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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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Conference Proceedings
Influence of self-bias on barrier and elongation properties of barrier coatings deposited on flexible PET films
Christian Hopmann, Karim Bahroun, Henrik Behm, Florian Winkler, May 2013
Polymers gain more and more market shares due to their favorable properties such as lightweight, flexibility and transparency which makes them suitable for food packaging, organic light emitting diodes (OLED) and flexible solar cells. Nonetheless, due to their macromolecular structure plastics do not offer sufficient barrier functionality against oxygen and water vapor permeation, which is a key demand in a variety of applications. A common solution in plastics processing is the deposition of thin silicon oxide layers using microwave (MW) excited plasma processes. Unfortunately for some applications silicon oxide layers do not fulfill requirements concerning elongation properties especially when deposited on flexible plastic films. It is known that because of the brittle behavior of the coatings, induced strain of 1 – 2 % results in a cracking of the deposited thin coating and therefore a loss in barrier properties. Adaption of the self-bias using a radiofrequency (RF) source is one possible way to enhance barrier properties due to deposition of coatings with a higher density. When deposited on flexible substrates, a possible impact on elongation properties has to be taken into account. Since a variation in self-bias leads to a change in surface structure, the mechanical properties of the films have to be taken into consideration.
Development of a Process Technology for High Volume Production of Thermoplastic Composites Based on Hybrid Rovings
Christian Hopmann, Roman Schöldgen, Arne Böttcher, Marco Pöhler, May 2013
Continuous fiber reinforced thermoplastics are increasingly used for lightweight construction parts due to their relatively easy processing. Yet, a cost effective use for structural components is still limited due to the absence of an appropriate and economic high volume production technology. Therefore, a new process technology for the production of lightweight parts within short cycle times is being developed at the Institute of Plastics Processing (IKV) at RWTH Aachen University. This paper presents first results of the research on the process technology based on fiber spraying and consolidation of preforms made of chopped hybrid rovings.
Recycling of Polylactide for Packaging Applications
Christian Hopmann, Sebastian Schippers, May 2013
Polylactide (PLA) is a bioplastic which has a high potential for packaging applications. Due to a high raw material prize and a limited availability the usage of PLA is limited apart from some niche products at the moment. Nevertheless, the number of applications is increasing. At the Institute of Plastic Processing (IKV) the recycling behavior of PLA is evaluated. Recycling helps to cut the raw material consumption and lowers material costs. Additionally, it improves the ecological balance. Following the industrial praxis different recycling strategies are analyzed. This paper gives a review about the multiple processing of PLA and the processing with melt degassing.
Continuous Extrusion of Physically Foamed Silicone Rubber Profiles
Christian Hopmann, Sarah Sitz, May 2013
The foaming of rubber products offers saving potential with respect to component weight, material consumption and costs, while damping properties can be improved. For foaming of high-temperature vulcanizing (HTV) silicone rubber, the use of chemical blowing agents is state of the art. Physical blowing agents such as inert gases have ecological, economical and process-engineering advantages. This paper presents results of a current research project focusing on the development of a continuous process for the physical foaming of solid silicone rubber using nitrogen as blowing agent. The main aim is the achievement of a constant process in order to produce homogeneously foamed rubber profiles and the identification of quality-determining parameters.
Interdependency of Machine Settings and Temperature Profiles - An Experimental Study on Extrusion Embossing for the Replication of Microstructures
Christian Hopmann, Stephan Eilbracht, Ralf Morgenroth, May 2013
Replicating microstructures for functional surfaces in a fast and economic way is crucial for many technical applications. In this paper an experimental study on the variothermal extrusion embossing is presented. Polyethylene and polypropylene grades are used to manufacture hydrophobic films. Microstructure geometries as well as static and dynamic surface behavior in contact with purified water are analyzed. A theoretical approach to estimate the distinctive temperature profile that is generated according to processing conditions (e.g. haul-off speed, temperature of the embossing roll, etc.) is verified experimentally. Thus, the assumption is confirmed that a set of processing conditions (responsible for a specific replication accuracy) can be transferred to another set of conditions while keeping the replication quality constant.
Piezo-Based Mold Design for Injection-Compression Molding of High Precision Plastics Lenses with Minimized Centering Error
Christian Hopmann, Paul Walach, May 2013
Centering errors in the alignment of the surfaces of optical lenses lead to aberrations. In spite of very precise molds and processes, a lateral offset between the two mold halves and therefore between the optical inserts occurs and leads to centering errors in the replicated optical components. A newly developed mold design with integrated piezo-actuators allows the adjustment of the die-sided optical insert and with it the minimization of the centering error. Therefore it is possible to influence and reduce the geometrical error and raise the optical performance of plastics lenses without a machining of the mold.
