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

Improving the Adhesion of Polyolefin Elastomers
Colin Li Pi Shan, Frank Gong, Grace Wan, Yongchun Chen, Yang Hong, Brian Yu, Bo Lü, May 2017

The adhesion of polyolefin compounds to polar substrates is one of the on-going challenges for many consumer and industrial applications. Due to differences in polarity and surface energy, the bonding of polyolefin thermoplastic elastomers to engineering plastics such as PET, PA, PC, PU, and other polar materials are largely unresolved. This paper discusses the development of an adhesion primer for the surface treatment of polyolefin elastomers to improve its adhesion to PET and PC in lamination and coating processes. Results indicate that adhesion primers containing maleic anhydride functionality or a combination of MAH and chlorine functionality are effective for bonding PET and PC to a polyolefin. Overall, a combination of a surface adhesion primer and the application method can be an effective solution to provide the needed bonding. Such technology can be further applied to resolve the adhesion challenges of polyolefin elastomers to polar fabrics and coatings.

Biodegradability of PLA in Compost Environment
Qi-Hong Liao, Yong-Chao Jiang, Lih-Sheng Turng, Chao Chan Chen, May 2017

Considering to environment issues, PLA is one of the most popular plastic and commonly used. This study is going to study the biodegradability after produced by compression molding and buried the specimens in the soil and compost condition within 7 weeks. The specimens was produced and followed pattern as following ASTM D882. Specimens are tested the changes of molecular weight, thermal properties and appearance week by week. The results show that PLA could be dissolved and disintegrated in the period. For the thermal properties, the decomposition temperature, Tg and Tm are all decreased by week and week. Molecular weight is conducted by GPC, it shows the molecular weight are dramatic decreasing from 115K to 5.1K of Mw within 7 weeks. PLA happens to absorbed moister, crystallized in high temperature, debonding, cracks, separated pieces, and disintegrated, and finally dissolved in the environment. So the PLA specimens are verified that PLA can absolutely and completely disintegration in the compost environment.

Optimizing Process Condition of Resin Transfer Molding: Determining Material Properties for Numerical Simulation
Jessica Lin, C-W. Wang, C-T. Heng, L-J. Bin, S-P. Sun, C-H. Hsu, Y. Yao, R-Y Chang, May 2017

Herein, we present the recent development in permeability measurement by an optical visualization method. We applied this technique to investigate materials commonly used in wind turbine industry, such as different types of fiber mats, distribution medium, PVC core material. Wind turbine industry utilizes predominately resin transfer molding (RTM) process to manufacture the components. The traditional-trail-error method in this case is not practical due to the high cost of producing the components. To the best of our knowledge, this is the first example of using an optical method in conjunction with a simulation tool to obtain out of plane (K33) permeability. The results demonstrate the promising potential of permeability measurement by the optical visualization method, and great relevance to industrially important processes such as RTM. The measured material properties are then used in process simulation to obtain optimal process conditions of RTM.

Predict and Solve Stress Mark on Product's Cosmetic Surface Using Controlled Sequential Valve Gating Simulation
Jessica Lin, Edward Suhartono, Hsien-Sen Chiu, Chih-Chung Hsu, Chen-Chieh Wang, Chih-Wei Wang, Nicola Pavan, May 2017

Surface defect like stress mark has been a major issue in automotive part produced by Sequential Valve Gating (SVG). This defect may still even show up as uneven gloss after painting and drying, which is critical for cosmetic surface appearance. To solve it, controlled SVG has been developed by which the valve pin's velocity profile can be set. Nevertheless, manufacturers still face challenges in optimizing their velocity profile to avoid the defect. Moldex3D adopts a moving mesh boundary technique to support the pin movement simulation. Viscoelastic (VE) fluid property is also considered to compute and illustrate the appearance of flow-induced residual stress for the stress-mark prediction. The results show that the controlled velocity profile can eliminate the residual stress pattern at the gate which can be an indicator to resolve the uneven gloss for a spoiler product.

