SPE Library

The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.

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Conference Proceedings

Smart Adhesion: Controlling Polymer Interfaces through Patterning

Alfred J. Crosby, May 2004

To understand the role of patterned geometries/topographies in controlling polymer adhesion and release, we fabricate controlled structures ranging from the nanometer to micron length scales on polymer surfaces. Our initial results focus on the effect of patterned arrays of micron-scale posts and holes on the adhesion of polydimethylsiloxane layers. To facilitate the exploration of the large, possibly non-continuous parameter space presented by this problem, we rely upon combinatorial methodologies to effectively screen multiparameter maps.

Micro-Thermomechanical Properties of Composite Polymer Surfaces as Probed by Scanning Probe Microscopy

Vladimir V. Tsukruk, May 2004

We present an overview of the microprobing approaches based on scanning probe techniques to study surface micro- and nano- thermomechanical properties. We focus on polymer composites and nanocomposites, ultrathin polymer coatings, and polymer multiphase molecules. We briefly review state-of-the art developments in the field of contact surface nanoprobing, scanning thermal microscopy analysis.

Confocal Raman Imaging of Heterogeneous Polymeric Materials

Chris A. Michaels, Donna B. Klinedinst, D. Bruce Chase, May 2004

Confocal Raman microscopy is a powerful tool for the characterization of spatial variations in material properties including chemical composition and crystallinity. The design of a custom Raman microscope will be described, as will applications of this technique to the characterization of the chemical microstructure and morphology of heterogeneous polymeric materials.

Near Field Infrared Microscopy of Polymer Surfaces

Larissa Stebounova, Slava Romanov, Boris Akhremitchev, Gilbert Walker, May 2004

We report recent results of the near field microscopy of polymers. Spatial resolution of chemical content at 100th the wavelength of light has been used to compare compositional imaging using infrared near field microscopy with the more commonly used method of AFM phase imaging.

Thermomechanical Probing of Molecular Mobilities in Nanoconfined and Structurally Constrained Polymeric Systems

René M. Overney, Tomoko Gray, Joseph Wei, Scott Sills, May 2004

The molecular mobility in nanoconfined and structurally constrained polymeric systems is a vital parameter in the advancement of future technological applications. We employed two scanning force microscopy methods, with which thermally activated structural transitions and molecular relaxation processes of ultrathin polymer films were examined. The potentials of these methods are illustrated involving polyelectrolyte membranes, dendronized nonlinear optical polymers and thin glassy homopolymer films.

Development of a Gelation Model for Methyl Cellulose Hydrogels

Sunil C. Joshi, Y.C. Lam, Li Lin, May 2004

The development of a gelation model for methylcellulose (MC) hydrogels is presented. The heat of gelation for aqueous solutions of different concentrations of MC SM4000 was measured using micro-DSC. Different mathematical formulations for modeling the experimental data were considered. The necessary constants were obtained empirically. Further analysis was performed to predict the total heat, the degree, and the rate of gelation. The effect of MC concentration on these parameters was investigated and discussed.

Fiber Reinforced Extruded Starch Foams

Gregory M. Glenn, Syed H. Imam, William J. Orts, Artur K. Klamczynski, May 2004

Cereal or tuber starches have been utilized in making low-density foam using a baking process. Foams made only of starch tend to embrittle and have poor mechanical properties. Fiber reinforced foams were made that had flexural properties similar to foam materials used in commercial food containers. Pulped fiber from wheat and rice straw was as effective as pulped hard and softwood fiber in improving foam properties.

Characterization of Structure and Viscoelastic Properties of Polypropylene Nanopolymer

Kamal K. Kar, Pradip Paik, Joshua U. Otaigbe, May 2004

High quality polypropylene nanopolymer has been synthesized over a range temperature and shear rate for the first time. Scanning electron microscopy, particle size analyzer and BET analysis reveals that it is spherical in nature and could be produced within a range of 0.17 to 45 ?m in diameter and minimum surface area of 16.2 m2/gm. Infrared spectroscopy, X-ray diffraction, dynamic mechanical analyzer and thermogravimetric analyzer are also used to characterize its structure, viscoelastic properties and thermal stability.

Optimum Content of Clay for Microcellular LDPE/Clay Nanocomposite Foams Blown with CO2

K.H. Wang, Y.H. Lee, C.B. Park, May 2004

This research investigates the optimum content of clay required to achieve microcellular LDPE/clay nanocomposite foams blown with CO2. The effects of clay content and clay dispersion on cell morphology are thoroughly investigated. Less than 0.1 wt% of clay addition produces a microcellular structure with a cell density of over 109 cells/cm3 and a cell size of about 5 ?m.

Methods of Expanding Polystyrene to Ultra Low-Density Foam

Chung P. Park, May 2004

Ultra low-density expanded polystyrene is obtained by an optimum formulation or by extended exposure to atmospheric steam. A polystyrene resin is rheologically modified to have both ease of flow and resistance against collapse. The collapse resistance is imparted either by light crosslinking of the resin with a silane compound or by adding a small amount of polyphenylene ether. Extended exposure to steam permits continuous extension of cell walls by reducing orientation. An expanded polystyrene loose fill material having an expansion ratio exceeding 200 has been achieved.

