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

Produce Rescue Center: A Working Model for Plastics Circular Economy

Carmelo Declet-Perez, February 2020

In 2017, the Montgomery County Food Bank (MCFB) and Dow partnered to create the Produce Rescue Center. The MCFB supports 65+ partner agencies in Montgomery County, TX. The Produce Rescue Center seeks to increase the amount of fresh produce that reaches people in need serviced through the partner agencies. In this presentation we will highlight the impact and accomplishments from the Produce Rescue Center and the role plastic packaging plays in this success. We will also discuss next steps for the project to complete a circular economy model for plastics packaging.

Improving Physical Properties in Sustainable Thermoplastic Elastomers through Incorporation of a TRA

Megan Robertson, February 2020

Thermoplastic elastomers (TPEs) are widely used in electronics, clothing, adhesives and automotive components due to their high processability and flexibility. ABA triblock copolymers, in which A represents glassy endblocks and B the rubbery midblock, are commercially available TPEs. The most commonly used triblock copolymer TPEs contain glassy polystyrene endblocks and rubbery polydiene midblocks. However, commercial TPEs are derived from petroleum. The manufacturing and disposal of petroleum-derived products have undesired environmental impacts, which promotes development of TPEs from sustainable sources. Vegetable oils and their fatty acid derivatives are attractive alternatives to petroleum due to their abundancy and low cost. Our group has previously reported replacing polydienes in commercial TPEs with sustainable polyacrylates derived from fatty acids. However, polymers with bulky constituents, such as the long alkyl side-chains of fatty acid-derived polymers, typically exhibit poor mechanical performance due to lack of entanglements in the rubbery matrix. To improve the mechanical properties, a transient network was incorporated into the fatty-acid derived midblock through hydrogen bonding. Specifically, triblock copolymers containing polystyrene endblocks and a midblock composed of a random copolymer of poly(lauryl acrylate) (derived from lauric acid) and acrylamide (which undergoes hydrogen bonding) were synthesized. Quantitative FTIR analysis confirmed the formation of a transient network. The polymers exhibits disordered spherical morphologies, desirable for application as TPEs. Rheological measurement revealed the order-disorder transition temperature reduced with increasing acrylamide content, beneficial for high temperature melting process. Importantly, triblock copolymers with hydrogen bonding in the matrix exhibited significantly higher modulus, strain at break, and tensile strength as compared to comparable polymers in the absence of hydrogen bonding.

The Role of Mechanical Recycling in the Circular Economy for Polyolefins (Paper)

John Dorgan, February 2020

The global production and use of plastics (especially polyolefins) continues to grow and is expected to double to nearly 800 million metric tons per year by 2040. The use of plastics has resulted in convenience and reduced overall energy consumption, though we are also beginning to recognize challenges due to the mismanagement of plastic waste. Public concern over issues such as ocean plastics, along with the emergence of the concept of the circular economy, has resulted in commitments by some consumer packaged goods (CPG) companies to use recyclable packaging and to use more recycled plastic in their packaging. Mechanical recycling is an established approach that provides an opportunity to better manage waste plastics by creating value from otherwise worthless waste. The increasing demand for recycled content should increase the recycled plastic price further, resulting in an increase in the global plastics recycling rate from the current level of approximately 12%. We will provide an overview of mechanical recycling technologies while also highlighting some of the technical limitations that prevent immediate widespread incorporation of recycled polyolefins into new packaging and other high value products. We will also discuss potential approaches to overcoming these technical challenges and the role of the REMADE Institute in these developments. In addition, we will discuss how mechanical recycling will be a critical first step in many of the chemical recycling approaches that are beginning to emerge.

