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Full-Text Articles in Chemistry
Development Of Electrochemical And Colorimetric Methods Using Inorganic Nanomaterials For Detection Of Biological And Environmental Compounds, Chanika Pinyorospathum
Development Of Electrochemical And Colorimetric Methods Using Inorganic Nanomaterials For Detection Of Biological And Environmental Compounds, Chanika Pinyorospathum
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research comprised of 2 parts including (1) lab-on-paper coupled with electrochemical method for C-reactive protein and colorimetric detection for phosphate ions and (2) the development of chromatographic techniques and its applications. In each part, it can be classified in 2 works. The first work of lab-on-paper is the electrochemical sensor that was fabricated from phosphorylcholine assembled electrodeposited gold nanoparticles onto screen-printed carbon electrode for C-reactive protein detection. Current of ferrocyanide decrease linearly when increase C-reactive protein concentration from 5.0 – 5000 µg L⁻¹. The calculated detection limit equals 1.60 µg L⁻¹. The final part of lab-on-paper is the colorimetry …
Study Of Substitution Reaction On Ring A Of Estradiol, Chanoknun Boonyaratsewee
Study Of Substitution Reaction On Ring A Of Estradiol, Chanoknun Boonyaratsewee
Chulalongkorn University Theses and Dissertations (Chula ETD)
Estradiol-conjugated anticancer drugs are the effective strategy that could specifically combat breast cancer cells, while minimizing the toxicity of the drug toward normal cells. Estradiol has been previously conjugated with drugs mostly at rings B, C and D. Functionalizations at ring A of estradiol introduce new types of conjugated drugs that could improve both the selectivity and efficiency in binding with estrogen receptor (ER). Using 4-cresol as the model, the nitration at meta-position was achieved, although with unsatisfied result of only 6% overall yield of the product. The practical results derived from diazo coupling on ortho-position of 4-cresol, which led …
Molecularly Imprinted Polymer Modified Optical Fiber Sensor Based On Surface Plasmon Resonance Spectroscopy For Determination Of Atrazine, Chidchanok Tabtimhin
Molecularly Imprinted Polymer Modified Optical Fiber Sensor Based On Surface Plasmon Resonance Spectroscopy For Determination Of Atrazine, Chidchanok Tabtimhin
Chulalongkorn University Theses and Dissertations (Chula ETD)
A sensitive sensor device based on surface plasmon resonance (SPR) spectroscopy was developed on an optical fiber and made to be selective to atrazine by molecularly imprinted polymer. The SPR probe was fabricated by deposition of gold nanoparticles on the uncladed surface of an optical fiber by self-assembly method. The size and distribution of gold nanoparticle was optimized by varying the soaking time of the optical fiber. The surface was further modified for selective sensing of atrazine with the molecularly imprinted polymer (MIP). The MIP was synthesized via 2 methods, the first was thermal polymerization method, the MIP was then …
Enzymatic Reaction Based Biosensor For Specific Detection Of Organophosphate Pesticides, Chonticha Sahub
Enzymatic Reaction Based Biosensor For Specific Detection Of Organophosphate Pesticides, Chonticha Sahub
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aims to design and develop two-biosensor platforms based on graphene quantum dots (GQDs) via enzymatic reaction for determining organophosphate pesticides (OPs). A first platform consisting of GQDs and active enzyme, GQDs/Enz platform, is simply fabricated in aqueous solution. Ongoing development of GQDs/Enz platform for effective OPs sensing by hybrid hydrogel (GQDs/Enz/Gels) was of great interest to improve the sensitivity and enzyme stability under the benefit of easy to be used for sensing approach. The GQDs/Enz and GQDs/Enz/Gels were constructed and characterized by general methods such as FT-IR, SEM and TEM. Based on the concept, H2O2 generated in situ …
Adsorption Of Tetrachloroaluminate Ion On Graphene Quantum Dots, Fadjar Mulya
Adsorption Of Tetrachloroaluminate Ion On Graphene Quantum Dots, Fadjar Mulya
Chulalongkorn University Theses and Dissertations (Chula ETD)
