Polymer Chemistry Commons^™

An Investigation Of The Use Of Cerium And Polyhedral Oligomeric Silsesquioxanes For The Protection Of Polymeric Epoxy Compounds In The Low Earth Orbit Environment, Jessica Miriam Piness

Dissertations

Low Earth orbit presents many hazards for composites including atomic oxygen, UV radiation, thermal cycling, micrometeoroids, and high energy protons. Atomic oxygen and vacuum ultraviolet radiation are of concern for space-bound polymeric materials as they degrade the polymers used as matrices for carbon fiber composites, which are used in satellites and space vehicles due to their high strength to weight ratios. Epoxy-amine thermosets comprise a common class of matrix due to processability and good thermal attributes. Polyhedral oligomeric silsesquioxanes (POSS) have shown the ability to reduce erosion in polyimides, polyurethanes, and other polymers when exposed to atomic oxygen. The POSS …

Influence Of Multiwall Carbon Nanotubes On Corrosion Performance And Water Hydrogen Bonding Of Epoxy-Amine Thin Films, Greg William Curtzwiler

Dissertations

This dissertation research sought to provide a fundamental basis of understanding to commence the systematic investigation of developing economically viable fully formulated epoxy-amine coating systems containing multiwall carbon nanotubes (MWCNT). Namely, a facile and rapid method for multiwall carbon nanotube surface modification and molecular structure interpretation was developed to assist in designing MWCNT-polymer interactions and achieving high levels of dispersion. Additionally, a rapid and quantitative method was developed to investigate the dispersibility potential of MWCNTs possessing a given surface modification in combination with a dispersion protocol which can further be utilized as a quality control metric in commercial applications. It …

Formation Of Nanostructured Epoxy Networks Containing Polyhedral Oligomeric Silsesquioxane (Poss) And Silica Nanoparticles, Amit K. Sharma

Dissertations

This dissertation is focused on structure-property-processing relationship studies based on well-defined polyhedral oligomeric silsesquioxane (POSS) modified epoxy networks to present a comprehensive understanding of hybrid network behavior. In this research, a monoamine functional POSS molecule is incorporated into the epoxy monomer as pendant unit to mimic common epoxy structures and then crosslinked to form well-defined epoxy hybrid networks. The POSS cages behave as nanosized pendant unit in the epoxy matrices, while the mass fraction of POSS cages is varied and the effects on physical properties are examined with respect to changes in network architecture.

A novel continuous reactor method is …

Bioinspired Design Of Wetting And Anti-Wetting Surfaces Via Thiol-Ene Photopolymerization, Li Xiong

Dissertations

Surface wettability is known to have a profound influence in both academic study and industrial application of materials. Superhydrophobic surfaces, with a static contact angle higher than 150° and a contact angle hysteresis lower than 10°, have received continued attention for their broad applications, such as self-cleaning, antifogging and frosting, and drag reduction. The continuous development of materials and approaches that used to create superhydrophobic surfaces has led to further exploration of coatings with other desirable properties such as superamphiphobicity, mechanical robustness and thermal stability.

In this work, coatings with super wetting and super anti-wetting properties were designed and fabricated …

Design And Synthesis Of Polymer Brush Surfaces With Complex Molecular Architectures And Morphologies, Wei Guo

Dissertations

The combination of surface-initiated polymerization (SIP) and postpolymerization modification (PPM) is a powerful technique for the fabrication of functional soft surfaces. Better understanding the influence of the aforementioned factors on the PPM effectiveness is valuable for fulfilling the potential of the PPM approach for the fabrication of functional soft surfaces. Specifically, by carefully balancing modification reactivity and limitation of mass transport, polymer brush with composition heterogeneity and gradient along the normal direction of the surface otherwise unattainable by methods of direct polymerization can be fabricated via the PPM approach which opens doors to new routes to polymer brush with complex …

Advancing Structure-Property Relationships In Functional Materials Via Thiol-Ene Photopolymerization, Brian Richard Donovan

Dissertations

Thiol-ene photopolymerizations provide a robust and versatile synthetic pathway to functional materials, and owing to the radical step-growth nature of polymerization and the resulting homogenous network structure, provide non-convoluted insight into how network chemistry influences and dictates macromolecular properties.

