Polymer and Organic Materials Commons^™

Polypropylene/Polyethylene Blends With Asymmetric Viscosity: Fabrication, Characterization, And Recycling Potential, Bernadine Daichendt

All Dissertations

Polyolefin materials, polypropylene (PP) and polyethylene (PE), are widely used in day-to-day life both commercially and industrially, offering versatile applications due to their mechanical and chemical properties. The high consumption rate of these materials makes them important targets for recycling efforts. However, there are multiple contributing factors leading to low recycling of PP and PE, chiefly sorting factors: chemical similarity, changed properties after multiple rounds of processing, and the use of processing aids. It is necessary to point out that, because of multiple melt processing cycles, recycled PP has decreased molecular weight due to chain scission. Conversely, recycled PE molecular …

Synthesis And Characterization Of Chemically Recyclable Polypropylene-Based Covalent Adaptable Networks, Andrii Tiiara

All Dissertations

Polyolefins (POs) are inexpensive engineering materials with excellent physical and mechanical properties, accounting for nearly 60% of all thermoplastics. However, large-scale recycling remains limited, with only ~15% undergoing mechanical recovery. This dissertation addresses this challenge by fragmenting and functionalizing polypropylene (PP) chains to generate macromonomers and employing them, along with industrial reactive PP macromonomers, to synthesize, depolymerize, and repolymerize chemically recyclable polypropylene-based polyolefins (CR-POs). These CR-POs incorporate ester linkages that form covalent adaptable networks (CANs), maintaining a gel fraction of ~70% while remaining melt-reprocessable via extrusion and compression molding.

First, the fragmentation of PP is investigated by microwave irradiation. Microwave …

Processing-Driven Crystallization, Morphology, And Mechanics In Pekk Composites, Nicholas Ryan Enos

Dissertations

This dissertation aims to understand how thermoplastic composites can be processed at faster manufacturing rates while identifying how processing variables influence crystallization, morphology, and mechanical properties. Throughout this dissertation, the influence of nano-scale additives, carbon fibers, rapid cooling, shear, and molecular weight on polymer physics, crystallization, morphology, and mechanics is investigated.

The inclusion of carbon nanotubes and graphene nanoplatelets accelerated crystallization, increased nucleation density, reduced lamellar thickness, and shifted governing Hoffman-Lauritzen growth regimes in PEKK. Velisaris-Seferis modelling identified a surface-induced nucleation mechanism in PEKK nanocomposites, and fast scanning calorimetry allowed for the study of rapid cooling rates, helping to identify …

Predicting Long-Term Creep Behavior Using Short-Term Stress Relaxation Data In Expanded Polyethylene Foam, Andrew M. Seelig

All Theses

Closed cell expanded polyethylene (EPE) foams are widely used for protective packaging due to their high energy absorption properties and recyclability. However, these foams can be subjected to sustained compressive stresses (13.78 - 36.20 kPa), depending on density and application, leading to time-dependent deformation (creep). Creep reduces cushioning performance, making its understanding critical for effective protective packaging. Two standards, ASTM D3575 and ASTM D2221, define methods for conducting compressive creep tests on foam materials, with test durations extending up to 1000 hours. Accelerated methods such as Time Temperature Superposition (TTS) and the Stepped Isostress Method (SSM) have been explored for …

Effect Of Polymer Contaminants Sourced From Coated Paper On The Performance Of The Resulting Recycled Paper, Ezekiel J. Guevarra

All Theses

The growing demand for sustainable packaging has accelerated the use of paper-based materials as alternatives to plastics. To provide barrier and functional properties, these materials are often modified with polymer coatings. While beneficial during use, such coatings can persist as contaminants during recycling, potentially disrupting fiber bonding and reducing the quality of recycled paper. This study examined the impact of extrusion-coated low-density polyethylene (LDPE) films and two aqueous dispersions (Vapor/Water-Barrier, Acrylic Film (VWAF) and Oil & Grease Barrier (OGBF)) on contaminant distribution and mechanical performance of recycled handsheets. Kraft paper coated at varying levels was repulped and formed into handsheets, …