The important thing in the mechanism of aluminium ion battery is the fast adsorption of tetrachloroaluminate [AlCl4]- on intercalation sites of bulk graphite which can increase the efficiency and lifetime of the battery. In this study, we modeled graphene quantum dots (GQDs) as cathode material. For the adsorption of [AlCl4]-, coronene (C24H12) and circumcoronene (C54H18) were used as the model of GQDs with three types of adsorption sites and standing positions. The charge of GQDs was modified to be 0 and +1 to address discharging and charging conditions. The distance between chlorine atom and carbon atom of GQDs was found …
Green Synthesis Of Guanidines Directly From Thiourea, Jakkrit Srisa
Green Synthesis Of Guanidines Directly From Thiourea, Jakkrit Srisa
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, one-pot synthesis of guanidines directly from isothiocyanates using DIB (diacetoxyiodobenzene) as a desulfurizing agent under a micellar condition in water was developed. The optimization study revealed that the use of 1wt%TPGS-750-M as a surfactant with NaOH as a base at room temperature can convert aromatic isothiocyanates and varieties of amines into the corresponding guanidines in good to excellent yields (69 - 95%). This green synthetic process in water can be applied to prepare guanidine at gram-scale quantity. The aqueous micellar medium was also reusable to give relatively the similar reaction yields for at least three cycles. The …
Application Of Capillary Electrophoresis For Determination Of Glycosaminoglycans In Biological And Cosmetic Samples, Kanokporn Chindaphan
Application Of Capillary Electrophoresis For Determination Of Glycosaminoglycans In Biological And Cosmetic Samples, Kanokporn Chindaphan
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, on-line preconcentration and determination of glycosaminoglycans (GAGs), especially chondroitin sulfate (CS), dermatan sulfate (DS) and hyaluronic acid (HA) using capillary electrophoresis (CE) was developed. Large-volume sample stacking using an electroosmotic flow (EOF) pump (LVSEP) technique was employed for on-line preconcentration and improvement of the detection sensitivity in CE method. Central composite design (CCD) was used to simultaneously optimize all parameters for CE separation. The optimized CE conditions were background electrolyte consisting of 200 mM sodium dihydrogen phosphate, 200 mM buthylamine and 0.5% w/v polyethylene glycol at pH 4.0 and separation voltage of -16 kV. Limit of detections …
Electrochemical Detection Of Herbicides And Antioxidants Using Nanomaterial-Modified Electrode, Kanokwan Charoenkitamorn
Electrochemical Detection Of Herbicides And Antioxidants Using Nanomaterial-Modified Electrode, Kanokwan Charoenkitamorn
Chulalongkorn University Theses and Dissertations (Chula ETD)
This dissertation focused on the development of a novel nanomaterial-based electrochemical sensors for pharmaceutical and environmental applications. The research is divided into two parts. In the first part, a low-cost and disposable sensor for the simultaneous determination of coenzyme Q10 (CoQ10) and α-lipoic acid (ALA) using manganese (IV) oxide-modified screen-printed graphene (MnO2/SPGE) electrode was developed. The incorporated MnO2 in the SPGE can greatly enhance the detection performance towards the oxidation of CoQ10 and ALA. The cyclic voltammetry (CV) and square-wave anodic stripping voltammetry (SWASV) were employed to investigate the electrochemical behavior of the developed sensor and also to perform the …
Dft And Dftb Investigations On Α–Mangostin Dye Adsorbed On Titanium Dioxide Electrode In Dsscs Application, Kanthira Kaewsud
Dft And Dftb Investigations On Α–Mangostin Dye Adsorbed On Titanium Dioxide Electrode In Dsscs Application, Kanthira Kaewsud
Chulalongkorn University Theses and Dissertations (Chula ETD)