The first facet of this dissertation focuses on the design and synthesis of bio-inspired, thin film adhesives for dry and aqueous adhesion. Drawing inspiration from the intertidal marine mussel, Chapter II details the synthesis of adhesive networks containing a monofunctional catechol-based monomer. The inclusion of a catechol group resulted in significant improvements in adhesion on a variety of substrates. In Chapter …

Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles

Dissertations

Processing carbon fiber composite laminates creates molecular-level strains in the thermoset matrix upon curing and cooling which can lead to failures such as geometry deformations, micro-cracking, and other issues. It is known strain creation is attributed to the significant volume and physical state changes undergone by the polymer matrix throughout the curing process, though storage and relaxation of cure-induced strains remain poorly understood. This dissertation establishes two approaches to address the issue. The first establishes testing methods to simultaneously measure key volumetric properties of a carbon fiber composite laminate and its polymer matrix. The second approach considers the rigidity of …

Polyisobutylene Telechelic Prepolymers By In Situ End-Quenching And Post-Polymerization Modifications, Bin Yang

Dissertations

This volume focuses on the development of telechelic polyisobutylene (PIB) prepolymers by combining end-capping of living carbocationic polymerization of isobutylene (IB) with suitable reactants and post-polymerization modifications. Alkylation kinetics of PIB tert-chloride with alkoxybenzenes using either TiCl₄ or AlCl₃ were investigated. Quantitative para-position end-capped products were only achieved if the alkoxybenzene/AlCl₃ molar ratio was greater than unity; while no such molar ratio is required for TiCl₄, but the alkylation rate was slower than AlCl₃ under the same conditions. Photopolymerization kinetics analysis of PIB triphenol tri(meth)acrylates with low and high M_ns, …

Rate Acceleration Of Organocatalytic Ring-Opening Polymerization Rough The Application Of Bis- And Tris- ( Io)Urea H- Bond Donors, Samuel S. Spink

Senior Honors Projects

Well-defined and functionalized polymers have a wide variety of applications in biomedical studies. Advancements in the fields of drug delivery, microelectronics, and medical imaging, among other applications, are predicated upon the development of methods for the synthesis of precision polymers. Organocatalytic ring-opening polymerization (ROP) of cyclic monomers is an effective route to the production of polymeric materials, namely polyesters and polycarbonates, whose biodegradable properties make them a viable option in biomedical research. Arguably, H-bond mediated catalysts are among the most selective catalysts for ROP, giving rise to highly functionalized polycarbonates, well-controlled polymerizations, and other custom tailored applications. With respect to …

Fluorescent Conjugated Polymers With A Bodipy-Based Backbone And Uses Thereof, Haiying Liu

Michigan Tech Patents

The present invention provides various fluorescent conjugated polymers with a BODIPY-based backbone. The invention also provides methods of using the polymers of the invention, such as for imaging and detection of cells, tumors, bacteria and viruses.

Enediyne Derived Conjugated Polymers, Keda Hu

Chemistry and Chemical Biology ETDs

The advance of conjugated polymers (CPs) is largely relied on the development of new polymerization methods, the discovery of novel polymers that possess unique chemical and physical properties, and understanding of their structure-property relationship. We have employed a set of trans-enediynes (trans-EDYs) for the preparation of four series of CPs, polydiacetylenes (PDAs), platinum-segmented PDAs, polytriacetylenes (PTAs) and boron doped polyacetylenes (BPAs). The resulting polymers displayed interesting optical and electrochemical properties which could be fine-tuned by the attachment of various side chains on the EDY moieties. We have applied acyclic EDY metathesis for the synthesis of PDAs, a class of CPs …

Sustainable Polymers: Plastics From Plants, Chris Schaller

Forum Lectures

Plastics and related soft materials are ubiquitous in today's world. This presentation takes a look at why polymers have useful properties, where they come from, and why attention has shifted toward new, biorenewable materials.

