Polymer Engineering and Science articles from April 2008

Polymer Engineering and Science archives from April 2008

Effects of thermal aging on isotactic polypropylene crystallinity.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Isotactic polypropylene (iPP) is used extensively as a matrix material in thermoplastic composites due to its excellent mechanical properties and relatively low cost. Since the long-term engineering properties of iPP are...

Effect of annealing and orientation on microstructures and mechanical properties of polylactic acid.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Polylactic acid (PLA) is a widely studied biomaterial, and it has been approved for use in a range of medical devices, including applications such as hard tissue and drug delivery [1-4]. PLA is also one of the most attractive...

Oxygen permeability of biaxially oriented polypropylene films.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Polypropylene is an attractive candidate material for packaging applications because of its low cost and good thermal stability. Biaxial orientation, by means of a tentering process, for example, imparts mechanical robustness...

Solid-state blending of poly(ethylene terephthalate) with polystyrene: extent of compatibilization and its dependence on blend composition.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION The blending of immiscible polymers via conventional melt and solution routes is often hindered by technical issues such as thermal degradation, inadequate mixing, undesirable side reactions, and dispersed-phase domain...

Rheological characterization of room temperature vulcanized silicone sealant: effect of filler particle size.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Polymeric materials are usually endowed with a lot of advantages over the virgin polymer systems in case of incorporation of inorganic filler particles into them, e.g. excellent viscoelastic behavior, increased mechanical...

Condensed-phase flame retardation in nylon 6-layered silicate nanocomposites: films, fibers, and fabrics.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Fire hazards have a great socioeconomic impact on the society. Textile materials being readily combustible serve as one of the ingredients of fire and pose a serious threat to human life and property in fire accidents....

Compression hysteresis of fibrous systems.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Nature and man-made fibers are widely applied polymer materials in practice. The mechanical properties, among which is the compression of fiber and fiber assembly are of great interest in many fields of engineering such as...

Foam formation from fluorinated polyphosphazenes by liquid C[O.sub.2] processing.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Only a limited number of polymers such as fluorinated polyacrylates, fluoroalkoxy polysiloxanes, and poly(difluoroethylene) are soluble in or are swelled by liquid carbon dioxide [1-3]. Thus, the discovery of additional...

Improved through-plane electrical conductivity in a carbon-filled thermoplastic via foaming.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Electrically conductive thermoplastic composites are growing in demand within the energy, electronic, and medical sectors for applications such as thermal switches, EMI shielding, blood sensors, and fuel cell bipolar separator...

Effect of molecular weight and molding conditions on the replication of injection moldings with micro-scale v-groove features.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Recently there has been a rapid increase in the production of polymer components for micro engineering application with micro- or nano-structured surfaces [1, 2]. The actual volume of the productions requires low cost...

Fibril formation of 1,3:2,4-Di(3,4-dimethylbenzylidene) sorbitol in polymer melts.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION The technology of blending and compounding polymers with different additives in order to gain enhanced performance or new function is well established. Sorbitol based nucleators are additives miscible in the polymer melt,...

Advanced injection molding mold and molding process for improvement of weld line strengths and isotropy of glass fiber filled aromatic polyester LCP.(liquid crystal polymers)(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Liquid crystalline polymers (LCPs) are exceptional plastics in that they maintain crystalline order of molecular chains of solid plastic also in melt state during injection molding process. The consequences are sharp melting...

Local thermo-oxidative degradation in injection molding.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Many applications of plastic parts have high demands for part quality and long-term performance. In certain fields of application, such as the medical field, product reliability is crucial. Examples are artificial lenses,...

Characterization of new formulations for the rotational molding based on ethylene-propylene copolymer/graphite nanocomposites.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Among the traditional polymer processing techniques, the rotational molding allows the processing of large parts, in a single step. Nevertheless, the main disadvantage of rotational molding is the long times of processing...

Effects of welding procedures on mechanical and morphological properties of hot gas butt welded PE, PP, and PVC sheets.(polyethylene, polypropylene, polyvinyl chloride)(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION In recent years, joining of plastic materials has been put on the agenda, since a second process is necessary to produce large and complex structures using semifinished plastic materials such as sheet, profile, and pipe. In...

Yield stress and rheological characterization of the low shear zone of an epoxy molding compound for encapsulation of semiconductor devices.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION An epoxy molding compound (EMC) for the encapsulation of semiconductor devices is a composite material filled with a large amount of silica filler. Therefore, its melt flow shows the behavior of a pseudo-plastic fluid having...

A comparative study of dispersing a polyamide 6 into a polypropylene melt in a Buss Kneader, continuous mixer, and modular intermeshing corotating and counter-rotating twin screw extruders.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION One of the key factors in achieving the desired final properties of polymer blends is the control of the control of phase morphology. The properties of blended polymers can vary considerably with the shape and size of the...

Simulation of the residual stresses in the contour laser welding of thermoplastics.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Laser technology already has a broad range of applications in the field of plastics welding technology, providing welding technicians with a welcome alternative to the series welding processes. Sample applications for laser...

Calculation and significance of the maximum polymer surface temperature T* in reciprocating cylinder-on-plate sliding.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Low thermal conductivity and low heating resistance of polymers are important limitations for sliding applications, although mechanical [1], chemical [2], or thermal [3] interactions favorably control their self-lubricating...

Determination of different morphological structures in PC/ABS open spiral injection moldings.(Polycarbonate /Acrylonitrile-Butadiene-Styrene)(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION In polymer blend injection molding, the morphology through the thickness of the specimen has been defined based on the final size; shape, and location of each distinguishable phase present and are widely reported over the last...

Synthetic 6FDA-ODA copolyimide membranes for gas separation and pervaporation: correlation of separation properties with diamine monomers.(diphthalic anhydride, aminophenyl ether)(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION The first polyimides were synthesized in 1908, but more research interest in preparation and application of polyimides was attracted since 1955 when high molecular weight polyimides were successfully obtained through the...

In-line measurements of the morphological parameters of PP/PA6 blends during extrusion in the transient mode.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Polymer blends are often developed to take advantage of the synergism of two or more distinct polymer components, avoiding the expensive and time-consuming process of developing a new material through a synthesis process [1]....

The mastication characteristics of powdered carbon black filled natural rubber during internal mixing.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION Since the molecular weight of gum natural rubber is very high, it shows strong elastic properties and is hard to process. Mastication is one of the basic steps during the processing of natural rubber. During mastication step,...

Synthesis and characterization of hollow polyaniline microtubes and microbelts with nanostructured walls in sodium dodecyl sulfate micellar solutions.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION In the past decade, significant attention has been focused on synthesizing one-dimensional nanostructures of conducting polymers because they have the advantages of low-dimensional organic conductors with high surface area,...

Thermal degradation and physical aging of poly(lactic acid) and its blends with starch.(Author abstract)(Technical report)
April 1, 2008... INTRODUCTION The use of biodegradable and renewable materials to replace conventional petroleum plastics for biodegradable and renewable materials for disposable applications is becoming popular [1-3]. Poly(lactic acid) (PLA), a synthetic...