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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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.
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.
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 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.
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.
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.
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.
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.
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.
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.
Continuous devulcanization of tire rubber crumb was performed using supercritical CO2 in an industrial scale twin screw extruder. A reasonably high throughput extrusion process has been developed and the effect of processing conditions has been studied. Using a fractional factorial design in three levels, the effects of process temperature, screw speed, and feed rate on the sol and gel fractions and degree of devulcanization of devulcanized rubber have been investigated.
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.
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.
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.
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.
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.
The current trend towards sustainability has created new interest in biodegradable plastics. While many investigations have examined the behavior of biodegradable plastics, the changes in properties that may occur during use have not been fully developed. The mechanical properties of seven types of biodegradable plastics were analyzed. In addition, the properties of polystyrene (PS) used in similar applications were examined. The effects of UV exposure, humidity and accelerated aging on the mechanical properties were studied. In general, the strength of several biopolymers was less than that of PS. Polylactic acid and wheatstraw had a higher strength than PS. The properties of biodegradable plastics deteriorated significantly upon exposure to UV radiation and humidity. Accelerated aging data indicates that after 6 months under ambient conditions, the biodegradable plastics also have a reduction in strength and modulus. Additional improvements may be necessary to resist environmental effects so that biopolymers can be effective replacements for traditional plastics.
Multi-walled carbon nanotubes (MWCNT)/ poly(vinylidene fluoride) (PVDF) and copper nanowires (CuNW) / PVDF nanocomposites with filler content ranging from 0.4 to 1.5 v% were prepared by the miscible solvent mixing and precipitation method followed by melt compression. The electrical and dielectric properties of MWCNT/PVDF and CuNW/PVDF nanocomposites were then compared; it was observed that the CuNW/PVDF nanocomposites had the highest real permittivity combined with a low dissipation factor (tan ?) due the presence of a thin layer of oxidation in the CuNW surfaces, which works preventing the direct contact between the conductive fillers.
Altuglas International, a division of Arkema Inc. has recently developed Plexiglas® Rnew acrylics, a new technology based on poly(methyl methacrylate)/biopolymer blends. These resins, containing ? 25% renewable carbon, are in line with Arkema’s commitment to sustainability while offering exceptional performance for transparent or opaque durable goods in medical, transportation, building and construction, and consumer applications. As opposed to many green plastics, where material performance must be sacrificed for bio-content, this technology allows for impact properties, chemical resistance, and processability far superior to traditional acrylic products.
PBT/PC blends provide an excellent balance of chemical resistance, mechanical strength (especially at low temperature), and processability for a wide range of applications. Recently, appliance applications started to demand more sustainable, environmentally-friendly and green materials without sacrificing any properties for their new generation products. To respond to this market requirement, a high recycle content PBT/PC blend with excellent chemical resistance properties, good FR performance, and great mechanical properties was developed. The use of a high recycle based PBT/PC blend is the key to opening a new door to the more sustainable and green world for future appliance applications.
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