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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Recycling

Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.

Agile Formulation of Recycled Polymers

Dr. Mark Sullivan and Hannah Melia, December 2023

Polymer recyclates have a variation in properties that can affect the end properties of recycled polymers. In this session, Dr. Mark Sullivan and Hannah Melia of Citrine Informatics will present a case study to show how AI can be used to rapidly reformulate recycled polymers to maximize the use of recyclates while consistently meeting end customer requirements. Learn from Citrine's experience from more than 10 years working in machine learning for materials and chemicals development.

FDA Guidance on Recycled Plastics in Food Packaging

Roger Pearson, Ph.D., March 2024

An overview of FDA regulations on using recycled plastics in food packaging, focusing on surrogate testing methods.

Comparison of Recycled Glass Fiber Reinforced Polypropylene

Karolin Kreuels, Dr. Peter Helmke, Marcus Meding, Prof. Dr. Reinhard Schiffers, March 2024

Study on CO2e accounting, mechanical properties, and circular economy approaches for glass fiber reinforced polypropylene.

Enhancing Sustainability in Rotational Moulding

Jake Kelly-Walley, Aldo Quaratino, Dr. Dharana Jayawardane, March 2024

Evaluation of stabilization effects on PCR/virgin polyethylene blend performance in rotational molding.

From Data to Action: Optimizing Recycling Strategies for Polypropylene

John Emmanuelle Estela-García, Allen J. Roman, Tim A. Osswald, March 2024

Optimization strategies for polypropylene recycling using mechanical and advanced methods to enhance material properties.

New System to Upcycle Comingled Waste Using Supercritical Water

Paul Boulier, March 2024

A novel system leveraging supercritical water to upcycle polyethylene and polypropylene waste into engineered materials.

Enhancing Sustainability in Rotational Moulding

Jake Kelly-Walley, March 2024

Evaluation of stabilization effects on PCR/virgin polyethylene blend performance in rotational molding.

Biodegradation Studies and Experiments for Materials in the Marine Environment - Part 3

Dr. Micheline Labrie, August 2023

In 2022, the University of Massachusetts Dartmouth established a state-of-the-art research and product development facility to advance the science, standards, and products related to biodegradability of plastics in the marine environment. The primary objective of the Biodegradability Laboratory is to test and develop new biodegradable materials suitable for use in various industries, such as textiles, packaging, and other sectors that contribute significantly to marine plastic pollution. This webinar will offer an overview of the laboratory's first year, highlighting the challenges, successes, and insights gained during the setup and testing of two Columbus Instrument's respirometry systems. A 60-channel and 80-channel aerobic Micro-Oxymax system were used to develop a standard operating procedure in adherence to the ASTM D6691 standard method. An overview of the full suite of instrumentation, equipment, and assays included in the standard operating procedure, biodegradation experiment setup and monitoring, and critical lessons learned will be covered.

Biodegradation Studies and Experiments for Materials in the Marine Environment - Part 2

Linda Amaral-Zettler, July 2023

The Marine Biodegradation Standard Test Method ASTM D6691 “Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials in the Marine Environment by a Defined Microbial Consortium or Natural Sea Water Inoculum” is currently under revision at the ASTM International and ASTM D7081 “The Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment”, withdrawn in 2014, is being reworked into a new standard specification “Specification for Non-Floating Biodegradable Products in the Aquatic Environment WK75797” and broadens the scope to include fresh and marine waters. ASTM D6691 optimizes conditions (temperature, surface area, nutrients) to accelerate the biodegradation test at 30°C, but new ISO test methods broaden this temperature to include more realistic temperatures encountered in the marine environment from 15°-25°C, and allow for the use of films in addition to powders for testing. This talk will provide a brief overview of existing ASTM and ISO/CEN marine degradation and biodegradation test methods and specifications and share experiences using open and closed respirometry systems followed during ISO Round Robin Marine Biodegradation Testing and subsequent follow-up experiments.