High Performance Supercapacitor Device Based On Polymer Derived Carbon Nanofiber With Enhanced Capacity At Elevated Temperatures, Charith Ranaweera

Paper and Posters Presentations

Recently, supercapacitors are attracting considerable interest as a promising energy storage device. In this study, we report the high performing supercapacitor based on cobalt oxide embedded carbon nanofibers (CNF@CO) fabricated by electrospinning of cobalt acetate and polyacrylonitrile mixture in to carbon nanofibers (CNF) and subsequent pyrolyzed at 800 oC under nitrogen atmosphere. Morphology and electrochemical properties of the fabricated CNF@CO was studied in detailed. Embedding of cobalt oxide in to CNF showed a remarkable improvement in the charge storage capacitance, specific capacitance of 360 F/g and 1100 F/g were observed for CNF and CNF@CO, respectively. We studied the effect of …

Combination Therapy Of Prostate Cancer Utilizing Functionalized Iron Oxide Nanoparticles Carrying Tnf-A And Lactonic Sophorolipids, James Beach, Tuhina Banerjee, Jyothi Kallu, Ryan Higginbotham, Richard Gross

Paper and Posters Presentations

Prostate cancer is one of the most prevalent forms of cancer afflicting men in the United States. In recent years, advances in the field of nanotechnology have allowed for new and innovative ways to treat various types of cancer and various other diseases. Our research focuses on the treatment of the LNCaP line prostate cancer utilizing iron oxide nanoparticles (IONPs) loaded with soluble TNF-a and lactonic sophorolipids (LSLs). TNF-a is a cytokine responsible for apoptosis initiation, while LSLs are naturally-glycolipids shown to alleviate inflammation and improve immune response in certain diseases. We hypothesized that this combination may possess a synergistic …

High-Quality Polyurethane Foams And Sheets From Sustainable Natural Resources, Sanket Bhoyate, Chungyang Zhang, Mihail Ionescu

Paper and Posters Presentations

Bio-polymers from sustainable natural resources serve mankind keeping environmental factors under consideration. Resources such as soybean, castor and orange oil are among highly cultivable agro-resources. Polyols formulated from these oils shows clean-environmental pathway for synthesizing polyurethane foams and sheets. Facile single-step synthesis, with negligible waste as well as byproducts produces 100% qualitative yield for polyurethane foams. Present work displays use of synthesized polyols in developing polyurethane foams and casts. Viscometry, FTIR spectroscopy, GPC and other chemical analysis were done to ensure the quality of the raw materials. Cast Sheets and foams were produced by chemical polymerization with di-phenyl methane diisocyanate …

Use Of Decahydrodecaborate As Flame Retardants In Coatings, Austin Bailey

Paper and Posters Presentations

As the need to protect the environment continues to increase, there is a growing demand for non-halogenated flame retardants. Two different decaborate compounds were combined with triphenylphosphine oxide into polyurethane and characterized. The thermal stability and the potential flame retardancy of the new materials were tested via thermogravimetric analysis and cone calorimetry. The cone test provided heat release rates and smoke release rates. Per the results of these tests the combination of the new decaborate, and triphenylphosphine oxide showed potential for flame retardancy at minimal amounts of flame retardant.

High Performance Carbon Nanofiber Supercapacitor Electrode With Tuned Porous Structure, Sanket Bhoyate

Paper and Posters Presentations

High performance capacitor devices based on electric double layer capacitor (EDLC) principle has wide advantage of higher range of cyclic stability, rate capability, temperature durability and chemically resistant. Carbon based materials such as graphene, carbon nanotubes, activated carbon and carbon nanofibers are well known supercapacitor materials derived till date. Creating pores within the physical structure has found to improve the EDLC capabilities of the material. Exfoliation of graphene, activation of carbon and activation of nanofibers via various different techniques seem to be too complicated, non-consistent and needs wide range of control parameters. Facile immiscible polymer blend technique followed by thermal …

Moleculary Targeted Nanomedicine: Role Of Hsp90 Inhibitor And Sophorolipids, Shuguftha Naz