Conformations of α–mangostin dye (1,3,6–Trihydroxy–7–methoxy–2,8–bis(3–methyl–2–buten–1–yl)–9H–xanthen–9–one) were studied and three conformers were found as three co-existing species in various media (in vacuo, acetonitrile and water). Geometries, electronic structures and UV–Vis spectra of all conformers in various media have been obtained using density functional theory (DFT) and time–dependent DFT (TD–DFT) methods. The conformers of α–mangostin dye were inspected as photosensitizers for application in dye sensitized solar cells (DSSCs) and their light–harvesting efficiencies (LHEs) within the range of 0.6757–0.7556 eV (in vacuo), 0.8286–0.8466 eV (in acetonitrile) and 0.8288–0.8465 eV (in water) were obtained. The open circuit voltage (VOC) of three conformers within the …
Speciation Of Arsenic Using Sulfur Containing Ligand And Cotton Wool By Icp-Oes, Kavee Triteeyaprasert
Speciation Of Arsenic Using Sulfur Containing Ligand And Cotton Wool By Icp-Oes, Kavee Triteeyaprasert
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aimed to develop a method for speciation of arsenic species including As(III) and As(V) in environmental samples. Cotton wool and sulfur containing ligands including ammonium pyrrolidinedithiocarbarmate (APDC), L–cysteine and diethyldithiocarbamic acid were used in a solid phase extraction and determination of arsenic by using inductively coupled plasma optical emission spectrometry. The separation parameters were studied including pH, ligand concentration, cotton amount, type of eluents and flow rate. It was found that at pH 2, 0.1% APDC concentration and 0.5 g of cotton, As(III) could form complex with APDC (As(III) – APDC) and was separated from As(V) by using …
Green Synthesis Of Gold Nanoparticles Using Wax Leaved Climber Cryptolepis Buchanani Latex And Biological Activities, Kittiphong Tongsuk
Green Synthesis Of Gold Nanoparticles Using Wax Leaved Climber Cryptolepis Buchanani Latex And Biological Activities, Kittiphong Tongsuk
Chulalongkorn University Theses and Dissertations (Chula ETD)
Gold nanoparticles (AuNPs) is the one of nanodrug carriers that have been popular in the current trend. To prepare AuNPs for biomedical applications, many techniques have been developed. However, both physical and chemical methods may cause energy consuming and toxic residues so green synthesis would be the most appropriate method for the preparation of AuNPs. The green synthesis of AuNPs could be provided by utilizing of fungi, bacteria and plant. In this work, we focused to use plant latex as reducing and stabilizing agents for the synthesis of AuNPs. The latex was collected from Cryptolepis buchanani, a folk medicinal plant …
Sequence Specific Nucleic Acid Sensing By Pyrrolidinyl Peptide Nucleic Acid And Nanomaterials, Kriangsak Faikhruea
Sequence Specific Nucleic Acid Sensing By Pyrrolidinyl Peptide Nucleic Acid And Nanomaterials, Kriangsak Faikhruea
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, fluorescence and colorimetric nucleic acid sensing platforms based on pyrrolidinyl peptide nucleic acid (acpcPNA) probe and nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), gold nanoparticles (AuNPs), and silver nanoparticles (AgNPs) were developed. The acpcPNA probe was modified by multiple lysine residues to provide positive charges which enhanced the adsorption of the probe to various types of nanomaterials. In fluorescence detection mode, this results in higher quenching efficiency, resulting in lower background signal. Recovery of the quenched fluorescence signal was achieved upon hybridization with the complementary DNA/RNA target due to the displacement of the probe from …
C-O Bond Formation On C-5 Of 2,4-Diaminopyrimidines, Natthakorn Uppatam
C-O Bond Formation On C-5 Of 2,4-Diaminopyrimidines, Natthakorn Uppatam
Chulalongkorn University Theses and Dissertations (Chula ETD)
This work aims to find a robust oxidation condition that can efficiently convert 2,4-diaminopyrimidines to its C5-hydroxylated derivative. Although Boyland-Sims oxidation of these substrates has been reported, this procedure suffers low yield and poor reproducibility. The conditions for Boyland-Sims oxidation of 2,4-diaminopyrimidines were thus re-optimized. The parameters that could affect the yields of the 5-hydroxy products were investigated using 2,4-diamino-6-ethylpyrimidine as a model compound. The reactions were performed at 0.10 mmol scale of the starting pyrimidine. The yields of the products were monitored by 1H NMR spectroscopy with reference to an internal standard. The reaction was reproduced at larger scale …
