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    Colorimetric Screen-Printed Label Using Low Molecular Weight Chitosan Grafted with Rosolic Acid for pH and Ammonia Gas Sensing
    (2024-10-15)
    Ronte, Arnat
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    Chalitangkoon, Jongjit
    ;
    Colorimetric sensing technologies are valued for their simplicity and adaptability, yet their large-scale production remains economically challenging. This study presents a cost-effective colorimetric pH sensor developed from low molecular weight chitosan (LC) grafted with rosolic acid (LCRA), engineered as a pH-sensitive colorant for screen-printing inks. LCRA was synthesized via a Mannich reaction and characterized using<sup>1</sup> H NMR, FT-IR, and UV-Vis spectroscopy. LCRA showed reduced crystallinity and thermal stability alongside notable improvements in water solubility compared to its LC precursor. The LCRA ink displayed compatibility with various substrates, including polypropylene spun bond, filter paper, and cotton, applying easily via screen printing without any dye leaching. Notably, it exhibited a responsive color change from orange-yellow to pink-red in response to pH adjustments between 4.0 and 12.0 and upon exposure to ammonia gas. These findings position the LCRA label as a versatile and efficient solution for visual pH detection across various applications.
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    Preparation of hydroxyapatite/poly(methyl methacrylate) and calcium silicate/poly(methyl methacrylate) interpenetrating hybrid composites
    (2007-10-01) ; ;
    Jermsungnern, Rapee
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    Rattanabodee, Sirirat
    Hydroxyapatite/poly(methyl methacrylate) (HAp/PMMA) and calcium silicate/poly(methyl methacrylate) (CS/PMMA) composites were prepared by interpenetrating bulk polymerization of methyl methacrylate (MMA) monomer in porous structures of HAp and CS. The porous HAp and CS templates were prepared by mixing their calcined powders with poly(vinyl alcohol) (PVA) solution, shaping by uniaxial pressing and then firing at 1,100°C for HAp and 900°C for CS. The templates were soaked in the solution mixture of MMA monomer and 0.1 mol% of benzoyl peroxide (BPO) for 24 h. The pre-composites were then bulk polymerized at 85°C for 24 h under nitrogen atmosphere. The microstructures of the composites showed the interpenetrating of PMMA into the porous HAp and CS structures. Thermogravimetric analysis indicated that the PMMA content in the HAp/PMMA and CS/PMMA composites were 13 and 26 wt%, respectively. Weight average molecular weights (M̄<inf>w</inf>) of PMMA were about 491,000 for HAp/PMMA composites and about 348,000 for CS/PMMA composites. Compressive strengths of these composites were about 90-131 MPa in which they were significantly higher than their starting porous templates. © 2007 Springer Science+Business Media, LLC.
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    Hydrothermal growth of ZnO nanostructures from nano-ZnO seeded in P(MMA-co-BA) matrix
    (2011-11-01)
    Pannasri, Piyaphan
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    ; ;
    Nookaew, Jiti
    Nano-ZnO synthesized by hydrothermal reaction were embedded in poly(methyl methacrylate-co-butyl acrylate) matrix (P(MMA-co-BA)) to produce the nano-ZnO/P(MMA-co-BA) nanocomposites via in-situ polymerization at 85 °C. The nano-ZnO/P(MMA-co-BA) nanocomposites were hydrothermal treated in the mixture solution of Zn(NO <inf>3</inf>) <inf>2</inf>•6H <inf>2</inf>O and NH <inf>4</inf>OH at 90 °C under various pH (i.e.7, 8, 9 and 10) and treatment time (i.e. 4, 6, 8, 10, 12 and 24 hrs). The nano-ZnO could act as seeding particles for hydrothermal growth of ZnO nanostructures on the surfaces of nanocomposites. The higher pH of basic solutions used in the hydrothermal treatment, the higher amount of Zn(OH) <inf>4</inf> <sup>2-</sup> nuclei would be created, leading to a modification of the ZnO morphology from nano-nuclei to nanorods, nanorods bushes (flower-like nanostructure) and nanofibers with nanospine. The increase of hydrothermal treatment time resulted in the increases of amount and length of multidirectional grown ZnO nanorods. Data of the contact angle measurement exhibited the increase of hydrophobicity of the nano-ZnO/P(MMA-co-BA) nanocomposites after hydrothermal growth of ZnO nanostructures. The nanocomposites treated at pH∈=∈10 for 24 hrs shows the highest hydrophobicity with the contact angle of 121. In addition, the thermal stability of the nano-ZnO/P(MMA-co-BA) could be improved by the formation of hydrothermal grown ZnO nanostructure on the nanocomposite surface. © 2011 Springer Science+Business Media B.V.
