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
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.
Diffusion at Polymer-Polymer Interfaces Probed by ATR-Attenuated Total Reflection
In this work we report on the quantification of concentration profiles across the polystyrene-polyvinyl methyl ether interface through ATR-Attenuated total reflection technique. Different narrow molecular weight distributions and different temperatures above and below the glass transition temperature of polystyrene were tested both in the one phase and two-phase regions. The effects of temperature and molecular weight on the diffusion mechanism are discussed in terms of the phase behavior.
Determining Tear Resistance in Blown Film Using a Single Specimen J-Integral Approach
A single specimen J-integral approach is developed to determine the fracture toughness of thin polyethylene blown films. The test is used to determine the amount of energy required to initiate crack growth as well as the energy required to propagate the crack. This paper presents preliminary findings using the single specimen J-integral approach on LLDPE blown films. A comparison between J, Elmendorf, and Dart is provided.
Crack Growth Studies for Polyacetyl Resins in Chlorinated Water
The crack growth resistance in chlorinated water has been measured for two polyacetal resins of different molecular weights. The crack growth rates were measured using single edge notched tensile specimens under constant stress at elevated temperatures. The crack resistance measured in hot water containing free chlorine were found to provide a reasonable explanation for the observed poor field performance of these resins in hot water plumbing applications.
Fluorescence Anisotropy Measurements of Oriented Polymers
Fluorescence anisotropy area scans of sheet and film specimens have been carried out using a fiber optic sensor that contains polarizing optical elements. Measurements on polyethylene terephthalate food packaging, which contains the fluorescent dye benzoxazolyl stilbene, are presented. In one case, a sheet cut from the side of a blow molded bottle displayed variation in biaxial orientation as a function of distance from the neck of the bottle. In another case, a thin film of shrink wrap material showed uniform biaxial orientation over the scanned area.
A Quantitative Investigation of Mixing in a Miscible SAN/PMMA Blend
Mixing of miscible additives into polymeric matrices is being investigated using the model blend SAN/PMMA. The normalized sample variance, as measured by FT-IR, is used to quantify the extent of mixing. The graph of normalized sample variance as a function of sample size reveals that there are at least two characteristic size scales present in short-time mixing samples. Theoretical calculations support this conclusion.
Three Dimensional, Nonisothermal Analysis of RTM and VARTM Processes Using hp-Adaptive Finite Element Method
A highly accurate numerical technique for the simulation of resin infusion in composite preforms using a transient, 3-D, non-isothermal, two-phase analysis is presented. An adaptive finite element method is used to solve the equations. The uniqueness of the present approach is that resin infusion is modeled as a weakly compressible, two-phase flow in a porous media. VARTM processes can be solved by accurately specifying air properties based on the vacuum conditions. The results presented indicate the usefulness of the model.
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