Synthesis Of Hydroxyapatite Nanoparticles For Polynucleotides Delivery In Dentistry, Natthaya Thepphanao
Synthesis Of Hydroxyapatite Nanoparticles For Polynucleotides Delivery In Dentistry, Natthaya Thepphanao
Chulalongkorn University Theses and Dissertations (Chula ETD)
Hydroxyapatite (HAp) nanoparticles-based miRNA delivery system has emerged as a promising therapeutic agent for bone regeneration application. In order to achieve high therapeutic performance, the development of HAp functions remains challenging. This study describes the influence of HAp characters on their biological activities with osteoblast cell by synthesized different sizes of rod-like HAp with 150-200 and 100 nm in size and the different shape of elongated particles with 100-150 nm in size. A comparison was carried out on cytotoxicity, cellular uptake, and miRNA binding capacities. The elongated and rod-like shapes of 100-150 nm illustrated the high cell viability, and interestingly, …
Glycosylation Of Thioglycosides With Bromodiethylsulfonium Bromopentachloroantimonate As Novel Activator, Ladawan Punrum
Glycosylation Of Thioglycosides With Bromodiethylsulfonium Bromopentachloroantimonate As Novel Activator, Ladawan Punrum
Chulalongkorn University Theses and Dissertations (Chula ETD)
Glycosylation is an important reaction in carbohydrate synthesis of complex molecules such as oligosaccharides, glycoproteins, and glycolipids. Thioglycosides are widely used as precursors in oligosaccharide synthesis due to their ease of preparation, high stability towards protecting group manipulations and variety of activation methods. Recently, bromodiethylsulfonium bromopentachloroantimonate (BDSB) was reported as a novel source of highly electrophilic bromine. It was used to efficiently initiate cation-π cyclizations of polyene at low temperature. Herein, we report a chemical glycosylation of thioglycosides activated by BDSB. Firstly, armed and disarmed glycosyl donors and glycosyl acceptors were synthesized by using modified previous method. Next, several reaction …
Metalloporphyrin-Sensitized Titania/Silica/Iron Oxide Nanocomposites And Their Photocatalytic Activities, Padtaraporn Chanhom
Metalloporphyrin-Sensitized Titania/Silica/Iron Oxide Nanocomposites And Their Photocatalytic Activities, Padtaraporn Chanhom
Chulalongkorn University Theses and Dissertations (Chula ETD)
New nanomaterials of the magnetic visible light active photocatalysts, tetra(4-carboxyphenyl)porphyrin (TCPP) with different metals [Mn(II), Fe(III), Cu(II), Zn(II) and metal-free] in the center adsorbed on titania-silica-iron oxide superparamagnetic composites (TSI) were synthesized successfully. The photocatalytic activities in methylene blue (MB) degradation were determined under incandescent lamp for 3 h. Their characteristics have been identified using UV-visible spectroscopy, X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The photodegradation results revealed that the metalloporphyrin sensitization helped TSI to absorb the light in visible region. Titania-silica-iron oxide nanomaterials with copper(II) tetra(4-carboxyphenyl)porphyrin (CuTCPP) can significantly …
Molecular Simulations Of Voltage-Gated Proton-Selective Channel, Panisak Boonamnaj
Molecular Simulations Of Voltage-Gated Proton-Selective Channel, Panisak Boonamnaj
Chulalongkorn University Theses and Dissertations (Chula ETD)
Voltage-gated proton-selective channels (Hv1) are a membrane protein that permeates proton across cell membranes. They play an important role in various physiological processes. Hv1 was found as a dimer in membranes. Molecular mechanisms underlying the proton conduction of Hv1 have been a subject of intense research but is still remained unclear. In this study, molecular dynamics (MD) simulations of Hv1 were carried out to gain better understanding of the structure-function relationship. The first part of this thesis involved with an investigation of the role of the C-terminal domain (CTD) in stabilizing the dimer structure of Hv1. MD data showed the …
Fluorescent Sensors From Salicylaldimine Derivatives For Metal Ions, Phoom Sangsuwan
Fluorescent Sensors From Salicylaldimine Derivatives For Metal Ions, Phoom Sangsuwan
Chulalongkorn University Theses and Dissertations (Chula ETD)