Torsion Properties of Cylindrical Polymer Foams

Denis Rodrigue, Yan Pelletier, Ryan Gosselin, May 2004

Solid state viscoelastic shear moduli (G' and G) of cylindrical polymer foams were measured as a function of frequency. Extruded samples were produced via a cylindrical die to obtain foams of various morphologies. To perform the shear measurements a modification of the torsion rectangular setup on an ARES rheometer was made. The setup calibration and test conditions are presented. The data are discussed and compared to simple models taken from the literature."

Prediction of Density Variation in Thick Microcellular Sheets

Krishna Nadella, Farhad Mehta, Vipin Kumar, Wei Li, May 2004

Earlier a process to produce thick flat microcellular sheets, in the 3 - 15 mm range for a number of thermoplastics such as PMMA, PS, ABS and PC was reported. In this paper a model to predict the density variation across the thickness of microcellular sheet is presented. This model builds on both the steady-state mass balance model and the skin thickness model for the solid-state microcellular process. The model is applied to predict density variation and mean density in a 1.5 mm thick microcellular PC and preliminary results are presented.

Effects of Nano-Particles on Density Reduction and Cell Morphology of Extruded mPE/Wood-Fiber/Nano Composites

G. Guo, K.H. Wang, C.B. Park, Y.S. Kim, G. Li, May 2004

This paper investigates the effects of nano-particles on cell morphology and foam expansion in the extrusion foaming of mPE/wood-fiber/nano-composites with a chemical blowing agent. The results indicate that the addition of clay generally decreases cell size, increases cell density and facilitates foam expansion. Furthermore, the foam material with added clay shows good char formation when it is burned.

Increase of Open-Cell Content by Plasticizing the Soft Regions with a Secondary Blowing Agent

Patrick C. Lee, Hani E. Naguib, Chul B. Park, Jin Wang, May 2004

This paper describes the effects of n-butane mixed with primary CO2 as a secondary blowing agent on cellpopulation densities, volume expansion ratios, and open-cell contents of low-density polyethylene (LDPE) and LDPE/polystyrene (PS) blends in extrusion. With the plasticizing effect of n-butane, a high open-cell content (up to 100%) over a wide range of processing temperatures was successfully achieved.

Solid-State Polyimide Foaming from Powder Precursors: Effect of Particle Morphology on the Diffusive Phenomena

Camilo I. Cano, R. Byron Pipes, May 2004

Solid-state foaming of polyimide powder precursors is studied by examining concurrent and competitive phenomena that determine the morphology and physical properties of the foam unit cell. Effects of particle size and shape on bubble nucleation and growth will be addressed.

Porous Polystyrene Foam Produced at Supercritical Conditions

Chang-Ming Wong, Wen-Chung Liang, Chih-Hung Ying, Ming-Lang Hung, May 2004

This work examines four polystyrene (PS) resins and PS resins with fillers. The materials .are processed into sheets and then the sheets are foamed at various supercritical conditions. The morphology of foam is studied and a large porous PS foam is also developed for a vacuum insulation panel.

Effects of CO2 Content on the Expansion Behaviors of PS Foams

Xiang Xu, Donglai Xu, Chul B. Park, May 2004

This paper discusses the effects of the blowing-agent content on the expansion behaviours of PS foams blown with CO2. Three groups of interchangeable filamentary dies were used to investigate the effect of the die geometry on the expansion ratio. A high CO2 content would be favourable to increase the expansion ratio. But the high CO2 content increased the solubility pressure and the amount of premature cell growth. When the amount of premature cell-growth exceeded a critical value, the expansion ratios were dramatically decreased, even at the optimum temperature.

Entrained Gas Process for Injection Molding

Jingyi Xu, May 2004

Entrained gas for injection molding, such as structural foam, microcellular foam, gas assist processing, has some common technical issues and safety concerns which are important to be fully understood for a safety system, and acceptable processing conditions. Several major issues are addressed and analyzed for machine and mold design, part design and handling.

Effects of Incorporating Recycled HDPE to Virgin HDPE and LDPE to Produce Tubular Film

José B. Sánchez, Erika Galvis, Rosalina Grimaud, Rosestela Perera, May 2004

This work presents the effects of incorporating post-consumer and post-industrial recycled HDPE to their virgin counterparts and to LDPE in different contents to produce tubular film for packaging. Tensile, surface and optical properties for each blend were measured.A reduction in the HDPEs blends physical properties and an increment in those of the LDPE/recycled HDPE blends were obtained as the recycled HDPE component was increased.

Nylon 66 - Maleated EPDM Polyblends

Rudolph D. Deanin, Sumit Mathur, May 2004

Nylon 66 was blended with maleated EPDM containing 0.5% of maleic anhydride. At 25% of maleated EPDM, impact strength increased 8-fold. On the other hand, modulus, strength, and DTUL decreased. The data suggested that the blend was too miscible, and might be improved by decreasing the maleic anhydride content to enhance phase separation.