The Role of Mechanical Recycling in the Circular Economy for Polyolefins (Presentation)

John Dorgan, February 2020

Biomass-based Renewable Polymers – A Pathway to a Sustainable Future

Joshua Yuan, February 2020

Major environmental challenges associated with petrochemical plastics need to be addressed via a) reduction of environmental contamination through enhanced recyclability at the end of service life and b) the supply of low cost renewable feedstock for plastics production. In particular, there is a large need for innovative plastics that are readily recyclable to lower environmental hazards and the renewable feedstocks for these plastics must be made widely and cheaply available. We have developed two aspects of advances to enable widespread production of such innovative plastics. On one front, we will develop various pretreatment, fractionation and metabolic engineering technologies to enable the efficient conversion of lignocellulosic biomass or lignin waste to PHA for bioplastics. On the other front, we have tailored lignin chemistry and designed lignin-based composite material both with enhanced performance and with controlled degradability at the end of service time. These innovative technologies produce desirable lignin-based plastics in the context of biorefinery design, in a manner that adds value for a lignocellulosic biorefinery. The overall impact could significantly enhance environmental sustainability by replacing the non-degradable plastics and enabling lignocellulosic bioproduction.

Polymerization Reaction Engineering: A Tool to Keep Polyolefins Relevant in the 21st Century

João Soares, February 2020

Polymerization reaction engineering (PRE) combines fundamentals of chemical engineering (transport phenomena, reaction engineering, and thermodynamics) and polymer science (chemistry, physics, and characterization) to create mathematical models that describe polymerization reactors from micro- to macroscale under different polymerization mechanisms and conditions. This powerful integrated approach helps scale up experimental results from laboratory to pilot plant, and finally to industrial scale. PRE is also essential to optimize the operation of existing reactors and design new polymerization processes. Polyolefins are made with comonomers that contain only carbon and hydrogen atoms. Their simplicity, however, is only apparent. Polyolefins have a wide range of applications (domestic appliances, automotive and aeronautical parts, and biomedical devices, just to mention a few) because their simple monomers (ethylene, propylene, 1-butene, 1-hexene, and 1-octene) can be combined in numerous ways to produce polymers with a variety of microstructures that give rise to their versatile properties. From a product development point of view, polyolefin microstructure is influenced by complex phenomena that takes place during the polymerization at different scales in the reactor, which is the realm of PRE technology. Olefin polymerization processes are among the most complex in the polymer industry. They require catalysts of different types, employ several reactor configurations, and comprise phenomena that range from microscale (polymerization kinetics at the active sites) to meso- (inter- and intraparticle mass and heat transfer resistances, and thermodynamic equilibrium), and macroscale (reactor residence time distribution, fluid dynamics, and thermodynamic equilibrium). All these phenomena combine to determine the microstructure, and consequently the application properties, of polyolefins. In this presentation, I will show how the integrated, multi-scale approach provided by the PRE approach can be used to understand polyolefins made in variety of processes and catalyst types.

New Nano-layer Blown Film Die & "Dry" Water Quench System (Paper)

Henry Schirmer, February 2020

The details of two complimentary patent pending inventions are described along with the actions taken to reduce them both to practice. A new modular disk die that uses very thin disks incorporating a doubly opposed melt distribution system capable of up to about 160 nano-layers using up to 12 different materials has been made. Included with the die is a new “dry” water quench system that has made blown film from a die with high clarity and sparkle without the usual cascading water mess. This system was tested successfully for downward blown film with a partial scale up for upward blown film. Further work is now taking place with both inventions to bring them both to commercial reality.

New Nano-layer Blown Film Die & "Dry" Water Quench System (Presentation)

