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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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Bioplastics and Renewable Technologies

3 Challenges of Testing Plastics
Sammi Sadler & Stephanie Williams, September 2023

The world of plastics is constantly evolving, with new applications such as high-performance polymers, additive manufacturing, and bioplastics continually emerging to transform the field. Common to all applications - old and new - is the importance of mechanical testing that ensures manufacturers are producing quality products. In this webinar we'll be discussing the specific challenges of testing plastics, the importance of repeatable and reliable mechanical testing results, and what you can do to improve your results. Topics

  • Overview of recent changes in key standards
  • Factors that influence test results – solutions and troubleshooting tips
  • How to increase laboratory efficiency and throughput to improve test times

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.

Novel Nanocellulose Based Supports For PHBV Composites - Synthesis And Properties
Kavan Sheth, Ting Zheng, James Sternberg, Craig Clemons, Srikanth Pilla, June 2022

Novel nano-cellulose based nano-structures modified with hyper-branched polymers were prepared by using isocyanate linking chemistry. The chemistry was investigated using FTIR spectroscopy. The composites were homogenized utilizing solvent casting followed by injection molding of the samples. The thermal properties of the prepared samples were investigated using DSC and TGA.

Effect Of Talc And Carbodiimide On The Hydrolytic Resistance Of A Poly(L-Lactic Acid) Compound
Nishant Singh, Celina Alvarado, Carlos A. Diaz, Baxter Lansing, Christopher L. Lewis, June 2022

In this work we examine the influence of talc and a polymeric carbodiimide on the hydrolytic degradation resistance of a commercially available Poly(L-Lactic acid) PLLA. Here, polymer blends containing 0-4wt% talc, a crystal nucleating agent and 0-1 wt% of a polymeric carbodiimide (CDI), an anti-hydrolysis agent, were melt blended and compression molded into plaques. Samples were then submerged in a phosphate buffer solution (PBS) at 50°C for up to 60 days. Results indicate that the presence of talc as the sole ingredient in the formulation increases the crystallization rate and this translates to an increase in the degree of crystallinity of compression molded plaques and a modest improvement in hydrolytic degradation resistance as compared to unfilled PLLA. The presence of CDI retards PLLA crystallization. In spite of this, compounds containing CDI exhibited much greater hydrolytic degradation resistance than PLA with the effect being more pronounced with increasing CDI concentration. Under DSC conditions, the addition of 1wt% talc to CDI containing compounds improved the non-isothermal crystallization rate at 5°C/min but this effect diminished as cooling rate increased and this explains the low crystallinity of compression molded samples. However, compounds containing both talc and CDI showed an improved hydrolysis resistance as compared to compounds containing only CDI implying that talc's role in reducing the rate of hydrolysis is caused by the hydrophobic characteristic of the material. It is envisioned that this work will help pave the way for the usage of PLA in durable applications where long-term resistance to humidity is anticipated.

Effect Of Plasma Treatment On Degradation Of Biodegradable Mulch Film
Swapnil Bhattacharya, Harshal J. Kansara, Celina E. Alvarado, Carlos A. Diaz, Jeffrey Lodge, Christopher L. Lewis, June 2022

Mulch films modify soil conditions thus improving crop output, hence are widely used across the world. Traditional PE (polyethylene) films do not degrade and must be disposed of afterwards. Biodegradable mulch films (BMFs) provide a much better alternative and are meant to be tilled with the soil after harvest. But most BMFs degrade slowly and accumulate in soil, harming the soil productivity. In this investigation we evaluate the effect of gliding arc plasma treatment on the behavior of a commercially available biodegradable mulch film based on polybutylene adipate co-terephthalate (PBAT) and polylactic acid (PLA). Following plasma treatment an initial increase in the hydrophilicity of the films is observed and this is attributed to an increase in oxygen containing species on the surface. Moreover, hydrophobic recovery is slow as indicated by contact angle measurements taken over a 30-day time. Thermal analysis results indicate no significant difference indicating that treatment is confined primarily to the surface. A treated film showed enhanced disintegration as compared to an untreated film following 65 days of composting in an aerated static pile compost. These results indicate that plasma treatment may aid the biodegradation of plastic mulch films and therefore eliminate their accumulation in soil.

