SPE Library

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

Effects of Viscoelasticity on Film Die Flow Uniformity

Hyunwoo Kim, Laura Dietsche, Patrick C. Lee, Joseph Dooley, May 2016

This study shows the effect of viscoelasticity on the flow uniformity in a film die. Flow simulations were conducted on flat die geometries based on the rheology of different resins with different viscoelasticity characteristics. The results have shown that viscoelasticity can have a significant influence on flow uniformity and flow distribution becomes less uniform as the elasticity of the resins increases.

Automatic Optimization of Extrusion Dies

Mahesh Gupta, May 2016

A newly developed extrusion die optimization software is used to optimize a sheet die and a square profile die with non-uniform wall thickness. The optimization software successfully optimized the two die geometries such that a uniform velocity distribution is obtained at the die exit without exceeding a pre-specified pressure drop across the die.

Holding Force Study of Polyolefin Resins for Stretch Hood Film Application

Yi Jin, Rajen Patel, May 2016

This paper investigated how polyolefin resin properties affect holding force performance for stretch hood film application. In this study, the effect of density/crystallinity and composition distribution on the holding force and elastic recovery of ethylene copolymers was examined. A large number of resins from different families were investigated in this study.

Effects of Annealing on the Bonding Properties of Polymer-Metal Hybrids

J. A. Puentes, I. Kuehnert, May 2016

Polymer adhesion to a metal plate using an intermediate polymeric reactive layer was evaluated. A novel in-house adhesive powder coating was applied and compared with commercial ones, the influence of metal surface and a subsequent annealing process of the samples on the adhesive strength was also assessed through atomic force microscopy (AFM), mechanical test and differential calorimetry (DSC). Interesting results were obtained in terms of successful adhesion between the polymer and the metal, especially in samples that were annealed with the in-house coating.

Optimization of Maddock-Style Mixers for Single-Screw Extrusion

Xiaofei Sun, Qian Gou, Mark A. Spalding, Timothy W. Womer, Ned Uzelac, May 2016

Maddock-style mixers are used extensively on singlescrew extruder screws to disperse materials into the molten resin matrix. Since the time LeRoy invented the device and Maddock perfected and commercialized it, the device has undergone several innovations. Two of these innovations have created processing issues. The goal of this paper is to describe the optimal flute geometry and mixing undercut dimension for a Maddock mixer with the goal of mitigating degradation gels and maximizing dispersive mixing stresses.

Short Pulsed Lasers in Marking

Jake Wieloch, May 2016

The world of laser technology continues to develop and grow. In the past 10 years lasers have evolved from CO2 and Nd:YAG systems to diode pumped and fiber lasers. The latest expansion is taking place in lasers that produce super short pulses. Some of these pulses are measured in the Pico and Femto second range.
This paper will look at what are the characteristics of a short pulsed laser, how the pulse width effects applications, and the applications that are using these lasers.

A Novel Synergist for Flame Retardant Glass-fiber Reinforced Polyamide 66

Zheng Qian, Veerag Mehta, May 2016

A novel silicon based synergist, DynaSil™, was used in glass-fiber reinforced polyamide 66 which is flame-retarded with organic phosphinate and traditional synergists. Mechanical, physical and thermal properties, as well as fire testing results, are reported. DynaSil™ helps to lower the using amount of organic phosphinate and traditional synergists in flame retardant glass-fiber reinforced polyamide 66 composites, meanwhile improving properties and fire performance and lowering the cost of the composites.

Novel Thermoplastic Polymer for Soft Touch Applications

Helen Lentzakis, Veerag Mehta, May 2016

Polymer Dynamix has developed a novel thermoplastic compound which combines an appealing soft, silky feel combined with flexibility. The results demonstrate that reactive modification decreases the Shore Hardness and increases the flexibility and soft, silky feel of a thermoplastic elastomer.

3D Printing Offers a Giant Step for Short Run Injection Molds

Gil Robinson, May 2016

Learn how 3D printed tools for injection molding can be used to save you time and money when creating short run prototypes from production grade plastics. This paper, will discuss the business rational behind this solution, show how some of our customers are using it and provide technical tips and tricks for success. We will also touch on a few of the future developments we see for this solution.

Long Chain Branched / High Melt Strength Linear Low Density Polyethylene for Blown and Cast Film Applications

Edward M. Phillips, May 2016

While the physical properties of LLDPE are highly desired for many blown and cast film applications, it lacks the melt strength compared with LDPE. While LDPE can be blended with LLDPE to improve melt processability, key properties are sacrificed. This paper describes a proven technique for obtaining LCB or HMS LLDPE by means of high energy electron beam modification that increases the melt strength of reactor grade LLDPE by 5-7 times without secondary compounding and without creating gels. These materials can be used as stand alone film grades or as melt strength modifiers for conventional LLDPE and other polyolefins.

