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
Effect of nucleating agent on properties of in-situ copolymer polypropylene and PP/POE Blends
Advances in Compounding and Extrusion - Presentation: Toughening of homopolymer polypropylene (PPH) in the post reactor step by incorporating external elastomers has become an attractive area of research. In this investigative work, PPH was post-reactor blended with different types of Polyolefin elastomers (POE) that were selected based on the co-monomer type and density. The performance behavior of PPH/POE blends with and without a nucleating agent was compared to in situ (in the reactor) modified PPH with Ethylene Propylene Rubber (EPR). The addition of POE in PPH, increased toughness at room temperature and the stiffness of the blends decreased. The addition of a nucleating agent was noted to improve the toughness and stiffness compared to their non-nucleated counterparts, while the tensile strength remained unchang ed. At -20°C, the impact strength results showed no significant improvement in PPH/POE blends with and without addition of the nucleating agent. The melting temperature and the crystallinity of PPH matrix decreased and the crystallization temperature rema ined unchanged. On the other hand, the nucleating agent has kept the melting temperature unchanged and increased the crystallinity and crystallization temperature of the blends. The morphology analysis have shown clearly the phase separation of the blends components thus demonstrating the immiscibility of the blend system. The addition of the nucleating agent was seen to decrease the domain size of POE phase thus leading to the improvement in the toughness properties of the blends. ICP materials have shown better mechanical properties and more uniform rubber dispersion than the blends system.
Multivariable Regression of Recycled HDPE
Sustainability Metrics and Characterization - Paper: Polyethylene has been adopted for a variety of industrial, agricultural, and packaging applications with an estimated market of $164 billion and a projected global demand growth of 4% through 2018. The pressure for landfill diversion strategies have increased with cons umer awareness of traditional end-of-life practices. Regulatory bodies have instituted minimum post-consumer recycled ( PCR ) content laws to increase the long-term sustainability efforts of polymer use in commodity goods (e.g., SB 270 in California); thus, the ability to empirically quantify the post-consumer recycled content is vital for compliance. A stepwise multivariable regression approach was employed to develop a n equation capable of empirically determining the post-consumer recycled content from a va riety of certification markers. The empirical equation determined the post-consumer content of unknown film samples within ~10 wt% of the true value.
Multivariable Regression of Recycled HDPE
Sustainability Metrics and Characterization - Presentation: Polyethylene has been adopted for a variety of industrial, agricultural, and packaging applications with an estimated market of $164 billion and a projected global demand growth of 4% through 2018. The pressure for landfill diversion strategies have increased with cons umer awareness of traditional end-of-life practices. Regulatory bodies have instituted minimum post-consumer recycled ( PCR ) content laws to increase the long-term sustainability efforts of polymer use in commodity goods (e.g., SB 270 in California); thus, the ability to empirically quantify the post-consumer recycled content is vital for compliance. A stepwise multivariable regression approach was employed to develop a n equation capable of empirically determining the post-consumer recycled content from a va riety of certification markers. The empirical equation determined the post-consumer content of unknown film samples within ~10 wt% of the true value.
In-process Monitoring of Recycled Polyethylene for Catalyst and Regulated Metals Using Novel Applications in X-ray Technologies
Sustainability Metrics and Characterization - Paper: Commercially available virgin and post - consumer recycled (PCR) polyethylene was characterized fo r catalyst (Ti, Pb, Al, Cr, Fe) during sheet extrusion of varying levels of PCR content (0, 30, 40, 90, 95 and 100%). An energy dispersive x-ray fluorescence (XRF) detection system was installed in the extrusion line directly after the die. The X-ray spectra and raw counts were obtain ed every 45 seconds and reported with sample time and sheet location within the roll. Data were uploaded every 45 seconds to a secured custom web-based software platform. Process samples were compared to bench top analysis using Inductively Coupled Plasm a Optical Emission Spectroscopy (ICP-OES). Our results indicate the potential use of XRF for in-process catalyst and regulated monitoring for polymer performance, safety and traceability in recycled plastics before and during conversion. More research is needed for validation of in-process monitoring systems for conversion processes and feedstock sources.
In-process Monitoring of Recycled Polyethylene for Catalyst and Regulated Metals Using Novel Applications in X-ray Technologies
Sustainability Metrics and Characterization - Presentation: Commercially available virgin and post - consumer recycled (PCR) polyethylene was characterized fo r catalyst (Ti, Pb, Al, Cr, Fe) during sheet extrusion of varying levels of PCR content (0, 30, 40, 90, 95 and 100%). An energy dispersive x-ray fluorescence (XRF) detection system was installed in the extrusion line directly after the die. The X-ray spectra and raw counts were obtain ed every 45 seconds and reported with sample time and sheet location within the roll. Data were uploaded every 45 seconds to a secured custom web-based software platform. Process samples were compared to bench top analysis using Inductively Coupled Plasm a Optical Emission Spectroscopy (ICP-OES). Our results indicate the potential use of XRF for in-process catalyst and regulated monitoring for polymer performance, safety and traceability in recycled plastics before and during conversion. More research is needed for validation of in-process monitoring systems for conversion processes and feedstock sources.