Effect Of Cryo-Milling On Pla/Cmc And Pla/ Caco3 Composites: A Comparison Study, Fatemeh Mahdiyeh-Boroujeni, Ron Kander

School of Design and Engineering Papers

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. Two different fillers, natural cellulose microcrystals (CMC) and mineral calcium carbonate (CaCO3), were incorporated into polylactic acid (PLA) at five different weight fractions. Biocomposite films were prepared using physical mixing and cryo-milling, followed by hot pressing. Cryo-milling was explored as a 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, …

The Science And Economics Of 3d-Printed Filament Recycling, Michael Domingo, Dane Freund, John Mcswiggin, Adam Meadows

Sustainability Conference

In recent years, 3D printing has grown rapidly, both in homes and commercially. This has led to increased demand for plastic filaments, many of which contribute to plastic waste. This project explores the potential of recycling household plastics into 3D printing filament, promoting sustainability and creating a circular economy. Materials like PLA, PETG, ABS, and polypropylene can be recycled or even composted. Existing research has shown that recycled filaments can maintain comparable tensile strength to their virgin counterparts, depending on the recycling process. Furthermore, implementing circular economy practices for plastics could save billions annually by mitigating pollution and reducing landfill …

Characterization Of The Fatigue Threshold Behavior Of Uhmwpe, Bethany B. Smith, Anurag Roy, Robert O. Ritchie, Lisa A. Pruitt

Faculty Journal Articles

Ultra-high-molecular-weight-polyethylene (UHMWPE) has been the material of choice for bearings in total joint replacements (TJRs) for decades as a result of its excellent wear resistance, chemical inertness, energetic toughness, low friction, and biocompatibility. Utilization of this polymer in orthopedic devices requires oxidation, wear, and fatigue resistance. Balancing these important properties by tailoring processing techniques and modulating microstructural features has been an ongoing endeavor in the field. Research into the clinical applications of UHMWPE has primarily focused on the challenges of wear and oxidation while studies into the realm of fatigue have been more limited. Literature gaps exist in fully understanding …

Ferric Metal-Organic Frameworks (Mofs)-Based Electrospinning Fibers For Supercapacitors, Samar A. Salim, Hani Nasser Abdelhamid

Nanotechnology Research Centre

Ferric-based metal-organic frameworks (Fe-MOFs) were synthesized and incorporated into poly(methyl methacrylate) (PMMA) using electrospinning to produce PMMA_Fe-MOF nanofibers. The materials were analyzed using X-ray diffraction (XRD), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). The electrospun materials were directly integrated into nickel foam (NF) electrodes for energy storage applications, e.g., supercapacitors. The electrochemical performance was assessed using cyclic voltammetry (CV), galvanostatic charge-discharge curves (GCDC), linear sweep voltammetry (LSV), and electrochemical potentiokinetic reactivation (EPR). The PMMA_Fe-MOF electrodes exhibited outstanding capacitive performance, achieving specific capacitances of up to 1017.5 F/g at 1 A/g for the 2.5 % Fe-MOF …

Understanding Structure-Property Relationships Within Polyolefin-Derived Vitrimer Systems, Mikaela Sadri

Dissertations

Polyolefins are extremely ubiquitous materials due to their satisfactory material properties, ease of synthesis, and low cost. Unfortunately, their extensive use has led to a global plastic waste mismanagement problem. As such, notable efforts have recently focused on converting these commodity polymers into vitrimers, or dynamic networks, to extend their use-life and tailor their properties. However, the fundamental polymer physics of these emerging materials, remain largely underexplored, hindering their widespread implementation. To address this challenge and enable a more sustainable future, the overarching goal of my dissertation research is to understand the fundamental structure-property relationships within complex polyolefin-derived vitrimer systems. …

Self-Poled P(Vdf-Trfe) Based Composites For Energy Harvesting And Wearable Sensor Applications, Lavanya Muthusamy

