Polymer Engineering and Science articles from May 2003

Polymer Engineering and Science archives from May 2003

Effects of molecular weight and molecular structure of low profile additives on the properties of Bulk Molding Compound (BMC).
May 1, 2003... INTRODUCTION Bulk Molding Compound (BMC) and Sheet Molding Compound (SMC) are composites generally containing thermosetting unsaturated polyester (UP) resin as the matrix, glass fibers or carbon fiber as reinforcement, and other...

Composites from PMMA modified thermosets and chemically treated woodflour.(polymethyl methacrylate)
May 1, 2003... INTRODUCTION The use of vegetable fibers and/or particles as reinforcement/filler of polymeric matrices has attracted growing interest in the past decade from both the academic and the applied points of view. Natural vegetable fibers...

Ethylene polymerization over mgo-supported zirconocene catalysts.
May 1, 2003... INTRODUCTION Metallocene catalysts have received much attention in industry because they can produce polymers with a narrow molecular weight distribution, uniform chemical composition or a stereo-specificity. Several types of metallocene...

Ternary composites based on PP-EPDM blends reinforced with flax fibers. Part I: processing and thermal behavior.
May 1, 2003... INTRODUCTION Short conventional fibers (glass, carbon, aramid, nylon, etc.) have been extensively used as reinforcements of polymeric matrices lately. They have been incorporated in plastics and rubber with the main objective of providing...

Ternary composites based on PP-EPDM blends reinforced with flax fibers. Part II: mechanical properties/morphology relationship.(polypropylene - ethylene-propylene-diene terpolymer)
May 1, 2003... INTRODUCTION It is well known that the addition of small quantities of elastomer improves the flexibility and impact resistance of PP, particularly at low temperatures (1-4). Among the available impact modifiers, ethylene-propylene-diene...

Barrier properties of injection molded blends of liquid crystalline polyesters (Vectra) and high-density polyethylene.
May 1, 2003... 1. INTRODUCTION Thermotropic liquid crystalline polymers (LCPs) are extremely good barriers against permanent gases and larger penetrant molecules. This is the reason for the emerging interest in these materials in packaging technology....

A method to control the dispersion of carbon black in an immiscible polymer blend.
May 1, 2003... INTRODUCTION The dispersion of carbon black (CB) in an immiscible blend has been studied quite extensively (1-3). One of the objectives in studying the dispersion of CB in immiscible blends is to optimize the dispersion of CB in the blend...

Effects of strain and temperature on the electrical properties of carbon black-filled alternating copolymer of ethylene-tetrafluoroethylene composites.
May 1, 2003... INTRODUCTION It is well known that the resistivity of carbon black (CB)-filled conductive polymer composites changes significantly when the composites are subjected to deformation. The deformation can be produced by mechanical strain or...

Investigation of fracture properties of epoxy at low temperatures.
May 1, 2003... INTRODUCTION Epoxide resins are widely employed in cryogenic engineering as impregnating materials, adhesives, or as matrices in fiber-reinforced composites. Thermal stresses, resulting from differential contraction, may be induced in the...

Evaluation of impact fracture toughness of polymeric materials by means of the J-integral approach.
May 1, 2003... INTRODUCTION Williams and Adams (1) have pointed out the difficulty of obtaining reliable data from instrumented impact tests at high impact speeds. The growing use of polymeric materials in engineering applications demands new...

Nano-alumina modified epoxy based film adhesives.
May 1, 2003... INTRODUCTION Epoxy-based film adhesives are being used increasingly for the fabrication and joining of aluminum and polymeric composite parts in the aircraft industry because of problems associated with conventional fasteners. While these...

Numerical simulation of film casting using an updated Lagrangian finite element algorithm.
May 1, 2003... INTRODUCTION Two main approaches exist for describing the motion of a body (1): the material formulation, where the conservation equations are applied to a control mass; and the spatial formulation, where the conservation equations are...

Gross melt fracture mitigation in converging dies: a singular behavior due to polymer wall slip.
May 1, 2003... INTRODUCTION It is well recognized that many polymer-processing operations (extrusion, melt spinning or film blowing) are disturbed by extrusion defects and flow instabilities, namely surface melt fracture (sharkskin), stick-slip defect...

Synthesis and characterization of ehylene vinyl-acetate/polyaniline blends prepared by emulsion polymerization technique.
May 1, 2003... INTRODUCTION Siddarmaiah The demand for electrically conducting materials with a good balance of mechanical properties and processable by conventional thermoplastic processing machines is steadily increasing. To achieve such goals, in...

Development of renewable resource-based cellulose acetate bioplastic: effect of process engineering on the performance of cellulosic plastics.
May 1, 2003... INTRODUCTION Sustainabiity, industrial ecology eco-efficiency and green chemistry are guiding the development of the next generation of advanced materials, products and processes. Biodegradable polymers and bio-based polymer products based...

Erratum.(Correction Notice)
May 1, 2003... "Gross Melt Fracture Elimination: The Role of Surface Energy of Boron Nitride Powders," by Manish Seth, Sawas G. Hatzikiriakos, and Thomas M. Clere, Polym. Eng. Sci., 42, 743-52 (April 2002). In this paper a modified technique based on...