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.
While the flow forces governing primary melt-based polymer processing techniques, such as extrusion and injection molding, have been extensively studied, characterization of forcesin secondary processes such as thermoforming is limited. In this work we utilize multilayer coextrusion to create an extruded film with 100s of alternating linear low density polyethylene (LLDPE) and isotactic polypropylene (iPP) layers; and by extension, 100s of interfaces. The combination of LLDPE, iPP, and these interfaces decreases the elastic storage modulus (E’) and broadens the rubbery plateau observed via dynamic mechanical analysis (DMA). The broadening of the rubber plateau is correlated with an observed improvement in LLDPE/iPP multilayer thermoformability compared to the homopolymer LLDPE and iPP films.
A three-level multivariate control system is described that transforms a vector of machine inputs to a vector of virtual process states, and then these virtual process states to key performance objectives. The multivariate system is implemented on a 150 mm (6 inch) screw diameter producing approximately 500 kg/hr of polyvinyl chloride (PVC) film having a nominal width around 1 m (37 inch) and a nominal thickness of 0.38 mm (0.149 inch). Validation is performed with respect to modeling and optimization of three performance objectives including production rate, energy efficiency, and process capability. The results suggest significant gains with respect to the Pareto optimality (efficient frontier) of energy efficiency and process capability.
This paper deals with the modeling of the conveying behavior of polymer melts in single-screw extruders based on a network-analysis approach. The polymer-melt rheology is strongly temperature-dependent and hence the temperature profile affects the pumping capability. In this work, we propose an approach to predicting the non-isothermal, coupled axial pressure and temperature profiles. We present the fundamental background of the implemented pumping and dissipation models and the network theory for modeling the axial pressure and temperature profiles. The simulation procedure for calculating the non-isothermal conveying characteristics is shown and a few exemplary simulation results are presented. The novel algorithm provides fundamental insights into the non-isothermal extrusion characteristics and enables screw design and process optimization in single-screw extrusion.
Adhesion promotion technologies have wide application in the numerous industries for a wide range of plastic parts, such as those made of PE, PP, PET, etc.
One method used to modify the surface of these and other polymer products to promote adhesion of coatings and adhesives is flame plasma.
This paper describes the theory behind natural gas, propane or LPG fired flame plasma surface treatment to promote adhesion of water based inks, coatings, adhesives, labels and other substrate laminates to polyolefin based substrates.
Critical parameters in flame treatment are, flame chemistry, flame geometry, plasma output and distance of the burner to the part. The interrelationship between these variables, and how to control them for optimum surface treatment, will be discussed.
The use of Schliren imaging technology, high speed photographs of the flame geometry, used to develop new burner designs, as well as advances in equipment technology will be presented.
A completely new patented process design has been developed and successfully implemented providing significantly improved control of the flame chemistry, while at the same time simplifying the process control and mechanical hardware required.
In addition, the new design improves the overall efficiency of the flame treating process
Troubleshooting & maintenance of flame plasma surface treating systems will be discussed.
In order to reduce the carbon footprint, carbon dioxide (CO2) can be used as a raw material for synthesizing innovative rubber materials. In the following, the process of testing and improving CO2-based rubber compounds is described. The substitution of parts of the polymer chain by CO2 contributes to a sustainable rubber industry. A wide range of different raw materials is provided by the manufacturer, compounded and then tested. In order to improve processability, compound recipes are modified and improved. The investigations focus on static and dynamical mechanical properties and caloric properties. After the ability to be processed in an internal mixer is proven and improved by the use of processing aids, the compounds are tested for extrusion and vulcanization. It is shown, that CO2-rubber compounds can be processed on a rubber extruder and can be vulcanized by using hot air and infrared radiation.
Simulation of the flow and extrudate deformation in two extrusion dies with gradually changing profile shape in successive sizers is presented. The change in the profile shape in sizers is used to employ a simpler die geometry and then deform the extrudate in sizers to the required final product shape. Effect of non-uniform exit velocity, cooling shrinkage and shape of sizer profiles on extrudate deformation is included in the simulation. The predicted extrudate shape and layer structure is found to match accurately with those in a coextruded product.
