Polymer Engineering and Science articles from March 2006

Polymer Engineering and Science archives from March 2006

Three-arm poly ([epsilon]-caprolactone) by extrusion polymerization.
March 1, 2006... INTRODUCTION Poly ([epsilon]-caprolactone) (PCL) and similar polyesters such as polylactides (PLA), poly hydroxyl butyrate (PHB), and poly hydroxy (butyrate-co-valerate) (PHBV) are biodegradable, and attention to their use in disposable...

Flash*.(gaps between parting surfaces in plastic molding)
March 1, 2006... INTRODUCTION During injecting mold filling and especially after the cavity fills, the mold separating force widens the inevitable gaps between parting surfaces. When theses gaps meet parting lines, plastic can penetrate. Called flash, if...

Compatibilization of starch-polyester blends using reactive extrusion.
March 1, 2006... INTRODUCTION Plastics obtained from petrochemical sources generally have lifetimes of hundreds of years when buried in typical solid waste sites, and thus have posed significant environmental threats [1]. These plastics have contributed...

Magnetorheological elastomers based on isobutylene-isoprene rubber.
March 1, 2006... INTRODUCTION Magnetorheological (MR) materials are a group of smart materials whose rheological properties can be controlled by the application of an external magnetic field. Up to now two main kinds of MR materials have been reported. MR...

Surface characteristics of untreated and modified hemp fibers.
March 1, 2006... INTRODUCTION Natural cellulosic fibers are extensively used as reinforcing material in polymer substrates due to their high specific properties, low cost, unlimited availability, and renewable nature. Composites manufactured using them...

Validation of three on-line flow simulations for injection molding.
March 1, 2006... INTRODUCTION A fundamental difficulty in injection molding and other dynamic polymer processing operations is the lack of observability and controllability of the polymer melt. Because of the presence of an opaque and rigid steel mold to...

Shear rheology and melt compounding of compatibilized-polypropylene nanocomposites: effect of compatibilizer molecular weight.
March 1, 2006... INTRODUCTION Commercial exploitation of isotactic polypropylene has been expanded rapidly since the development of 'Zieglertype' catalysts in 1950s. It is because of polypropylene's attractive characters of low cost, low weight, heat...

Low-profile mechanisms in a PVAc/polyester blend.
March 1, 2006... INTRODUCTION Unsaturated polyester (UP) resins are widely used as a matrix for thermoset-based composites because of their low cost and versatility [1]. They most often constitute the organic matrix in sheet molding compounds (SMC) or bulk...

Effect of processing conditions on the formation of polypropylene/organoclay nanocomposites in a twin screw extruder.
March 1, 2006... INTRODUCTION The melt intercalation method is frequently used for the preparation of layered silicate-based nanocomposites. This method was first proposed by Vaia et al. [1, 2]. They showed that the intercalation of polymer chains into the...

Swelling behavior of poly(sodium acrylate)/kaoline superabsorbent composite.
March 1, 2006... INTRODUCTION Superabsorbents are slightly crosslinked hydrophilic polymers that can absorb, swell, and retain thousands times of aqueous liquids of their weights. Since the first superabsorbent reported by the U.S. Department of...

Addition compatibilization of PP/PS blends by tailor-made copolymers.(polypropylene)(polystyrene)
March 1, 2006... INTRODUCTION The polymer blends of commercial interest are frequently developed starting from incompatible components [1]. Large and nonhomogeneous particulate morphologies result from direct components blending, which exhibit low...

Reactively formed ENPT copolymers as compatibilizers in ternary blends of poly(ethylene naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide).
March 1, 2006... INTRODUCTION Various polymers can be blended to develop novel materials, with a range of favorable characteristics. However, most such blends are thermodynamically immiscible because the components have different solubilities [1, 2]. The...

Synthesis, characteristic, and application of new flame retardant containing phosphorus, nitrogen, and silicon.
March 1, 2006... INTRODUCTION Flame retardants (FRs) can improve fire performance of polymers to meet the requirement in electrical engineering and the electronic, transportation, and building industries. They have been widely studied and used in polymer...

Homopolymerization of epoxy monomers initiated by 4-(dimethylamino)pyridine.
March 1, 2006... INTRODUCTION One of the possible ways of polymerizing epoxy monomers is through the use of small amounts of Lewis bases that act as initiators of the anionic polymerization [1]. Commonly used initiators (often named "catalytic" curing...

Polymerization compounding of polyurethane-fumed silica composites*.
March 1, 2006... INTRODUCTION The problems encountered during the development of new composite materials are often attributed to the lack of interactions between the substrate and the polymer matrix, an insufficient dispersion of the substrate, or a poor...

The draw ratio-Deborah number diagram: a useful tool for coating applications.
March 1, 2006... INTRODUCTION In polymer processing, rheological properties of the material can be a limiting parameter to process performances and final product properties because of processing instabilities. Especially in the film production, coating,...

Determination of orientational states in impact-polystyrene specimens by near-infrared polarization spectroscopy.(Author abstract)
March 1, 2006... INTRODUCTION Many properties of polystyrene products are sensitive towards orientational phenomena. The anisotropy of transparent polystyrene products is often determined by birefringence measurements. However, this simple technique cannot...