Ink-Wash and Warpage Defect Prediction from the in-Mold Decoration Process Simulation
Jessica Lin, Shih-Po Sun, Tung-Huan Su, David Hsu, May 2017

We introduced in this paper a simulation tool designed to predict the most common defects related to the in-mold decoration process. Ink-wash is the most obvious aesthetic problem caused by high temperature or high shear from the incoming melt. Warpage is another dimensional uncertainty defect due to the poor heat conduction of the film. Overcoming these problems often requires mold fixing including critical gate location change. Mold filling simulation could help identify these potential problems in the early mold design stage. However, conventional simulation techniques require tedious work of thin layer mesh making of the decoration film. It is therefore essential to develop a quick preprocess tool without losing simulation accuracy.

Long Fiber Orientation and Structural Analysis Using Moldex3D, Digimat and ABAQUS Simulations
Jessica Lin, Huan-Chang Tseng, Chia-Hsiang Hsu, Rong-Yeu Chang, May 2017

Long fiber-reinforced thermoplastic composites open up exciting new possibilities for the green automotive industry, owing to excellent mechanical properties, advantageous weight reduction, and economical fuel consumption. However, fiber microstructure including fiber orientation and fiber length, is a very critical issue to cause anisotropy in mechanical properties and warps. For an injection-molded, long-glass fiber composite part, we use Moldex3D to obtain an accurate fiber orientation prediction. Thus, mechanical properties depending on the predicted orientation is calculated via Digimat. It is ultimate to explore changes in stress with respect to strain in the ABAQUS structural analysis. All of the predictions are compared with experiments herein.

Effect of Multi-Walled Carbon Nanotubes on Poly(e-Caprolactone) Foaming Behavior
Tong Liu, Yu-Chen Wu, Qing-Lin He, Meng-Meng Wang, Tai-Rong Kuang, Xiang-Fang Peng, May 2017

In this paper, we investigated the effect of multi-walled carbon nanotubes (MWCNT) on the foaming behavior of poly(e-caprolactone) (PCL). The PCL/MWCNT nanocomposites prepared using HAAKE Rheometer, and the resulted composites were subsequently foamed using supercritical carbon dioxide (Sc-CO2) foaming technology. Results showed that the involvement of MWCNT promoted crystallization of PCL matrix and improved the crystallinity of PCL matrix, which is attributed to the enhancement of melt strength. Morphological analysis presented that the MWCNT was well-dispersion in the PCL matrix at low loading. In Sc-CO2 foaming process, the addition of MWCNTs led to higher cell densities, smaller cell sizes and uniform cell morphology in the composite foams. The results indicated that the MWCNT nanoparticle acted as a heterogeneous nucleation agent in the PCL matrix, and provided more nucleation site during the foaming process.

CPET Packaging with Enhanced Seal Characteristics by the Incorporation of a Polyolefin Seal Surface
JianCheng Liu, May 2017

Polyolefin seal layer was incorporated into crystalline PET (CPET) rigid packages (e.g. trays) to better control the seal and peel performance. The adhesion bond between polyolefins to CPET is destructive and inseparable, which exceeds common means of bonding technology (e.g., adhesives or tie layers) and prevents delamination while peel strength can be tuned with different easy peel lidding options. This new product was also passed preliminary tests under retort and oven conditions. Regrind with PE surface was studied in order to reclaim flakes in the CPET manufacturing process and the compatibility of PE matrix with PET was further analyzed.

Rheology of Acrylonitrile Butadiene Styrene with Hollow Glass Microspheres for Extrusion Process
Peng Liu, John Lindahl, Ahmed Arabi Hassen, Vlastimil Kunc, May 2017

The influence of hollow glass microspheres (HGM) on the rheological properties of a commercially available Acrylonitrile-butadiene-styrene (ABS) polymer was investigated. ABS/HGM composites were prepared with various HGM contents. The rheology of the ABS/HGM composites was characterized to provide insight into the influence of the temperature and sphere concentration on the flow behavior under shear. Linear viscoelastic measurements show that both complex viscosity and storage moduli exhibit about 4 orders of magnitude increase with increasing HGM concentration from 40 vol% to 50 vol%. The viscosity increase is more pronounced at low frequency shear rates.

