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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Intelligent Labels as a Basis for Auto-Sorting of Plastic Packaging
Polypropylene (PP) from packaging is a significant polymer in the mixed plastics waste stream and closed loop recycling of it back into packaging would enable considerable carbon savings to be realised and generate significant revenues. Recent estimates suggest that 143,000 tonnes of the total PP packaging is used for food-grade application. One of the remaining barriers to closing the loop on the recycling of PP food packaging waste back to food grade applications is the absence of an automated method for sorting PP packaging waste to separate a stream consisting of at least 99% PP packaging that has been previously used for food from other non-food PP packaging.
Machine readable inks (including fluorescent pigments) have shown great potential for the identification and separation of plastic packaging. Unlike existing NIR sorting practices, these technologies are not polymer specific and could be applied to targeted streams like food grade PP packaging and others, using commercial labelling and decoration methods and sorted using MRF infrastructure with only minor modification.
This report describes the work of an identification technique which is based on fluorescent pigments that can be applied to labels and packaging as a machine readable ink (MRI) to enable the automatic separation of target materials such as the sorting of food grade PP packaging for closed loop recycling.
Based on the audit of commercial of PP waste indicating that 55% detectability of existing packages together with potential yields of 98% from the sorting trials, it can be estimated that of the 143,000 tonne of PP food packaging, 77,077 tonnes could be recovered each year in the UK. This would increase dramatically if label design and application was modified to better accommodate identification and sorting requirements.
Thermally Conductive Polycarbonate for Electronics
The LED lighting market continues to grow rapidly as consumers recognize the benefits of this technology over incandescent and fluorescent fixtures. However, the relatively high price of LED bulbs has forced manufacturers to explore ways to reduce costs. Since the electronic component costs are usually fixed, other components such as the simple heat sink offer an opportunity to reduce costs and improve performance through unique assembly processes.
Developers at Bayer MaterialScience have created several polycarbonate grades aimed at LED applications, each with a potential to reduce cost, through the elimination of secondary operations and improved design freedom. This list includes thermally conductive polycarbonate.
Thermal management of electronics has traditionally been handled using highly conductive metal alloys. The unique properties of thermally conductive polycarbonate and the lower processing temperatures compared with die casting provide an integrated assembly opportunity that can reduce cost and eliminate thermal interface, potting materials and assembly steps.
Two polymer technologies, thermally conductive polycarbonate and polyurethane have been combined to allow in-mold electronic component assembly and encapsulation reducing the number of components while creating a finished part in a mold without additional manual assembly.
Compared to traditional manufacturing, this process reduces labor cost, increases supplier competition and improves thermal contact by elimination of relatively low conductivity thermal interface materials (TIM).
Enhanced Thermal Conductivity of Polybutylene Terephthalate Composites Using 2D and 3D Hybrid Fillers
Polymer composites filled with hexagonal boron nitride (hBN) are of great interests to researchers nowadays because they are considered to be potential candidates used for heat conduction and electrical encapsulation. In this paper, two grades of hBNs (AC6041 and PTX 60) of different sizes and structures were used as hybrid fillers in order to enhance the formation of thermally conductive networks. The effective thermal conductivity (keff) of the composites was tailored by varying the hybrid filler compositions. The keff reached a maximal value when the volume fraction of hBNAC6041 in the hBNs varied from 50% to 67% at a filler loading of 18.7 vol. %. In addition, an empirical model was proposed to explain the competing effect of using hybrid fillers on the PMC?s keff.
High Temperature Air Channel Testing of Thermally Bonded PVC Geomembrane Seams
ABSTRACT: The objective of this paper is to present a procedure for high sheet temperature air channel testing of dual track thermal seams for 0.75 mm thick PVC geomembranes. This objective is accomplished by developing relationships between seam peel strength and seam burst pressure for sheet temperatures ranging from 46.7øC to 62.8øC during field air channel testing. This paper extends the original relationships presented by Thomas et al. (2003a) and Stark et al. (2004) that only extend to 46.7øC because a sheet temperature greater than 46.7øC is frequently encountered during hot summer months. The original relationship is extended to 62.8øC using the Arrhenius model and a polynomial equation is presented that can be used to convert the sheet temperature during field air channel testing to the air channel pressure required to ensure the specified seam peel strength of 2.6 N/mm (15 lb/in) is met or exceeded. Thus, the proposed relationship and equation allow the seam peel strength to be verified by field air channel testing without conducting destructive tests.