An in-situ forming and sensing was developed as a high-throughput screening of fluorescent chemosensors for metal ions. The 45 salicylaldimines, formed in-situ from the condensation between 5 salicylaldehydes and 9 amines, in 96 well-plates were photographed under black light along with the 5 salicylaldehydes in the absence and presence of 18 metal ions. The library of fluorescence response images of these 50 chemosensors were processed into RGB values. The PCA of theΔRGB, the differences between those of images with and without the metal ions, showed 9 sensors with normalized loading value over 70%. The sensor array constructed from these 9 …
Hybrid Materials From Covalent Organic Frameworks And Ionic Liquids, Ranida Maliyaem
Hybrid Materials From Covalent Organic Frameworks And Ionic Liquids, Ranida Maliyaem
Chulalongkorn University Theses and Dissertations (Chula ETD)
Covalent organic frameworks (COFs) are new type material, whereby their wide range of properties derived from the chemistry of frameworks and their regular porosity. Here in, we reported the successful syntheses of the novel hybrid materials between porous COF material and ionic liquids (ILs). The crystalline porous powder of boroxine‑based COF, so called COF‑5, is reproducible via a condensation reaction between hexahydroxyltriphenylene and phenyldiboronic acid under a mild condition using a conventional heating method. The as‑synthesized COF-5 was characterized with PXRD, FT-IR, TGA and BET techniques, showing that the material contained 1D regular channels caused by π-π stacking of the …
Detection Of Sulfonamide Residues By Paper Spray Mass Spectrometry, Surased Suraritdechachai
Detection Of Sulfonamide Residues By Paper Spray Mass Spectrometry, Surased Suraritdechachai
Chulalongkorn University Theses and Dissertations (Chula ETD)
Sulfonamide antibiotics are commonly used veterinary drugs in livestock to prevent or treat infectious diseases. Their residues in food are of concern since they can cause adverse health effects and development of bacterial resistance. In this work, a practical method for detection and quantification of sulfamethazine, one of sulfonamide antibiotics, in pig body fluid samples is developed via the combination of simple extraction and paper spray mass spectrometry. The method required minimal sample preparation and low analysis time while providing high sensitivity and accuracies in pig whole blood (LOD = 10.1 ng/mL, %recovery = 95.4-104.1%), pig serum (LOD = 4.6 …
Fabrication And Mechanical Properties Of Hyaluronic Acid Microneedle Arrays For Transdermal Drug Delivery, Teeranut Rutwaree
Fabrication And Mechanical Properties Of Hyaluronic Acid Microneedle Arrays For Transdermal Drug Delivery, Teeranut Rutwaree
Chulalongkorn University Theses and Dissertations (Chula ETD)
Dissolvable microneedles have been widely investigated as an alternative of hypodermic injection or other drug delivery methods. Various polymers have been used to fabricate microneedles. Type of polymers affects mechanical properties and dissolution rate of microneedles. In this study, five formulations of hyaluronic acid (HA)/ polyvinylpyrrolidone (PVP) composite microneedle patches (HA/PVP at 100/0, 75/25, 50/50, 25/50, 0/100) were fabricated. The crosslinked HA microneedles were also fabricated. Mechanical properties of the obtained microneedles were determined by universal testing machine and durometer. The skin-penetration ability and dissolution rate of HA/PVP microneedles were also investigated using porcine skin. The results show that microneedle …
Synthesis Of Halogenated Flavonoids As Anti-Dengue Agents, Thao Huynh Nguyen Thanh
Synthesis Of Halogenated Flavonoids As Anti-Dengue Agents, Thao Huynh Nguyen Thanh
Chulalongkorn University Theses and Dissertations (Chula ETD)
Flavonoids have been recognized as promising compounds with various bioactivities. Certain flavonoid derivatives exhibited more potent activities than their parent compounds. Recently, halogenated flavonoids have been addressed for their anti-dengue activity. In this research, a series of twenty-two brominated and iodinated flavonoid derivatives were synthesized and explored for dengue infection inhibition. Seventeen derivatives have been investigated for the first time. 8-Bromobaicalein, 6,8-dibromopinocembrin, 6,8-dibromopinostrobin, 6,8-diiodopinostrobin were disclosed as effective and non-toxic anti-dengue agents. These compounds displayed remarkably low EC50 as well as high CC50, which could be considered as potent therapeutic agents. Moreover, the preliminary screening on brominated O7-ether chrysins discovered …
