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

Resistance Heating Of Carbon Fiber Reinforced Thermoplastics – Influences On Heating Rate And Temperature Distribution
Jochen Wellekoetter, March 2019

Continuous fiber reinforced thermoplastics (CFRTP) experience increasing demand by industry. Compared to their thermoset counterpart, they are considered to allow for shorter production cycles and offer more and better joining and recycling solutions. Usually, continuous fiber reinforced semi-finished parts are produced and then prepared for a back injection molding process to add functional integration. The resistance or joule heating process utilizes the electrical conductivity and accompanying heat dissipation of embedded carbon fibers. Thus, a short and homogenous heating process can be achieved. The main challenges that arise with resistance heating are the optimization of the electrical contact pieces as well as the shape and build of the semi-finished part. The heating process of several variations of contact pieces and shapes are monitored using thermal imaging. An algorithm is developed to automatically analyze key aspects of the heating process allowing for easy comparison of different parameter sets. Key results show that rounded edges for copper contact pieces and high contact forces yield homogenous temperature distributions and prevent hot spots while higher voltages result in less homogenous temperature distributions but higher heating rates.

Rheological Method Development: Using Rheological Tools To Predict Thermoformability
Mary Ann Jones, March 2019

Extrusion thermoforming of very large parts such as those used in the appliance industry can exceed the melt strength limits of a given polymer. This study was undertaken to define new rheological tests capable of defining the molecular design required to avoid excessive sag in the heating step of the thermoforming process and to identify the optimum temperature for forming. Damping factor (tan  = G’’/G’), also known as “tan delta”, can be used as a tool to identify fabrication conditions, molding window size, and the effect of added recycle streams. In addition, we compare polymer families that challenge our ability to thermoform large parts. Semi-crystalline materials must be run at or above their melting point temperature (Tm). Tm is well above the glass transition temperature (Tg) and the temperature delta (Tm - Tg) may exceed the width of any rubber plateau region in the melt state. These rheological characteristics are related back to the entanglement density of a given polymer and compared to the width of the rubber plateau.

Statistical Modeling Of The Squeak Noise Occurrence Of Natural Rubber
Byunghyun Kang, March 2019

In this study, the occurrence of the squeak noise according to various material / environmental factors of natural rubber was found through friction test using custom built friction tester. Material factors such as rubber hardness, surface roughness and additive content, and environmental factors such as heat aging, temperature, surface moisture, friction speed and frictional load are considered. And the hypothesis test was conducted to determine whether there was a significant correlation between each factor and the occurrence of squeak noise. Afterwards, logistic regression analysis and neural network analysis, which considers the interactions among these factors, were performed using the statistically significant factors in the occurrence of squeak noise obtained by the hypothesis test, and a probability model of the occurrence of the squeak noise was developed. And we compared the occurrence of the squeak noise predicted by the two models with the actual occurrence of the squeak noise, and the result shows 88.15% and 87.16% of accuracy, respectively. We also verify the accuracy of two models by using receiver operating characteristic curve (ROC curve), which illustrates the diagnostic ability of a model.

Study On Thermal Characteristics And Mechanical Properties Of Poly(Lactic Acid)/Paraffin Wax Blends
Yann-Jiun Chen, March 2019

Poly(lactic acid) (PLA) plastics have been popularly applied on many bio-degradable products and claimed as a green polymer materials for environmental concerns. In this study, a poly(lactic acid) (PLA)/paraffin wax (PW) composites with blends containing different amounts of PW and different compounding times have been developed and investigated. These composites blends were prepared by a micro-compounder with twin screw. Then, a neat PLA and the PLA/PW composites have been used to fabricate tensile specimens by micro injection molding machine. Effects caused by different compounding time and PLA/PW ratios, the thermal behavior and mechanical properties have been tested and investigated. Moreover, distribution and dispersion of PW in the PLA matrix have been observed in optical microscope and then calculated for comparison. Experimental results showed that the addition of PW yields significant improvements in ductility and toughness compared to that of neat PLA. The crystallinity and complex viscosity have also been improved. Finally, the samples of PLA/PW made by longer compounding time exhibits better distribution. Results of this study can be used for developing PLA/PW composites for bio-prosthesis for implants applications. Keywords: poly(lactic acid); paraffin wax; compounding time; injection molding;

