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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Improving Mold Efficiency through Optimization of Collapsing Core Technology
Mold performance is measured by key factors including: cycle time, cavitation, efficiency, parts/hour, mold set-up time, and maintenance requirements. For parts like caps and closures these factors are critical to overall part costs. In this paper we will look at methods for improving mold performance by evaluating tooling for a closure. Cost savings will be evaluated by comparing unscrewing style tooling to collapsing cores. There will also be a review of recent advances in collapsing cores which have allowed for additional gains, including: efficient part ejection, faster conversion or replacement, and reduced set up time.
A Dimensional Analysis of the Micropelletization Process Using Rayleigh Distrubances
A newly developed technique allows production of pellets with a spherical shape and size in the micrometer-scale. This is achieved by extruding a polymer melt through a capillary and perturbing it with a hot air stream. Experimental measurements are used to model such process of micropelletization in dimensionless form. In this work, critical capillary numbers have been estimated and increments in pellet size are obtained as a function of process variables. This would contribute to avoid the necessity of simulation or experimental test of the process when predicting pellet size as a function of processing conditions.
A procedure for evaluating the effect of microgeometry modifications on mixed material gears operating under extreme conditions of tolerance and temperature
Performing load distribution analyses on plastic gears allows one to predict the effects of gear tooth microgeometry on the noise and stress performance of the gear pair. This paper seeks to identify the “best” profile crown for the minimization of corner contact and transmission error for a 5:1 ratio spur gear pair. Following the microgeometry selection, a study of the effects of the temperature and tolerance stack-up on the performance is shown. When accounting for the tolerance and temperature effects, it is shown that there is a shift in contact towards the end of contact for the two worst case temperature situations and for one of the cases, transmission error remained unchanged but in the other extreme case transmission error increased, but still was under the original perfect involute gear set. It is interesting to note that because of the very fine pitch and the loading being very low because of the plastic gear capacity, the microgeometry corrections seem to be so small that they might be considered impossible to manufacture. This is one of the great quandaries facing the plastic gear designer who wishes to minimize the noise of plastic gears.
Understanding of Shrink Films through Viscoelastic Behavior of Polymer Films
In this study, a known viscoelastic materials model was used to apply and validate to a typical shrink film history. Literature review of critical materials properties for a published viscoelastic model was investigated and used to design series of experiments to obtain essential materials parameters (E, ?, ?l, C, and ?) in support of the chosen model for PETG films. The materials parameters were successfully obtained and technical computing software (Mathematica) was used for the integration to calculate the shrinkage. The comparison of the predicted and experimental shrinkage agreed with each other and was shown in this work.
Thermal and Crystallization Behavior of Poly(Lactic Acid) and Poly(Trimethylene Terephthalate) Blend Fibers
Biodegradable poly(lactic acid) (PLA) and poly(trimethylene terephthalate) (PTT) blend fibers were prepared in this study. PLA and PTT were blended in a twin screw extruder with varied contents of PTT 0-50 wt%.The PLA/PTT blend fibers were prepared by melt spinning technique. Thermal properties and crystallization behavior of PLA/PTT blends were investigated. PLA fiber was glossy and transparent while PTT fiber was opaque. The spinning of PLA/PTT blends fiber was difficult due to the difference in melting characteristic of PLA and PTT. However, the PLA/PTT blend fiber was successfully spun at PTT content of 10 wt% with the barrel temperature of 250 °C and would be suitable for textile application.
The Role of Surface Interactions in Renewable Poly(Butylene Succinate)-Silica Nanocomposites
Polymers from renewable resources are beginning to compete with conventional fossil fuel derived materials as fossil resources become increasingly expensive and difficult to extract. The same lightweight, high-strength properties of petroleum-based polymers and composites are required for renewable materials, and a better understanding of processing properties will improve their prospects in the market. One route to widening the thermophysical property window of biobased polyester poly(butylene succinate) (PBS) is the incorporation of reinforcing fillers. In this work, PBS is melt-mixed with high-surface-area fumed silica to create nanocomposites. The surface of the silica nanofiller is chemically modified to explore the effects of surface functionality on filler dispersion and required mixing energy. Rheological and thermal measurements show that structural properties of the filler have a larger influence than surface modification. Comparison of blending techniques provides guidance for improved nanocomposite preparation. The demonstrated mechanical property improvements over neat polymer enable a broader range of applications for these novel renewable materials.