Benzimidazole Derivatives Of Perylene Diimide For Organic Field-Effect Transistor, Tianchai Chooppawa
Benzimidazole Derivatives Of Perylene Diimide For Organic Field-Effect Transistor, Tianchai Chooppawa
Chulalongkorn University Theses and Dissertations (Chula ETD)
The poor solubility of perylene derivatives has been a key factor that prohibits the application of these thermally stable compounds in organic field-effect transistors (OFET) devices. In this research, the effort to enhance the solubility and exploring FET property of benzimidazole derivatives of perylene diimide were investigated. The perylene diimide core structure was functionalized by aryloxy moieties. Unfortunately, the isomeric products were still poorly soluble in common organic solvents, which made them impossible to separate and purify. Thus, the synthetic plan and goal were completely revised to the benzotriazatruxene derivatives, which were highly soluble in organic solvents such as dichloromethane …
Green Synthesis Of Gold Nanoparticles Using Natal Lily Crinum Moorei Extract And Biological Activities, Warinda Marujiwat
Green Synthesis Of Gold Nanoparticles Using Natal Lily Crinum Moorei Extract And Biological Activities, Warinda Marujiwat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Crinum moorei as medical herb has different pharmacological activities such as anti-cancer and anti-inflammatory properties. Gold nanoparticle (AuNP) is an interesting anti-cancer drug carrier which can solve anti-cancer drug's problems with good biocompatibility, non-toxicity and suitable size for the intracellular uptake to treat to the target cells. From the beginning, other reducing agents were used to synthesize AuNPs. However, they lead to the contamination of chemicals on AuNP's surfaces which limits the medical application or long process and time consuming. Therefore, plant extracts were studied to make a remarkable dual function: the synthesized AuNPs agent and drug agent. In this …
Development Of Headspace-Solid Phase Microextraction And Gas Chromatography-Mass Spectrometry/Olfactometry For Analysis Of Volatile Compounds From Chicken Products, Wongkanok Yoosong
Development Of Headspace-Solid Phase Microextraction And Gas Chromatography-Mass Spectrometry/Olfactometry For Analysis Of Volatile Compounds From Chicken Products, Wongkanok Yoosong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Gas chromatography-mass spectrometry/olfactometry coupled headspace solid phase microextraction (HS-SPME-GC-MS/O) was applied to analysis of volatile compounds from raw chickens and boiled chickens. The HS-SPME was 50/30 mm DVB/CAR/PDMS. The extraction temperature of boiled chicken was 50 °C for 30 min and raw chicken were extracted at room temperature. The SPME Probes were analyzed by GC-MS with a HP-5MS capillary column. 16 volatile compounds were identified in the boiled chickens in four chemical classes including aldehydes, aromatic hydrocarbon, alcohols and ketones and 20 volatile compounds were identified in raw chickens in three chemical classes including aldehydes, alcohols and esters. The identification …
Synthesis And Antidiabetic Activity Of Furofuran Lignans Containing Multiphenolic Groups, Titiruetai Doungwichitrkul
Synthesis And Antidiabetic Activity Of Furofuran Lignans Containing Multiphenolic Groups, Titiruetai Doungwichitrkul
Chulalongkorn University Theses and Dissertations (Chula ETD)
Synthesis of furofuran lignans containing multiphenolic groups (6-12) was carried out. The starting material samin (5) was obtained by acid hydrolysis of sesamin (2), which was isolated from sesame seed oil. A series of target lignans were synthesized from samin (5) and a varity of phenolics through Friedel-Crafts reaction, yielding desired products (6). To increase number of hydroxy moieties on the synthesized lignans, oxidative reaction using lead (IV) tetraacetate was performed. Removal of methylenedioxy of furofuran lignans containing a phenolic moiety produced unexpected products which contains para-quinone together with ortho-dihydroxy moieties on furofuran core structures (8-9). Consequently, to avoid oxidation …
