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.
In this work, polyamide, polyamide, polybutyleneterephthalate and polyetherimide films were treated in an APGD unit using various applied voltages, frequencies and dwell times. The results show changes in the surface chemistry (FTIR); the degree of change in dynamic contact angle was found to be dependent on the polymer type, dwell time and electrical characteristics of the plasma.
Normal force measurement issues and the fragile nature of the 2K FRT are major problems with the current ARES Rheometer system. In an attempt to overcome these two issues a custom designed semiconductor strain gage based transducer was successfully installed in an ARES Rheometer. A comparison of the performance of a Rheometric Scientific series 2K FRT and the strain gage based transducer was performed. A comparison of sensitivity, accuracy and drift of data is shown for these two transducers.
The utilization of high Tg polymers to sequester low molecular weight electroactive organic compounds in the active layers of light emitting diode and photovoltaic devices has been demonstrated. The high Tg polymer allows for increasing the layer Tg, decreasing the crystallization rate, improving the mechanical properties and offering the capability of employing low cost fabrication processes. LED and PV device data demonstrating the concept will be presented.
Polymer blend technology was used to create highly anisotropic membranes for fuel cell applications. An important factor for creating structures of high proton conductivity and low methanol permeability was the application of electric fields of selected magnitude and frequency during the formation of the membrane.
Vapor grown carbon nanofiber (VGCNF) reinforced polyoxymethylene (POM) composites were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrical resistivity was also analyzed. The thermal stability of the composites was affected by VGCNFs. A drop of 14 orders of magnitude of volume resistivity was obtained by inclusion of 5 wt% VGCNFs. VGCNFs were shown to act as defects, the crystallinity was lowered and the crystallization was delayed.
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.
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 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.
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.
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.
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.
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.
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.
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.
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.
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."
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.
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.
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 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.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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