Influence of Particle Size in Multi-Layer Rotational Molding with a Multiphase Interlayer to Generate Mechanical Adhesion
Martin Löhner, Dietmar Drummer, May 2017

Rotational molding shows the potential to build up multi-layer parts by sequential adding of different materials into a rotating cavity. The limited compatibility of several materials to each other reduces the potential material combinations significantly. Former investigations showed the general applicability of a multi-phase interlayer to bond incompatible materials during the rotational molding process. Within this interlayer interlocking occurs between the two materials. This work investigates the influence of particle size on the material distribution and peel strength for the material combination Polyethylene and Polyamide 12. It is shown, that the material distribution is depending on the particle size added to generate the interlayer whereas the peel strength is mostly unaffected if the interlayer thickness exceeds the particle size. For thinner interlayers smaller particles show higher peel strengths and a varying interphase region.

Advanced Applications for HDPE Pipe with New PE-RT Material
Wes Long, May 2017

Canfor’s Prince George Pulp & Paper Mill in Prince George, BC, Canada operates a bleach plant effluent system for the production of Bleached Kraft Pulp. The original underground fiberglass reinforced pipe (FRP) presents an elevated risk to both environment and production targets. Over the past five years there have been over 10 repairs required to maintain integrity of the pipeline. The primary objective of the project was to create a more reliable pipeline and reduce the risk of a major leak event and subsequent consequences. With temperatures up to 75°C, standard PE4710 materials were not suitable for this application. A brand new PE-RT product that expands the use of PE into larger diameter industrial applications allowing continuous operating range from -45°C to 82°C with intermittent temperatures up to 95°C was selected to replace the underground fiberglass piping.

Methodology to Improve Injection Molding Energy Performance: Successful Case Studies
Iván D. López, Juan C. Ortiz, Alexander Hernández, Omar Estrada, May 2017

Energy efficiency of injection molding is critical to increase the sustainability indexes of this process and to reduce production cost. The Energy Gap Methodology (EGM) is presented as a valuable tool to prioritize the interventions to increase the energy efficiency in injection molding and other polymer processes. This methodology identifies four gaps: production, process, technological and R&D gaps. Three industrial successful case studies reducing energetic gaps in injection molding are presented, obtaining specific energy consumption (SEC) reductions between 9 and 15%.

Reduction of Energy Consumption in Injection Molding of Polypropylene Parts through the Optimization of Mold Thermal Control
Giovanni Lucchetta, Davide Masato, Marco Sorgato, May 2017

The environmental impact of the injection molding process is mostly due to electricity consumption. This is particularly significant for packaging applications, which are the largest application sector for the plastics industry. In this work, electricity consumption measurements of the process were performed, considering a large packaging plant. In particular, the energy consumption related to mold thermal control were analyzed and minimized through a representative case study. The effects of alternative cooling channels configurations and different process parameters were experimentally investigated, considering also their influence on the quality of the molded parts. The results indicated that the common industrial practice for mold thermal control is highly inefficient. The implementation of electricity consumption measurements allowed the optimization of molds thermal control leading to considerable economic savings.

Investigating Filler Orientation of Functionalized Thermoset Molding Compounds during Injection Molding
Torsten Maenz, Andreas Jakobinski, Gerrit Hülder, Michael Gehde, May 2017

Thermoset molding compounds are showing great potentials in applications that demands high temperatures, high media resistance and good mechanical properties. Customized properties such as enhanced heat conductivity or magnetic properties that can be achieved through functionalization are often sought after in the thermoset as well as in the thermoplastic industry. This paper deals with the orientation of magnetic and heat conductive fillers in epoxy molding compounds, which are essential for part design and process control.

Material Characterization of CF-Nonwovens with Thermosetting Matrices
Jasmin Mankiewicz, Michael Heber, Ernst Cleve, Jochen S. Gutmann, May 2017

Regarding the need of robust and lightweight materials there is an increasing market for carbon fiber (CF). Therefore blending fabrics produce a huge amount of valuable process waste like prepregs which are out of specification and end-of-life products. The carbon fiber is regained from polymer matrix by new recycling methods. These fibers are chopped and can be reused for manufacturing isotropic fleece by wet-laid process. Created fleeces are impregnated with thermosets by resin transfer molding (RTM). At the beginning the isotropy of the fleece is verified by a circular disk and a 4-point bending test. After that the influence of different fiber surface weights and homogeneity, as well as no significant effect of various dispersing agents are identified. In addition to that the interrelation between fiber volume content, fiber length and specific values (tensile strength, flexural stiffness, Young's modulus) is analyzed. Referring to the results for thermosets with virgin fibers the process is transferred to recycled fibers.