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    Preparation and characterization of hydroxyapatite/poly(ethylene adipate) hybrid composites
    Hydroxyapatite/poly(ethylene adipate) (HAp/PEA) composites were prepared by in situ ring-opening polymerization of cyclic oligo(ethylene adipate) (C-OEA) within the porous HAp templates. HAp was firstly prepared by a co-precipitation method using calcium hydroxide and phosphoric acid and then shaped as a rectangular porous template. PEA precursor was synthesized by bulk polymerization of dimethyl adipate and ethylene glycol in the presence of tetraisopropyl orthotitanate. C-OEA was obtained by cyclo-depolymerization of the PEA precursor under high dilution condition using dibutyl tinoxide as a catalyst. The HAp/PEA composites were prepared by immersing the porous HAp templates in the mixture solution of C-OEA and dibutyl tinoxide catalyst overnight and ring-opening polymerizing at 180, 200 and 220°C for 24 h. The ring-opening polymerized PEA formed as a thin film coating on the surface of porous HAp template. The HAp/PEA composites contained PEA in the range of 20-26 wt%. The weight-average molecular weights of ring-opening polymerized PEA were in the range of 3800-4450 g/mol. Compressive strength of the HAp/PEA composite was significantly increased from 25 MPa in the porous HAp template to 140 MPa in the composite. © 2008 VSP.
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    Photocrosslinked Poly(Vinyl Alcohol)–Tung Oil–Natural Rubber Films: A Sustainable Solution for Enhanced Water Resistance and Mechanical Properties in Biodegradable Packaging
    (2025-06-20) ;
    Jianprasert, Apichaya
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    Sintoppun, Tanaporn
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    Yamaguchi, Masayuki
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    This study introduces a novel approach to addressing the water resistance limitations of poly(vinyl alcohol) (PVA)-based biodegradable films by developing a ternary blend system incorporating tung oil (T) and natural rubber (R), forming PTR films. Photocrosslinking, combined with thermal and redox catalytic systems, facilitated the creation of enhanced network structures, as confirmed by FTIR analysis, particularly at tung oils conjugated double bonds. Dynamic mechanical analysis (DMA) revealed significant shifts in glass transition temperatures (T<inf>g</inf>), signifying enhanced crosslink density and interconnectivity between the components. The resulting PTR films demonstrated remarkable improvements in water resistance, evidenced by higher solid remain percentages, reduced water absorption, and significantly lower water vapor permeability (WVP). Mechanical properties, including tensile strength and Youngs modulus, improved by up to 150% (from 6.6 MPa of PT0R15-r-np to 16.3 MPa of PT0R15-r-p30) and 870% (from 6.6 MPa of PT0R15-r-np to 16.3 MPa of PT0R15-r-p30), respectively, due to the formation of robust network structures. Contact angle measurements and reduced moisture content further underscored the enhanced hydrophobic and moisture barrier properties. These findings establish photocrosslinked PTR films as a sustainable and high-performance option for biodegradable packaging applications, offering practical advantages such as reduced processing temperatures and production times.