When Standards Get In the Way of Innovation

Jeffrey Quill, Sean Fowler, May 2016

Standardization is a cornerstone of modern civilization. The weathering testing industry of today exists because of the work of standards writers around the world. However, there can be too much of a good thing. Test standards in weathering sometimes get in the way of innovation. For example, the most common cycle for testing polymeric materials in xenon arc test chambers is the 102/18 cycle. That is, the test is run for 102 minutes with light only, followed by 18 minutes of light plus water spray. Users of weathering standards assume the prevalence of this test cycle must mean that it has been carefully validated for a wide variety of materials over the decades. They may also assume that this cycle was developed to provide good correlation to natural outdoor weathering, with extensive scientific research and statistical analysis to support its broad application. They assume incorrectly. The origin of this cycle dates back to the Victorian era when the first carbon arc weathering test chambers were developed. Rotating racks completed one revolution in two hours, and specimens were sprayed with water for 18 minutes as they moved past the fixed spray nozzles in the chamber. In other words, the 102/18 cycle was set in stone a century ago and has rarely been questioned since then.
Standards have also hindered innovation by overstepping their boundaries. For decades automotive OEMs bemoaned the lack of correlation between their laboratory tests and real outdoor test results. Through the development of SAE J1960 and similar standards, OEMs wrote their testing requirements around specific pieces of hardware rather than test conditions designed to simulate and accelerate natural weathering conditions. Flaws and limitations in the old technology thus became standardized, precluding any improvements to the test methods. A few of the OEMs decided to do something about it, and this was the origin of ASTM D7869, which is a true state of the art weathering test standard fo

Selecting the Best Remediation Option for Failing CPVC Piping Systems

Duane Priddy, Rowland Hall, Dan Beaudoin, May 2016

Chlorinated polyvinylchloride (CPVC) is widely used for many piping systems including potable water, hydronic heating/cooling, corrosive liquid drains, and fire suppression systems. CPVC is popular because of its ease of installation and corrosion resistance. However, as with all plumbing products, occasionally pipes or fittings may fail. Our goal as forensic scientists is to determine the root cause of failure of the CPVC piping and to provide the client with data that will help them select the most appropriate remediation option for their building. This paper presents four unique case studies, the forensic tools we used to evaluate the CPVC piping systems, and the logic behind the remediation option selected by the client.

Impact Modeling of Single-Ply TPO Roofing Systems

T. Luo, H.F. Nied, Li-Ying Yang, S. Bhawalkar, May 2016

A finite element model was developed to simulate dynamic stress distributions in thermoplastic polyolefin (TPO) roofing systems subjected to severe impact events, e.g., hail and hard object strikes. In order to build an integrated TPO layered composite roofing system model, separate sub-models are developed that include: the TPO membrane, polyester reinforcement scrim, low modulus closed-cell foam and fiber-glass stiffened facer sheets. A hyperelastic Mooney-Rivlin model of the TPO membrane is utilized to simulate the membrane’s large-deformation mechanical response during simple impact tests. Straightforward force-contact measurements on the TPO membrane material and low modulus foam backing, using spherical indenters, are shown to provide sufficient material properties for the impact model of interest. It is demonstrated that the local failure modes for the layered composite roofing system can be adequately characterized by using relatively simple failure criterion for each of the individual component layers in this type of roofing system. Both high-speed indentation and ice ball impact experimental tests have been performed to evaluate and verify the predicted performance of a single ply TPO roofing system. Excellent correlation is obtained between model predictions and experimental dynamic indentation tests.

Troubleshooting Extrusion Using chillWARE Computer Simulation for Sagging and Collapsing of Pipe Ends

Kenny Saul, Martin Spitz, Gregor Hiesgen, May 2016

The Extrusion process is a complex process in which a good product quality can only be achieved when all the parameters of influence (e.g. design of machinery, throughput, temperature set up, cooling situation, vacuum level, etc.) are set correctly. In everyday production on only one extrusion lines several products have to be produced (often more than 100 different products on 1 line). Following, process parameters have to be changed quite often to adjust the machine for the demands of the new product. During such a product change procedure, very often product quality problems occur.
Frequent problems like sagging, roughness on surfaces, geometric problems, deformations or a bad mechanical strengths are caused very often by the cooling situation and can often easily be reduced, if correct process parameters would be used. In this paper the use of a computational system is presented to analyze the reasons and possible solutions for such problems during extrusion. The computational system is based on finite difference method and finite element method and shows the capability to calculate the cooling process, the crystallization time and the residual stress distribution in the product.