The Effect Of Hygrothermal Exposure On The Thermal Conductivity Of Nanocellulose Based Foams
Whitney LaMarche, March 2019

Environmentally friendly insulation and packaging materials, driven by consumers and growing stringent global regulations against plastics, make biobased alternative materials a competitive market. Cellulose-based foams, consisting mainly of cellulose, are a greener replacement option over traditional petroleumbased insulation materials. One of the challenges associated with cellulose-based foams is their susceptibility to moisture, especially at elevated temperatures. Composite foams of nanocrystalline cellulose (NCC) and polyvinyl alcohol (PVA) were fabricated using a freeze casting method with a wide range of cooling rates during freezing. The physical properties of the foams, i.e., density, porosity and thermal conductivity were then evaluated before and after hygrothermal exposure at 40 °C with a relative humidity range from 96 to 77%. The results showed that the foams prepared with the highest rate of freezing exhibited the lowest relative density (0.019 g/cm3) and the lowest thermal conductivity (20 mW/mK). In general, the foams’ thermal conductivity increased after hygrothermal exposure. However, the foams with the highest freezing rate exhibited recoverable thermal conductivity behavior after exposure to heat and moisture. The possible mechanism for the differences were also discussed.

The Importance Of Chemical Stabilization In Recycled Material For Corrugated And Conduit Polyolefin Pipes
Ian Query, March 2019

Much attention has been given to stabilization packages for polyolefin pressure pipes over the past couple decades, however corrugated and conduit pipes have generally been ignored with respect to more robust stabilization packages. Certain groups such as the Florida Department of Transportation have set rules establishing oxidative resistance in HDPE corrugated pipes, but few others have followed this example. A discussion of the simplicity and importance of pipe resin stabilization as well as examples from stabilized pipes will be covered.

Why Titanates And Zirconates Are Better Than Silanes
Salvatore Monte, March 2019

Added to the hopper just like a color concentrate, 2 to 3 parts of a phosphato titanate or zirconate in pellet masterbatch form per 1,000 parts of filled or unfilled compound provides a method (Function 1-Coupling) for in-situ interfacial nano-surface modification of most all inorganic and organic materials in a compound independent of the interface’s hydroxyl content and absent the need for water to effect hydrolysis for coupling as with silanes while providing metallocene-like repolymerization catalysis (Function 2-Catalysis) and (Function 3) nano-intumescence for flame retardance resulting in: the use of larger amounts of regrind and recycle; copolymerization of blends of dissimilar addition and condensation polymers such as HDPE, PP and PET; prevention of delamination of PP/HDPE blends; faster production cycles at lower temperatures producing thermoplastic parts having less heat stress differentials, better finish, and increased stressstrain strength; and control of burn rate and burn rate exponent. Compounds having subject additives age better due to the removal of water at the polymer-reinforcement interface normally left when using a silane or no additives that cause loss of adhesion during water boil tests.

Open Cell Foams - An Emerging, Low-Cost Bacteria Adhesive Surface for Energy And Environmental Applications
Pavani Cherukupally, March 2019

Bacteria adhesive surfaces (BAS) have diverse applications, such as water treatment, biofuels, and solvents production. However, currently their large-scale usage is hindered by high materials cost. Inexpensive open-cell foams can potentially serve as substrates for low-cost BAS, enabling their wider usage. This work demonstrates a passive approach for attachment of Escherichia coli or E. coli to a polyester polyurethane open-cell foam surface using pH of the wastewater. The foam’s ionic-responsive charge property was used to bind negatively charged bacteria to its pore surface at different pH conditions. At the best pH condition, the foam adsorbed E. coli with over 99% efficiency. The pH-driven bacteria adhesion to foam surface is simple, effective, and passive, therefore has potential for industrial-scale applications.

