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 development of crystallinity and polymer chain orientation in the biaxial stretching process of cast polyamide 11 (PA11) films was investigated. The characterization of the stretched films was done with birefringence measurements, wide angle X-ray diffraction (WAXS), differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS). Biaxial orientation factors were represented in a White-Spruiell orientation isosceles triangle. As distinct from polyamide 6 (PA6) and polyamide 612 (PA612), DSC scanning of as-cast PA11 film were crystalline and exhibited a little change in crystallinity by aging at room condition. The glass transition temperature (Tg) increased during aging. PA11 highly biaxially stretched in an elevated temperature had monoclinic and triclinic crystals, respectively. The dimensions of the crystals were changed with the stretching conditions.
The melting mechanism of LLDPE in a groove-feed extruder was studied through crash-cooling the machine and examining the solidified polymer on the screw. The solids-conveying angle appeared as high as 70° near the end of the grooves, reducing to the helix angle of the flight within the melting zone of the screw. Melting was dependent on the dissipated mechanical energy derived from the high internal friction within the solid bed and solids deformation whilst in the grooved feed section.
A new patent pending barrier screw geometry incorporating modifications to the solids channel of the barrier section of the screw was introduced to improve melting and mixing efficiency. The new design geometry repeatedly deforms the solid bed to improve melting and mixing. Cross channel pressure gradients and screw pull-outs obtained from crash cooling experiments were used to investigate the working principles of the new design. The results were compared to those obtained under similar conditions with a conventional barrier screw.
Specimens of two semicrystalline biodegradable thermoplastics, polyester-amide and polyhydroxybutyrate, injection molded at various settings, have been tensile tested. Upper limits to wall thicknesses with respect to surface appearance were found less severe than for traditional plastics. Molding settings appeared important for mechanical behavior. A higher degree of crystallization was obtained for polyhydroxybutyrate when the cooling rate was decreased. The lowest possible mold fill pressures appeared preferable, increasing ductility for both materials.
There are applications and devices which require controlled distribution of material functionality (electrical, optical, catalytic, magnetic) in two or three dimensions. At the nanometer length scale, attempts to meet this challenge have included template-mediated materials chemistry (Martin 1994) in which track-etched membranes, porous alumina and zeolites serve as the nanoscale reaction vessels for the synthesis of the functional materials. The ability to control both the length scale and the spatial organization of block copolymer morphologies makes these materials particularly attractive candidates for use as templates in the synthesis of functional nanocomposites. Appropriate choices of the repeat units of the block sequences renders them capable of selectivity sequestering preformed inorganic nanoclusters or selectively solubilizing inorganic reagents for in-situ cluster synthesis. Methods exist to produce nanoscale voids which percolate through the structure, leading to processes which coat or backfill the channels with functional materials. Electroless plating methodologies which have been used to apply surface of metals to polymer films can be adopted to produce metallic structures selectivity within block copolymer domains.
Rajendra K. Krishnaswamy, Mark J. Lamborn, May 2000
Various LLDPE resins that encompass those polymerized using Ziegler-Natta, metallocene and chromium oxide based catalysts were blown into film and their tensile properties were investigated in relation to molecular orientation. The direction-dependent (MD vs. TD) tensile properties were observed to be significantly different from those of isotropic polyethylene specimens of comparable density. These were explained in terms of orientation and lamellar organization features. Excellent correlation between Elmendorf tear and tensile yield characteristics added credibility to previous hypotheses that specimen stretching and its associated microstructural deformations plays a significant role in Elmendorf tear tests.
This paper presents experimental results on the blends of metallocene polyethylenes (mPE) for recycling of xerographic toners by reactive extrusion. The experiments were carried out in a reactive twin screw extruder. The evaluation of the mechanical properties and morphology for different blend consist of black xerographic toners with mPE with and without compatibilization by reactive processing. It is rather surprised that the impact strength property is synergistic behavior. The impact strength and the modulus of elasticity of the blends using compatibilizer can be significantly improved. Morphology studies employed scanning electron microscopy (SEM) show that not only the domain size of the phase of black toner can be reduced but also the interfacial adhesion can be enhanced by proper compatibilizeation. Phase morphology and domain size indicate that efficient dispersion was obtained for the compatibilized system whereas the phase of black toner was agglomerated in the interfaces without compatibilization.