All Dissertations

The growing demand for flexible, low-power, and self-powered wearable electronic systems has accelerated research interest in polymer-based sensors and energy harvesting technologies. Among piezoelectric polymer materials, Poly(vinylidene fluoride-trifluoro ethylene) [P(VDF-TrFE)], over the years, has garnered significant attention due to its unique piezoelectric properties, high dielectric constant, mechanical flexibility, thermal stability, chemical resistance, biocompatibility and compatibility with scalable fabrication processes. Despite its advantages, conventional P(VDF-TrFE)-based devices often require external poling and face limitations in integration with low-cost, flexible substrates. To overcome these limitations, this research study explores the nanofiller approach, along with facile fabrication processes, and structural design strategies aimed at …

Designing Self-Healable Aromatic Copolymers And Olefinic Composites, Samruddhi Yashwant Gaikwad

All Dissertations

Self-healing polymers capable of recovering from mechanical damage are promising materials for advanced applications, especially those involving mechanical and/or physical fatigue. In these studies, we have developed techniques to achieve autonomous self-healing in commodity Styrene/n-butyl acrylate copolymers. The mechanism of self-healing in the designed polymers involves inter-and/or intrachain non-covalent interactions between π-cloud and polar linkages of acrylic nBA in random/preferentially alternating copolymers. A combination of spectroscopic tools, thermo-mechanical analysis, and molecular dynamics (MD) simulations has been used to elucidate the mechanism of self-healing. These studies further show the incorporation of dipolar C-F groups to understand the effect of having fluorinated …

Controlling Electroless Deposition On Polymer Interfaces Towards Discrete Functional Particle Synthesis, Grecia Pierina Alvarado Munoz

Graduate Theses and Dissertations

Electroless deposition is a process that facilitates the formation of metal layers on surfaces through the reduction of metal ions onto a surface in the presence of a sacrificial reducing agent. This process can be applied to synthesize conductive metal layers on insulators such as glass or polymers. The kinetics of heterogeneous deposition depend on the interfacial surface chemistry, including the presence of added catalyst materials, as well as the bulk chemical environment, such as the concentration of metal ions and sacrificial reductants. Furthermore, the homogeneous formation of metal nanoparticles may compete with the deposition reaction, adversely affecting the control …

Polymer-Enhanced Nanopore Sensing, Eugene Gyasi Agyemang

Graduate Theses and Dissertations

The resistive pulse technique characterizes single analytes by detecting fluctuations in the ion current as they pass through a narrow orifice connecting two electrolyte-filled chambers, each containing a single electrode. The amplitude, shape, frequency, and duration of these fluctuations primarily provide information about the analyte’s size, shape, concentration, and net surface charge, respectively. One configuration for resistive pulse measurements is of an electrolyte-filled nanopipette immersed in a bath, where the nanopipette tip acts as the nanoscale orifice. It was previously shown that incorporating the large quantities polymer polyethylene glycol (PEG 8K, 50% w/v) into the external electrolyte bath dramatically enhanced …

Preparation And Characterization Of Electrospun Pvdf-Based Nanocomposite Fibers For Energy Harvesting And Storage Applications, Ahmed Ramzy, Electrochemistry And Corrosion Laboratory, Physical Chemistry Department, National Research Centre, Dokki, Cairo, 12622, Egypt, Ahmed M. El-Mahalawy

Nanotechnology Research Centre

This study introduces the development of multifunctional electrospun polyvinylidene fluoride (PVDF) composite films doped with potassium octatitanate (KTO) for advanced energy applications. The research tackles key challenges in energy generation and storage through innovative material design and detailed characterization. Adding 0.2 wt% KTO to PVDF electrospun fibers resulted in a notable increase in crystallinity to 78.51 %, marking a significant enhancement in material properties. Structural analysis using X-ray diffraction and Fourier transform infrared spectroscopy confirmed optimal phase composition, while morphological features were verified through field emission scanning electron microscopy. The composite films showed exceptional electrochemical performance, with bulk electrolyte resistance …

Effect Of Sorbitol Plasticizer On Bioplastics Properties Based On Oil Palm Empty Fruit Bunches (Opefb) And Jackfruit Seed Starch, Nia Sasria, Vita Nur Afifah, Gusti Umindya Nur Tajalla