Polyisocyanurate Foams Preparation Catalyzed By Mixtures Of Copper-Amine Complexes/Potassium 2-Ethylhexanoate, Teeraporn Suwannawet
Polyisocyanurate Foams Preparation Catalyzed By Mixtures Of Copper-Amine Complexes/Potassium 2-Ethylhexanoate, Teeraporn Suwannawet
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, a new catalyst system for the preparation of polyisocyanurate (PIR) foam was developed. The mixture of copper-amine complex:potassium 2-ethylhexanoate (K-15) and metal-ethanolamine complex:K-15 were used as catalysts. Two copper-amine complexes and two metal-ethanolamine complexes, namely Cu(OAc)2(en)2, Cu(OAc)2(trien), Cu(OAc)2(EA)2 and Zn(OAc)2(EA)2, respectively; where en = ethylene diamine, trien = triethylenetetramine and EA = ethanolamine, were used as catalyst for blowing and gelling reactions. K-15 was used as a catalyst for trimerization reaction. These catalysts could be further used in the preparation of PIR forms without purification. Characterization of catalysts were done by using UV-visible spectroscopy. The factors investigated …
Improved Barrier Properties Of Pp/Ldpe Composite Film: Effect Of Montmorillonite And Poly (Lactic Acid), Supornpat Mooninta
Improved Barrier Properties Of Pp/Ldpe Composite Film: Effect Of Montmorillonite And Poly (Lactic Acid), Supornpat Mooninta
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, the properties of polypropylene (PP) were improved for single layer film application by incorporating low density polyethylene (LDPE), poly(lactic acid) (PLA) and montmorillonite (MMT). The polymer composites was prepared by melt blending using a twin screw extruder and the film was produced by cast film extruder. The addition of LDPE in PP improved the elongation at break and tear strength. The PP/LDPE blend at the ratio of 80:20 (w/w) was selected for blending with PLA and MMT and the PP/LDPE/PLA/MMT composite showed the increased tensile modulus while the elongation at break decreased with increasing PLA and MMT …
Surface-Enhanced Raman Scattering Technique For Polycyclic Aromatic Hydrocarbons Detection Using Thiol-Functionalized Silver Nanoparticle Films, Sathita Taksadej
Surface-Enhanced Raman Scattering Technique For Polycyclic Aromatic Hydrocarbons Detection Using Thiol-Functionalized Silver Nanoparticle Films, Sathita Taksadej
Chulalongkorn University Theses and Dissertations (Chula ETD)
The detection of polycyclic aromatic hydrocarbons (PAHs) is developed based on surface-enhanced Raman scattering (SERS) using silver nanoparticle films as SERS substrates. The films are fabricated by a Langmuir Blodgett (LB) method and the surface of AgNP films are functionalized with various types of aromatic and aliphatic thiols, i.e., naphthalenethiol, phenylethanethiol, pentanethiol, octanethiol, and dodecanethiol, to create a hydrophobic layer for PAHs to attach on and stay in hot spot. The results indicate that nine kinds of PAHs with different structures, i.e., anthracene, chrysene, naphthacene, naphthalene, phenanthrene, pentacene, perylene, pyrene, and triphenylene, can attach on the surfaces of thiol-modified AgNP …
Preparation And Characterization Of Starch Films Reinforced With Citrate Cellulose Nanocrystals, Prapaporn Nakarat
Preparation And Characterization Of Starch Films Reinforced With Citrate Cellulose Nanocrystals, Prapaporn Nakarat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Citrate-modified bacterial cellulose nanocrystals (citrate CNCs) were prepared by a green one-pot dual acid (citric and hydrochloric acids) method and used them to reinforce three types of starch films; corn, wheat and rice starch films. The average length and width of citrate CNCs were 583 and 46 nm, respectively. The degree of citrate substitution on CNCs was 0.075 and its crystallinity index was closely to the original bacterial cellulose. The effect of various amount of citrate CNCs (0-20%wt of starch) on film property was study. Three starch films showed the same trend of examination results. The film thickness of most …