Blends of polystyrene (PS), and polymethyl methacrylate (PMMA) with poly(ethene-co-octene) elastomer (POE) were investigated. The experiments were performed in a counter-rotating reactive twin screw extruder. The evaluation of mechanical properties and morphology were completed to determine stress-strain behavior, impact, domain size, and interfacial adhesion for the blends. The results of tensile strength, modulus of elasticity, and impact properties for the blends show that incompatible and synergistic behavior over a wide range. Morphology studies using scanning electron microscopy (SEM) indicate that the domain sizes of rubber phase in the blends are rang from 1 to 15 ?m and a variety of interfacial adhesion behavior. All the blends displayed phase-separated. The blends of polystyrene / poly(ethene-co-octene) elastomer with compatibilization illustrate that not only the domain size of the phase of elastomer can be reduced but also the interfacial adhesion can be enhanced. The mechanical properties of the blends using compatibilization , such as impact strength and tensile strength, can be improved.
A new capillary rheometer has been developed which is gas driven using a high-precision pressure controller. The flow rate is determined on-line. A precision pressure transducer controls the applied pressure to a maximum 21 MPa with an accuracy of better than 0.1%. The rheometer described here has a twin barrel system. Due to the equilibrium N2-pressure control in both barrels, creep tests can be performed, applying constant pressure irrespective of the installed die geometry. The flow rate from each barrel is independently measured.
Mark A. Spalding, Joseph R. Powers, Phillip A. Wagner, Kun Sup Hyun, May 2000
Flow surging in single-screw, plasticating extruders is the variation of the machine's rate with time, and it generally leads to higher production costs, lost production, and often higher scrap rates. Flow surging can originate from many different sources including machine controls, resin feedstock variation, screw geometry, and machine temperature. This paper will focus on flow surging that originates from improper solids conveying, and it will present experimental data and corrective action to eliminate or minimize surging.
Rong-Yeu Chang, Alice S. Lin, David C. Hsu, Fu-Ming Hsu, May 2000
Air trap problem is crucial to notebook connectors that have complicated rib-hole structure and thickness variation. Engineering experience is usually not enough to provide a suitable gate-runner system design for these intricate parts. In this work, various design proposals are examined via mold filling simulation in order to avoid potential air-trap and void problems. This approach is proved to be effective to notebook connector mold designer for verifying design on computer before mold is constructed.
Melt temperature measurement and control are important to understand when optimizing or studying extrusion systems. This extrusion parameter is not as simple to measure as it may seem. This discussion will include the devices that are typically used for the measurement and control of melt temperature and the methods of employing the devices to get meaningful results. Accurately knowing the melt temperature level of a given system allows an accurate comparator for possible improved equipment design. Adjusting melt temperature via altering machine parameters for optimized extrusion results requires that the measured value is a meaningful number. A general discussion of melt temperature in extrusion will be carried out for this tutorial and the measurement and control of this important parameter will be discussed.
Micro-opto-electro-mechanical sensors (MOEMS), where optics are integrated with micro-electro-mechanical systems (MEMS), are logical candidates for sensing flow, temperature and pressure in harsh environments. MOEMS offers small size, high frequency response, immunity to electromagnetic interference, and resistance to degradation from exposure to harsh environments. However, interfacing MEMS with fiber optics is quite challenging. Here we discuss the possibility of coating the fiber with a pressure sensitive polymer (polydiacetelene) to increase its coupling strength to a MEMS' deformable diaphragm. Interestingly, we noticed that the coated fiber, in this case, was itself sensitive to hydrostatic pressure and could be directly used as a pressure sensor. The sensitivity, reproducibility and the structure of this simple and inexpensive structure are discussed in this work.