Micro Molding with Bioabsorbables: Not Your Average Thermoplastics
Lindsay Mann, May 2017

This whitepaper explores Micro Molding with Bioabsorbables. For micro medical components, there is a wide variety of materials to choose from and many new micro medical applications are relying on bioabsorbable materials because the materials dissolve or absorb into the body, eliminating the need for additional surgeries and minimizing concerns about adverse effects.Across the board with plastics, the rules are different when you mold it so small. But when it comes to bioabsorbable resins, they require a much more extensive and specialized approach than thermoplastics. By understanding how processing bioabsorbables differs from thermoplastics, medical OEMs can understand the key factors needed for optimizing the design and production of their bioabsorbable products.

Method for Degrading Polyethylene Sheet Samples in an Oxidative Environment
Susan Mantell, Evan Cosgriff, Mrinal Bhattacharya, May 2017

Stress cracking is a failure mode that must be considered when evaluating the lifetime of polymer components. In modeling this failure mode, mechanical properties as a function of the extent of degradation must be evaluated. This paper describes an apparatus and method for degrading thin polymer sheets in an oxidative environment. A model system of PE in hot chlorinated water with an oxidation reduction potential of approximately 825 mV is considered. The oxidative environment is achieved by a water bath with temperature, pH and free chlorine controlled to 60-65°C, 5.2 +/- 0.5 ppm free chlorine, and 6.3 +0.5/-0.0 pH. Under these conditions, the molecular weight of 50-60 micron thick PE sheets was reduced by 60% and the strain at break for the sheets was reduced by 90% after 1000 hours exposure.

Improving the Patient Experience of Your Drug Delivery Using Polymers with Improved Tribology
Kirsten Markgraf, May 2017

In medical and pharmaceutical devices, such as injection pens, inhalers, lancing devices or surgical instruments, metal and ceramic components are increasingly being replaced by engineering polymers. Their light weight and the dimensional accuracy derived from precision molding, combined with good wear resistance and low coefficients of friction, often make engineering polymers a better solution than metal. In many medical and drug delivery devices the device components must slide against each other in complex systems containing multiple materials. To allow the device to work smoothly, particularly in the activation of the device, they must not create noise, wear or too much friction, and retention of low and consistent activation forces during the life-time of the drug delivery device are required. This performance has to be achieved in sophisticated designs, across a range of temperatures, different chemical environments, and with a range of speeds and forces in operation. This presentation reviews common engineering polymers, the benefits and disadvantages of external lubrication and gives insight into a smart material selection process. Slip and wear properties are described as well as scientific analytical methods to deliver optimal performance, reduced risk of failure and increased patient comfort.

Modeling Three-Dimensional Non-Newtonian Flows in Single-Screw Extruders
Christian Marschik, Wolfgang Roland, Bernhard Löw-Baselli, Jürgen Miethlinger, May 2017

Modeling the multidimensional non-Newtonian flow of shear-thinning polymer melts in single-screw extruders generally requires the use of numerical methods. We present a heuristic approach to predicting the three-dimensional, fully developed, isothermal flow of power-law fluids in single-screw extruders that avoids complex and time-consuming numerical simulations. By applying a heuristic optimization algorithm, we approximate numerical results obtained from a comprehensive parametric design study, yielding an analytical relationship for the output-pressure gradient relationship depending on four independent parameters: (i) height-to-width ratio (h/w), (ii) pitch-to-diameter ratio (t/Db), (iii) power-law index (n), and (iv) dimensionless pressure gradient in the down-channel direction (pp,z). The new approach is demonstrated to provide a close approximation to numerical solutions.

Modeling and Simulation of the Inflation Step in the Two-Stage Gitblow-Process
Yannick Martin, Elmar Moritzer, Björn Landgräber, Stefan Seidel, May 2017

The innovative two-stage GITBlow process combines the advantages of injection molding and blow molding. This is achieved by producing a preform using gas-assisted injection molding, which is then inflated by a second gas injection within a larger cavity in the same mold. The components obtained have a large volume/wall thickness ratio, while, at the same time, featuring elements that are typical of injection molded parts, e.g. ribs. This paper presents the simulation of the inflation behavior under consideration of inhomogeneous preform temperature. For this purpose, a spring-dashpot model is developed to describe the viscous and viscoelastic behavior of the plastic material. The findings obtained in the simulations are then verified with experimental results.

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