Influence of Post-Consumer Recycled Content (PCR) and Pigments in Polyethylene Properties
Sustainability Metrics and Characterization - Paper: Commercially recycled linear low-density polyethylene (LLDPE) pellets containing pigments were blended individually by weight then extruded with varying levels of recycled content. Either calcium carbonate only (white) or a mixture of white and carbon black pigment were blended with recycled polymer at virgin/recycled ratios of 0, 20, 40, 60, 80, and 100% wt/wt. Each blend was evaluated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. Linear relationships were investigated for statistical significance of PCR content and pigment on extruded sheet properties. Extractions in n-hexane were carried out in accordance with Code of Federal Regulations (CFR) Title 21, B, Part 177.1520 to determine compliance for uses with direct food contact. Results of thermal and spectrophotometric analysis did show potential for PCR marker identification. All extractives were below allowable threshold of 5% per CFR suggesting the potential use of recycled polyethylene for direct food contact applications. More research is needed to evaluate the use of various feedstock sources of recycled polyethylene for direct food contact application.
Influence of Post-Consumer Recycled Content (PCR) and Pigments in Polyethylene Properties
Sustainability Metrics and Characterization - Presentation: Commercially recycled linear low-density polyethylene (LLDPE) pellets containing pigments were blended individually by weight then extruded with varying levels of recycled content. Either calcium carbonate only (white) or a mixture of white and carbon black pigment were blended with recycled polymer at virgin/recycled ratios of 0, 20, 40, 60, 80, and 100% wt/wt. Each blend was evaluated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. Linear relationships were investigated for statistical significance of PCR content and pigment on extruded sheet properties. Extractions in n-hexane were carried out in accordance with Code of Federal Regulations (CFR) Title 21, B, Part 177.1520 to determine compliance for uses with direct food contact. Results of thermal and spectrophotometric analysis did show potential for PCR marker identification. All extractives were below allowable threshold of 5% per CFR suggesting the potential use of recycled polyethylene for direct food contact applications. More research is needed to evaluate the use of various feedstock sources of recycled polyethylene for direct food contact application.
Model Validation for Composite Railroad Ties Using Micro-Mechanics Modelling and Experimental Four-Point Bend Testing Made from Recycled Polyolefins
Sustainability Metrics and Characterization - Paper: The purpose of this research is to model the deflection behavior of railroad ties fabricated from recycled polyolefin post-consumer/post-industrial waste composed of HDPE (High Density Poly Ethylene) and PP/FG (Poly Propylene/Fiber Glass). A technical challenge in predicting the final part performance is a limited understanding of the impact of microstructural variations due to processing variability on the final produced part's spatially varying material properties. The ties fabricated using extrusion molding techniques have a solid shell region on the outer surface and an inner foamed core. The foamed core region has cells of differing dimensions and the resulting effective material properties will vary as a function of the cell size and density. The shell and the foamed core regions are an alyzed using micromechanics models for the prediction of the stiffness. The stiffness of the foamed core is calculated using the Monte Carlo method to investigate the macroscopic sensitivity to microstructural variations. The elastic moduli obtained from micromechanics is used for the shell and foam regions in a Finite Element model, and the computational results are compared to those obtained from experimental four point bend test results with a difference between the model and experiment being less than 2% for the predicted effective stiffness.
Model Validation for Composite Railroad Ties Using Micro-Mechanics Modelling and Experimental Four-Point Bend Testing Made from Recycled Polyolefins
Sustainability Metrics and Characterization - Presentation: The purpose of this research is to model the deflection behavior of railroad ties fabricated from recycled polyolefin post-consumer/post-industrial waste composed of HDPE (High Density Poly Ethylene) and PP/FG (Poly Propylene/Fiber Glass). A technical challenge in predicting the final part performance is a limited understanding of the impact of microstructural variations due to processing variability on the final produced part's spatially varying material properties. The ties fabricated using extrusion molding techniques have a solid shell region on the outer surface and an inner foamed core. The foamed core region has cells of differing dimensions and the resulting effective material properties will vary as a function of the cell size and density. The shell and the foamed core regions are an alyzed using micromechanics models for the prediction of the stiffness. The stiffness of the foamed core is calculated using the Monte Carlo method to investigate the macroscopic sensitivity to microstructural variations. The elastic moduli obtained from micromechanics is used for the shell and foam regions in a Finite Element model, and the computational results are compared to those obtained from experimental four point bend test results with a difference between the model and experiment being less than 2% for the predicted effective stiffness.