From Petroleum To Biobased Crude: A Thermoplastic Polyurethane From Lignin-Oil Without Isocyanates
James Sternberg, Srikanth Pilla, David G. Brandner, Reagan J. Dreiling, Arik Ringsby, Jacob S. Kruger, Gregg T. Beckham, June 2022

The movement to transfer from petroleum-based products and materials to renewables does not necessarily have to bypass the use of oil. A new type of “black-gold” is readily abundant from the earth’s most abundant source of aromatic carbon: lignin. While fractionation of petroleum yields fuels and chemicals for a diverse set of industries, lignin fractionation using targeted catalysts has demonstrated the ability to generate monomers and oligomers rich in functional groups for polymer synthesis. This study explores the use of lignin-oil, generated from reductive catalytic fractionation of popular wood, to a hydroxyl-rich mixture of aromatics that is used to synthesize a thermoplastic non-isocyanate polyurethane. The lignin-oil is first converted to a cyclocarbonated derivative using a benign synthetic sequence and further polymerized with a diamine to yield the non-isocyanate TPU. While more work is underway to optimize the reaction conditions and meet typical mechanical properties of commercial materials, initial analysis shows thermoplastic behavior and flexible properties consistent with traditional thermoplastic polyurethanes.

Compounding and Characterization of Polylactic Acid-Sawdust Deep Eutectic Solvent Extracted Lignin
Saurabh Pawale | Karun Kalia | Dylan Cronin | Xiao Zhang | Amir Ameli, August 2021

There is an ever increasing need for sustainable and biobased materials. Plant-based feedstock such as cellulose and lignin can potentially become competitive resources as alternatives to fossil-based materials. Lignin as an inexpensive feedstock has been examined toward preparing polymer composites. It however faces some challenges including its detrimental impact on the mechanical and thermal properties of the resultant composites. This work reports the fabrication and characterization of polylactic acid/lignin composites with the incorporation of a new type of lignin, called deep eutectic solvent (DES) extracted lignin. White fir sawdust was used as feedstock to extract DES lignin. For comparison, commercial alkali lignin (CAL) was also used as a benchmark. PLA/lignin composites containing 0-15 wt.% lignin were fabricated using twin screw extrusion process followed by compression molding. Composites characterization were conducted using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. The results revealed that the mechanical and thermal behaviors of DES lignin composites significantly outperformed their CAL counterparts. For composites with 15 wt.% DES, the tensile strength, Young’s modulus, and elongation at break dropped by ~33, 7 and 45%, respectively, compared to those of neat PLA. However, the composites with 15 wt.% CAL showed 90, 45 and 86% drop in the strength, modulus, and elongation, respectively. The initial thermal degradation temperature of PLA dropped by ~ 8-27 °C with the incorporation of 5-15 wt.% DES lignin. On the other hand, the introduction of CAL to PLA lowered the degradation temperature by ~89-124 °C. DSC also showed a drop in the glass transition temperature (Tg) and melt temperature (Tm) for both the composites but the drop was less significant for DES lignin composites. The good performance of PLA/DES lignin composites may be associated with the DES lignin’s high purity, low heterogeneity, low molecular weight, fine particle size as well as its homogenous dispersion and compatibility with PLA matrix.

Self-reinforced Polylactide Composites Manufactured by Melt Spunbond Technology
Amirjalal Jalali | Anthony Tuccitto | Sandra Romero-Diez | Patrick C. Lee | Chul B. Park, May 2021

A series of stereocomplex polylactide (SC-PLA) blends (PLLA 95 wt%/PDLA 5 wt%) were prepared by spunbond technology. For this, the compounds of linear PLLA, and low and high molecular weight as well as branched PDLAs were spun at two different temperatures. They were spun at 190 °C, which was below the melting temperature of the stereocomplex crystals. And, they were melt-spun at 230 °C, which was above the melting temperature of the stereocomplex crystals. Morphological observation of the etched samples showed that the samples spun at 190 °C demonstrated tiny spherical crystals exhibiting diameters in the range of 100–200 nm; however, the samples spun at 230 °C showed thin fibers in the size range of 60–70 nm. The obtained results were supported by shear and elongational rheological measurements. Moreover, crystallization kinetics of the samples was also enhanced after spinning and was largely dependent on the spinning temperature. Tensile modulus and strength of the spun samples was also significantly improved. The spun samples also presented a considerable decrease in boiling water and hot air shrinkage.

