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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The stress-optical coefficient function of two optical grade polycarbonates (PC) has been determined by simultaneous measurements of the relaxation modulus and strain-optical coefficient function. Based on these measurements, linear viscoelastic and photoviscoelastic constitutive equations were applied to evaluate residual thermal birefringence in quenched PC plates. Numerical results have been compared with the measurements.
A common experimental obstacle encountered during mechanical testing of fibers is that the cross-section area and transverse strain are difficult to assess directly. A laser diffraction technique has been found adequate to measure fiber diameters within the range of 10-100 um during tensile testing with a precision of ±10%. Fiber transverse strain is evaluated by SAXD and used to determine Poisson’s ratio and study deformation at different length scales of fibers with hierarchical structure.
In this study the influence of plug design, namely plug volume, plug taper, plug depth and plug temperature on the wall thickness distribution, weight and compression strength in thermoformed polypropylene cups was investigated. It was observed that the plug volume was the most importance factor for part shape. Plug depth had a significant effect on the bottom and corner thicknesses and part weight. Plug temperature and plug taper had a significant effect only on the compression strength.
PVA (Polyvinyl alcohol) with various molecular weights (Mw) were electrospun with a Calcium Phosphate based sol. Fibers on the order of 2 ?m with uniformly distributed sol particles were obtained. Electrospinning process may be facilitated with high molecular weight polymers. The distribution of sol in the electrospun structure may depend on polymer/sol ratio. XRD results indicate that the fibers after calcination consisted predominantly of hydroxyapatite.
An efficient and inexpensive approach was developed to prepare conductive polystyrene (PS) films via a simple solution dispersion method. Carbon nanofiber (CNF), which has a similar structure as multiwall carbon nanotubes and a high performance/price ratio, was used as the filler in this research to achieve conductivity in polystyrene films. A good dispersion was achieved within the polystyrene solution system even without using any surfactants. A low percolation threshold at about 0.75wt% has been achieved.
The magnitude of recovery force in shape memory polymers is usually low and must be augmented. In this work, a network is introduced in shape memory thermoplastic polyurethane (PU) by the addition of reactive nanoclay in an effort to improve the recovery force. In this case, nanoclay particles were allowed to tether to PU chains by chemical bonding. This report covers preliminary results on thermal, mechanical, and shape memory properties of clay-PU nanocomposites.
We describe a new method of point-of-origin quality detection for injection molding systems. The method encompasses data acquisition, Multivariate modeling, reject control and data reporting, provides in-line quality detection of injection molded parts, and real-time reports on fault contributors. We discuss real-world production applications in which MVA is applied using real-time molding parameters to predict quality, with a goal of Parametric Release.
The electrical conductivity and rheological properties under steady shear flow of carbon black-filled PDMS are measured as a function of filler loading, matrix viscosity and shear rate, upon application of an AC electric field. The effects of electric field are most notable at low filler loadings and low matrix viscosities.
The morphology of PC/ABS blend injection moldings is investigated using a spiral flow test mold. The results show that the specimen thickness would significantly affect the internal structure. Effect of specimen thickness on morphology of dispersed ABS phase in skin and core layers is extensively discussed in the relation to the mechanical properties.
In this research, we observed the cell nucleation and initial growth behaviours of PP foaming with N2 under various experimental conditions in a batch foaming simulation system. We found that the nucleating agent content, initial temperature, initial pressure (i.e., gas content), and pressure drop rate during foaming had significant effects on cell density and cell growth. The branched PP (WB130)/N2 had a higher cell density than the linear PP (HE351)/N2.
Foaming of thermoplastic is gaining interest because of its potential to decrease the weight of automotive parts. Understanding of the thermophysical properties of PP/gas mixtures is critically important in this context. This paper presents a newly developed experimental technique that captures the melt pendent drop images locally, determines the boundary locations precisely and then reconstructs those images to accurately measure the swelling of the polymer due to gas dissolution at elevated temperatures and pressures.
In this paper, a rheological die with a slit channel was designed to determine the solution viscosity of supercritical CO2 in non-crosslinked high-melt-strength (HMS) polypropylene (PP). The shear viscosity was modeled as a function of temperature, pressure, gas content, and shear rate. With interest in producing highly expanded foam sheets using an annular die, an analysis of the annular die pressure profile using the measured viscosity data was also conducted.
Foaming experiments were performed in extrusion using HDPE and Nitrogen. Talc was used as a nucleating agent, and three levels of pressure drop rate were applied. The use of talc significantly increased the cell density and reduced the role of pressure drop rate in cell nucleation.
The Center for Advanced Engineering Fibers and Films, an NSF Engineering Research Center, has developed a modeling package which couples polymer process stages and a materials database in a visualization-based environment. We will describe the no-cost academic version of this code, including a discussion of the background of the modules, along with examples of potential student projects.
A cooling system is applied to improve the cooling efficiency in the field of the injection molding. In this paper, the cooling system was simulated by commercial injection molding and heat transfer CAE software. The conditions of simulated cooling system were classified for the mold base material and cooling channel. After experiments of the injection molding using the simulated results of the cooling conditions, cooling efficiencies were analyzed.
Interfacial failure between carbon-fiber/polyimide composites under high and low temperature exposures was characterized. Based on microscopic photos taken after exposures at -196°C and 250°C and thermo-elastic failure analysis, transverse microcrack formation of composites was investigated.
Mechanical, thermal, and physical properties of five thermoplastic resins compounded using solid glass beads and fibers as additives was studied. Melt flow index is found as the most affected property as a function of bead size and bead-to-fiber ratio. Criticality of bead-to-fiber ratio in relation to product quality and processing is discussed. Material costs are also examined with respect to key property changes and a selection method is suggested to find an optimum.
Change of physical and chemical, reological and physicomechanical properties of High Density Polyethylene (HDPE), exposed by thermal oxidation in shift current conditions with using of the rotational viscosimeter, is considered.It is shown, that products of oxidation form in the polymer melt and solid polymer an independent phase (gel), and have sharply distinguished from initial HDPE polarity, fluidity, physical and chemical properties.
The usage of WPC is rapidly growing, but these still suffer from lack of toughness, which can be improved by adding a small amount of GFR. Tensile tests of WPC specimen with varying amounts of wood-fiber content and 5% GRF were carried out. Significant improvements in properties were observed.
The effect of maleic anhydride grafted polypropylene (PP-g-MA) as a compatibilizer on mechanical, rheological, and morphological properties of rossells/PP and sisal/PP composites was investigated. The fiber loading was 20wt% and the compatibilizer contents were varied from 1-10 phr. The tensile strength and unnotched impact strength of the composites increased with increasing the compatibilizer content.
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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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