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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Laser Beam Welding of Plastic Micro Parts
By means of laser beam welding it is possible to join plastic parts in micro system technology. Based on existing macroscopic process variants for laser beam welding a appropriate process technology for the joining of plastic micro parts has been developed at IKV. For welding of plastic parts the influences of material and process parameters on the quality of the weld line have been investigated. Apart from this investigation high influence is expected by using filling materials like carbon black. Investigations of microscopic melt zones produced by the focused laser beam are presented.
Difference in Integral Aggregate Structure for Co-Neutralized Carboxylate Ionomers
The purpose of this study was to determine the arrangement of atoms inside ionic aggregates for ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers neutralized with a combination of sodium and zinc. Significant qualitative differences were found as a function of sodium:zinc ratio. The implications of the differences in aggregate structure on the rheological behavior of these mixed-cation systems is discussed.
High Speed Toolholders
High Speed Milling requires many considerations for the toolholder. Cleanliness, Balance and Accuracy become even more important as the spindle RPM rises. With milling speeds rising through ten, thirty, and fifty thousand RPM, and with 100,000 RPM lurking on the horizon the ordinary toolholder and features may no longer be adequate. This paper deals with selecting the toolholder that will assure optimum performance.
Distribution of Material in an Injection-Molded Container
The distribution of material (weight) in an injection-molded container was quantified by cutting the container precisely into segments. Molding conditions were varied, and different polypropylene grades were used. The material distribution remained nearly uniform when increasing the packing pressure. Increasing the packing time above a certain limit, however, mainly packed material close to the gate. The material distribution was also affected by material parameters such as melt flow rate and nucleation. The shrinkage and the compressive strength of the container were related to the material distribution.
Flow Patterns in Special Twin Screw Mixing Elements
The flow behavior of a Newtonian fluid through special mixing enhancers in a modular intermeshing co-rotating twin screw extruder has been examined. The mixing enhancers are slotted screws and gear mixing elements. In addition to pressure and drag flow characteristics, particular attention has been directed to residence time distribution in such devices. The data obtained are useful for guidance in the selection of appropriate mixing elements and the validation of flow simulation models for twin screw extruders.
Hygrothermal Effects on Physical Aging and Structural Recovery of an Epoxy Thermoset
We have investigated the hygrothermal effects on thin epoxy films (c.a. 60 µm thick) using mass uptake, swelling and uniaxial creep compliance measurements inside a dew formation-free transparent chamber capable of arbitrary relative humidity and temperature controls. We show that the physical aging behavior in humidity down-jumps in RH are the first demonstration of an asymmetry of approach induced by moisture changes in a material. Preliminary efforts to extend the TNM-KAHR models of structural recovery to account for moisture induced aging effects are presented.
Roll Design: A Review of the Basics
Over the years many advances have been made in the production of flat sheet in the areas of die design, screw design, and polymers. However the design of a critical part, the cooling roll, is often given little consideration by the processor. The intent of this paper is to review some of the parameters that the roll designer uses to determine the design of the roll. The basic equations for calculating PLI (pounds per linear inch), and deflection of the roll, the heat removal rate required, and a method for approximating the required flow rate through the roll are explained.
Thermosetting Resins from Vegetable Oils
A range of polyols and thermosetting polyurethanes was prepared from soybean, corn, sunflower, safflower, canola, peanut, olive and castor oils. The products were rigid plastics if the polyol hydroxyl number was 160 mgKOH/g or above, or rubbers when the OH number was below that value. Tg of the resins showed linear dependence with the hydroxyl number. The exception was castor oil, which was rubbery, although the OH number was 164 mgKOH/g, which was attributed to the presence of double bonds.
Does Color Memory Exist?
While the scientific literature contains information about how the brain stores and retrieves memory, there are no references in the recent literature about the ability to remember a color. Data collected over a several year period shows that this ability is rather poor, even after short periods of time. Only thirty percent of participants at plastics coloring seminars were able to correctly identify a color observed only an hour earlier.
Performance Optimization of Transparent PS Packaging with Clear Elastomers
Clear, high styrenic elastomers (HSE) are commonly extruder blended with general purpose polystyrene (GPPS) to make sheet, which is thermoformed into articles for packaging and single service applications. The ability to adjust the blend parameters gives the processor an advantage over other clear polymers in meeting customer cost and performance demands. Transparency and impact resistance of such blends are affected by the HSE and GPPS selection, and the blend ratio. This paper discusses the influence of these parameters, with emphasis on GPPS selection.
