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

PVC / Layered Silicate Nanocomposites: Preparation, Characterization, and Properties

Noble Francis, Daniel F. Schmidt, May 2007

Optically transparent nanocomposites were prepared via twin-screw extrusion of a medical-grade flexible PVC resin and an organically modified montmorillonite. Intercalation and orientation of the montmorillonite layers were observed via x-ray diffraction. A positive influence on barrier properties was noted, including a five-fold increase in oxygen barrier at minimal clay loading. Consistent with the literature, no significant changes in thermal stability in air were observed.

Preparation and Characterization of Polyester Thermoset Xerogels for Tissue Engineering Scaffolds

Poonam Borgaonkar, Sachin Sharma, Daniel F. Schmidt, Ming Chen, Sankha Bhowmick, May 2007

Porous polyester thermoset xerogels have been produced via sol-gel chemistry. The pore structure of these materials is tunable and can be altered independent of or in tandem with alterations in composition by adjusting solvent quality, solids content, and processing methodology. Cytocompatibility studies on selected xerogels imply effects of both pore size and materials chemistry, with fully aliphatic polyesters with large pore structures allowing for the growth of mammalian cells.

Modeling of Expansion of Extruded Filamentary Foam

Zhenjin Zhu, Jing Wang, Chul B. Park, May 2007

This paper undertook a numerical study to characterize expansion of extruded polystyrene foam blown with CO2. The effects of processing parameters on foam expansion outside filamentary extrusion dies were examined. Efforts were made to optimize the processing parameters for the achievement of highly expanded foams.

Rigid PVC-Based Nanocomposites Produced through a Novel Melt-Blending Approach

Laurent M. Matuana, Omar Faruk, May 2007

Based on the fusion behaviors of PVC, the influence of compounding route of PVC/Montmorillonite nanocomposites, on their properties, including flexural, tensile, dispersion, and morphology was studied. The experimental results indicate that both the extent of property improvement and dispersion of nanaoparticles in PVC/Montmorillonite nanocomposites are strongly influenced by the degree of gelation achieved in PVC compounds during processing.

Interfacial Adhesion between Hydroxyapatite and Poly(?- Caprolactone) and Their Electrospun Composite Toughness

Shing-Chung Wong, Avinash Baji, May 2007

The interfacial adhesive strength between hydroxyapatite (HAP) and poly(?-caprolactone) (PCL) were determined using T-peel tests. Their composite fracture toughness was determined using essential work of fracture concept. Electrospinning techniques were employed to obtain nanometer scale PCL fibers with and without HAP reinforcements which also create micrometer-scale porosity in the structure. The effects of HAP morphology and HAP content on mechanical properties were evaluated.

Manipulating the Orientation at End of Fill

Brian A. Young, May 2007

Orientation of polymer chains has been shown to have a major effect on component properties. The chain orientation at the end of fill of a component is different from most other areas. Overflows have been used in various areas of the plastics industry to improve weld line strength and provide a more consistent gas channel in gas-assist molding. This study will investigate if the use of overflows to change the orientation of the polymer chains provides a more capable molding condition.

Involving Non-Engineering Students with Engineering Students to Enhance the Learning Experience

Jonathan Meckley, May 2007

Allowing engineering students to work with students of other disciplines offers them an experience they can take with them as they begin their career in industry. The college students take the project from concept to a manufactured product. At the beginning of the project, psychology students interact with sixth-grade students to determine the best features to include in a car. The marketing students will then create a display and video commercial for each car.

The Effect of Overflow Tabs on Affected Area

Jeremy Haibach, Trevor Thorwart, Josh Glessner, May 2007

The purpose of this project was to determine the effect of overflow tabs on ‘affected area’. It was done because overflow tabs could prove to be very important in the medical industry, where tight tolerance parts are needed. Along with that industry, parts with limited gating locations could also use overflow tabs to provide more consistent flow throughout the part.

Rubber-Assisted Embossing Process

Pratapkumar Nagarajan, Katherine Abbott, Donggang Yao, May 2007

This study investigated a rubber-assisted embossing process for structuring thin polymer films. The main advantages of a rubber support instead of a hard counter tool include simplification of the embossing tool, protection of the embossing master, buildup of high pressure, and ease of mold separation. With rubber-assisted embossing, thin polystyrene films in a thickness of 25 ?m were accurately patterned with microgrooves of characteristic dimensions on the order of 100 ?m.