Due to complex viscoelastic nature of the polymers, it is challenging to process multicomponent structures with uniform layer thicknesses. Although multilayered structures have been processed in a broad array of polymer materials and formulated to service a wide range of applications, a clear understanding of the effects of viscosity matching on the uniformity of the layer periodicity is not well understood. Significant work on viscous encapsulation and secondary flow patterns in the die channels affecting the layer structures has been previously reported. However, further evaluation of these effects on wide range of materials in commercial coextrusion lines has been limited. In this paper, we look to extend the initial studies of rheology in multilayered materials via layer multiplication coextrusion approaches and demonstrate preliminary results on model systems that illustrate the effect of mismatched viscosity on coextrusion multilayered polymer materials systems.
Steve Amos | Baris Yalcin | Andrew D’Souza | I. Sedat Gunes, May 2011
Fillers have been in use since the early days of plastics. Today’s enormous growth of
the polymer industry is due to the unique properties of fillers they impart to polymers.
Glass bubbles (low density hollow glass microspheres) as fillers have been incorporated into thermoset polymers for decades. They are tiny hollow spheres and are virtually inert. These glass bubbles are are compatible with most polymers. Until recently, their use with thermoplastic polymers has been limited because of high rates of bubble breakage from the high shear forces to which they are exposed during such thermoplastic processing operations as extrusion compounding and injection molding. At issue has been the strength of the glass microspheres.
Screw is the heart of an extruder. It is fact that mixing capability of a single screw is poorer than of a twin screw. More precisely, the dispersive action (breakdown) of a twin screw extruder is always better than of a single screw extruder. For producing new blends or alloys, as well as for mixing powdered feedstock or regrinds -- twin screw extruders give unparalleled dispersion. No surprise that twin screw extruders cost more than single screw extruders.
Kim McLoughlin Senior Research Engineer, Global Materials Science Braskem
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Kim drives technology programs at Braskem to develop advanced polyolefins with improved recyclability and sustainability. As Principal Investigator on a REMADE-funded collaboration, Kim leads a diverse industry-academic team that is developing a process to recycle elastomers as secondary feedstock. Kim has a PhD in Chemical Engineering from Cornell. She is an inventor on more than 25 patents and applications for novel polyolefin technologies. Kim is on the Board of Directors of SPE’s Thermoplastic Materials & Foams Division, where she has served as Education Chair and Councilor.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Gamini has a BS and PhD from Purdue University in Materials Engineering and Sustainability. He joined Penn State as a Post Doctorate Scholar in 2020 prior to his professorship appointment. He works closely with PA plastics manufacturers to implement sustainability programs in their plants.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Tom Giovannetti holds a Degree in Mechanical Engineering from The University of Tulsa and for the last 26 years has worked for Chevron Phillips Chemical Company. Tom started his plastics career by designing various injection molded products for the chemical industry including explosion proof plugs and receptacles, panel boards and detonation arrestors for 24 inch pipelines. Tom also holds a patent for design of a polyphenylene sulfide sleeve in a nylon coolant cross-over of an air intake manifold and is a Certified Plastic Technologist through the Society of Plastic Engineers. Tom serves on the Oklahoma Section Board as Councilor, is also the past president of the local Oklahoma SPE Section, and as well serves on the SPE Injection Molding Division board.
Joseph Lawrence, Ph.D. Senior Director and Research Professor University of Toledo
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Dr. Joseph Lawrence is a Research Professor and Senior Director of the Polymer Institute and the Center for Materials and Sensor Characterization at the University of Toledo. He is a Chemical Engineer by training and after working in the process industry, he has been engaged in polymers and composites research for 18+ years. In the Polymer Institute he leads research on renewably sourced polymers, plastics recycling, and additive manufacturing. He is also the lead investigator of the Polyesters and Barrier Materials Research Consortium funded by industry. Dr. Lawrence has advised 20 graduate students, mentored 8 staff scientists and several undergraduate students. He is a peer reviewer in several journals, has authored 30+ peer-reviewed publications and serves on the board of the Injection Molding Division of SPE.
Matt Hammernik Northeast Account Manager Hasco America
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Matt Hammernik serves as Hasco America’s Northeast Area Account Manager covering the states Michigan, Ohio, Indiana, and Kentucky. He started with Hasco America at the beginning of March 2022. Matt started in the Injection Mold Industry roughly 10 years ago as an estimator quoting injection mold base steel, components and machining. He advanced into outside sales and has been serving molders, mold builders and mold makers for about 7 years.
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How to reference articles from the SPE Library:
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers, ISBN: 123-0-1234567-8-9, pp. 000-000.
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