Thirty-Year Durability of a 20-Mil PVC Geomembrane
In 1971, twenty circular aquaculture ponds were constructed for the W. K. Kellogg
Biological Research Station in Hickory Corners, Michigan. The 30.5-m-diameter research ponds were lined using a 0.51-mm-thick fish-grade PVC geomembrane. Over the years the ponds became congested with dense, persistent stands of cattails, trees, and other vegetation, which required the ponds to be cleared and relined in September 2000 in order to allow the initiation of new experiments. The lack of holes in the exhumed geomembrane suggests that it resisted biological attack from microorganisms and also root penetration. Laboratory testing shows that the tensile behavior of the nearly 30-year-old PVC geomembrane is within current specifications for new 0.51-mm-thick PVC geomembranes. Test results also indicate that performing laboratory tests at in-situ moisture conditions provides a better estimate of the field properties of PVC geomembranes than desiccating the material prior to testing, as is required by ASTM Standard Test Methods.
Curing Kinetic and Viscosity Behavior of Liquid Silicone Rubber for Reaction Injection Molding Analysis
Computer-Aided Engineering (CAE) analysis for the Reaction Injection Molding (RIM) process is very useful to predict problems in design process. For the accurate prediction, the curing reaction of the materials during the process has to be estimated accurately. However, the curing reaction of the LSR is very difficult and restrictive to measure because it is a highly complicated behavior. Accordingly, it is desirable to analyze the curing reaction with finding interrelated components among various measurement methods. Isothermal and non-isothermal tests were carried out to study the curing kinetics behavior using Differential Scanning Calorimetry (DSC). The viscosity measurements were also carried out to study the viscosity behavior using rotational rheometer.
A New CMR-Free Polyamide Imide Resin
Polyamide imide [PAI] resin polymers are well-known thermally stable polymers that are used for many high performance coating applications due to their excellent adhesion, temperature resistance, and high strength.
For the various coating uses, PAI resins are used in solvent-based formulations. However, ever-evolving regulations dictate the need to find a solution and replace the traditionally used n-methyl- and ethyl-pyrrolidone [NMP/NEP] solvents. NMP is the most-commonly used solvent in a variety of coating applications. In the 1980?s and 1990?s NMP was used to produce ?environmentally friendly? coatings, replacing cresol as the predominant solvent at that time. Now NMP and NEP have been classified as reprotoxic chemicals, based on the EU REACH regulations and, once again, PAI users face a similar threat which will close entire segments in Europe unless an alternative solvent can be found.
As a key sustainability initiative, Fujifilm Hunt has successfully developed a proprietary alternative solvent solution to the REACH-classified CMR (carcinogenic, mutagenic, reprotoxic) chemicals currently available for PAI coating applications.
Epoxy Silicate Composite Dielectric Characterization by TSDC Techniques
Understanding the magnitude and mechanisms of charge release associated with the dielectric properties of materials has implications on the reliability assessment of microelectronics. Insulators protect devices from conductive currents. However, due to dipole-charge and interface trapping, a release current typically appears around the glass transition. The effect of fillers on the charge release is a critical parameter in investigating the reliability of dielectrics. In this paper, thermally stimulated depolarization current (TSDC) was done to analyze the prediction of material behavior. Parallel thermal measurements were done using DSC to analyze the uncharged material relaxations.
Prediction of Short-Term Behavior of Polyamide 6 by Using the Strain Energy Density Theory
The Strain Energy Density Theory represents a useful tool for the prediction of the short term viscoelastic behavior of materials. The key in this m is the strain energy density ?SED? of the material. Indeed, by conducting two strain-ramped experiments with different strain rates, it can be established a law that links each point on one curve, to another point on the second curve, provided that the two linked points have the same SED. Once the law parameter is obtained, and by using of a known stress-strain curve, one can predict the stress-strain curve for any other strain rate. This work assesses this technique on a technical thermoplastic which is the polyamide 6. To ensure more accuracy, the test strain is recorded using a non-contacting video extensometer. The processing of the experimental data have allowed to identify; firstly a law that connects the strain to the SED, secondly, a law that links the parameter of the law to the SED.