Henry Schirmer, February 2020

Application of Sulzer Technologies in the Polyolefins Production

Simone Ferrero, February 2020

Sulzer Chemtech is a product division of Sulzer, headquartered in Winterthur, Switzerland, and is active in the field of process engineering. Since several decades is active in the development and supply of process solutions for mixing, reaction, devolatilization and upgrading for different polymers. One of the key technologies from Sulzer in the polymer field is the, so call, DEVO, a devolatilization/degassing technology able to remove unreacted monomer, solvent or impurities from a polymer stream. In the recent years, Sulzer develop devolatization technology applications in the fields of polyolefins. When devolatilizing residual monomers, solvents or impurities, technologies based on static mixing may offer several potential. First of all, Devolatilization it determines polymer quality, applicability and value, moreover Sulzer technology, exhibiting low shear, gentle heating, optimized volume usage and absence of heavy rotating equipment, significant energy savings may be realized while maintaining or even improving product quality. Additionally, maintenance costs are typically lower as well. The Sulzer Polymer technology are presented with focus on the different aspects of the devolatilization technology. Polyolefins based case studies are discussed and each case that bring to an industrial application is analyzed starting from the experimental work carried out on pilot scale were Sulzer verify the technology on the customer material in the R&D test center in Switzerland.

Study of the Impact of Induced Condensing Agents on Ethylene Polymerization in Gas Phase Reactors (Paper)

Amel Ben Mrad, February 2020

A widely-used approach to control overheating in the gas phase polyethylene systems is the so-called “condensed operating mode” where liquid species are injected together with the monomer feed. These liquid species, usually alkanes, are called "induced condensing agents" (ICA). Upon entering the reactor, the liquefied components vaporize and the latent heat of evaporation helps to cool the system. It has recently been demonstrated that the inert species most typically used for this purpose can strongly influence the solubility of all species in the growing polymer particles. Different thermodynamic models are available that can capture this type of behavior, but all of them rely on a set of adjustable parameters than cannot be predicted a priori. To add to the complications, very limited solubility data is available for multicomponent systems; it is therefore very difficult to obtain realistic model parameters for olefin polymerization systems. We have chosen to work with the Sanchez-Lacombe equation of state, as it is one of the most widely applied thermodynamic models in polymer industry. The interaction parameters used in the Sanchez-Lacombe Equation of State will be identified by fitting equilibrium solubility data which are measured experimentally using a pressure-decay technique in standard laboratory equipment. A simple operating protocol allows us to generate solubility data for a limited cost. Gas phase composition is measured with an upgraded Micro GC, allowing us to estimate individual solubilities in mixes of different process gases. All this thermodynamic data has been incorporated into a single particle model to estimate the concentration and temperature gradient through a growing polymer particle. This model underlines the importance of using an accurate thermodynamic and diffusion model in order to have a good representation of the dynamics of mass and heat transfer in the polymer particle. It also demonstrates the impact of using different type and quantity of ICA on the particle characteristics.

Study of the Impact of Induced Condensing Agents on Ethylene Polymerization in Gas Phase Reactors (Presentation)

Amel Ben Mrad, February 2020

Polyolefin Molecular Simulation for Critical Physical Characteristics (Paper)

Andrea Browning, February 2020

The physical properties of polyolefins determine the suitability of the polymers for various products and industries. The combination of monomer, comonomers, and chain microstructure can all impact these properties. The physical properties can be predicted and explored using molecular simulation. We have developed efficient molecular modeling methodologies that take advantage of advances in compute hardware to study polymers and to evaluate the physical properties. Among the physical properties critical to polyolefins that can be explored by molecular simulation are glass transition, order transition, and solvent interaction. The glass transition can be determined by a systematic study of the volume versus temperature behavior. In addition to the glass transition of a single structure, the uncertainty within a single simulation and across multiple replicates can be determined. During the slow cooling of polyolefins, ordering can also occur. This ordering is impacted by the branching behavior of the polymers. Finally, the solvent behavior of polyolefins can be explored through simulations of direct interactions. In this talk the simulation methods for these properties will be described and examples in linear and branched polyolefins will be given.