Manufacturing of Elastomeric Hollow Bodies Using the Projectile Injection Technique
Christian Hopmann, Clemens Behmenburg, May 2013
Injection molding is the most important process to manufacture complex polymer parts. However, today the injection molding of elastomers almost entirely produces solid workpieces. Functionalized complex hollow components, e. g. for the conduction of medias, are often manufactured in costly multistep processes. The projectile injection technique offers a new approach to easily produce elastomers in a one-step process into complex hollow parts. This paper discusses the requirements on peripheral equipment and mold design and gives impressions of the effect of the process parameter variations on important quality criterias for this innovative process.
Temperature and Sliding Distance Dependency of Assembly Molded Friction Clutches
Daniel Merken, Dietmar Drummer, May 2013
The market for mechatronic actuator devices in the automotive sector, as well as in the field of white goods (household appliances), brown goods (home entertainment), and red goods (air conditioning in buildings) has been growing constantly throughout recent years [1, 2]. During use, the actuators not only have to mechanically withstand the nominal load, but often also higher peak loads. Peak loads occur, for example, in the case of blocking, reaching the end position of the adjustment rail of a car seat or a car mirror. There are four commonly used approaches for overload protection: adjustment of component to applied load over-sizing of mechanical parts - limiting load electrical current limitation - use of sensors use of a mechanical overload protection system. An over-sizing of machine elements, e.g. gears, is easily achievable but not desirable, since overall weight and costs increase. Electrical current limitation and use of sensors are almost weight-neutral, since the circuit board will be extended by only a few electronic components. However, with a higher level of complexity, the risk of defects rises and overload protection in an unpowered state, e.g. for the case of vandalism, is not possible. Another approach is the use of a machine element with an integrated mechanical overload protection, such as a friction clutch. A friction clutch combines the function of motion transmission and mechanical overload protection. A benefit is its full function in an unpow-ered state, which thus provides effective protection against vandalism. The technology of assembly injection molding opens up an economic way to produce these plastic multi component machine elements, see Fig. 1. When made by assembly injection molding, additional costs due to a more complex mold have to be taken into account, though, by using function integration within transmission components, this cost increase can be kept low. Well-defined design should allow weight and com
Shear and Extensional Rheological Evaluation of Polylactide-Nanographite Platelet Nanocomposites through Constitutive Equations
Esmaeil Narimissa, Rahul Gupta, Nhol Kao, Sati Bhattacharya, May 2013
Polymer based nanocomposites are fabricated through the incorporation of nanoscale inorganic solids into polymeric matrix. The focus of this research was on the production and rheological investigation of polylactide (PLA) and nanographite platelets (NGP) based bionanocomposites. In the current study, the linear viscoelastic behaviour of the samples was investigated in order to study the effects of the enhanced dispersion of NGP fillers on the rheological properties of the nanocomposites. Uniaxial extensional experiments were also carried out to analyse the impacts of the nanofillers on linear viscoelastic envelope (LVE) and non-linear viscoelastic behaviour (strain hardening region) of the nanocomposites. Furthermore, in order to provide an accurate prediction of the extensional viscosity behaviour of PLA/NGP nanocomposites, the modelling of strain-hardening behaviour of neat PLA and its nanocomposites was investigated using steady shear viscosity, relaxation spectrum and damping function based on Papanastasiou-Scriven- Macosko (PSM) version of Kaye-Bernstein-Kearsley-Zapas (K- BKZ) model.
Evaluation of Mechanical Property and Flame Resistance on Bio-Based Polymer Compounds
Hiroyuki Nishimura, Nobuyuki Imamura, Hiroki Sakamoto, Yuji Higuchi, Shinichi Kawasaki, Takahiro Nishino, Masayuki Okoshi, Hiroyuki Yamamoto, May 2013
This paper describes the evaluation of the mechanical properties and flame resistance on bio-based polymer compounds of Poly (lactic acid) (PLA) and Polyamide 11 (PA11). A compounding technology and mechanical properties of PLA and PA11 using a compatibilizer were firstly studied to improve the thermal resistance and the impact strength of PLA. Some compositions of PLA/PA11 blends using a compatibilizer were investigated. After some flame retardants which were not halogenated and toxic materials were blended to the composition of PLA/PA11/compatibilizer, the mechanical properties and flame resistance were also evaluated as compared with the commercialized PLA and Polycarbonate (PC) alloy. The flammability test was conducted with the multi-cone calorimeter to obtain the relation between the heat release rate or the integrated heat release value and the combustion time.