Biodegradation Studies and Experiments for Materials in the Marine Environment - Part 1

Dr. Jo Ann Ratto, June 2023

Marine debris continues to be an immense problem, thus eliciting the global emphasis on pollution prevention. Biodegradable polymers have historically been studied as a solution to reduce solid waste for the military. However, biodegradation is a challenge for most materials in the marine environment. A tiered approach to evaluate polymers in the marine environment will be reviewed. The Tier 1 method utilized an optimized environment, sample preparation and conditions to evaluate biodegradation by respirometry. A Tier 2 test used weight loss as a function of time to evaluate actual items in the marine environment, and a Tier 3 test had items positioned in the deep sea for weight loss studies. Toxicity as well as disintegration were also studied for all samples that underwent biodegradation testing. Overall, this tier 1 approach was a valuable screening method for polymers while tier 2 and 3 were real-life test methods for determining the fate of polymers in the marine environment. Sample data will be displayed to show the types of materials that biodegrade in the marine environment.

Design for Sustainability — A Case Study with Appearance Nylon

Bruce M. Mulholland, March 2023

Material selection during the design phase can dictate a final part's ability to be recycled or not. This paper looks at an appearance part that transformed three different material solutions into a single material solution such that the final part was now recyclable and produced at lower cost. A look at the technical challenges and solutions to achieve this result is included.

Effect of Reactive and Non-Reactive Coupling Agents on Mechanical Properties of Recycled Polyethylene Terephthalate Filled With Ground Tire Powder

Aboulfazl Barati, March 2023

Accumulated used polymers and tires cause several ecosystem issues in landfills. A practical method was proposed to reuse recycled polyethylene terephthalate (rPET) and ground tire rubber (GTR) powder by melt composite process. A composite material was developed in this work using GTR for reinforcement and rPET for matrix. The effect of two non-reactive (styrene-butadiene-styrene (SBS) and styrene-ethylene-butadiene-styrene (SEBS)) and three reactive (ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA), ethylene-glycidyl methacrylate (EGMA) and SEBS grafted with maleic anhydride (SEBS-g-MA) coupling agents on the mechanical properties of the composite material were evaluated. Mechanical tensile and impact strength properties were evaluated to determine how coupling agents affect composite behavior. All reactive coupling agents improve the mechanical behavior of composite materials, whereas non-reactive ones have little effect. EMA-GMA and EGMA are more reactive with rPET than SEBS-g-MA. Using 10 wt% of EMA-GMA in the composite of rPET/GTR (4:1) increases the tensile strain and impact strength (950% and 23%, respectively) and decreases maximum tensile strength and Young’s modulus (16% and 35%, respectively).

Reactive Extrusion for Upcycling Post-Consumer Polypropylene and Its Use as a Compatibilizing Agent

Olivia Ferki, March 2023

Polyolefins functionalized with reactive side groups are known to provide improved properties to blends of incompatible resins including processability, homogeneity, and mechanical properties. However, experimentation and use of compatibilizers are limited to virgin based grafted resins, which incurs additional costs for processors. Thus, there is increasing interest in upcycling post-consumer polyolefins to higher value secondary feedstock streams that offer interfacial adhesion of polymer blends. In this work, we propose a melt grafting strategy to achieve reactive functionality and apply the method to post-consumer polypropylene with the purpose of demonstrating recycled polyolefins capabilities as compatibilizers. Experiments are performed using a semi-batch co-rotating micro-conical twin screw extruder at various screw speeds and temperatures. The torque and grafting percentages are controlled by varying the concentration of dicumyl peroxide and maleic anhydride. The functionalized polypropylenes are characterized using spectroscopy and thermal analysis techniques to determine the grafted content and resulting processing behavior. The reactive extrusion process is compared with that for functionalizing virgin polypropylene, and the scale up and economics are discussed.

