks.
January 1, 2004... INTRODUCTION In compression molding of fiber reinforced polymers the fibers are suspended in a molten matrix and the whole is compacted by the application of pressure. Beyond the percolation threshold the fibers form a load-supporting...

Surface characteristics of hydrosilylated polypropylenes: effect of co-catalyst and reaction temperature.
January 1, 2004... INTRODUCTION Polypropylene (PP) is a major commodity polymer used in the plastics industry. Its low price, good thermal and mechanical properties, chemical inertness, crystallinity, and hydrophobic character are desired in many...

Mechanical properties, water swelling behavior, and morphology of swellable rubber compatibilized by PVA-g-PBA.
January 1, 2004... INTRODUCTION As a novel functional material, water-swellable rubber (WSR) can stop water not only by means of elastic sealing but also by means of swelling in water. It is a kind of multicomponent blend, composed of rubber, water-absorbent...

The synergistic effect of boron nitride particle and die on the capillary extrusion processability of mLDPE.
January 1, 2004... INTRODUCTION It is well known that the productivity of processes such as film casting, film blowing, and coasting is limited by the onset of melt fracture. Much research has been carried out to investigate flow instability in polymer...

Investigation of fundamental data for nitrile butadiene rubber in monochlorobenzene and o-dichlorobenzene.
January 1, 2004... INTRODUCTION The catalytic hydrogenation of nitrile butadiene rubber (NBR) is an important industrial process, resulting in a tougher and more stable derivative, namely, hydrogenated nitrile butadiene rubber, which has found wide...

Variations in surface gloss on rubber-modified thermoplastics: relation to morphological and rheological behavior.
January 1, 2004... INTRODUCTION The rheology and morphology of a multi-phase polymer system are subjects of intense interest from both technical and scientific standpoints. The impact properties of a number of engineering thermoplastics can be markedly...

Structure and properties of poly(ethylene-co-chlorotrifluoroethylene) and polyvinylidene fluoride exposed to water, hydrochloric acid, hydrobromic acid and tetrachloroethylene.
January 1, 2004... INTRODUCTION Fluoropolymers are used extensively as linings or coating materials to protect steel or glass-fiber rein-forced plastics (FRP) in metal-aggressive environments and often at elevated temperatures. Their excellent thermal...

On the modeling of quiescent crystallization of polymer melts.
January 1, 2004... INTRODUCTION Many processes involving polymers, such as film blowing, fiber spinning, and injection molding, involve the crystallization of the polymeric melt while it is being cooled and subject to deformation. The final properties of the...

Peroxide crosslinking of Ziegler-Natta thermoplastic polyolefins.
January 1, 2004... INTRODUCTION Peroxide cross-linking is a well-known technique to improve the elasticity of EPM rubbers. The basic mechanisms of this process and in particular the competition between visbreaking and cross-linking have been extensively...

Color of pigmented plastics--measurements and predictions.
January 1, 2004... INTRODUCTION Many colored injection-molded plastic components are used in the interior of a car in order to minimize weight and costs and to optimize functionality. The design engineer has the task of guaranteeing the quality impression in...

Shear rate and wall slip velocity functions of polyvinyl chloride melts based on slit die viscometry data.
January 1, 2004... INTRODUCTION Capillary and slit viscometers are widely used to study the shear behavior of polymer melts and well-developed procedures exist for converting the resulting viscometry data into shear stress versus shear rate function...

Influence of untreated and novel electron beam modified surface coated silica filler on dynamic mechanical thermal properties of ethylene-octene copolymer.
January 1, 2004... INTRODUCTION It is well accepted that the surface activity of a filler influences significantly reinforcement in the filled composites. It provides a physicochemical contribution to reinforcement (1). The chemical nature of a particle...

A rheokinetic study of bulk free radical polymerization performed with a helical barrel rheometer.
January 1, 2004... INTRODUCTION According to the general theory (1,2), the rate of a bulk free radical polymerization can be expressed as R = -[d[M]/dt] = [([f[k.sub.i]]/[k.sub.t])[.sup.1/2]] [k.sub.p][I.sup.1/2][M] (1) The negative sign is added in...

Crystallization kinetics of poly (L-lactide) in contact with pressurized C[O.sub.2].
January 1, 2004... INTRODUCTION The presence of C[O.sub.2] in a polymer affects the polymer's properties in both the molten and solid states. The dissolved C[O.sub.2] changes the glass transition temperature, [T.sub.g] (1-9), and crystallization temperature,...

A study on sliding wear of ultrahigh molecular weight polyethylene/polypropylene blends.
January 1, 2004... INTRODUCTION Ultrahigh molecular weight polyethylene (UHMWPE) exhibits a very low wear coefficient and a moderate coefficient of friction when it is sliding against steel or other materials (1). A large number of studies on friction and...