Enhanced Graphene Exfoliation and Dispersion in Injection Molded Polypropylene Nanocomposites Processed with Supercritical Fluid
The effects of melt processing nanocomposites of graphene and polypropylene (PP) with supercritical fluid (SCF) were investigated. Blends of 0.5% graphene (by wt.) were mixed via traditional twin-screw extrusion and with supercritical-fluid gas-laden pellets injection molding-foaming technology (SIFT). Tensile bars were formed using traditional injection molding (IM) and microcellular injection molding (MIM). Samples with graphene had lower melt viscosity and higher thermal stability than their neat PP counter?parts. MIM and SIFT samples with graphene had increased tensile strength. Property enhancements were greater where SCF was used (MIM and SIFT). The ability of SCF to increase exfoliation and dispersion of graphene was determined by X-ray diffraction and Raman spectroscopy. Better exfoliation and dispersion of the nanofillers resulted in the observed property enhance?ments.
Functional Additives for Polymers -- Porcessing Aids, Light Weighting and Thermally Conductive Fillers
The Advanced Material Division of 3M Company provides several additive classes for polymers used in various applications. 3M? Glass Bubbles can provide light weighting for polymers with and without reinforcing and other fillers. Up to 10% weight reduction can be achieved while maintaining physical properties. Weight reduction potential can be maximized when combined with MuCell? technology. 3M? Cooling Fillers can be used to provide high through plane thermal conductivity with high electrical resitivity. Polymer Processing Additives can be used to speed extrusion and prevent die lip build-up during masterbatch compounding or profile extrusion such as door ding strips, mud flaps and door seals.
Preparation and Characterization of Cellulose Nanofiber Reinforced Poly (Butylene Succinate) Nanocomposites
Biodegradable nanocomposites were prepared from poly(butylene succinate) (PBS) and isora nanofiber (INF), a cellulosic nanofiber extracted from Helicteres isora. The nanocomposites were processed using a brabender twin-screw compounder and an injection-molding machine. The effects of INF on the mechanical (tensile and flexural), viscoelastic and thermal properties of the nanocomposites were investigated. The tensile and flexural moduli of PBS-INF nanocomposites increased with INF content, whereas the toughness and strain-at-break decreased. The tensile and flexural strengths increased up to 1.5phr INF loading beyond which they declined owing to agglomeration of INF. The storage modulus of the nanocomposites increased with the INF content. The addition of INF did not affect the Tg significantly. The area integration under tan ë curve decreased with INF loading indicating that PBS-INF nanocomposites exhibited more elastic behaviour with increasing INF. The addition of INF did not alter the thermal stability of PBS, significantly.
Mechanical and Morphological Properties of Microcellular Polypropylene Single-Polymer-Composites Prepared by Microcellular Injection Molding
Recyclable microcellular polypropylene (PP) single-polymer composites (SPCs) with uniaxial fibers were successfully produced by microcellular injection-molding process. Nitrogen in the supercritical state was used as the physical blowing agent in the microcellular injection molding experiments. The tensile properties of the microcellular PP SPCs with uniaxial fibers were determined. The microcellular PP SPC prepared with an injection pressure of 40 MPa, a nozzle temperature of 205 øC, a holding time of 5 sec and a cooling time of 20 sec has the tensile strength of 23.70 MPa, 24.34% higher than that of the microcellular non-reinforced PP, 7.93 % lower than that of the solid PP. The weight of the microcellular PP SPC is 1.024 g, 11.50% lower than that of the solid PP, 2.09% higher than that of the microcellular non-reinforced PP. The morphological properties were also observed using scanning electron microscope (SEM).
Modeling and Simulation of Internal Circulation Two-Platen Injection Molding Machine Based on AMESim
The internal circulation direct hydraulic two-platen clamping system opened a new era of the development of the injection molding machine. This paper established the hydraulic system models for the internal circulation clamping system by AMESim. Displacement of the moving platen, pressure in the mold-clamping cylinders and flow in the internal circulation valves were calculated. The simulation results showed that the system design was reasonable and reflected the real dynamic characteristics of hydraulic system. The modeling and simulation for the internal circulation two-platen injection molding machine laid the foundation for further studies.
A Study of Two Processing Induced Part Failures
Of the four pillars required for the successful development of a plastic part; material selection, part design, processing, and service environment, processing is often assumed to be the most controllable. Even when the service environment has been properly defined, the best design principles implemented, and the appropriate material selected, seemingly insignificant changes in processing can grossly and adversely affect an otherwise well developed product. This paper will explore two case studies where the failure of the parts can be traced directly back to changes in the processing parameters and how these changes ultimately predisposed them to premature failure.