Film Recyclability Study Using a Micro Blown Film Line

Jin Wang, Ph.D., March 2023

The Association of Plastic Recyclers (APR) has published several methods for evaluating the recyclability of polyethylene plastic films. Although the methods are developed for lab-scale process equipment, a large amount of film is typically required for a complete evaluation. To accelerate screening of new film structures and compositions, we have developed a small-scale workflow based on a LabTech Micro Blown Film Line. It only requires 200 grams of materials to blow a film for film properties characterization. In this paper, we will present three case studies to demonstrate this workflow. First case study is the effect of paper label residuals in the post-consumer recyclate (PCR) on the film properties. Second case study is on the recyclability of a PVOH coated film. And the third case study is on the effect of compatibilizer (RETAINTM 3000 Polymer Compatibilizer from Dow) on the recyclability of an EVOH containing multilayer film. The advantages of this workflow are: 1) low materials consumption (200 grams vs > 4 lbs per formulation); 2) fast elimination of formulations that cannot be used in the blown film process; and 3) film properties that provide some indication or ranking of the formulations with different recycle content. Although this workflow may not have high resolution of film properties for complicated film formulations (such as those using a small amount of compatibilizer), it accelerates recyclability assessments for blown film.

Novel Compatibilization Solution for PE/PA or EVOH

MiaoMiao Xiao, March 2023

Multi-materials plastic films are especially important in our daily food packaging. It can combine different polymers to achieve a range of properties, which can’t achieve by mono-material film. It can protect the food, increase the shelf life of packaged food, and reduce the food waste. However, the recycling of the multi-material packaging film faces big challenges due to the incompatibility of different materials. With the increasing awareness of plastic pollution issues, there is a clear and present need to find a way to recycle multi-material film structures to support the goals of the circular economy. Compatibilizer can help improve the compatibility of polar and non-polar components in the films by increasing the interfacial adhesion between the two phases. In the research, we developed a novel polyethylene (PE)/Polyamide (PA) or ethylene vinyl alcohol (EVOH) compatibilizer. Based on the tensile, dart impact and tear test results, with loading of this novel compatibilizer to the PA or EVOH at 1:10 ratio, up to 20% PA or EVOH can be incorporated into PE stream without scarifying too much mechanical properties and meet the Association of Plastic Recycler (APR) recognition requirements. The microscopy pictures clearly showed that the compatibilized blend has a homogeneous morphology while the blend without compatibilizer has clear 2 phases. This novel compatibilizer provides the possibility of recycle-ready multi-material film structure design and improve the sustainability of the multi-material films.

Novel Approach to Increase Sustainability Rates for PET Compounds

Yuzhen Yang, March 2023

Global plastics recycling rates are low and the market share of recycled plastics is less than 10% at the moment. People are searching for different ways to further improving the recycle rates for plastics, especially for PET. However, companies’ sustainability efforts have been hampered because recycled PET (rPET) can exhibit poor mechanical properties compared to virgin PET (vPET) due to the lower intrinsic viscosity (IV). At Kaneka, we know additives can significantly improve the prospects for recycled plastics. The newly developed IV booster MV-01 showed promising performance when used in rPET. The study shows that at low dosing level MV-01 in rPET can improve the IV to the same level as vPET even after 4 passes. In addition, the mechanical property, transparency, YI, and Haze are all well maintained. Therefore the recycle content of PET can be significantly improved after adding MV-01 to the PET compound.

Role of Renewable Resources in Polymer Industries: Materials for Sustainable Future

Ram Gupta, Ph.D., March 2023

Tim Dawsey and Ram K. Gupta National Institute for Materials Advancement, Pittsburg State University, 1701 South Broadway Street, Pittsburg, Kansas 66762, United States The current shift from solely depending on petroleum sources to seeking renewable alternatives is attributable to their fast depletion, erratic prices, and the need to reduce our carbon footprint. For instance, the polyurethane industry currently calls for renewable (and less toxic) polyols and isocyanates for their synthesis over the traditional petroleum-based ones. To tackle these issues, we have investigated the role of vegetable/fruit oils in the preparation of polyurethane foams. Different approaches such as thiol-ene click chemistry and epoxidation, followed by ring opening, were used to convert these oils into polyols. The effect of the synthesis process on the properties of polyurethanes was studied. One of the major issues in polyurethanes is their high flammability. To reduce the flammability of polyurethane foams, different types of flame-retardants (additive and reactive) were investigated during the foaming process. The effect of flame-retardants on the physicomechanical and flammability of the foams was investigated in detail. Most of the foams displayed density in the range of 30-55 kg/m3 which is suitable for many applications. The compressive strengths of these foams were higher than 160 kN/m2. Except for some high concentrations of flame retardants, most of the foams showed closed cells greater than 90%. It was found that the burning time of the foams reduced significantly after the addition of flame retardants. For example, foam prepared using sunflower oil-based polyols showed a reduction in burning time from 79 seconds to 2 seconds after the addition of 13.61 wt.% of dimethyl methyl phosphonate. The effect of various flame-retardants and the role of bio-based polyols on the properties of polyurethane foams will be discussed. Our research suggests that a variety of bio-based materials can be used for the polyurethane industries with a reduced impact on the environment.