Broadband Dielectric Spectroscopy of Carbon Nanotube Filled Polystyrene Foamed Nanocomposites
This study investigated the dielectric properties of foamed multi-walled carbon nanotube / polystyrene (MWCNT/PS) nanocomposites over the broadband frequency range. Different carbon nanotube concentrations were prepared from a 20 wt.% MWCNT / PS masterbatch using a melt-mixing technique in a twin-screw extruder. A chemical blowing agent was used to foam the nanocomposites in a micro injection molding machine. A foam relative density of approximately 0.55 – 0.65 was obtained for all the samples, regardless of the MWCNT loading. Compression molding was applied to fabricate unfoamed nanocomposites for comparison purposes. Specimens were characterized by applying direct current (DC) and alternative current (AC) electrical conductivity tests and using scanning electron microscopy and dielectric spectroscopy tests. The DC electrical conductivity tests showed a large difference between the foamed and compression molded nanocomposites. The percolation threshold of the foamed nanocomposites was observed to be much higher than that of the compression molded composites. The AC conductivity of the nanocomposites showed that this material property is frequency dependent in the insulative region and that it is almost independent from frequency in the conductive region. The dielectric spectroscopy showed a higher dielectric permittivity for compression molded composites, due to the higher probability of MWCNTs neighboring each other. Since chemical foaming deteriorated the formation of a conductive network, a lower dielectric loss was observed for the foamed nanocomposites. The results of this study showed that chemical foaming of nanocomposites broadened the insulator-conductor transition, which decreases the risk of manipulating conductive polymer composites (CPCs). Furthermore, the dissipation factor decreased with the foaming of nanocomposites. Chemically foamed MWCNT/PS nanocomposites show good potential for use in charge-storage applications.
Performance Evaluation and Morphology Observation of PET/PP Blends in Injection Molding
In this research, the adsorptive properties of L-Menthol, the moisture vapor transmission rate (MVTR), and the mechanical properties of poly (ethyleneterephthalate) (PET), polypropylene (PP), and their blends, fabricated by injection molding targeted the container for solutions, which containing lipophilic chemical such as L-Menthol were evaluated. The result shows that, if the content of PP is more than 50%, the MVTR can meet the global acceptance criteria. On the other hand, When the content of PET/PP=5/5, the tensile properties were lowered (This is negative), and when the ratio of PET/PP=3/7, the anti-adsorptive properties of L-Menthol was lowered (This is negative).
Biobased and Biodegradable Ternary Blends: Investigation of Properties via Experimental and Theoretical Routes
Biobased and biodegradable ternary blends from poly (lactic acid) (PLA), poly(3-hydroxybutyrate-co- hydroxy-valerate) (PHBV), and poly(propylene carbonate) (PPC) were melt-compounded using a K-mixer and fabricated using an injection molding machine. The miscibility, degree of crystallinity, thermal stability, and mechanical properties were investigated. The blends were observed to be immiscible. PPC provided greater thermal stability in the blends compared to PHBV. The toughness and strain-at-break of the ternary blends were far superior to that of the binary blends due to the synergistic effect of the dispersed components. The stiffness and strength of the blends were consistent with those of the PLA matrix. The existing micromechanical models fit well for stiffness but under-estimated the tensile strength. As such, a new empirical model was developed that took into consideration the flexibility that exists between the immiscible blends.
Heat Seal Characteristic of Environmental Friendly Films From Thermoplastic Rice Starch Filled Poly(Lactic Acid)
An environmental friendly biodegradable polymer film was prepared from poly(lactic acid)/thermoplastic starch (PLA/TPS) blend by cast film process at 0, 5 and 10 wt% of TPS. The PLA/TPS blend films were heat sealed by a heat seal tester at a heat bar temperature of 90 and 100 °C. The heat seal time was varied from 0.5 to 2.0 s with a constant seal pressure of 0.2 MPa. The effect of heat seal conditions on heat seal properties of PLA/TPS films was investigated. Heat sealed strength was carried out by peel testing. Differential scanning calorimetry was used to analyze thermal properties and crystallinity of the heat sealed PLA/TPS films. From the results, heat sealed strength of PLA/TPS blend films decreased when increasing the heat sealed times. PLA films was peelable at the heat sealed temperature of 90 °C. PLA/TPS heat sealed films exhibited greater crystallinity than the PLA heat sealed film.
Characterization of Polyethylene Pipe Degradation by FTIR Microspectroscopy Imaging Method
Polyethylene (PE) pipe life time prediction was carried out by using FTIR micro spectroscopy imaging and DTA analysis. The FTIR imaging method was used for considering the rapid change of the yield stress ratio of the specimen by the tensile test due to thermal degradation of PE after the hot air exposure at 120 °C. From the results, PE structural change took place after the reduction of antioxidant in the specimen. The results have been in an agreement with the evaluation of DTA analysis for the surface and inside area of the specimen. The FTIR micro spectroscopy transmission and ATR imaging method makes it possible to exactly and easy clarify the degradation mechanism of the PE pipe.
Benefits of Hollow Glass Microspheres in Glass Fiber Reinforced Thermoplastics
Hollow Glass Microspheres, due to their unique spherical geometry and low density, provide several benefits in glass fiber reinforced composites. They help produce lighter weight parts in order to achieve stringent fuel economy targets for automotive and aerospace manufacturers. They also provide productivity benefits through shorter cooling times, enhanced dimensional stability and less warpage – helping to reduce waste and improve throughput. This paper demonstrates these benefits with effective formulation strategies in glass fiber filled polypropylene and polyamides.