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    Bacterial cellulose and bacterial cellulose/chitosan films containing mangosteen pericarp extract for wound dressings
    (2021-01-01)
    Moonsungnoen, Pronpatsorn
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    ;
    Appropriate wound dressings for maintaining a moist wound environment, inducing re-epithelialization and protection from infection have been widely developed. Recently, many biocompatible polymers and bioactive substances have been extensively used for wound healing applications. In this study, bacterial cellulose film (BC-MPE film) and bacterial cellulose/chitosan film (BC/CH-MPE film) containing 1.56 mg/mL of mangosteen pericarp extract (MPE) were prepared. Antibacterial activity, cytotoxicity, physical and mechanical properties of the dry films were investigated. The BC film with MPE presented non-cytotoxic effect after 20 h of exposure to mouse fibroblast cell line (L929). The prepared films performed carrier of bioactive compounds that exhibited antibacterial activity against bacterial infection in burn wounds. The morphology of the films showed the characteristic of ultra-fine network structures with the entrapment of compounds. In addition, the compact structure was observed due to the rapid moisture loss during vacuum drying process. SEM images also showed that BC/CH-MPE film formed layers with chitosan entrapment causing the film to become thicker than BC-MPE film. The formation of MPE and chitosan in modified films was also confirmed by FTIR. The compact structure of BC/CH-MPE film led to the decrease in cumulative release of xanthone, WVTR and WAC. Moreover, the existence of chitosan in BC layers provided more flexible properties than the non-chitosan film. The chitosan addition demonstrated an influence of barrier film to protect the wound. Therefore, BC and chitosan were considered as suitable candidates for wound dressing material and xanthone content of MPE promoted wound healing as an effective therapeutic agent.
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    In vitro drug release profiles of pH-sensitive hydroxyethylacryl chitosan/sodium alginate hydrogels using paracetamol as a soluble model drug
    (2017-06-01)
    Treenate, Pitchaya
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    The aim of this study is to investigate in vitro drug release profiles of pH-sensitive hydrogels composed of hydroxyethylacryl chitosan (HC) and sodium alginate (SA). The hydrogels were crosslinked by dipping method using different ionic crosslinkers (e.g., Ca<sup>2+</sup>, Zn<sup>2+</sup> and Cu<sup>2+</sup>). The crosslinking reaction was confirmed by FT-IR. Swelling behavior and stability of the hydrogels in simulated digestive media were investigated. The result indicated that the combination between HC and SA could delay the degradation time of the hydrogels. Calcium crosslinking system showed higher stability than that of zinc or copper crosslinking system. In vitro drug release profiles were studied using paracetamol as a soluble model drug. The amount of paracetamol release in simulated gastric fluid (SGF) was relatively low (<20%). In simulated intestinal fluid (SIF), the burst release of paracetamol was depressed with increasing HC content and/or applying crosslinker. The HC75SA25 formulation demonstrated the linearity of drug release profile. Additionally, the amount of drug release from the 0.5 M calcium HC50SA50 hydrogel in SIF was lower than 20%. The comprehensive results of this study suggested their potential in the application of site-specific oral drug delivery in intestine and colon.
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    Antimicrobial nanolayer films of chloroxylenol–carboxyethylchitosan–modified silver nanoparticles for enhanced surgical suture performance
    (2024-07-20)
    Chittratan, Pakawat
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    Chalitangkoon, Jongjit
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    ;
    Antimicrobial surgical suture materials incorporating chloroxylenol-carboxyethylchitosan-modified silver nanoparticles (CECSX-AgNPs) were successfully prepared using the Layer-by-Layer (LbL) deposition technique. Chitosan (CS) was covalently affixed with chloroxylenol as hydrophobic functional groups (PCMX), yielding chloroxylenol-chitosan (CSX) and later hydrophilic acrylic acid onto the CSX skeleton, providing a novel water-soluble antimicrobial agent of chloroxylenol-carboxyethylchitosan (CECSX). <sup>1</sup>H NMR confirmed the successful substitution of PCMX and acrylic acid onto CS, with %DS<inf>PCMX</inf> and %DS<inf>AA</inf> of 8.0 and 33.0, respectively. CECSX successfully stabilized AgNPs via the chemical reduction method, resulting in CECSX modified AgNPs. The colloidal solution exhibited a yellowish hue, spherical shape, monodispersity with an average particle size of 4.8 ± 2.4 nm, and a zeta potential value of −20.97 ± 0.03 mV. Minimum inhibitory concentration (MIC) values for CECSX-AgNPs against E. coli (ATCC25922), S. aureus (ATCC25923), and A. baumanii (ATCC19606) were determined as 25, 12.5, and 1.56 mg/L, respectively. Using the LbL deposition technique, CECSX-AgNPs were successfully deposited onto various suture materials including cotton, polyamide, and polypropylene. Remarkably, CECSX-AgNPs coated surgical sutures exhibited the highest bacterial reduction of 99.99 %. These findings underscore the efficacy of CECSX as a high-performance stabilizing agent for AgNPs production, providing outstanding antibacterial activity on diverse surgical suture materials and promoting the wound healing process.