Fountain Flow in Water-Assisted Melt Filling

Xu-Hui Liu, Han-Xiong Huang, May 2007

Water-assisted injection molding (WAIM) provides a new means to manufacture hollow parts at lower costs. However, little work has been done to understand how the polymer melt flows under applying high pressure water. Experimental investigations on the melt flow, especially the fountain flow during water-assisted melt filling in an emulated mold were conducted in this work. The experimental results revealed the formation of fountain flow during melt filling under applying high pressure water.

Freezeout in Extruder Melt Sections

Stephen J. Derezinski, May 2007

When screw speed is increased, barrel cooling will result to maintain control of the set product temperature. This can lead to barrel temperatures below the crystallizing temperature of the polymer, and a thin layer of frozen polymer can accumulate on the barrel walls. The analysis of this frozen layer or freezeout" condition and an analytical expression for estimating the layer thickness is presented along with supporting data."

Flow Stability and Thickness Uniformity in Continuous Extrusion

Stephen J. Derezinski, May 2007

For continuously extruded products, such as sheet and profile extrusions, thickness uniformity is a key quality factor, and it is directly linked to flow oscillations or flow disturbances at the die. Many sources of flow oscillations in the extrusion system are identified, and methods are shown on how to configure the melt delivery system to minimize their transmission to the die. These methods are illustrated with a model based on the theory of hydraulic transients.

Cyclic Data Leads to More Accurate Finite Element Analysis

Ward Narhi, May 2007

Finite Element Analysis (FEA) is only as accurate as the material models employed and it must correctly represent application specifics for the FEA to be as precise as possible. Two areas of concern for FEAs of elastomers are cyclic versus non-cyclic testing, and, strain dependent models. Ideally the analyst should be able to choose a strain based non-cycled material model or cycled material model depending on whether the application is a static or semi-dynamic application.

Shape Changing Mechanisms in Microprofile Extrusion

Donggang Yao, Zhihong Fu, May 2007

Profile extrusion is a well-established practice in the polymer industry. Adaptation of profile extrusion to microfabrication, however, is difficult due to scaling-related process changes. Particularly, the effect of surface tension increases as size reduces and could significantly contribute to cross-sectional shape change in microprofile extrusion. In this study, the role of surface tension in microprofile extrusion was numerically studied and compared with that of die swell. Strategies were proposed to reduce the surface tension influence and produce precision microprofiles.

Preparation of Nanoblend Polymer by Polymerization in Polymer and its Nano Cellular Foams

Tetsuo Otsuka, Kentaro Taki, Masahiro Ohshima, May 2007

A new method of preparing polymer blends with nanoscale-islands is proposed. The polymethyl methacrylate (PMMA)/ polystyrene (PS) blend, which has PMMA slands dispersed in nanoscale order, was prepared by the method: dissolving MMA monomer and polymerizing the monomer in PS matrix could provide higher molecular weight of PMMA and create highly dispersed PMMA domains in PS matrix owing to gel effects and diffusion mixing. The resulting polymer blend was foamed with CO2. Nanocellular foam could be prepared using the polymer blend morphology as a template where bubble nucleation was localized in PMMA domains. The effects of blend ratio, foaming temperature and depressurization rate on bubble diameter as well as bubble density were investigated. The higher depressurization rate at lower foaming temperature made cell diameter smaller and the density larger. The higher PS composition in blend made the density larger. The cell 40-50 nm in average diameter and 8.5x1014 /cm3 was obtained as the finest nanocellular foams.

