Ronald Kander

To combat the growing issue of petroleum plastic waste, alternative bio-based polymers are being developed. Many of these biopolymers are made from bio-derived materials, or are biodegradable, but the most promising polymers fall in both categories. Polyhydroxyalkanoates (PHAs) are one such class of polymers, and poly-3-hydroxybutyrate (P3HB), the most popular PHA, has shown great potential. This study utilized two types of cotton-derived glucose, alongside commercial glucose, as a feedstock for the biosynthesis of P3HB by Cupriavidus necator (also known as Ralstonia eutropha). The fermentation took place in a 2-L bioreactor, showing potential for scale-up. A single-solvent extraction method was created and utilized to reduce process complexity and chemical consumption of the polymer extraction. Both cotton-derived glucoses were shown to produce more P3HB than commercial glucose. The resulting P3HB samples were compared to each other and to the literature based on polymer yield and thermal characteristics. While all samples averaged a smaller yield than seen in the literature (indicating the need for optimization of the bacterial growth and metabolism with a growth curve in our future work), the cotton-derived glucose was shown to yield more P3HB than commercial glucose. Further, cotton-derived P3HB had very similar thermal properties to the commercial glucose-derived P3HB (and to values from the literature) with onset of thermal degradation ranging from 185 °C to 263 °C, cold crystallization temperatures ranging from 24 °C to 28 °C, and melting temperatures ranging from 147 °C to 151 °C. Lastly, all samples were shown to have a similar percentage crystallinity, ranging from 38% to 45%, which is slightly lower than that reported in the literature. P3HB made from cotton-derived glucose was shown to have potential as a scalable, sustainable alternative process.

To combat the growing issue of petroleum plastic waste, alternative bio-based polymers are being developed. Many of these biopolymers are made from bio-derived materials, or are biodegradable, but the most promising polymers fall in both categories. Polyhy-droxyalkanoates (PHAs) are one such class of polymers, and poly-3-hydroxybutyrate (P3HB), the most popular PHA, has shown great potential. A large drawback to large scale use of P3HB is the cost of its production. Production from local waste carbon sources, in largescale bioprocessing equipment, and using less chemically intensive extraction, drastically reduces P3HB’s cost. In America, the cotton industry offers millions of tons of cellulosic waste each year that can be transformed into a glucose solution. This study utilized two types of cotton-derived glucose, alongside commercial glucose, as a feedstock for the biosynthesis of P3HB by Ralstonia eutropha. The fermentation took place in a 2-L bioreactor, showing potential for scale-up, and a single-solvent extraction method was used, reducing chemical consumption. The resulting P3HB samples were compared to each other and to the literature based on polymer yield and thermal characteristics. First, while all samples averaged a smaller yield than seen in literature, the cotton-derived glucose was shown to yield more P3HB than commercial glucose. Further, cotton-derived P3HB had very similar thermal properties to the commercial glucose-derived P3HB. Lastly, all samples were shown to have a similar percent crystallinity, though slightly lower than that seen in literature. P3HB made from cotton-derived glucose was shown to have potential as a scalable, sustainable alternative process.

This study examines a new approach for improving the dispersion of hydrophilic fillers into a hydrophobic polymer matrix, a long-standing challenge that often limits the thermal and mechanical performance of biocomposites. We investigated two different types of fillers—natural cellulose nanocrystals (CNC) and mineral calcium carbonate (CaCO₃)—introduced into polylactic acid (PLA) at five different volume fractions. PLA-based biocomposite films were fabricated using physical mixing and cryo-milling methods, followed by hot pressing to study their effects. Cryo-milling was explored as a promising strategy to enhance filler distribution within the matrix. Thermal properties, crystallization behavior, and mechanical performance were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. CNC addition slightly lowered the glass transition temperature (Tg), while CaCO₃ raised it; both fillers promoted crystallization, although overall crystallinity remained relatively stable. Mechanically, tensile strength and strain decreased with filler addition, but CNC composites, particularly those prepared by cryo-milling, retained better ductility. Both CNC and CaCO₃ increased the modulus of PLA composites, with CaCO₃ providing a greater improvement. Although cryo-milling improved nanoparticle dispersion within the PLA matrix, better interfacial bonding is still needed. Future strategies, such as surface modification of fillers—like PEG-coating CNC—are recommended alongside improved mixing methods to optimize composite performance for sustainable applications.