Compostable Adhesive Formulations for Extrusion Lamination
Sayli Bote | Alexander Ermlich | Shilpa Manjure, May 2021

In this work, two compostable adhesive formulations, i.e., Resin A – MPP (Major PLA phase) and Resin B – MINPP (Minor PLA phase), were developed and evaluated for their performance as an adhesive in the extrusion lamination process. The densities of both the resins were in the range of 1.26-1.32 g/cc. The MFI values of Resin A and Resin B were 5 and 3 (g/10 min at 190ºC/ 2.16 kg), respectively. The complex viscosity of Resin A was lower than the complex viscosity of Resin B. The percent neck-in of Resin A at 235ºC was almost 4 times as that of Resin B at same conditions. The percent neck-in increased with increasing the temperature and distance from the die. Multilayer laminates were made using cellophane and metalized cavitated PLA as substrates, and Resin A or Resin B as adhesive. The adhesive strength of the Resin B to the cellophane was 20 g/cm, which was 10 times higher than the adhesive strength of Resin A (2 g/cm) to the cellophane. Also, the adhesive strength over the period of two weeks did not decrease significantly.

Prediction of Enzymatic Degradation of Poly-g-Caprolactone with Esterase Using a Reaction Model
Iftekhar Ahmad | Mohammad Abubakar Kha, May 2021

An enzymatic degradation mechanism of Poly- ε-Caprolactone (PCL) is discussed in this paper. A ping-pong bi-bi reaction mechanism with esterase is chosen to obtain the model equations. The reaction rate constants were either estimated or fitted in the model. The model is then utilized to predict concentration vs time plots for PCL and a degradation product, hydroxycaproic acid. The reaction between the enzyme and polymer is found to be rate limiting because of the limited polymer surface available for reaction. The predictions of the model are compared to experimental results reported in literature.

Preparation and Characterization of Polylactic Acid-Sawdust Deep Eutectic Solvent Extracted Lignin
Saurabh Pawalea | Karun Kaliaa | Dylan Croninb | Xiao Zhangb | Amir Ameli, May 2021

There is an ever increasing need for sustainable and biobased materials. Plant-based feedstock such as cellulose and lignin can potentially become competitive resources as alternatives to fossil-based materials. Lignin as an inexpensive feedstock has been examined toward preparing polymer composites. It however faces some challenges including its detrimental impact on the mechanical and thermal properties of the resultant composites. This work reports the fabrication and characterization of polylactic acid/lignin composites with the incorporation of a new type of lignin, called deep eutectic solvent (DES) extracted lignin. White fir sawdust was used as feedstock to extract DES lignin. For comparison, commercial alkali lignin (CAL) was also used as a benchmark. PLA/lignin composites containing 0-15 wt.% lignin were fabricated using twin screw extrusion process followed by compression molding. Composites characterization were conducted using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. The results revealed that the mechanical and thermal behaviors of DES lignin composites significantly outperformed their CAL counterparts. For composites with 15 wt.% DES, the tensile strength, Young’s modulus, and elongation at break dropped by ~33, 7 and 45%, respectively, compared to those of neat PLA. However, the composites with 15 wt.% CAL showed 90, 45 and 86% drop in the strength, modulus, and elongation, respectively. The initial thermal degradation temperature of PLA dropped by ~ 8-27 °C with the incorporation of 5-15 wt.% DES lignin. On the other hand, the introduction of CAL to PLA lowered the degradation temperature by ~89-124 °C. DSC also showed a drop in the glass transition temperature (Tg) and melt temperature (Tm) for both the composites but the drop was less significant for DES lignin composites. The good performance of PLA/DES lignin composites may be associated with the DES lignin’s high purity, low heterogeneity, low molecular weight, fine particle size as well as its homogenous dispersion and compatibility with PLA matrix.