Flame Retardants in Consumer Products: Overview and Perspective on the Proposed CPSC Ban
Andrew J. Worthen, Ph.D. | Jared M. Schwartz, Ph.D. | Davis E. Lee, Ph.D. | Kristin R. Robrock, Ph.D. | Renee M. Kalmes, Ph.D., October 2018

The US Consumer Product Safety Commission (CPSC) voted on September 20, 2017 to initiate rulemaking which will potentially ban organohalogen flame retardants (OFRs) in some types of consumer products. At the same time they issued a guidance document which recommends that manufacturers refrain from using non-polymeric organohalogen flame retardants in those products. In light of the CPSC actions, this paper summarizes alternative flame retardants currently commercially available to manufacturers, technical considerations of formulation changes, testing options, and an outlook for the future of flame retardants in consumer products.

Machine Upgrades & Rebuilds
Adam Covington, June 2018

What to do with an aging fleet of rotomolding machines? • Sell • Scrap • Maintain & pray • Rebuild & Upgrade

Interfacing with Floor Associates
Ken Bather, June 2018

Nice Sounding Title ...but… Why this presentation • Changing workplace • Changing workforce • Changing attitudes towards co-workers • Changing attitudes towards work & expectations

Rotational Molding Design Case Study - Car Wash Kiosk
Michael Paloian, June 2018

in the Beginning - Initial Meeting: • Highlight major design objectives • Review possible product configurations • Define major product requirements • Review schedule • Investment & cost • Discuss marketing objectives. Current Products – vacuum formed & sheet metal construction

Fuel Tank Regulations
Andrew Meloeny, June 2018

Regulations can be found in all industries: Automotive, Small Off Road Engine (SORE), Marine, Large Spark, etc. This presentation will focus on fuel tanks for the Small Off Road Engine (SORE) Industry. So what is a Small Off Road Engine (SORE) Application?

Nylon 6.6/9: A Lower Melting Temperature Nylon
Bobby Richards, June 2018

Copolymers of Nylon 6 - Benefits: • Good Gasoline Permeability • Long Term Heat Stability • Great Design Flexibility • Good VOC Behavior. Nylon 669: • Excellent Resistance to Hydraulic Fluid • Higher Wear Resistance • Extruded Monofilament • Much Lower Costs than High Number Nylons.

Polyethylene - Expanding Options for Rotational Molded Products
Sandy Scaccia, June 2018

Why Polyethylene? • It is easy to mold. • It is widely available in rotomolding grades. • It has good physical properties. • Cost – offers a cost competitive solution to end users. • Knowledge and Confidence - molders are very familiar with it. • Market Identification – end users know rotomolding is a Polyethylene based industry and therefore design products to suit the capabilities of the material.

Functional Color Concentrates TekTuff™ Impact Enhancement
John Wood | Edwin Tam, June 2018

Teknor Apex Company Capsule: • Founded 1924 • Privately held company, for long term growth and stability • Fully equity financed • Worldwide production, marketing, sales, R&D • Continuous growth through re-investment of profits • Employing ~2,200 staff • Acquired DSM Sarlink TPVs November 2010 • Acquired Viking Polymers rigid PVC February 2014 • Acquired PTS April 2016

Forces On Threaded Inserts
Steve Harris | Connor Landsverk, June 2018

Threaded Inserts: • “How strong is this insert?” • “What is the Torque Strength of this insert?” • Mechanical bond between insert & substrate • Typically Threaded for secure attachment of bolts and fittings • Failure is dictated by their ultimate function!

Effects of Mixing Methods of Color on Mechanical Properties of Rotationally Molded Parts
Anthony Wagner | Nathan Rader-Edkin, June 2018

Equipment Used: • Medkeff-nye Shuttle PD Rotational Molder • 12”x12”x12” Test Box • Ez-Logger Data Acquisition Tool • Leistritz Twin Screw Extruder • Webco Reduction Grinder • PlasMec High Intensity Mixer • Falling Dart Impact Tester • Tinius-Olsen Universal Tester

New Technology in Design, Materials & Processing
Jon Ratzlaff | Glenn Larkin, June 2018

Outline: • Machine – Persico Electric • Mold – 5 Gallon Water Can • Resins – MDPE & LDPE • Design • Processing • Impact Data • Conclusion

Analysis of Internal Temperature Curves for the Process Control of Complex Parts
Denis Rodrigue, June 2018

Content: • Introduction on rotomolding process control • Data profiles • Curve analysis • Conclusion • Acknowledgements

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