Polyolefin Molecular Simulation for Critical Physical Characteristics (Presentation)

Andrea Browning, February 2020

Predicting Molecular Weight and Composition Distribution for Gas-Phase Polyethylene Products

Yan Jiang, February 2020

A mathematical model was developed to simulate a laboratory-scale gas-phase ethylene/1-hexene copolymerization process using a multi-site metallocene catalyst. The kinetic scheme includes activation, propagation, chain-transfer to hydrogen, β-elimination, deactivation and reinitiation. A three-site model with 33 parameters was developed to predict number-, weight- and Z-average molecular weights, along with polymerization rate and overall hexene incorporation. In addition, the model predicts the molecular-weight and comonomer-incorporation distributions for the polymer accumulated in the reactor at the end of the batch. Statistical methods were used to rank the kinetic parameters from most-to least-estimable, based on the available industrial data. A mean-squared-error criterion was used to determine the appropriate number of parameters to obtain reliable model predictions. Parameters were estimated, using gas flow rate and composition data obtained over the course of each experimental run, along with polymer characterization data at the end of each run. Data sets not used for parameter fitting were used for subsequent model validation.

Overview of the Current Plastic Recycling Landscape

Manuel Prieto, February 2020

Trends in plastic waste management, recycling and reuse are evolving rapidly – the demand for single use plastics continues to grow and more complex plastic applications are further challenging existing infrastructure. Finding a solution requires action across all steps of the value chain (from product design to consumer education to collection to separation to recycled polymer reuse), as well as across stakeholders (from chemical companies to converters to brand owners to recycling companies to governments to investors and public figures). Chemical recycling, conversion, and decomposition technologies offer further flexibility to recover and reuse a broader set of materials and potentially provide the missing piece in the recycling equation. However, the economics of these technologies is not yet proven.

Chemical Recycling: Upcycling of End-of-Life Plastics

Carlos Monreal, February 2020

There is no time to lose in figuring out how to solve the plastic challenge and increase both the recycling rates and the recycled content in product. In parallel of this regulatory drive, many large brand owners have committed to reach 100% of recyclable packaging by 2030. Plastic Energy has developed a solution to address low-value mixed plastics that cannot be mechanically recycled. The Thermal Anaerobic Conversion (TAC) produces recycled oils (TACOIL) from end-of-life plastics. The TACOIL is then used as a new feedstock for the (petro)chemical industry to generate recycled plastics by replacing virgin oil with TACOIL. Our TAC process is a low-pressure thermal depolymerization process patented in Europe and the US. To be more specific, the shredded, densified and then molten feedstock is pumped into the oxygen free reactors at a controlled rate and temperature. The multicomponent hydrocarbon vapour produced in the reactor passes through our patented contactor vessel which finally controls the hydrocarbon chain length and quality before entering the condensation system. The TACOIL is then be subjected to various additional purification / polishing steps before being sent to the steam-crackers of the chemical industry. In addition of having two industrial plants running 24/7 more than 330 days per year for the past 3 years, Plastic Energy through its experience has managed to stabilise the output the specifications required by the chemical industry. This has led to the value-chain validation of the circularity of the Plastic2Plastic process by the ISCC+ to produce the Certified Circular Polymers. This chemical recycling process effectively upcycles the plastic through conversion to the original monomers in each process of recycling, making it safe and reusable as a food-grade product. After explaining the technical and industry experience of reach an optimal product and efficient operations, the presentation will stress some real-life Plastic2Plastic applications developed with the value-chain, and will continue on the upscaling and expansion of the capacities of Plastic Energy and the potential of the chemical recycling industry in improving recycling and creating a circular economy.

China’s Plastic Waste Import Ban: Global & Regional Implications

Jim Rounick, February 2020

China used to import large volumes of polymer waste from around the world. The sudden 2017 decision by the Chinese government to ban imports of recyclables created a supply chain gap for plastic waste processors in China. He-Ro will outline how this supply chain gap issue has been addressed by the PR China plastic waste processors & how the value chain has adapted. With additional plastic waste bans now in place in other Asian countries, will this ’new system’ created by the plastic waste processors be rolled out across Asia and the rest of the world? Will their learnings form a base for other countries to build their own supply chain infrastructure?