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    Study on Crosslinked Structure and Thermal Properties of Polymer Networks Based on Tung Oil and PVA with Different Catalytic Systems
    (2017-04-01)
    Jianprasert, Apichaya
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    ;
    Yamaguchi, Masayuki
    This work focuses on the effect of different catalytic systems on network structures and thermal properties of the polymer networks from poly(vinyl alcohol) (PVA) and Tung oil. The polymer networks based on Tung oil and PVA using potassium persulfate (KPS) as a thermal catalyst or KPS and sodium thiosulfate as a redox catalyst were performed at 60 °C and 80 °C. FTIR results confirmed that Tung oil could be crosslinked by both catalysts. Moreover, at 60 °C, it can be seen that the crosslinking reaction with the redox catalyst could occur better than with the thermal catalyst. To prove the crosslinking reaction of PVA in the polymer networks, water resistance of the polymer networks was also investigated. It was found that the PVA was successfully crosslinked by thermal catalyst but was not by redox catalyst. Besides, from this result, it could be suggested that, in the redox system, structure of the polymer networks was mainly formed by Tung oil. From DMA results, T<inf>g</inf> of PVA with the thermal catalyst is higher than that with the redox catalyst because of the network formation of PVA in thermal catalytic system. While the T<inf>g</inf> of Tung oil in the polymer networks with the redox catalyst is higher than that with the thermal catalyst. This is reasonable because the crosslinking reaction of Tung oil with the redox catalyst could easily occur better than with the thermal catalyst. Altogether, crosslink structure of Tung oil exhibited major influence on properties of PVA/Tung oil polymer network.
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    Development of Bilayer Chitosan–Carrageenan Hydrogel Film for Enhanced Controlled Release of Turmeric–β-Cyclodextrin Complex in Wound Dressings
    (2025-11-01) ;
    Sintoppun, Tanaporn
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    Chantaranara, Prapassorn
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    Punpairoj, Prapaporn
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    Deatvakkanee, Pitchapa
    This study presents the development and evaluation of a bilayer hydrogel film designed for controlled drug delivery in wound dressing applications. The outer layer, composed of chitosan and glycerol, exhibited excellent water resistance, flexibility, and favorable moisture-handling properties, including high water vapor permeability and moisture absorption, which are critical factors for maintaining an optimal wound environment. The inner drug-loaded layer, formulated with carrageenan and loaded with either free turmeric or turmeric–β-cyclodextrin inclusion complex (TCD), served as the drug reservoir. Films incorporating TCD exhibited significantly enhanced turmeric solubility and drug release efficiency compared to those containing uncomplexed turmeric. Among the tested formulations, CS-TCD1, which featured a thinner drug-loaded layer, achieved the highest performance, with approximately 68% cumulative release over four days. While the release kinetics showed a strong correlation with the Higuchi kinetic model (R<sup>2</sup> = 0.9927), further analysis using the Akaike Information Criterion (AIC) and the Korsmeyer–Peppas model indicated an anomalous (non-Fickian) transport mechanism, governed by both diffusion and matrix swelling or erosion. These results highlight the importance of matrix architecture and drug solubilization strategies in the design of hydrogel-based drug delivery systems for wound care.