Makara Journal of Science

In bioplastics, natural materials that are easily decomposed are used to minimize plastic waste. In this research, the compositions used were cellulose from oil palm empty fruit bunches (OPEFB), jackfruit seed starch, and carboxymethyl cellulose (CMC) as a filler with sorbitol as a plasticizer. This study aimed to analyze the effect of a sorbitol plasticizer on bioplastic properties. The study began by extracting jackfruit seed starch and OPEFB cellulose. Subsequently, bioplastics were prepared by varying sorbitol, namely 0 (S – 0), 0.5 mL (S – 0.5), 1 mL (S – 1), and 1.5 ml (S – 1.5), with CMC 20%. …

Synthesis And Radical Polymerization Of N,N-Diallyl Phthalimide, Oytura S. Maksumova, Feruza A. Pulatova, Dilnozakhon I. Tursunova, Feruza A. Makhmudova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is the synthesis of iodine N,N-diallylphthalimide and the study of its radical polymerization. In this regard, the synthesis of iodine N,N-diallylphthalimide was carried out in two stages: at the first stage, phthalic anhydride reacts with allylamine and forms allyl phthalimide, at the second stage, allyl phthalimide reacts with allyl iodide to form iodine N, N-diallyl phthalimide. Radical polymerization of the synthesized quaternary salt of N, N-diallyl phthalimide was studied in the presence of the initiator dinitrile azobisisobutyric acid at relatively low temperatures. Kinetic features of the polymerization reaction of iodine N, N-diallyl phthalimide were considered. …

Poly(Pyridinium Salt)S Containing 9,9-Bis(4- Aminophenyl)Fluorene Moieties With Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline And Light-Emitting Properties, Pradip K. Bhowmik, David King, Haesook Han, Andras F. Wacha, Matti Knaapila

Chemistry and Biochemistry Faculty Research

Main-chain conjugated and non-conjugated polyelectrolytes are an important class of materials that have many technological applications ranging from fire-retardant materials to carbon-nanotube composites, nonlinear optical materials, electrochromic materials for smart windows, and optical sensors for biomolecules. Here, we describe a series of poly(pyridinium salt)s-fluorene containing 9,9-bis(4-aminophenyl)fluorene moieties with various organic counterions that were synthesized using ring-transmutation polymerization and metathesis reactions, which are non-conjugated polyelectrolytes. Their chemical structures were characterized by Fourier transform infrared (FTIR), proton (1H) and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers, and elemental analysis. They exhibited polyelectrolytic behavior in dimethyl sulfoxide. Their lyotropic liquid-crystalline phases were …

Effects Of Aloe Vera/Chitosan Ratios On The Tensile Properties Of Aloe Vera/Chitosan/Polyvinyl Alcohol Nanofibrous Membranes For Wound Care Dressing, Harini Sosiati, Abdul Rahman, Kelvin Kurniawan Sahputra, Miftahul Faruq Ibnul Fatoni

Makara Journal of Science

Chitosan (CS) and Aloe vera (AV) are functional and antibacterial materials compatible with polyvinyl alcohol (PVA), which confers medical and healthcare potential. This study prepared and then characterized the influence of CS/AV ratios on the tensile properties of CS/AV/PVA nanofibrous membranes for wound care dressing materials. The CS/AV/PVA membranes were fabricated using an electrospinning technique at varying AV/CS/PVA volume ratios: 0:0:100, 0:20:80, 5:15:80, 10:10:80, 15:5:80, and 20:0:80. All membranes were subjected to tensile testing as per the ASTM 882 standard, and the nanofiber’s morphology was examined using scanning electron microscopy. Changes in the tensile strength related to the formation of …

Myceli-Yum: Elucidating Structure-Property Relationships For Polymer Degradation By Mycelial Digestion, Jordan Scott Ford

Master's Theses

Since the industrial entrance of polymer plastic materials, plastic has become ubiquitous in both everyday use and waste. Due to inefficiencies and knowledge gaps, current recycling methods are not able to account for the high scale of plastic waste, resulting in the bulk of this waste being landfilled, mishandled, and deposited in the environment. Mycelium, the microorganism responsible for fruiting mushroom bodies and mold growth, holds potential to reduce plastic waste and can potentially be utilized as a method of industrial recycling. Following a drug-design approach, the active site of mycelial enzymes responsible for natural biopolymer degradation have been assessed …