M. Tabib-Azar, B. Sutapun, T. Srikhirin, J. Lando, May 2000
A simple evanescent-field fiber- optic electric-field sensor is reported. The sensor is constructed by coating the exposed fiber-optic core with a polymer-dispersed liquid crystal (PDLC). The effective refractive index of the liquid-crystal polymeric coating [poly(methyl methacrylate)(PMMA)/E7] has a large dependence on the direction and the magnitude of an any electric field present. This dependence was large enough to enable simple transmission measurements to detect the presence of an applied electric field. By coating a PDLC film onto the exposed core of the optical fibers, we are able to detect an electric field. The sensors showed good sensitivity and reproducibility and a polarity dependence was observed. The time response of the device is dominated by the RC time constant of the structure rather than the response of the PDLC and is approximately 3 minutes with 15-20 minute relaxation time. Using an electric circuit model of the device we also discuss how these response times can be improved by many orders of magnitude.
Extensional melt rheology and processing characteristics of conventional high pressure low density polyethylene (LDPE) and Ziegler-Natta linear low density polyethylenes (LLDPE) are compared with both narrow and broad molecular weight distribution (MWD), long chain branched (LCB) metallocene polyethylenes. The effects of MWD and LCB on the melt behaviour of these different types of polymers will be presented in terms of their dynamic linear viscosities and their strain-hardening behaviour from transient tensile stress growth experiments. Film processability properties will also be discussed.
Takahisa Yasuzawa, Yoshinori Kanetoh, Teruo Tachibana, May 2000
Until now it has been difficult to estimate quantitatively the vibration behavior of FRTP parts using computer simulation. The reason was that the conventional simulation model did not express appropriately the damping properties of vibration (dependence on the temperature, amplitude, frequency and moisture content) and the orthotropic Young's modulus. Therefore, a new simulation model was proposed through measuring the damping factor of the specimen and the experimental modal analysis of the parts. Based on this model, the simulation result of the realistic vibration behavior on the FR-nylon product (e.g. air intake manifold) proved to be in good agreement with the experiment.
Thomas Hsieh, David C. Hsu, Alice S. Lin, Andy G. Day, Rong-Yeu Chang, May 2000
Weld line problem is crucial to a Pentium-II connector support part on appearance and mechanical consideration. In this work, a CAE tool is adopted during the product-development in order to detect potential weld line problem of the design. Various design revisions are proposed and tried on the computer. This approach is proved to be cost-and-time-effective to shorten time-to-marketing and avoid molding problem by improving design in advance.
Electrically conductive polyaniline (PANI) was thermally blended with polystyrene-polybutadiene-polystyrene (SBS) at different weight compositions. The resultant blends were capillary extruded in order to generate a drawing process in the PANI. Microscopic analysis of the extrudates revealed that the PANI was deformed during the process to produce elongated structures. Electrical measurements showed the relationship between the electrical conductivity and the weight fraction of PANI in the blends.
Jianwei Xu, Lawrence Acquarulo, Charles O'Neil, May 2000
A water-soluble polymer (Polyoxazoline) was used to treat nickel coated graphite (NCG) fiber and the treated fiber was then used to reinforce ABS, Polycarbonate and Polyetherimide. The water-soluble polymer improves the compatibility of the fiber in the thermoplastic resin matrix thereby providing an improved thermoplastic composite material with optimum mechanical and electrical performance.
Nylon 6-clay hybrid is a molecular composite of Nylon 6 and uniformly dispersed silicate monolayers of synthesized saponite. Nylon 6 has two crystalline forms, ? and ?. The a phase is the thermodynamically most stable crystalline form but the ? phase is not. In this study, the nylon 6/synthesized saponite has prepared by the intercalation of e-caprolactam and then exfoliating the layered synthetic saponite by subsequent polymerization. The DSC thermal analysis and X-ray diffraction methods were used to investigate the crystal structure change of nylon 6/synthesized saponite. The results indicate the presence of crystalline transition in nylon 6 nanocomposites. The effect of thermal annealing on the crystalline structure of nylon 6 nanocomposites in the range between Tg and Tm is also discussed.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
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
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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