Influence of Molecular Weight and Polydispersity on Interfacial Tension between Polystyrene and Polyethylene
The influence of temperature, molecular weight and polydispersity on interfacial tension between polyethylene and polystyrene was studied in this work. The molecular weight of monodisperse samples of polystyrene was varied from 13,000 g/mol to 400,000 g/mol. The effect of polidispersity was studied using bimodal, trimodal and multimodal polystyrene samples prepared by solvent evaporation. It was shown that the interfacial tension increases as a function of molecular weight and decreases as a function of polydispersity.
Effects of Lubricants on Processing of Metallocene LLDPE
Fatty acid ester and amide lubricants were evaluated as processing aids in a 1.0 MI film grade mLLDPE. The effect of the lubricants on extruder energy and output of laboratory extruders fitted with a capillary rheology die and with a two inch film die were determined. Additives were found that reduced the amount of extruder energy required to process the mLLDPE. These additives also increased the output of the extruders per unit of extruder energy.
Thermogravimetry (TGA) of Polymers Poster
This poster describes Thermogravimetry (TGA) as a useful analytical tool for the plastics industry. Whether a TGA is used for compositional analysis of material, identification of filler in the material, a material's carbon black content, or moisture content, this poster will be valuable to engineers, scientists, and technicians.
Studies of the Thermal and Thermooxidative Degradation of Polypropylene during the Processing and Usage
Due to the extensive use of polypropylene, the comprehension of its stability and degradation processes is essential. In particular, our interest was to distinguish the differences between thermal and thermooxidative effects on its properties. The influence of temperature and atmospheric conditions on the time dependent aging process of PP was investigated. By means of suitable analyses, it has been proved that inert conditions can significantly reduce the degradation of polypropylene both in use and while processing.
Biaxial Vibration Welding of Polypropylene
Vibration welding machines with biaxial amplitudes were designed to close the gap between traditional linear friction movement and ultrasonic welding. Several advantages are claimed, although no scientific results on this innovative joining technology have been published so far. In this work, linear/biaxial vibration welding experiments have been made on sensor-equipped machines. A considerable influence of amplitude on temperature in the welding zone and of joining pressure on short-time mechanical joint strength exists for polypropylene plates.
Investigation of a Thin-Walled Thermoplastic Metal Hybrid
Based on the researched material combinations, warpage of a T-formed thermoplastic metal composite with a large contact area depends mainly on the shrinkage of the thermoplastic and on the pre-heating temperature of metal parts. The bearing strength increases linearly with the number of the rivet holes and depends on their geometries and the pre-heating temperature. The adhesion between the zinc-plated steel and PA6-GF30 at the pre-heating temperature of 250°C is greater than the tensile resistance of the thermoplastic part.
Progressive Failure Analysis of Fiber Composite Structures
A progressive failure analysis of fiber reinforced composite laminates using finite element analysis is presented. The progressive failure model is based on the Hashin-Rotem failure criterion, which separates fiber and matrix failure modes. In the analysis, the lamina material properties are reduced depending on the failure mode until ultimate failure of the laminate is reached. The progressive failure analysis is compared to published tensile experiments on various carbon/epoxy laminated structures with good agreement.
Rheological Properties and Numerical Simulation of S-PVC Formulations in Extrusion Dies
We report effects of formulation and sample preparations on measured rheological properties relevant for constitutive modelling of die flow in PVC extrusion. Numerical simulations are performed in order to separate non-isothermal and viscoelastic effects in the extrusion experiments as well as self-consistency between constitutive models and measurements.
Design of a Novel Extrusion System for Manufacturing Microcellular Polymer
The described system for the production of microcellular hollow fiber is based on the thermic extrusion of polymers under addition of CO2 as a blowing agent by means of pressure build-up and drop-off. The design of a novel extrusion system is presented according to this concept, which involves a modular configured co-rotating twin screw extruder, a gear melt pump and a designed die. Microcellular foams have been successfully produced using this system.
Melt Extruded Open-Cell Microcellular Foams for Membrane Separation: Processing and Cell Morphology Relationship
This paper presents an experimental study on the manufacture of microcellular polycarbonate in a designed twin-screw extrusion system using CO2 as blowing agent. Open-cell microcellular polycarbonate foams in the form of hollow fiber were produced with a cell density on the order of 109-1010 cell/cm3 and an average cell size in the range of 5-10 µm. The effects of the processing conditions on the cell morphology and the cell-opening technique are described.
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