SPE Library

PRESTRESSED DOUBLE NETWORK GLASSES

Zhan H. Yang, Andrew T. Detwiler, Alan J. Lesser, May 2012

Prestressed Double Network epoxy, a new type of sequential Interpenetrating Polymer Network, was developed by reacting an epoxide monomer with various molar ratios of two curatives. Postcure was conducted while the partially cured resins were at 50% compressive strain. The application of pre- stress did not change the glass transition temperature, or coefficient of thermal expansion. However, a marked increase in fracture toughness is observed, accompanied by strong birefringence and visible roughness on the fracture surface.

RECENT INSIGHTS ON THE USE OF BETA NUCLEATION TO IMPROVE THE THERMFORMING CHARACTERISTICS OF POLYPROPYLENE

Philip Jacoby, May 2012

Beta nucleation can be used to improve the thermoforming characteristics of polypropylene. The benefits of beta nucleation include a broader processing window, better material distribution, improved rigidity and crush strength, and higher productivity. In this paper we will show how the properties of the thermoformed part depend on the processing conditions used, and how new, high activity beta nucleating agents can lead to lighter weight, lower cost products with unique visual characteristics.

ANALYSIS OF THE FLUID ASSISTED INJECTION TECHNIQUE BY USING ULTRASONIC

Christian Hopmann, Walter Michaeli, Sebastian Becker, May 2012

The gas assisted and water assisted injection molding technique are well-established processes for the production of parts with (functional) hollow space. The quality of these parts highly depends on the internal part properties such as the residual wall thickness. Hence this paper deals with the online use of ultrasonic measurements to visualize the hollow space formation and to determine the residual wall thickness of the molded parts.

BATCH FOAMING BEHAVIOR OF TPU MATERIAL

Kun Chang Lin, Chia-Hsun Chen, Hsin-Chih Peng, Chen-Feng Kuan, Hsu-Chiang Kuan, May 2012

This paper investigates the foaming behavior of thermoplastic polyurethanes (TPU) in a customized foaming system using carbon dioxide (CO2) as a physical blowing agent. Foams with different cellular morphology have been obtained depending on different TPU material and foaming conditions. The influence of different TPU material and foaming conditions (pressure, temperature and time) on the expansion behavior and the foam structure are discussed.

INFLUENCING THERMOFORMING PROPERTIES OF POLYPROPYLENE FILMS WITH ADDITIVES

Christain Hopmann, Walter Michaeli, Maren Begemann, May 2012

ELECTRICALLY CONDUCTIVE PLASTICS COMPOUNDS BASED ON SYNERGETIC FILLER COMBINATIONS

Christian Hopmann, Walter Michaeli, Jan Fragner, May 2012

Electrical conductive plastics compounds based on one type of filler show limited electrical conductivities. By combining different fillers synergetic effects can be obtained regarding not only the electrical conductivity but also the mechanical properties or processability. In this paper the synergetic effect of carbon fibers combined with carbon black, carbon nanotubes and a low melting metal alloy in a polypropylene matrix is discussed

A FULLY THREE DIMENSIONAL NUMERICAL APPROACH SIMULATING THE MELTING ZONE IN A SINGLE-SCREW EXTRUDER

Walter Michaeli, Christian Hopmann, Sebastian Grammel, May 2012

This paper presents a fully 3D numerical approach to simulate the melting process in a single screw extruder using the software Fluent distributed by ANSYS, Inc. The model predicts the melting length, pressure build?up and the velocity and temperature distribution within the channel. The screw geometry is modeled as a helical shaped channel and the principle of reversed kinematics is applied. The solid bed is modeled as a fluid with a very high viscosity.

TROUBLESHOOTING COEX FILM PROBLEMS BY CONSIDERING PROCESS-PROPERTY RELATIONSHIPS

Barry A. Morris, May 2012

Coextrusion is a complex process where many processing and structure design factors affect performance. As a result, problems can be difficult to troubleshoot. This paper explores some of the recent advances in the science of coextrusion with a focus on using this knowledge to prevent and troubleshoot problems. Issues involving multilayer film design and properties (compared to monolayer films), curl and adhesion are discussed.

MEASUREMENT OF THE STRAIN-DEPENDENT POISSON'S RATIO FOR THE CRASH SIMULATION OF TECHNICAL THERMOPLASTICS

Ch. Hopmann, Barbara Heesel, May 2012

In order to predict the crash behavior of thermoplastic parts an adequate material description is needed. For this purpose plastics?specific material models have been developed. The calibration of these requires extensive material data. Besides the knowledge of the Young’s modulus and the flow curves also that of the strain dependent Poisson’s ratio is crucial for a high simulation quality. This paper deals with the measuring techniques and the measured contraction behavior of different thermoplastics.

EFFECT OF MATERIAL VISCOSITIES ON PURGING IN EXTRUSION PROCESSES

Christian Hopmann, Walter Michaeli, Janina Overbeck, May 2012

Material changeovers steadily grow in importance in the context of the sinking batch sizes in extrusion plants. For understanding the influences on material changeovers, the changeover performance of polyolefins in a simple round strand die has been examined. In this regard the viscosity of the material turned out to be the key factor.