Calculation of the Anisotropic, Temperature-Dependent Thermal Expansion Coefficient (TEC) of Parts Made From Short-Fiber-Reinforced Polymers
Martina Vetter, Dietmar Drummer, May 2013
For the design of injection molded parts made of short-fiber-reinforced polymers, the anisotropic, geometry- and temperature-dependent thermal expansion coefficient (TEC) is often needed at the early stages of the design process, for example during material selection. The data usually available from material suppliers does not consider temperature dependency and the influence of geometries such as part thickness. State-of-the-art calculation methods such as the rule of mixture neither include these effects. Hence the development of simple models designed to estimate the TEC at the early stages of development is of interest. This paper deals with a method for engineers working in research and development to calculate the geometry- and temperature-dependent anisotropic TEC of parts made from short-fiber-reinforced polymers under consideration of fiber orientation. To evaluate the validity of the method, the results from the calculations were compared to measurements conducted on parts of different thicknesses. Here a good correspondence with the anisotropies of the TEC in different part directions was achieved.
Non-Isothermal Melt Crystallization Behavior of Poly(Ethylene Terephthalate)/Graphene Nanocomposites
Shigeru Aoyama, Yong Tae Park, Christopher W. Macosko, May 2013
Poly(ethylene terephthalate)(PET)/graphene nanocomposites were prepared by melt mixing to characterize their gas permeability and mechanical properties. With 2 wt% of few layered graphene, PET/graphene composite films show more than 70% decrease in N2 gas permeation and 10–21% increase in storage modulus, E'. Their non-isothermal crystallization phenomena from the melt were also investigated by differential scanning calorimetory (DSC). Crystallization temperature, Tc, of PET/graphene nanocomposites was higher than that of PET/MWCNT nanocomposites. This suggests that the nucleation effect of graphene was higher than that of MWCNT and was enhanced with the increase in concentration of graphene. On the other hand, PET/graphene nanocomposites show shorter half crystallization time, t1/2, than neat PET at lower concentrations, and t1/2 increased along with concentration of graphene. From Raman spectroscopy, it was shown that PET chains in nanocomposites are confined strongly in the presence of an excess of graphene. This confinement effect suggests that crystal growth rate of PET was suppressed by graphene in nanocomposites.
Raman Spectroscopy Study on the Addition of Peroxides as a Dispersing Additive in Multiwalled Carbone Nanotube Reinforced Polypropylene Composites
Shyam Sathyanarayana, Ganiu Olowojoba, Christof Hübner, Jan Diemert, Petra Pötschke, Frank Henning, May 2013
The addition of peroxides as a dispersing additive for multiwalled carbon nanotubes (MWCNT) incorporated in polypropylene is investigated with Raman spectroscopy both in the melt and on the extruded composite. Peroxide addition results in lowering of the melt viscosity of PP in addition to enhancing the defect concentration of the MWCNT. The better melt infiltration due to the former and evidences of CNT functionalization from the latter result in improved MWCNT dispersion quality in PP.
An introduction of the Planetary Extruder and areas of application
Harald Rust, Michael W. Batton, Thomas Malzahn, May 2013
Presenting and explaining the functions and history of the planetary extruder. Covering the advantages in physical characteristics, to include contact surface availability per rotation of the central spindle, Energy exchange capabilities (thermodynamics), control of mechanical energy and mixing properties. Technical advances made over the years in areas of manufacturing and employment of the planetary extruder in areas of de-gassing possibilities, individual blending of raw materials, liquid injection, mass- temperature and pressure measurement, control over fill degrees and residence times. Showing the advantages and applications of a modular built planetary extruder, in the adaptation of dis-continuous production processes into continuous processes. Introducing areas of application where the planetary extruder has shown major advantages and is used today throughout the world.
R&D Tax Credits – U.S. Tax Savings for U.S. Innovation
Michael J. Devereux, May 2013
One of the most under-utilized tax savings opportunities for companies in the plastics industry is the U.S. Credit for Increasing Research Activities (R&D tax credit). The R&D tax credit rewards companies who invest resources in innovation, product development, mold design, new materials or resins, and process development/improvement. In addition to Federal tax savings, several states have a similar program that rewards companies for the development or improvement to its products or processes. The types of activities that may qualify for the R&D tax credit include, but are not limited to the following: Developing new product designs Improving functionality or reliability or existing products Designing new molds or improving transfer molds Experimenting with processing variables to improve processes Improving manufacturing processes through automation Experimenting with new resins Performing PPAP or First Article inspections on new parts This article will discuss the following: The types of activities that may qualify for the R&D tax credit The types of expenditures that are eligible for the R&D tax credit The different methodologies for calculating the R&D tax credit The types of documentation necessary to substantiate a R&D tax credit claim The determining factors of whether the costs of externally-produced molds may be included as qualified expenditures The possible utilization of the R&D tax credit to offset taxes paid up to five years ago A case study of a plastics processor claiming the R&D tax credit
Properties of clay nanocomposites based on PETG by twin-screw extruder using supercritical CO2
Kwangho Jang, Jong Han Choi, Sangmook Lee, Jae Wook Lee, May 2013
A twin-screw extrusion process for PETG/clay nanocomposites using supercritical carbon dioxide was studied. Well-dispersed nanocomposites enhance the superior properties of the PETG/clay nanocomposites. So, we studied to achieve a good dispersion of the individual silicate layers of the clay. For even more enhancement of the dispersion of the clay in polymeric phase, supercritical CO2 can be employed in the processing of the nanocomposites due to the fast diffusion into the clay particles. The properties of PETG/clay nanocomposites are investigated by rheometer, thermal analyzer, permeability tester, and mechanical tester. The effects of clay contents and CO2 feed rate on the rheological and barrier properties of PETG/clay nanocomposites are presented. The results show that the rheological and thermal properties of the nanocomposites increase with the addition of clay. From the permeability test of nanocomposites, the barrier properties also increase. Moreover, the analysis of the nanocomposites also reveals that the use of supercritical CO2 leads to an increase of the rheological and barrier properties. From the results above, we strongly suggest that the use of supercritical CO2 assisted twinscrew extrusion is an effective way to improve the superior properties of PETG/clay nanocomposites.