Optimization of Gasket Materials for Packaging Containers

Yash Sinha, May 2007

The U.S Army Armament Research, Development and Engineering Center's (ARDEC) Packaging and Support Division, Picatinny Arsenal, New Jersey initiated a Product Improvement Program (PIP) to solve the deterioration problem in the gasket of the metal/plastic containers for mortar ammunition. This PIP was funded by PM-Mortars. The PIP addressed gasket material properties including: durometer, hardness, compression set, impact resistance, and other physical properties (app. A). The goal was to find a gasket material that would improve the seal, long-term storage, and transportation capability of both the PA154 (120-mm) and PA156/PA157 (81-mm) metal/plastic containers. Four materials that were recommended by ARDEC's Warhead, Energetics and Combat-support Armaments Center (WECAC) Material Laboratory were ethylene propylene diene (EPDM), styrene butadiene rubber (SBR), neoprene, and natural rubber (60). In addition, natural rubber (40), currently used on the 120-mm A154 metal/plastic container, was used as a baseline. The 60 and the 40 are the durometer reading. A down select process would be used to determine the best gasket candidate by good performance in environment and material testing.Based on successful testing, an engineering change proposal (ECP) will be submitted to implement the best gasket material in both the 120-mm and 81-mm metal/plastic containers.

Chemical Recycling of Pet with Solid State Shear Pulverization Technology

Behzad Shirkavand Hadavand, Hossein Hosseini, May 2007

Post-consumer PET (polyethylene terephthalate) bottles have been recycled into film and sheet products ever since the Containers and Packing Recycling Law came into effect in 1997. There has been a growing need, however, for a chemical recycling process. In this process post-consumer PET bottles are recycled into monomers that can be used as feed stocks for the recycled production of PET bottles for beverages. This paper reveals a chemical recycling process using an alkali solution in order to depolymerize PET material in to its monomers (terephthalic acid and ethylene glycol) within a short time. Unlike ther researchers, we did not use the flakes of PET, but used powdered PET produced based on solid state shear pulverization (SSSP) technology to achieve maximum yield (98%) and purity (95%) of the monomers in a short reaction time. The powdered PET has unique physical properties that affect experiment conditions temperature and pressure. The resulting terephthalate salt was treated with sulfuric or hydrochloric acid to yield highly pure terephthalic acid. Results show that the best percentage conversion of PET flakes is 1.5mol/l NaOH for 2 hours in 200 °C and for PET powder 1 .5 mol/l NaOH for 1.5 hours in 150 °C.

UV Curable Ink-Jet Formulations for the Ever Expanding Realm of Industrial Applications

S.E. Edison, May 2007

Digital inkjet printing has escaped the traditional confines of the graphic arts market and exploded into the realm of industrial applications. UV curable inkjet inks are enjoying the fastest growth due to their instantaneous cure, excellent jetting, and green" attributes. The industrial possibilities are limitless and each application requires a specific ink formulation to meet precise requirements. The inks must demonstrate robust characteristics including high flexibility and elongation abrasion resistance adhesion to a myriad of substrates including metals low surface energy plastics glass and ceramics as well as excellent lightfastness and rapid curing. This paper explores the challenges that a formulator encounters while pursuing industrial opportunities and offers suggestions to create inks that are a perfect match for each application."

Synthesis and Characterization of Polyacrylamidechitosan Hydrogels

Pedro Ortega-Gudiño, Juan C. Sánchez-Díaz, Fausto Becerra, Agustín Martínez-Ruvalcaba, Alejandro González-Álvarez, May 2007

Polyacrylamide/chitosan hydrogels were synthesized in aqueous itaconic acid solution (1% w/w), in order to determine its swelling kinetics at various chitosan concentrations. Analysis of the hydrogel swelling behavior indicated that the network properties of the gel changed depending on the swelling pH, as well as the amount of chitosan, showing a decrease in swelling capacity when the chitosan concentration was increased; this behavior can be explained due to the presence of the chitosan ionic groups.

Dynamic Mechanical and Dielectric Properties of Polypropylene Nanocomposites

Syh-W. Huang, Yeh Wang, May 2007

In this work we report on the investigation of the dynamics of maleic anhydride grafted polypropylene (PPgMA) and PPgMA-based nanocomposites by means of dielectric relaxation spectroscopy (DRS) and dynamic mechanical thermal analysis (DMTA). We study the effects of different PPgMAs on the miscibility with the organoclay, and examine the effect of organically modified silicate filler on the dynamics of PPgMA. Our results suggest that the _-relaxation process, corresponding to the glass transition of PPgMA, is significantly affected by the clay loading. The increase in Tg is a direct result of polymer-filler interactions that reduce the polymer chain mobility. Furthermore, in the nanocomposite materials a separate high-temperature process due to Maxwell-Wagner-Sillars (MWS) polarization was observed with dielectric relaxation spectroscopy.