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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A Numerical Approach for Optical Characteristics of Injection-Molded Lens
Birefringence distribution of an injection-molded lens is numerically calculated. A simplified numerical approach is proposed that can be used for studying the effect of key molding parameters and evaluating optical property of the lens. Numerical results showed that the melt temperature and holding pressure have significant effects on the optical property of the lens. It also suggested that the holding pressure should be determined with special care to obtain lenses with satisfactory optical characteristics.
Stress Relaxation in Polycarbonate Parts Subjected to Non-Uniform Tensile Stress
Short-term stress relaxation of polycarbonate parts, with non-uniform tensile stress, is compared to that under uniform tensile stress. The non-uniformity in stress distribution is induced by drilling small holes in the test specimens. The data obtained provide helpful design considerations in pin-type fastening assemblies.
Crack Development around Drilled Holes in Polycarbonate Parts Subjected to Flexural Deformation
Injection molded polycarbonate parts, with and without small drilled holes, were subjected to a three-point flexural deformation. A special bending test set-up was designed to maximize the exterior fiber tensile strain in the drilled hole zone. The data show a significant change in behavior of polycarbonate under flexural deformation and brittle-like fracture in the drilled hole zone.
Lattice Boltzmann Simulations as a Tool to Examine Multiphase Flow Problems for Polymer Processing Applications
In this article we give a brief introduction to lattice Boltzmann methods, show why they are a particularly useful tool for the examination of complex multiphase systems and point out their advantages over traditional CFD methods. We present an overview of the method that allows simulation of viscoelastic two component systems, as well as some application of the method to simple model systems.
A New Generation of Materials for the Calendering Industry
While polyvinyl chloride (PVC) has been employed in the calendering industry for many years, other polymers have not been as widely used. Ethylene styrene interpolymers (ESI) demonstrate the requisite rheological properties and thermal stability to be successfully used in the calendering process. Commercial scale validations were performed on ESI based formulations. Examples of the applicability of ESI to calendering are discussed.
Viscoelastic Properties of Rotational Molding Resins
The processability of polyethylene for rotational molding applications is dependent on both viscosity and elasticity. Two samples were compared with equivalent viscosities but differing degrees of elasticity. The resin with decreased elasticity had a shorter cook time and rotomolded parts exhibited better physical properties and fewer air bubbles. Further testing is proposed to quantify more clearly the differences in elasticity.
Morphology and Mechanical Property of Poly(Phenylene Oxide) Modified Polypropylene Blends
Morphology and mechanical behavior of isotactic polypropylene (iPP) and Noryl poly(phenylene oxide) (Noryl PPO) blends were studied. Large PPO particle sizes and wide size distribution were found in the iPP/PPO blends if no compatibilizers were added. The addition of a compatibilizer tremendously improved PPO particle dispersion and particle-matrix interfacial adhesion in PP. This, in turn, greatly improves the fracture toughness of iPP. The results showed that phase morphology has a significant effect on the mechanical performance of these blends.
VT-Drifts Studies of Polymer Thermal Decompositions
Polymer thermal analysis by using variable temperature diffuse reflectance Fourier transform infrared spectroscopy (VT-DRIFTS) is described. Structure-specific information derived from non-isothermal VT-DRIFTS employing ramp and step heating profiles are compared. Techniques for correlating polymer solid-state structure with infrared spectral features and for distinguishing between reversible and irreversible temperature effects are described. Specific examples of using VT-DRIFTS analysis for characterizing the thermal decomposition mechanisms of poly(styrene)and a nitro-aromatic polymer are given.
Consolidation of Commingled Glass and Polypropylene Roving
Prior to processing, composite materials must be consolidated to allow the formation of a continuous polymer matrix phase and the removal of voids. The composite material studied in this research consists of continuous commingled glass and polypropylene rovings. The consolidation of this material as well as mats composed of unidirectional and woven glass rovings were studied using a specially designed tool mounted on a compression machine. Fiber volume fractions with and without polymer were measured as a function of compressive stress.
The Measurement of Thermoset Cure Properties with a Novel Rheometer
The measurement of thermoset cure properties on very hard materials such as epoxies is very difficult especially if they are coated onto a fabric. The application of a new parallel plate rheometer allows the measurement of such cure properties in one simple test. The sample is held firmly in a sealed and pressurized sample chamber. The dies are directly heated resulting in improved repeatability and resolution of gel and cure times. A robust torque transducer allows direct measurement of the final shear modulus in materials. Examples of cure tests are presented for several thermosets.