Paper and Posters Presentations

Oncogenic K-RAS, one of the major histologic subtypes of Non-Small-Cell Lung Cancer (NSCLC) accounts for 25% of the lung cancer related deaths. Hsp90, a ubiquitously expressed molecular chaperone is considered to be a promising target for therapeutic intervention. It is known to interact with several client proteins that are important in the pathogenesis of the cancer. Ganetespib, an Hsp90 inhibitor has been shown to have superior anti-tumor activity in several K-RAS mutant NSCLC cell lines. In addition, lactonic sophorolipids (LSL), a class of chemo-enzymatically modified glycolipids, are known to be promising immunomodulators and have shown to decrease the mortality rate …

Poly(Ethyl Glyoxylate)-Poly(Ethylene Oxide) Nanoparticles: Stimuli- Responsive Drug Release Via End-To-End Polyglyoxylate Depolymerization, Bo Fan, Elizabeth Gillies

Chemistry Publications

The ability to disrupt polymer assemblies in response to specifi c stimuli provides the potential to release drugs selectively at certain sites or conditions in vivo. However, most stimuli-responsive delivery systems require many stimuli initiated events to release drugs. “ Self-immolative polymers” offer the potential to provide amplifi ed responses to stimuli as they undergo complete end-to-end depolymerization following the cleavage of a single end-cap. Herein, linker end-caps were developed to conjugate self-immolative poly(ethyl glyoxylate) (PEtG) with poly(ethylene oxide) (PEO) to form amphiphilic block copolymers. These copolymers were self-assembled to form nanoparticles in aqueous solution. Cleavage of the linker …

Polymer Micelle Formulation For The Proteasome Inhibitor Drug Carfilzomib: Anticancer Efficacy And Pharmacokinetic Studies In Mice, Ji Eun Park, Se-Eun Chun, Derek Alexander Reichel, Jee Sun Min, Su-Chan Lee, Songhee Han, Gongmi Ryoo, Yunseok Oh, Shin-Hyung Park, Heon-Min Ryu, Kyung Bo Kim, Ho-Young Lee, Soo Kyung Bae, Younsoo Bae, Wooin Lee

Pharmaceutical Sciences Faculty Publications

Carfilzomib (CFZ) is a peptide epoxyketone proteasome inhibitor approved for the treatment of multiple myeloma (MM). Despite the remarkable efficacy of CFZ against MM, the clinical trials in patients with solid cancers yielded rather disappointing results with minimal clinical benefits. Rapid degradation of CFZ in vivo and its poor penetration to tumor sites are considered to be major factors limiting its efficacy against solid cancers. We previously reported that polymer micelles (PMs) composed of biodegradable block copolymers poly(ethylene glycol) (PEG) and poly(caprolactone) (PCL) can improve the metabolic stability of CFZ in vitro. Here, we prepared the CFZ-loaded PM, PEG-PCL-deoxycholic …

Phosphonium-Functionalized Polymer Micelles With Intrinsic Antibacterial Activity, Benjamin Hisey, Paul J. Ragogna, Elizabeth Gillies

Chemistry Publications

New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)− polycaprolactone block copolymer, and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution. The size, morphology, and ζ -potential of the assemblies were studied, and their abilities to kill Escherichia coli and Staphylococcus aureus were evaluated. It was found that the minimum bactericidal concentration depended on the phosphonium alkyl chain length, and different …

Effects Of Molecular Structure And Packing Order On The Stretchability Of Semicrystalline Conjugated Poly(Tetrathienoacene-Diketopyrrolopyrrole) Polymers, Chien Lu, Wen-Ya Lee, Xiaodon Gu, Jie Xu, Ho-Hsiu Chou, Hongping Yan, Yu-Cheng Chiu, Mingqian He, James R. Matthews, Weijun Niu, Jeffery B.-H. Tok, Michael F. Toney, Wen-Chang Chen, Zhenan Bao

Faculty Publications

The design of polymer semiconductors possessing high charge transport performance, coupled with good ductility, remains a challenge. Understanding the distribution and behavior of both crystalline domains and amorphous regions in conjugated polymer films, upon an applied stress, shall provide general guiding principles to design stretchable organic semiconductors. Structure–property relationships (especially in both side chain and backbone engineering) are investigated for a series of poly(tetrathienoacene-diketopyrrolopyrrole) polymers. It is observed that the fused thiophene diketopyrrolopyrrole-based polymer, when incorporated with branched side chains and an additional thiophene spacer in the backbone, exhibits improved mechanical endurance and, in addition, does not show crack propagation …