Foamcore Blow Molded Structural Components for Transportation Applications
With emphasis on weight reduction throughout the transportation industry, there is a renewed effort to remove as much mass as possible to improve vehicle performance.
JSP has developed and optimized a blow molding process that combines traditional blow molding with an injection molded particle foam core. This process; called Foamcore, utilizes traditional blow molding equipment combined with a particle foam injection unit to produce a composite blow molded part with a solid foam core.
JSP?s Foamcore technology allows for simpler designs, higher strength to weight ratios, lower part weight, all while using exiting tooling (with minor modifications). Multiple polymers can also be used including Polypropylene, Polyethylene, Polystyrene, etc. for both skin and core materials.
This paper will describe recent advancements of this technology, and how they allow for improved mechanical properties to be realized in the area of transportation applications for structural and semi-structural components. Other features discussed include improvements in thermal insulation, sound abatement, as well as recyclability and End-Of-Life requirements.
Developments in the Production of High Surface Area Fibers and Nonwovens for Filtration
Sub-micron fibers are expected to bring value to applications where properties such as sound and temperature insulation, fluid holding capacity, softness, barrier property enhancement, high electrochemical activities (electrodes in fuel cells and Li-ion batteries) and filtration performance are needed. This presentation will focus on the various processes used for forming webs made up of sub-micron fibers and will review the latest technologies in Electrospinning, Meltblowing, Melt Fracture, Solution blowing, Bicomponent fiber formation, and Supersoninc nozzles.
Catalytic Technology and Controlled Chemical Release for Post-Harvest Preservation of Fruits and Vegetables
Roughly 1/3rd (1.3 billion tonnes) of the food produced in the world for human consumption gets wasted every year. Fruits and vegetables have highest wastage rates of almost 40-50%. This is partly due to ethylene action and improper storage and handling. Ethylene, a catalyst generated by climacteric fresh produce is responsible for their ripening. Ripened fruits have more risk of microbial spoilage due to increased sugar %. Improper handling, storage, lack of cold chain etc in post-harvest conditions further increases the loss. In the past, we have reported ?niche? technologies for fruit preservation, such as chemical agents responsible for adsorption and destruction of ethylene. In continuation, now we are introducing some more ?unique? technologies such as using a) Catalytic converters (of ethylene to ethylene oxide), b) Ethylene adsorbers and c) Halogen releasers. We believe that these simple and cost-effective techniques will be the trendsetters to reduce horticultural wastage considerably and in the end benefit the farmer, the retailer and also the consumer. Efficacy of these products was tested by using them as novel additives in flexible packaging, punnets etc. which are commercially used for storage and transport of various fruits and vegetables in which they were effective in reducing ethylene from the storage area. We also experimented use of these products by incorporating them in a plastic film and all through we could acquire considerable shelf life extension of both climacteric and non-climacteric fruits and vegetables. We firmly believe by using such value-added packaging post harvest horticultural losses will be considerably reduced and it can result in a service to mankind.
Extrusion Performance Fluids - Crucial in Maintaining Water-Cooled Extruder Efficiencies
Many manufacturers of water-cooled extrusion equipment typically recommend that either distilled water or properly-treated water [1,2] be used to control barrel zone heater/cooler temperatures. While many industrial water treatment professionals treat and maintain cooling towers, chill rolls and other Utility Water Systems in extrusion plants, few, if any, have attempted to solve the corrosion, fouling and mineral deposition issues typically experienced in extruder barrel cooling systems (Process Water Systems).
This paper summarizes our experiences over the past fourteen years developing and successfully applying Extrusion Performance Fluids (EPF) as safe and effective coolants in water-cooled extrusion applications. Key documented case studies and simple extrusion maintenance procedures will be discussed which form the basis for a pending US Patent  on EPF and its associated technologies.
Long Chain Branching of Polypropylene via UV Radiation: Effect of Coagent and Other Radiation Variables on Continuous Modification
Continuous photomodification of polypropylene (PP) has been conducted in order to scale up a previously developed batch process for commercialization purposes. Utilizing this process PP rheological properties were modified by incorporation of long chain branches (LCBs).
Trimethylolpropane triacrylate (TMPTA) was employed as a coagent along with benzophenone (BPH), which was the photoinitiator. The effects of TMPTA presence, BPH concentration, and radiation duration on viscoelastic properties and gel content were studied. Gel permeation chromatography (GPC) was used to confirm formation of LCBs in the photomodified PP.
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