Polymer Engineering and Science articles from August 2008

Polymer Engineering and Science archives from August 2008

Production and characterization of membranes of recycled waste materials: cellulose acetate, obtained from sugarcane bagasse with polystyrene from plastics cups.(Technical report)
August 1, 2008... INTRODUCTION Brazil is the world's major sugarcane producer and the 2006/2007 harvest reached 457 million metric tons. Because of federal incentive, this production tends to increase since many new sugarcane mills will be assembled. Only...

Effect of intercalating agents on clay dispersion and thermal properties in polyethylene/montmorillonite nanocomposites.(Technical report)
August 1, 2008... INTRODUCTION Layered silicate based polymer nanocomposites have attracted considerable interest since nanometric scale dispersion was obtained in polyamide/clay composites (1). Compared with conventional polymer composites, such structure,...

Tribological behaviors of aligned carbon nanotube/fullerene-epoxy nanocomposites.(Technical report)
August 1, 2008... INTRODUCTION The tribological behaviors of polymer composites have drawn considerable interest because of their importance in ultra-light weight aerospace structures (1), gears (2), bearings. (3), bullet-proof helmets (4), among others....

Real-time wide-angle X-ray diffraction during polyethylene blown film extrusion.(Technical report)
August 1, 2008... INTRODUCTION Films produced by blown film extrusion are widely used in packaging applications (1). The effect of blown film process parameters on the microstructure and the mechanical properties, viz. tensile and tear strength, have been...

Interfacial modifications in PS/PMMA and PVC/EVA blends by E-beam and microwave irradiation: a free volume study.(polystyrene/polymethyl methacrylate, polyvinyl chloride/ethylene-vinyl acetate)(Technical report)
August 1, 2008... INTRODUCTION Blending is a widely used technique in polymer research to improve the physical/mechanical properties of homopolymers (1). Polymer blends with exploitable combination of properties are an alternative to meet the steadily...

Investigation of LDPE blown film instability induced by air cooling.(low-density polyethylene)(Technical report)
August 1, 2008... INTRODUCTION Instability in polymer processes, which have free surface flows, such as fiber spinning, cast film, and blown film, limits the rate of industrial production and may give rise to unacceptable production quality. Bubble...

Photooxidative behavior of polystyrene-montmorillonite nanocomposites.(Technical report)
August 1, 2008... INTRODUCTION For the last three decades, the study of polymer-clay nanocomposites has attracted great interest from academic groups and industries as these materials often exhibit excellent mechanical, thermal, and gas barrier properties...

Effects of initiator type in rigid polyurethane foams.(Technical report)
August 1, 2008... INTRODUCTION Polyurethanes (PUs) are versatile engineering materials that find a wide range of applications, because their properties can be readily tailored by the type and composition of their components (l-3). PUs are used as foams,...

A new application of biosurfactant for the preparation of polycaprolactone/layered silicate nanocomposites.(Technical report)
August 1, 2008... INTRODUCTION Over the last decade, polymer/clay nanocomposites had been received a considerable industrial and academic interest for conquering the shortcomings of conventional composites. This is due to the fact that inorganic clay...

Detecting crystallization structure evolution of polypropylene injection-molded bar induced by nucleating agent.(Technical report)
August 1, 2008... INTRODUCTION The microstructure of polymer injection-molded bars has been intensively researched in the last 10 years because the microstructure is very important for the end-use properties of the molded articles. During injection-molding...

Semiempirical, squeeze flow, and intermolecular diffusion model. II. model verification using laser microwelding.(Technical report)
August 1, 2008... INTRODUCTION When two surfaces made from the same polymer are brought together in the molten state, the surfaces will conform to each other to achieve intimate contact and over time with intermoleular diffusion and chain entanglements,...

Unusual thermal degradation of maleic anhydride grafted polyethylene.(Technical report)
August 1, 2008... INTRODUCTION Polymers, in general, exhibit lower thermal stability in air than in nitrogen because of oxidative degradation. However, some polymers have better thermal stability in air, such as poly(methyl methacrylate) (PMMA) and...

Numerical and experimental investigation of shrinkage behavior of precision injection molded articles. I. Development of lateral motion modeling.(Technical report)
August 1, 2008... INTRODUCTION Birefringence, residual stress distribution, and shrinkage affect the mechanical and/or optical quality of molded articles. Therefore, one wants to control or manage them especially for a precision injection molding. In this...

Numerical and experimental investigation of shrinkage behavior of precision injection molded articles. II. Results and Discussion.(Technical report)
August 1, 2008... INTRODUCTION In the accompanying paper, Part I, new lateral motion models have been developed by modeling the stickiness between the mold wall and polymer surface. New models are designed to be capable of expressing more general lateral...

Ultrasound aided extrusion process for preparation of polyolefin-clay nanocomposites.(Technical report)
August 1, 2008... INTRODUCTION Polymer nanocomposites have opened a new horizon for a promising class of hybrid materials by incorporation of particulate fillers into polymer matrices to improve or modify properties of neat polymers. In recent years,...

Valorization of poly(butylene terephthalate) wastes by blending with virgin polypropylene: effect of the composition and the compatibilization.(Technical report)
August 1, 2008... INTRODUCTION The recycling of postconsumer plastic wastes has been a focus of attention in the past decade (1), and may be explained by limited natural resources, rising waste-handling costs, and environmental regulations. Blending...

Fiber-particle morphological transition and its effect on impact strength of PS/HDPE blends.(polystyrene/ high-density polyethylene)(Technical report)
August 1, 2008... INTRODUCTION The postextrusion processing involved in the production of polymer films and ribbons are of great industrial importance in transport of materials and packaging. The process consists of the following steps: extrusion of a...

Supercritical carbon dioxide-induced melting temperature depression and crystallization of syndiotactic polypropylene.(Technical report)
August 1, 2008... INTRODUCTION In the recent years, the use of new metallocene catalysts has allowed producing syndiotactic polypropylene (sPP) with high stereoregularity and interesting mechanical properties (1-3). Extensive studies (4-14) have shown that...

Luminance of injection-molded V-groove light guide plates.(Technical report)
August 1, 2008... INTRODUCTION Edge-lit backlight systems have been widely used in industry due to several advantages over traditional devices. They consume less energy, are light weight, and have highly uniform intensity. The backlight industry requires...

New aramid-based nanocomposites: synthesis and characterization.(Technical report)
August 1, 2008... INTRODUCTION Nanocomposites are an important class of new generation materials, which typically exhibit properties superior to those of their individual components. To optimize the performance properties of these materials, the dispersion...

Thermomechanical analysis and modeling of the extrusion coating process.(Technical report)
August 1, 2008... INTRODUCTION Extrusion coating is commonly used to coat a substrate with a polymer film. As shown in Fig. 1, it combines a film extrusion and stretching with a "calendering" step to apply the film on the substrate. The first step...

Electronic structure evidence for all-trans poly(methylvinylidene cyanide).(Technical report)
August 1, 2008... INTRODUCTION Photoemission, particularly light polarization dependent photoemission (1), (2), can be very successful in establishing that the highly dipole-ordered polymers, prepared by Langmuir Blodgett techniques (3), (4), have dipoles...