APPLICATION OF MODELING TO SPEED FLEXIBLE PACKAGE DEVELOPMENT

Barry A. Morris, May 2012

Models developed by DuPont or found in the literature are described that help the package engineer design new package structures by optimizing package performance, minimizing cost and ensuring the film or laminate can be fabricated on converting equipment. A case study is presented to illustrate how the use of these tools can speed up new package development.

USE OF X-RAY TOMOGRAPHY FOR EFFICIENT PACKAGE DESIGN

Sudheer Bandla, Jay C. Hanan, May 2012

With the current trend for lightweighting, accurately modeling the complex interactions between the closure and bottle is critical for a package design. X-ray Microtomography, a non-destructive technique is shown as a tool for studying design and geometrical features of beverage packaging. It allows seeing through the assembly, to determine actual dimensions to a micron resolution and reconstruct a real 3D geometry for FE analysis. This technique also helps identify critical locations for better material distribution.

CRYSTALLIZATION OF ACETAMINOPHEN/POLY(ETHYLENE OXIDE) MIXTURES

Min Yang, Costas G. Gogos, Peng Wang, May 2012

A model drug acetaminophen was mixed with PEO, and the morphology, nucleation numbers, and crystallization kinetics of PEO were altered accordingly. The spherulitic growth rate and isothermal DSC endotherm were analyzed by Hoffman-Lauritzen theory and Avrami theory, respectively. It was found that the fold surface free energy increased significantly with increasing drug content, indicating the chain folding of PEO became much more difficult in the presence of the small molecule drug.

THEMOPLASTIC STARCH AND POLYETHYLENE BLEND FOR BLOW MOLDED BOTTLE

Gregory J. Anderson, May 2012

HDPE was blended with TPS and blow molded into bottles. The packaging related GHG emissions were reduced 80 percent. The method involved two extruders. The first converted the starch into TPS, while the second mixed the HDPE and TPS for a co-continuous morphology. Further dilution during the melt forming stage resulted in fine droplets of TPS dispersed throughout. The TPS was used in various layer combinations without sacrificing the appearance or performance of the bottles.

EXPLOITING CHAOS: SHOULD POLYMERIZATION REACTORS BE CHAOTIC?

Sadhan C. Jana, Chang Do Jung, May 2012

This study established the benefits of chaotic mixing in polymerization of two immiscible components by considering one-step synthesis of thermoplastic polyurethanes from aliphatic diisocyanate, chain extender, and a soft segment diol. The efficient mixing in chaotic flow reduced the time scale of mixing and led to faster polymerization.

MAXIMIZING TALC BENEFITS IN DURABLE PLA APPLICATIONS WITH LUZENAC HAR®

Saied H. Kochesfahani, Caroline Abler, Jerome Crepin-Leblond, Frederic Jouffret, May 2012

The use of talc in PLA compounds for durable applications has been studied, and it is shown that talc could significantly increase stiffness, reduce thermal expansion (CLTE), and enhance thermal stability and HDT of crystallized PLA compounds. The high aspect ratio Luzenac HAR talc could be used to maximize these functions or to achieve desired mechanical properties at lower talc loadings, which may be desirable for compostability or other requirements.

LASER DIRECT STRUCTURING OF THERMALLY CONDUCTIVE POLYMERS: AN INNOVATIVE THERMAL MANAGEMENT APPROACH

Scott R. Sabreen, May 2012

Thermally conductive polymers open up a vast range of design concepts for the thermal management of optoelectronic systems based on high-brightness light emitting diodes. This paper presents an innovative material approach for manufacturing three-dimensional thermoplastic circuit carriers, combining a selective, laser-assisted metallization technology and highly filled polymers with thermal conductivities up to 8 Wm-1K-1.

DIGITAL PRINTING OF PLASTICS A NEW FRONTIER FOR INDUSTRIAL PRODUCT DECORATION

Kasper Nossen, May 2012

Piezo inkjet technology offers microprinting and macroprinting processes new and exciting product applications. This technology offers opportunities unparalleled in markets for entrepreneurial manufacturers and specialty printers.

TRANSFER EFFICIENCY VERSUS COATING WASTE REDUCTION

Ken Eyestone, May 2012

This paper will discuss published transfer efficiency of a spray applicator versus the real transfer efficiency of the spray applicator. The testing protocols used to determine the published transfer efficiency of a spray applicator will be discussed in relation to actual use of the spray applicator in a manufacturing coating process. The most common sources of material waste and the methods to reduce them to acceptable levels will be used to guide the reader to maximize the real transfer efficiency of their spray application system.

CALCIUM SULFATE WHISKERS(CSW)REINFORCEMENT OF POLYMERS - A REVIEW

George C. Hawley, Lisette Akor, May 2012

Calcium sulfate whiskers (CSW) were patented in 1974. But then the price was too high. In the last 5 years, interest in CSW as reinforcement has grown due to availability and low cost relative to polymers. Surface treated CSW have been found to increase notched Izod impact properties of polypropylene by 60%. CSW increase strength, stiffness and HDT in PA6, PA66 and PBT. CSW improves friction materials based on phenolics, PA66/PVDF blends, and PTFE.