Effects of Different Carbon Nanoparticles to the Morphology of PS/Carbon Nanocomposite Foam
Shu-Kai Yeh, Ming-Qing Ke, Kuo-Chung Cheng, Wen-Jeng Guo, Ren-Jei Chung, May 2013
In this study, polystyrene / carbon nanocomposite foams were made by in-situ polymerization and solution compounding. The foam was made by batch foaming using CO2 as the blowing agent. Various carbon nanomaterials such as nanographite, carbon nanofiber (CNF), carbon nanotube (CNT) and thermally reduced graphene (TRG) were used as the nucleation agent. In addition, processing variables such as foaming pressures and temperatures were also studied. The results indicated that TRG is the best nucleation agent because it possesses the highest surface area among these carbon nanomaterials. The cell morphology changed dramatically in the presence of carbon nanomaterials. This discovery not only opened up a new route for producing foams of a similar structure at a low foaming pressure, it also created a new application for graphene nanomaterial.
Manufacturability Study of Nano-Enhanced Fiber Reinforced Polymeric Composites (FRPC)
Ziwei Zhao, Na Zhang, Jose M. Castro, James L. Lee, May 2013
Due to the ever increasing cost of energy, there is an increased demand of lightweight materials. Towards that goal, we need to take advantage of new material developments such as is the case of nanoreinforced polymeric composites. The use of nanoparticles has shown improvement in mechanical properties of fiber reinforced polymeric composites (FRPC) but with adverse effect on processability, thus fully understanding the manufacturability of these processes is critical. Vacuum Assisted Resin Transfer Molding (VARTM) is the primary molding technique considered due to its significant advantages over other molding techniques and large size capacity. In this process, permeability plays a key role in determining processability. Understanding how permeability of these nano-enhanced FPRC is affected by the addition of nanoparticles is the main focus of this study.
Nano Direct Process for Compounding of Nanocomposites
Paul Andersen, Marina Matta, May 2013
Numerous varieties of polymer nano-composites have been developed on the laboratory scale and characterized regarding their properties. These include, nanofiller based on exfoliated clay, nanosilver, carbon nanotubes (both single and multiple wall geometry), zinc oxide, silica, and graphene among others. Carbon nanotubes (CNT) are of particular interest as they play a special role when it comes to improving or creating electrical conductivity in a polymer matrix. Currently most CNT based nano- composites are produced on co-rotating twin-screw compounding extruders via split feeding the polymer and the CNTs. However, processes using aqueous nano suspension are on the rise and offer new opportunities regarding technical performance, economical viability and reduction of health concerns related to the particle size of the CNTs. By using well pre-dispersed suspensions, which are already available on the market, it becomes easier to produce nanocomposites that provide the required characteristics, such as electrical conductivity. Also the usage of aqueous solutions enables dust-free handling of the carbon nanotubes. This presentation will introduce the Nano Direct Process and show its advantages in comparison to the conventional melt-mixing process.
Injection Molded Multi-Walled Carbon Nanotube/Polystyrene Composites: Effects of Alignment on Electrical Properties
Mohammad Arjmand, Uttandaraman Sundararaj, May 2013
The effects of multi-walled carbon nanotube (MWCNT) alignment on the electrical properties, i.e., electrical conductivity, electromagnetic interference shielding effectiveness (EMI SE), real permittivity and imaginary permittivity of MWCNT/polystyrene composites in the X-band (8.2 to 12.4 GHz) were investigated by comparing the electrical properties of injection molded samples, where MWCNTs were aligned, versus compression molded samples, where MWCNTs were randomly distributed. The results showed that the MWCNT alignment reduced the electrical conductivity and EMI SE tremendously. Nonetheless, it was observed that the MWCNT alignment significantly improved the dielectric properties of the MWCNT/polystyrene composites.


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