Viscoelastic Simulation of Bi-Layer Coextrusion in a Square Die: An Analysis of Viscous Encapsulation
The Giesekus model is used for viscoelastic simulation of a bi-layer flow in a square die. In contrast to the experimental data reported in the literature, in the present work even with viscoelastic effects included in the simulation, encapsulation of a high viscosity polymer by a lower viscosity polymer could not be captured. Since the viscous encapsulation could not be captured with a purely viscous formulation either, it is concluded that the difference in the wettability and surface tension of the two polymers is probably the major factor resulting in the encapsulation.
Precision Milling of Hardened Tool Steel for Micro Mold Making
High volume production of micro parts from metals or plastics requires appropriate replication processes like micro metal forming or micro injection molding. Regardless which replication process is applied micro molds and their manufacture - very often made from hardened tool steels - are crucial for an economic success. Here precision milling has shown its great potential and examples for the mold making as well as replication are given. Nevertheless, the decisive measure for parts’ quality are often their mechanical properties and testing of micro parts shows specific challenges.
Methodology for Generation of Time-Temperature-Transformation (TTT): Solid and Cellular EPDM rubber
The vulcanization kinetics of solid and cellular EPDM is studied using Differential Scanning Calorimetry (DSC). This study uses dynamic DSC to obtain the total heat of vulcanization and isothermal DSCs show the reaction rate behavior at constant temperatures and the presence of the diffusion in the process, using a novel technique (quasi-isothermal tests). Modeling employs modified Hernandez-Ortiz and Osswald methodology that uses a non-linear regression routine and is based on Kamal-Sourour model to calculate the kinetic variables of the reaction; also includes DiBenedetto’s equation to find the diffusion variables. The TTT-cure diagrams are built by numerical integration of the adjusted kinetic model and vitrification line is calculated by the change of glass transition temperature (Tg) with curing degree.
Using Novel Ethylene-maleic anhydride (EMAh) Copolymers To Upgrade Recycled Nylon To Match or Exceed Prime Virgin Nylon Performance
Nylon is widely used in many applications. There is a vast amount of recycled nylon coming from the carpet and textile and other industries. Due to degradation and loss of viscosity, this recycled nylon has reduced performance and limited its use. The unique chemistry of alternating copolymers of ethylene and maleic anhydride provide several advantages for upgrading recycled nylon. This paper discusses the results obtained with compounding prime grade nylon as well as recycled nylon with the addition of small quantities of this copolymer and specific property improvements for applications in injection molded compounds. The resulting compounds are performance that can match or exceed prime virgin nylon at 30-50% cost savings.
Optimization of 'Feedstocks' for Replicative Process in Micromanufacturing
Dimensional precision and microdetails of metallic parts/devices, associated to a low cost production, requires the use of replicative processes in analogical of micromanufacturing. If powder injection molding (PIM) is a well-established process, metal powder hot embossing is now emerging. In this work 316L stainless steel parts were processed from powder using hot embossing. In this process the development of suitable feedstocks is crucial to assure the quality of the final parts. This study is a part of a larger project of the Engineering & Tooling sector, named Tooling EDGE.
Life Cycle Analysis of Various Paint Products Used In The Production Of Consume Products
In the Beckers organization sustainability has become a very important topic. It is a broad topic and from here we have been deriving areas of focus for our sustainability program. One vital step towards the pursuit of sustainable development would involve an in-depth look into the carbon exposure of the organizations’ value chain and operation. The Beckers organization undertook this activity by completing a life cycle analysis of our 4 major paint products that are commonly used in the production of mobile consumer products. This investigation was part of an initiative that was take with the support of The Natural Step, a nonprofit organization that provides support to organization committed towards sustainable development. The life cycle analysis was conducted within defined boundary conditions and had revealed that various paint technologies appear to contribute to varied levels of equivalent CO2 emissions.
Temperature, Pressure Characterization, and Surface Analysis of Elastomeric Hockey Pucks
The mechanical and material properties of two different forms of elastomeric hockey pucks were found. In order to determine the cause in performance variation, an analysis of temperature variations, surface roughness and pressure distributions was performed. The surface roughness and pressure distributions varied from puck to puck, indicating a possible cause for altered game play. After removing the pucks from a freezer and storing them in an ice bucket for the duration of game play, game and practice pucks increased in temperature at similar rates. Controlling the rate of heating could provide a consistent vertical bounce for both types of puck and standardized for league play. The data demonstrated that the quality of pucks differs from each individual manufacturer, while batch to batch variations from the same manufacturer were negligible. Due to constant changes in temperature of the elastomeric hockey pucks, the thermal expansion and, the resulting oscillating stresses can affect puck performance. In doing so the pucks would become more predictable based on their elastomeric makeups.
Cosmetic and Vibrant Effects in IMD
Product differentiation is one of the key features of selling products and generating competitive edge over the competition. Branding is more important than ever, especially, in the consumer electronics industry. The cosmetic nature of differentiated products drives sales, as the products have become an integral part of everyday life. Most of the products these days offer the same or similar functionality. One of the ways to make these products stand out from a crowded market, is to introduce new decorative, cosmetic and eye catching effects to the housings of the products. These decorative effects can be achieved in a variety of ways, including printing and holographic foiling. These products can then be used in 2d/3d format with the combination of ink technologies and Insert Injection Moulding.
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