Application Of Electrochemical Sensors For Nanomolar Detection Of Chromium (Vi) In Drinking Water And Development Of Graphene Based Ionophore-Doped Polymeric Membrane Electrode, Fatma Ali Al-Amoody

Student Theses and Dissertations

Toxic chemicals like chromium (VI) pose a great risk to humans and environment. In this study, we used ion-selective electrode like glassy carbon (GC) to detect trace analysis of chromium in the form of hydrogen chromate ion (HCrO4-) in drinking water. The surfaces of GC electrodes were electrochemically modified by polymerizing with poly 3-octylthiophene (POT) using cyclic voltammetry followed by plasticized polyvinyl chloride (PVC) to form a double polymer membrane. They were then used in the stripping voltammetry technique whereby current showed a linear response of hydrogen chromate ion between 30 nM to 1300 nM in drinking water. Graphene is …

Asymmetric Membranes For High Capacity Lithium-Ion Battery Electrodes, Ian Byrd

College of Graduate Studies: Theses & Dissertations

Lithium-Ion Batteries (LIBs) have broad applications such as portable electronic devices, electric vehicles, and for green energy storage from intermittent sources. Current LIBs are limited by their low capacity materials at both the anode and cathode. At the anode, graphite suffers from a low capacity of only 372 mAh g^-1. The most commonly used cathode material is LiCoO₂ which has a meager capacity of 140 mAh g^-1. Thereby the broader applications of LIBs are limited due to these low capacities. It is imperative to develop higher capacity materials to further improve the performance of LIBs. …

A Quartz Crystal Microbalance Study Of Thiol:Ene Poly(Ionic Liquid) Polymerization And Gas Absorption, Yueming Wu

Murray State Theses and Dissertations

ABSTRACT

The polymerization process of, and gas absorption by, imidazolium-containing thiol:ene poly (ionic liquid)s (PILs), prepared from bisallylimidazolium bis(trifluoromethyl sulfonyl)imide [NTf₂^-] and pentaerythritoltetrakis(3 mercaptopropionate), was studied. The thiol:ene PILs examined were recently reported by groups at Murray State University. The advantage of thiol:ene PILs over other reported PILs is that thiol:ene polymers are made rapidly by UV exposure and exhibit high mechanical and thermal stability due to high cross-linking. The properties of interest for the thiol:ene PILs were studied using a quartz crystal microbalance (QCM). QCM techniques are based on the piezoelectric effect, where certain crystals (e.g., …

นาโนคอมพอสิตของพอลิแล็กทิกแอซิด/เอทิลีนไวนิลแอซีเทตโคพอลิเมอร์เติมด้วยนาโนไฮบริด พอลิเมทิลเมทาคริเลต/ซิลิกา, จัสมิน พงค์เกษม

Chulalongkorn University Theses and Dissertations (Chula ETD)