Kinetics of Epoxy Curing in Composites Containing Glass Fibers or Glass Fibers Commingled with Polypropylene
Glass fibers used in this study are silane-treated woven glass mats and anhydride-treated polypropylene woven glass mats. The influence of these treatments on the epoxy resin curing kinetics is studied. Isothermal and dynamic kinetic parameters from Differential Scanning Calorimetry (DSC) are determined and compared. Based on enthalpies as a function of time results, the autocatalytic model is chosen for the analysis.
In-Line Investigation of Shear-Induced Morphology Transition in Liquid Crystalline Polymer/PET Blends
The morphology of a compatibilized polyethylene terephthlate and thermotropic liquid crystalline copolyester blend is investigated via in-line optical microscopy and light scattering. It was found that the droplet-fiber transition in the liquid crystalline polymer is dependent upon the reactivity, the viscosity ratio and the shear field. The fibers are strongly oriented along the flow direction. The formation, deformation and stability of fiber microstructure under different flow conditions are discussed.
Variation of the Self-Nucleation Domains in ABC Triblock Copolymers with Semicrystalline B and C Blocks
The self-nucleation behavior of the polyethylene (PE) block within polystyrene-block-poly(ethylene-co-butylene)-block-polycaprolactone triblock copolymers was investigated. The extent of self-nucleation was found to be highly dependent on the PE content of the copolymers. The self-nucleation was almost completely suppressed when the PE content was 15% by weight.
Thermogravimetric Analytical Techniques
Thermogravimetry (TG) is an important tool for materials characterization. Hyphenated and multihyphenated methods greatly enlarge the scope of TG. Some thirty different experimental approaches were identified, many with a proven record, but some new and promising but in need of confirmation, such as video-imaging-TG, flash-TG- MS and quench-TG. A review of the state of modern thermogravimetry is given.
TG-MS Family Tree
Strengths and weaknesses of thermogravimetry - mass spectrometry (TG-MS) in qualitative and quantitative industrial problem solving are outlined. The main features of the TG-MS hardware components are reported. Emphasis is laid on the great variety in design options, both for the TG, MS and interface components. The user's requirements for ideal TG-MS instrumentation are described and hyphenated TG-MS options are evaluated. HRTG-EI/SI QMS extended with a chemometrics software package is currently the most advanced option.
Mechanism of Organotin Stabilization of Poly(Vinyl Chloride). 3. the Structure and Equilibria of Alkyltin Alkyl Mercaptopropionates and Their Compatibility with PVC
A series of alkyltin 2-ethylhexyl mercaptopropionates was synthesized and their structure and equilibria with alkyltin 2-ethylhexyl thioglycolates and alkyltin chlorides studied by IR and 119Sn NMR. Compatibility with PVC was determined using DMA analysis of glass transition temperatures. The implications of these results on PVC stabilization are discussed.
Use of Non-Contact Scanning Technology as a Means to Reduce Product Development Lead times
The objective of this presentation is to discuss the implementation of a non-contact scanning inspection method that can reduce product development lead times by greatly reducing the time to qualify and/or quantify a product for production. The equipment, requirements, and methodology of this CAD based inspection method will be discussed. Additionally, case studies supporting this advanced inspection process will be presented.
Predicting Drop Breakup Using Model Flows
This work characterizes the deformation and breakup of a single drop subjected to a sudden onset shear flow. The drop is immersed in a second fluid with which it is immiscible. A cylindrical couette device is used to create simple shear flow on a time scale which is extremely short compared to the time scale of the deformation of the drop. Two breakup mechanisms were observed:elongative end pinching and capillary wave breakup.
Film Casting of a Low Density Polyethylene Melt
Film casting is one of the major commercial film manufacturing processes. Although various investigators have studied the process, no comprehensive set of data is available. In this study, film casting experiments of a LDPE polymer melt are conducted. The rheological properties of the melt, the film tension, the velocity profile, and the film width profile due to necking in will be presented. The thickness profile of the solidified film and the edge bead profile will also be reported. These experimental data will be useful for process analysis and verification of film casting simulation.
New Light Stabilizer for Coextruded Polycarbonate Sheet
Weatherable polycarbonate sheet can be produced by coextruding a cap layer containing a UV absorber over a minimally-stabilized bulk layer. A new UV absorber based on hydroxyphenyltriazine chemistry has been developed that is especially suited to this application. The product provides superior long term weatherability due to its strong UV absorbance and its excellent photostability. It is also relatively nonvolatile, and has only a minimal effect on melt viscosity.
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