Developments in End-of-Life Technologies for Multilayer and Barrier Flexible Packaging

Terence Cooper, February 2020

Flexible packaging is more economical than other formats because of its lower material and energy consumption and manufacturing and transport costs. It also provides reduced waste of packaged products, particularly food, generates much less packaging waste than rigid formats and has favorable LCAs. Consequently, its use, particularly in multilayer barrier films and pouches, has been steadily growing and replacing rigid packaging. Despite this, it is still opposed by environmental groups due to difficulties in end-of-life collection, sorting and processing and concerns about “single-use” packaging and sustainability. Because of its film and multilayer construction, and often food-waste contamination, post-consumer flexible packaging is not readily mechanically recyclable and is presently generally landfilled, so that environmental groups have pressured food and other companies to stop using it. To combat this, and to eradicate landfilling, the food, packaging and recycling industries are supporting a wide range of initiatives including: a). improved mechanical recycling systems to handle film packaging and the development and introduction of supporting collection, identification and sorting technologies and infrastructure; b). new package designs and materials facilitating mechanical recyclability by reducing polymer types and number of layers, mono-material and all-polyethylene pouches, compatibilizer incorporation, and using barrier adhesives and coatings and recyclable and biodegradable barrier materials; c). economic film layer separation and recovery methods; d). chemical recycling processes to produce monomers or valuable feedstocks; e). waste-to-energy recovery systems such as anaerobic gasification and plasma pyrolysis; and f). pyrolytic waste-to-fuel and waste-to-chemicals recovery operations. These developments are surveyed to demonstrate the wide range and intensity of current activities.

Recycled Material Standard (RMS)

Laura Thompson, February 2020

The Recycled Material Standard (RMS) is in early development stages and is ultimately meant to serve as a voluntary, market-based tool to be implemented by value chain participants and audited independently by credible third-party certification bodies. The purpose of the standard is to address some of the challenges that brands, their suppliers, and the recycling industry are facing in trying to incorporate higher amounts of recycled content into packaging or finished products. The RMS is being developed by GreenBlue for common packaging materials including paper, plastic, glass and metal, but could be employed for the same materials in markets other than packaging (e.g. the use of recycled plastic in composite lumber). The RMS will use two independent tracking system options which will be defined in separate parts of the standard: 1. The chain of custody (CoC) system will specify material management requirements within an organization in order to demonstrate that recycled content materials and products purchased, labelled and sold as RMS certified originate from recovered materials (derived from post-consumer and post-industrial sources). The chain of custody system will allow for claims to be made using either an average percentage method or credit-based claims. 2. The attributes of recycled content (ARCs) will be a certificate-based trading scheme tracked through a registration body to provide an investment mechanism for new processing capacity. Organizations purchasing ARCs will help support the development of new, additional capacity for processing recycled materials. Purchasing ARCs will also allow companies to communicate the environmental benefits associated with these materials in place of virgin raw materials.

Agilyx's Role in Commercial Recovery of Chemical Value in Post-Use Plastics

Barry Cavinaw, February 2020

Global plastic recycling rates are stagnant at roughly 10%. At the same time, plastic production exceeds 300 million tons a year and is projected to continue growing. Polyolefins account for nearly half of the world's plastics. Agilyx was established with the primary goal of dramatically increasing the world's recycling of plastics and polymers. This single focus led to innovations in polymer depolymerization technology that Agilyx deploys on a commercial scale. As Agilyx treats post-use plastics as a hydrocarbon reserve and a valuable resource, new business models emerge that support the circular plastics industry. Its 15+ years of experience working with its technology has resulted in a profound understanding of post-use polymers as well as their supply chains and variability. The company advances circular solutions for polyolefins and polystyrene using its proprietary pyrolysis technology in conjunction with vertical feedstock management. Ongoing research and development programs bolster Agilyx’s leading position in the market through continuous innovation and improvement to overall process performance, financial profiles, and the development of new product slates. Agilyx creates chemical and circular recycling pathways for end-of-use plastics through innovations, know-how, and processes that are environmentally and economically sustainable.