Improved Troubleshooting and Appropriate Maintenance in Injection Molding Using Adequate Measuring Technique

Kenny Saul, Martin Spitz, Gregor Hiesgen, May 2016

Injection molding is a sensitive process. After implementing a stable process to achieve the required product quality, there are many potential external disturbances that might lead to downtimes or off-quality production. Machine manufacturers do a lot of research to adjust the process and react on external disturbances, e.g. varying residual moisture of the resin [1]. Disturbances coming from the central cooling unit, air compressors or the nitrogen generator can also lead to low product quality or high production costs, but have not been studied sufficiently as of today.

Simulation Based Determination of the Crystallinity Distribution in Polymer Pipes

Gregor Hiesgen, Kenny Saul, Martin Spitz, May 2016

The crystallinity and density of extruded semi crystalline polymer products has an intensive influence on the mechanical, geometrical and optical properties. Basically, the final polymer morphology depends on the overall production process. For semi crystalline polymers, the crystallization process can be separated into three sequential stochastic processes: 1. Nucleation: Arising of spherulite origins 2. Growth: filling the space, starting from the origins 3. Secondary Crystallization: compilation of the final crystalline structures Thus, the overall production process has an impact on the degree and type of crystallinity. The crystallization process is very complex and is influenced by the thermal and structure-mechanical history during the production process. A unified modeling of the different phenomena is hard to realize.
The simulation system chillWARE® is utilized to calculate the degree of crystallinity in dependency of the cooling process (thermal history) for polymer pipes. It is shown, how the distribution of the degree of crystallinity and density can be influenced by using alternative cooling technologies like internal pipe air cooling.

The Melt Temperature Variation in the Barrel of Injection Molding Machine

Joohyeong Jeon, Jinsu Gim, Byungohk Rhee, May 2016

Experimental observations on the melt temperature variation in the barrel of injection molding machine are reported in this article. To examine the temperature variation in depth, the accuracy of temperature sensor should be much higher than the sheathed thermocouple used widely in the field. A novel temperature sensor with a less heat capacity than the usual sheathed type sensors was developed in this study. The effects of some process conditions on the variation were examined. The experimental results showed that the melt temperature in the barrel was affected by the process conditions such as the screw rotation speed and the heater temperatures as well as the injection rate. Also additional conditions such as the shot volume, the dwell time after plasticizing and the length of feeding section were examined.

Investigation of Fiber Breakage Phenomena for Different Fiber Types in Injection Molding

Chao-Tsai (CT) Huang, Huan-Chang Tseng, Rong-Yeu Chang, Sheng-Jye Hwang, May 2016

The lightweight technologies become the driving force for people in automotives and other developments in recent years. Among those technologies, using short and long fiber-reinforced thermoplastics (FRT) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fiber inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. In this study, we have integrated the screw plastification, to injection molding for fiber microstructures investigation. Specifically, we have paid our attention on fiber breakage prediction during screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage can be higher even if the compression ratio is lower. Moreover, the fiber breakage phenomena for two types of fibers (glass fiber and carbon fiber) are also investigated. It shows that carbon fiber is easier to be broken. Also the carbon fiber length distribution has higher peak at the exit of the screw.

Tannic Acid: A Bio-based Intumescent Char-forming Additive for Nylon 6

Weeradech Kiratitanavit, Zhiyu Xia, Ankita Singh, Ravi Mosurkal, Ramaswamy Nagarajan, May 2016

Intumescent and char forming additives are typically blended into certain types of commercial plastics to impart resistance to fire propagation. Intumescent compounds such as ammonium polyphosphate/ melamine/ pentaerythritol, silica gel/potassium carbonate are already used as flame retardant (FR) additives. In this work, a naturally occurring polyphenol, namely tannic acid, is explored as an intumescent and char forming additive for polyamide - Nylon 6. The tannic acid was meltblended into Nylon 6 and the compounded plastic was evaluated for thermal stability, total heat release (THR) and heat release capacity (HRC). It was found that HRC and THR of nylon blended with tannic acid decreased by 50% and 20% respectively.

Scratch Resistance of Thin polymeric Films: Effect of Orientation and Polyethylene Content

Marouen Hamdi, Hung-Jue Sue, May 2016

Thin films are extensively used in many industrial applications such as automotive, electronics and packaging industries. However, their properties are significantly affected by several mechanical damages like scratch. Little has been done to understand the scratch behavior of polymeric thin films. Here, we consider investigating the impact of orientation and ethylene addition on the scratch resistance of PP thin films using an ASTM/ISO standard. Experimental results show that scratch resistance has improved with higher film orientation and lower ethylene content. A comparison between machine direction and transverse direction shows that scratch performance is much better in MD. Also, an FEM simulation has been performed to support the experimental findings. It is believed that this study is beneficial to design polymeric films with better scratch resistance.