Bimodal Poly(Ethylene Terephthalate) Blends: Effect of Molecular Weight Distribution on Material Properties
This study presents an investigation of bimodal poly(ethylene terephthalate) blends using injectionmolded parts. The blends were characterized for intrinsic viscosity, molecular weight distribution, crystallization, and tensile mechanical properties. The data shows that injection molding preserves the intended bimodal molecular weight distribution, despite typical inherent material degradation from processing. Our results show that the maximum effect was observed when the high molecular weight component is at 10 wt.%.
Effects of Processing Parameters on Colour Variation and Pigment Dispersion during the Compounding in Polycarbonate Grades
The objective of this work is to study the variations of how independent processing parameters such as temperature, speed, and feed rate affect the dependent responses for consistent output colour (L*, a*, b*, dE*). In this study, the compounded material was processed on an intermeshing twin-screw extruder (TSE) and injection molded to evaluate their effect on the colour stability, rheology and dispersion of the polycarbonate resins. Focus was extended to the interaction of the speed, which correlates to the dispersion and colour changes.
Antimicrobial Additives for the Healthcare Market: An Overview
This presentation will cover what an antimicrobial additive is and how this class of additives differs from disinfectants. Furthermore, what types of chemistries are commonly encountered will be discussed. Lastly the current global regulations that cover the use of antimicrobials will be covered.
Direct Extrusion of PVC on the Planetary Roller Extruder
When processing PVC via the direct extrusion method, the polymer is fed continuously into a compounder without prior stabilization. Additives like stabilizers, plasticizers, lubricants, fillers and others are added simultaneously, but separately, thus stabilization and mixing takes place in the compounder. This approach requires a carefully balanced setup of the first section of the extruder, which differs considerably to conventional PVC dry-blend processing.
Understanding Dimensional Variation in Common Mechanical Processes, How It Differs in Plastic Parts, and Minimizing It
This paper breaks down the causes of variation in mechanical parts into its constituents. It then distinguishes the variation in other processes from plastic parts where the material selection, design rules, tooling and processing have a much greater effect on variation. Once these differences are understood, two very powerful CAD based tools are introduced to be used to minimize the tolerance build up.
Influence of Rheology on Part Dimensions and Production in Injection Molding
The present work was conducted to assess the influence of polymer viscosity variation from batch to batch on the part dimensions and production interruptions. The results show however that parameters such as mold temperature, barrel temperature profile and holding pressure have much more influence on these two production quality indicators than the polymer viscosity.
Cellular Polymers for Oil/Water Mixtures Separation – Evaluation of Process Conditions
This study investigates the usage of cellular polymers for large scale oil/water separation. The model polyester polyurethane foam was characterized for sustainability and oil adsorption efficacy in a batch system. The temporal mass uptake and its efficacy were experimentally optimized at various temperatures and stirring speeds. With favorable surface, morphology, and bulk properties in conjunction with process conditions, and a mass uptake of 21 g/g of foam, this polymer lends itself as a very promising material for oil adsorption.
Self-Assembled Protein-Rubber Nanocomposites
Gliadin from wheat was compounded in synthetic isoprene rubber (IR) to form a reinforcing nanophase in situ. The compounded protein aggregated into ß-sheets, which varied in quantity based on compounding conditions and protein preparation. At all conditions studied, the protein-filled IR exhibited higher modulus compared to unfilled IR. XRD revealed the crystal structure of ß-sheets.
Compression Molded Protein-PVA Nanocomposite Films
Wheat gluten protein was incubated in an aqueous solution of poly(vinyl alcohol) (PVA) to form a reinforcing nanophase in situ. Protein reinforcement of PVA up to 340% was observed during mechanical testing. Spectroscopic examination revealed an anisotropic fiber nanostructure high in ß-sheet content. Nanofibers persisted after moderate compression molding, but degraded with severe processing. Processing conditions also affected the thermal properties of PVA.
PEBA: TPE Materials for High Performance Applications
TPE-A, or PEBA, chemistry is considered to be the most high-performing TPE in the market. PEBA (PolyEtherBlockAmide) is a block copolymer based on polyamide and polyether segments. Subtle differences between the grades are based upon the chemistry of the polyamide and polyether as well as the ratios of each in the block copolymer. This session will describe technically describe the chemistry and properties of the polymer, both mechanical and analytical. It will also describe key applications where PEBA chemistry is currently or could be used.
Sustainability of PVC (Vinyl) Pipe: A Comprehensive Environmental Review
• Thorough review of LCA data • Transparently report the findings to the water, sanitary sewer, and storm drainage industries • Support the goals and vision of the 2010 USEPA Clean Water and Safe Drinking Water Infrastructure Sustainability Policy and the 2015 USEPA National Water Program on Climate Change • Ensures the long-term sustainability of water and sewer infrastructure • Comparative review of competing pipe products
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