Polymer Engineering and Science articles from February 2004

Polymer Engineering and Science archives from February 2004

Preface.
February 1, 2004... Film and fiber processes represent a large segment of the plastics industry and the R & D activities of many research labs. These processes take advantage of orientation of polymer macromolecules and stress-induced crystallization to develop...

Crystallization and orientation development in fiber and film processing of polypropylenes of varying stereoregular form and tacticity.
February 1, 2004... INTRODUCTION Stereoregular crystalline polypropylene was first synthesized in 1955 by Natta and his co-workers (1, 2). It was the isotactic form (iPP), which has asymmetric carbon atoms with all the same d or l configurations throughout...

Characterization of polyethylene terephthalate films drawn in hot water.
February 1, 2004... INTRODUCTION The reduction of the mechanical properties of polyethylene terephthalate (PET) by small amounts of sorbed water has been previously reported (1). Sorbed water molecules in PET (around 1% in mass) are known to lead to classical...

Biaxial deformation of polyamide-6: assessment of orientation by means of infrared trichroism.
February 1, 2004... INTRODUCTION The processing-structure-performance relationship for a semicrystalline polymer like polyamide-6 (PA-6, nylon-6) is quite complex. The ultimate mechanical behavior depends on the structure of the product (degree of...

Blends, hydrogen bonds, and orientation: understanding the role of interactions.
February 1, 2004... INTRODUCTION Two main phenomena are known to result in the final observed orientation of a polymer: first, initial deformation, and second, relaxation towards an equilibrium state, which can occur both during and after deformation. ...

Biaxial Stretching and structure of various LLDPE Resins.
February 1, 2004... INTRODUCTION Polyethylenes are by far the most widely used resins in the film industry. They are used for a variety of applications and in different film processes; blown film, cast film and biaxially oriented films (double bubble...

Structural organization and drawability in polyamide blends.
February 1, 2004... INTRODUCTION Polymer films used in food packaging are required to exhibit good properties in a wide variety of domains (mechanical, optical, gas permeability, processing...). Multilayer films are currently used in order to fulfill such...

Structure and properties of an oriented fluorosulfonated/PTFE copolymer.
February 1, 2004... INTRODUCTION Nafion[R] is the commercial name for the perfluorinated ionomer membranes developed by DuPont in the 1960s (1). The Nafion polymers are initially synthesized in the precursor form shown below: [FORMULA NOT REPRODUCIBLE IN...

Dynamics and criteria for bubble instabilities in a single layer film blowing extrusion.
February 1, 2004... INTRODUCTION Film blowing extrusion converts conventional polyethylenes such as high (HDPE), linear low (LLDPE) and high-pressure low density (LDPE) polyethylenes into thin plastic films. It is one of the most important forming processes...

Effects of carbon nanotubes on the crystallization behavior of polypropylene.
February 1, 2004... INTRODUCTION The discovery of carbon nanotubes and carbon nano-structured materials has inspired a range of potential applications (1-4). More specifically, the use of carbon nanotubes in polymer/carbon nanotube composites has attracted...

Fiber draw using draw pins under isothermal conditions.
February 1, 2004... INTRODUCTION In this paper we model the draw process of as-spun, undrawn fiber with elastic-plastic constitutive behavior. In an isothermal draw process involving a series of rollers with increasing surface speeds, the tension in the...

PBT/PET conjugated fibers: melt spinning, fiber properties, and thermal bonding.
February 1, 2004... INTRODUCTION Non-woven fabric, also called bonded fabric, represents one of the fastest-growing areas of interest in the textile industry (1). It has been extensively used in areas such as agriculture, construction, automotive, civil...

Synthesis of unsaturated polyester-clay nanocomposites using reactive organoclays.
February 1, 2004... 1. INTRODUCTION Unsaturated polyester (UP) resins are widely used as matrices for polymer composites because of low cost and easy handling. The thermal cycles leading to the final product generally include curing and post-curing periods....

Structure modification of isotactic polypropylene by bi-component nucleating systems.
February 1, 2004... INTRODUCTION The heterogeneous nucleation induced modification of structure and properties by semicrystalline thermoplastic polymers is a widely studied topic. Especially in the case of an isotactic polypropylene (iPP) and of related...

Electroless plating of copper on fluorinated polyimide films modified by surface graft copolymerization with 1-vinylimidazole and 4-vinylpyridine.
February 1, 2004... INTRODUCTION Conventional polyimides (PIs), such as poly(pyromellitic dianhydride-co-4,4'-oxydianiline), i.e. (PMDA + ODA)-based PI, have been widely used as dielectric and packaging materials in the microelectronics industry because of...

Curing and pyrolysis of cresol novolac epoxy resins containing [2-(6-oxido-6H-dibenz(c,e)(1,2)oxaphosphorin-6-yl)-1,4-naphthalenediol].
February 1, 2004... INTRODUCTION Epoxy, one of the most important polymeric materials in the electric, electronic, or aerospace industries, has excellent physical properties such as moisture resistance, good thermal stability, excellent mechanical strength,...

Bubble removal in rotational molding.
February 1, 2004... 1. INTRODUCTION Rotational molding is used to produce chemical tanks, automotive and commercial aircraft parts, backyard play equipment, toys, and many other items. It is an attractive alternative to injection and blow molding because the...

Effects of electron beam irradiation on poly(ethylene 2,6-naphthalate)/poly(ethylene terephthalate) blends.
February 1, 2004... INTRODUCTION In recent years, several technologies for high-energy irradiation in air have been intensely investigated for possible use in industrial applications. In general, the effects of high-energy irradiation on polymers can lead to...

SI metric units.
February 1, 2004... The following list shows the names, symbols, and equivalence of the more common quantities allowed in the SI metric system. The prefixes and symbols for the more common multiple units are also shown. Neither list is complete. Full details are...