Supply chain management (SCM) involves complexities and uncertainties in the flow of goods and services from raw materials to end users. Inaccurate estimation of raw materials, labor, or equipment can lead to financial losses and environmental impacts. This study explores the application of system dynamics modeling (SDM) in manufacturing hemp-reinforced polymer composites (HRPC) to optimize resource usage. Using SDM software STELLA^® (Version 3.7.3), selected for its affordability and features, the research demonstrates how system dynamics (SD) can enhance sustainability by minimizing materials, labor, and equipment, reducing energy consumption. A literature review identified a gap in existing research, as we found no prior studies simulating HRPC manufacturing using SDM. The study concludes that SDM is an effective tool for optimizing resource use and improving manufacturing efficiency. By simulating multiple supply chain scenarios in a risk-free environment, the model helps reduce resource consumption and enhance sustainability. Additionally, outputs from the STELLA^® model can be used as inputs for life cycle assessment (LCA) to quantitatively measure environmental impacts.

In supply chain management (SCM), the flow of goods and services from raw materials to the end user involves significant complexities and uncertainties at each stage. Computer modeling and simulation offer powerful tools to address these challenges, as they can efficiently analyze operational issues that are otherwise time-consuming and difficult to explore. Inaccurate estimation of raw materials, labor, or equipment often leads to financial losses and environmental impact, a concern for many manufacturing companies. The purpose of this study is to explore the application of system dynamics modeling (SDM) in the manufacturing of hemp-reinforced polymer composite (HRPC), with the goal of optimizing material, labor, and equipment usage. By applying system dynamics (SD), the manufacturing unit can enhance sustainability by minimizing the use of materials, labor, and equipment, thereby lowering energy consumption. For this research, the SDM software STELLA® was chosen for its affordability, ease of use, and comprehensive features, making it a strong choice compared to other leading software options. Our literature review revealed a significant gap in existing research, as we could not identify any study currently exploring the simulation of HRPC material manufacturing using SDM. Our study concludes that SDM simulation serves as an effective method for optimizing materials, labor, and equipment in the manufacturing of HRPC materials. By simulating various supply chain scenarios in a risk-free environment, the model reduces resource consumption and improves manufacturing efficiency, hence promoting sustainability. Furthermore, outputs from the STELLA® model can serve as inputs for life cycle assessment (LCA) to quantitatively evaluate environmental impacts.

The pursuit of an environmentally sustainable manufacturing process requires the substitution of less damaging and recyclable solutions for harmful reagents. This study aims to assess the effectiveness of using cellulose microfibrils synthesized via different hydrolysis reactions as reinforcing agents in polyvinyl alcohol (PVA) at varying concentrations. The investigation explores the morphology, thermal properties, and chemical behavior of the cellulose particles. The cellulose microfibrils (CMFs) produced using citric acid exhibited the highest yield and aspect ratio. Notably, particles from organic acids demonstrated greater thermal stability, with oxalic acid-derived particles displaying the maximum thermal degradation temperature. Subsequently, cast films of PVA reinforced with the cellulose microfibrils underwent comprehensive analyses, including Fourier transfer infrared (FTIR) spectroscopy, thermal degradation temperature (T_d), differential scanning calorimetry (DSC), and tensile strength tests. The thermal behavior of cast films experienced notable changes with the addition of cellulose particles, evidenced by increased melting and crystallinity temperatures, along with a rise in the degree of crystallinity. The incorporation of cellulose particles led to a substantial improvement in mechanical properties. Films containing CMF displayed higher Young’s modulus, and the sample incorporating 5% CMF derived from citric acid exhibited the most significant increase in modulus.