นาโนคอมพอสิตของพอลิแล็กทิกแอซิด/เอทิลีนไวนิลแอซีเทตโคพอลิเมอร์ (อีวีเอ) ถูกเตรียมด้วยนาโนซิลิกาและนาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกา (1, 3 และ 5 ส่วนโดยน้ำหนักต่อเรซินร้อยส่วน) ด้วยการผสมแบบหลอมเหลวในเครื่องผสมแบบปิดตามด้วยเครื่องอัดแบบ โดยนาโนเลเท็กซ์ของพอลิเมทิลเมทาคริเลต/นาโนซิลิกาถูกสังเคราะห์ด้วยกระบวนการเกิดพอลิเมอร์ ‘อิน ซิทู’ ดิฟเฟอเรนเชียลไมโครอิมัลชัน ซึ่งนาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกาที่เตรียมได้มีร้อยละการกราฟต์เท่ากับร้อยละ 90.9 และมีขนาดอนุภาคเฉลี่ยและพื้นที่ผิวเท่ากับ 43.4 นาโนเมตร และ 71.3 ตารางเมตรต่อกรัม ตามลำดับ จากการศึกษาสัณฐานวิทยา พบว่า อนุภาคนาโนไฮบริดแสดงลักษณะโครงสร้างแบบแก่น-เปลือก ที่มีนาโนซิลิกาเป็นแก่นกลางและพอลิเมทิลเมทาคริเลตเป็นเปลือก ขั้นแรกพอลิเมอร์ผสมพอลิแล็กทิกแอซิด/อีวีเอที่อัตราส่วนต่างๆ (อีวีเอ ร้อยละ 10-30 โดยน้ำหนัก) ได้ถูกเตรียม และพบว่า ความทนแรงกระแทกและการยืดตัว ณ จุดขาดได้รับการปรับปรุง ขณะที่ยังส์มอดุลัสและเสถียรภาพทางความร้อนมีค่าลดลงเมื่อเติมอีวีเอลงในพอลิแล็กทิกแอซิด เนื่องด้วยพอลิเมอร์ผสม 90/10 พอลิแล็กทิกแอซิด/อีวีเอมีสมบัติเชิงกลที่เหมาะสม จึงถูกเลือกเพื่อเตรียมนาโนคอมพอสิตด้วยนาโนซิลิกาและนาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกา จากผลการทดลอง พบว่าการเติมนาโนซิลิกาหรือนาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกาในพอลิเมอร์ผสม 90/10 พอลิแล็กทิกแอซิด/อีวีเอ ได้ปรับปรุงความทนแรงกระแทกและเสถียรภาพทางความร้อน หากแต่การยืดตัว ณ จุดขาดมีค่าลดลง นอกจากนี้ การเติมนาโนซิลิกาส่งผลให้ความทนแรงดึงและยังส์มอดุลัสมีค่าลดลง ขณะที่ความทนแรงดึงและยังส์มอดุลัสของนาโนคอมพอสิตด้วยนาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกา มีค่าเพิ่มขึ้น โดยสรุป พบว่านาโนไฮบริดของพอลิเมทิลเมทาคริเลต/นาโนซิลิกา แสดงประสิทธิภาพในการเสริมแรงได้ดีกว่านาโนซิลิกาที่ปริมาณการเติมสารตัวเติมที่เท่าๆ กัน เนื่องจากมีแรงยึดเหนี่ยวระหว่างพอลิเมอร์-สารตัวเติมที่มากกว่า

Nitric Oxide Release From Poly(Lactic-Co-Glycolic Acid) Nanoparticles And Titanium Alloy, Nina A. Reger

Electronic Theses and Dissertations

Current methods for the treatment of bacterial infection involve the use of systemic antibiotics, which are high concentrations of antibiotics delivered over a long period time. Unfortunately, the use of systemic antibiotics can cause harmful side effects to the patient and increases the possibility for antibiotic resistance. The delivery of antibiotics or alternative antimicrobial compounds, such as nitric oxide, directly to the site of infection would decrease the amount of antibiotic necessary to treat a bacterial infection.

Poly (lactic-co-glycolic acid)/polyvinyl alcohol nanoparticles and a titanium- aluminum-vanadium metal oxide alloy implant were surface functionalized to deliver nitric oxide. Polymer nanoparticles can …

Synthesis Of Multifunctional Polyacrylates And A Binding Group To Hemoglobin For The Treatment Of Traumatic Brain Injuries, Marina Michaud

Honors College Theses

Hemoglobin based oxygen carriers (HBOCs) hold promise as an effective emergency treatment of severe traumatic brain injuries (TBI). In the latest generation of HBOCs, polynitroxyl-pegylated hemoglobin (PNPH), cell-free hemoglobin is modified with TEMPO and PEG which reduce the toxicities associated with earlier generations of HBOCs. In our efforts to optimize the economic and therapeutic impacts of PNPH’s we have synthesized polydimethylaminoethyl methacrylate (poly-DMAEMA) under controlled living conditions via reverse addition-fragmentation chain transfer (RAFT) polymerization. The poly-DMAEMA was then successfully functionalized via quaternization of its NMe₂ groups using chloroacetate derivatives of the TEMPO and PEG. This process was quantitative and …

Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera

Honors Undergraduate Theses

In this thesis, we investigate biological molecules on a micron scale in the ultraviolet spectral region through the non-destructive confocal absorption microscopy. The setup involves a combination of confocal microscope with a UV light excitation beam to measure the optical absorption spectra with spatial resolution of 1.4 μm in the lateral and 3.6 μm in the axial direction. Confocal absorption microscopy has the benefits of requiring no labels and only low light intensity for excitation while providing a strong signal from the contrast generated by the attenuation of propagating light due to absorption. This enables spatially resolved measurements of single …

ผลของตัวเร่งปฏิกิริยาของสารประกอบเชิงซ้อนคอปเปอร์-แอมีนกับเทอเทียรีแอมีนต่อการเตรียมโฟมพอลิยูรีเทนแบบแข็ง, ชาภิชญ์ จันทรสร

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาเกี่ยวกับผลการเสริมกันของตัวเร่งปฏิกิริยาร่วมระหว่างสารประกอบเชิงซ้อนคอปเปอร์-แอมีนกับตัวเร่งปฏิกิริยาทางการค้าต่อการเตรียมโฟมพอลิยูรีเทนแบบแข็ง สารประกอบเชิงซ้อนคอปเปอร์-แอมีนที่สังเคราะห์ขึ้น คือ สารประกอบเชิงซ้อนคอปเปอร์-เอทิลีนไดแอมีน [Cu(OAc)2(en)2] และ สารประกอบเชิงซ้อนคอปเปอร์-ไตรเอทิลีนเตตระมีน [Cu(OAc)2(trien)] ในรูปแบบสารละลายในเอทิลีนไกลคอล ตัวเร่งปฏิกิริยาทางการค้าที่ใช้มี 3 ชนิด คือ ไดเมทิลไซโคลเฮกซิลแอมีน (DMCHA) และไตรเอทิลีนไดแอมีน (TEDA) ซึ่งเป็นตัวเร่งปฏิกิริยาประเภทเทอเทียรีแอมีน และโพแทสเซียมออกโทเอต (KOct) พิสูจน์เอกลักษณ์ของสารประกอบเชิงซ้อนคอปเปอร์-แอมีนโดยใช้เทคนิคยูวี-วิสิเบิลสเปกโทรสโกปี และเอฟทีไออาร์สเปกโทรสโกปี ศึกษาการเตรียมโฟมพอลิยูรีเทนแบบแข็งด้วยระบบตัวเร่งปฏิกิริยาร่วม 6 ระบบ คือ Cu(OAc)2(en)2 : DMCHA, Cu(OAc)2(trien) : DMCHA, Cu(OAc)2(en)2 : TEDA, Cu(OAc)2(trien) : TEDA, Cu(OAc)2(en)2 : KOct และ Cu(OAc)2(trien) : KOct โดยศึกษาเวลาที่ใช้ในการเกิดปฏิกิริยา คือ เวลาเกิดครีม, เวลาเกิดเจล, เวลาที่โฟมไม่เกาะติดกับผิววัสดุ และเวลาที่โฟมหยุดฟู พิสูจน์เอกลักษณ์โฟมที่ได้ด้วยเอทีอาร์-เอฟทีไออาร์สเปกโทรสโกปี จากผลการทดลองพบว่าตัวเร่งปฏิกิริยาร่วม Cu(OAc)2(en)2 : DMCHA และ Cu(OAc)2(trien) : DMCHA สามารถเร่งปฏิกิริยาได้เร็วกว่าการใช้ตัวเร่งปฏิกิริยาชนิดเดียว คือ Cu(OAc)2(en)2 หรือ Cu(OAc)2(trien) หรือ DMCHA โดยดูได้จากเวลาที่โฟมไม่เกาะติดกับผิววัสดุมีค่าลดลง โฟมพอลิยูรีเทนแบบแข็งที่เตรียมได้จาก Cu(OAc)2(en)2 : DMCHA และ Cu(OAc)2(trien) : DMCHA มีสมบัติเชิงกายภาพและสมบัติเชิงกลที่ดีเทียบเท่ากับโฟมที่เตรียมจาก DMCHA