3D Printing Sustainable Biocomposites From Recycled PLA and Micro-Crystalline Cellulose
Akhilesh K. Pal | Erick O. Cisneros-López | Arturo U-Rodriguez | Feng Wu | Manjusri Misra | Deborah F. Mielewski | Alper Kiziltas | Amar K. Mohanty, April 2021

The motivation for this work was to increase the economic life of recycled poly(lactic acid) (rPLA) (30 wt%) by utilizing it with virgin PLA (70 wt%) in the presence of a fiber-based reinforcing filler, micro-crystalline cellulose (MCC) and an epoxy-based chain extender. A conventional melt extrusion technique was used to fabricate the strands with and without MCC and chain extender in the PLA/rPLA blend matrix. It was observed that the complex viscosity of rPLA was improved significantly after the addition of the chain extender, which resolved the issue related to excessive polymer flow during processing and hence made it possible for use in fused deposition modeling (FDM)-based 3D printing. The addition of the chain extender improved the impact strength of 3D the printed PLA/rPLA specimens. The voids in the 3D printed material contributed to the reduced weight of the developed sustainable composites. The modulus and tensile strength of the 3D printed sustainable biocomposites were improved significantly, and impact strength increased by ~10% by reinforcing the blended matrix with 5% of MCC.

Antioxidant Activity Effect of Isosorbide into Flexible Polyurethane Foams
Gwangseok Song, May 2020

Isosorbide alkylene oxide (ISB-AO) was obtained by reacted with isosorbide and alkylene oxide, a non-toxic bio-based bicyclic diol composed of two fused defurans to increase the reactivity of isosorbide. A flexible polyurethane foam was prepared using isosorbide alkylene oxide based isocyanate prepolymer (IAISO) consisting of a reaction of isosorbide alkylene oxide and isocyanate. FPUFs containing various types of IAISO have been successfully manufactured without significant degradation of the appearance and physical properties of the final foam. IAISO based FPUF also showed better antioxidant activity by preventing discoloration. Thus, IAISO using bio-based diols with improved reactivity can be valuable raw materials (or additives) born from environmentally friendly FPUFs without seriously compromising the physical properties of these FPUFs.

Degradable Plastics/Wood Hybrids For Sustainable Packaging Solutions
Simon Wurzbacher, May 2020

The costs for degradable plastics are in comparison to bulk plastics still high. To increase the market share of degradable-plastics-based products the reduction of the plastic used itself could be suitable option. To keep the degradable properties of the product suitable materials for a hybrid are wood or woodbased products like carton. In this paper, the combination of wood and degradable plastics to a hybrid material by overmolding was investigated. In this feasibility study the effects of injection molding on wood as an insert and the bonding strength between the two materials was analyzed.

Degradation Behavior of Aliphatic and Aromatic Biomass-based Copolyesters for Agriculture
Margaret Sobkowicz, May 2020

This work concerns the synthesis, characterization and evaluation of enzymatic degradation kinetics in three biobased polymers: poly(hexamethylene succinate), poly(hexamethylene 2,5-furan dicarboxylate) and a copolymer containing hexamethylene succinate (HS) and hexamethylene 2,5-furan dicarboxylate (HF) units. All three comonomers are available from renewable resources, and their use in agricultural films and coatings would reduce the incidence of microplastics in soils, and could also provide functionality in controlled release applications. We find that copolymerization of the aliphatic and aromatic monomers reduces the crystallinity in the polymer, thus increasing the degradation rate.

Vibration Welding of Agave Fiber Biocomposites
Curtis Covelli, May 2020

In this study, the welding of several formulations of injection molded agave-fiber filled biocomposites were studied. A 240Hz vibrational welder was used and weld pressure, amplitude, and weld time were varied to determine their effects on lap shear weld strength. Strength testing was performed with a universal testing machine. The morphology of the weld zones was also analyzed to gain insight into the mechanics of the welding.

Pushing the Limits to the Next Level: A New Mold Steel for Demanding Plastics and Biocomposites Designed for the Best Polishability
Magnus Brannbacka, May 2020

The increasing use of advanced engineeringplastic compoundsand biocomposites causes problems in the mold thatcan bederivedfrom a combination of wear and corrosion. The degradation of the tool steel resultsin increased maintenance, downtime and in worst case premature breakage of the mold.Manufacturing of optical devices, such as lenses, demands an extremely goodsurface finishof the mold[1]. In addition, it should be reached as fast as possible to reduce lead times.Uddeholm Tyrax® ESR isa newpremium martensitic tool steel from Uddeholm,developed to cope with these problems by combining corrosion resistance with high hardness,very goodwear resistanceand excellent polishabilitywithout compromising on ductility.The recommended hardness of Uddeholm Tyrax® ESR is in the range of 55-58 HRC.










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