Life Cycle Assessment Comparing Fossil-Based and Bio-Based Plastic Gloves

Anthony Keyes, Ph.D., March 2023

This presentation provides an example of comparative Life Cycle Assessment for fossil-based and bio-based polymers that are non-compostable and compostable respectively. In this instance, fossil-based and non-compostable gloves made from polyethylene were compared with our commercial bio-based and compostable gloves utilizing ISO 14040:2006, ISO 14044:2006 and ISO 22526:2020 standards. As bio-based materials are created on a much shorter timescale than fossil-fuel reserves, some consider bio-based polymers to be a form of carbon sequestration. This means that bio-based polymers can be said to have a lower feedstock carbon emission burden than fossil-based alternatives. A major discrepancy, however, when comparing fossil-based and bio-based materials largely arises due to how biogenic carbon is accounted. This normally stems from how bio-based materials have their system boundaries drawn, where sequestration of CO2 is immediately tied to end-of-life emissions and taken as a net zero summation. This handling is the current methodology employed by the European Union Product Environmental Footprint (EU PEF) which states, “removals and emissions of biogenic carbon sources shall be kept separated in the resource use and emissions profile”. We compare this mindset to that of ISO standards and give a representative understanding where fair comparisons are possible for fossil-based and bio-based plastics, and when fossil-based materials are preferentially benefited with this tactic. In doing so, this presentation will provide the audience with an understanding on the bias LCA methods have against bio-based materials when biogenic carbon is not properly accounted for and give specific criteria which allows for a fair comparison with their fossil-based counterparts.

Using Amorphous PHA as a Biobased Performance Additive in Non-Compostable Product Formulations

Rajendra Krishnaswamy, March 2023

PHAs or polyhydroxyalkanoates are recognized for their unique ability to biodegrade in many natural environments including marine, home compost and industrial compost sites. As a result, PHAs are used in many applications where end of life is a critical value proposition. We have previously highlighted the value proposition of blending an amorphous grade of PHA (PHACT A1000P) from CJ Biomaterials in various compostable product formulations including those based on PLA, PBS, PBAT and starch. In this presentation, we will address new opportunities for A1000P in the non-compostable space. Specifically, we will highlight applications where incorporating A1000P into the formulation brings benefits that include biobased carbon content, flexibility and toughness. Examples will include enhancing the performance of products based on Acetal polymers, Nylon-11 and Nylon-12 and EVA.

Effective Processing Aid to Enhance Melt Strength of Clear PLA Without Increasing Melt Viscosity

Shusuke Yoshihara, March 2023

Combining its own technology in polymerization and polymer rheology, Kaneka North America provides the processing aid to enhance the melt strength of bioplastics like PLA. The poor melt strength of PLA causes drawdown and sagging in the melt process, leading to low productivity. The processing aid dramatically increased the melt strength of PLA at 1 % loading level. During the extrusion process, it reacts to PLA and creates a comb structure. But it didn’t affect optical properties without forming gels. It was also designed to keep the melt viscosity low so that the processing rates can be high. It worked for PHA as well. The 1% addition doesn’t impact on the certification of biodegradability. This technology could enable access to more cost-competitive and sustainable bioplastics with a broader application window. Blow molding of bottles, film blowing, fiber spinning, and foaming could be facilitated by the materials exhibiting the high melt strength.