Monvisade, Pathavuth

Preferred name

Alternative Name

Monvisade, P.

Main Affiliation

School of Science

pathavuth.mo@kmitl.ac.th

Now showing 1 - 8 of 8

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Preparation of hydroxyapatite/poly(methyl methacrylate) and calcium silicate/poly(methyl methacrylate) interpenetrating hybrid composites
(2007-10-01)
Monvisade, Pathavuth
;
Siriphannon, Punnama
;
Jermsungnern, Rapee
;
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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Preparation and characterization of hydroxyapatite/poly(ethylene adipate) hybrid composites
(2008-06-01)
Siriphannon, Punnama
;
Monvisade, Pathavuth
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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Poly(ethylene terephthalate)/hydroxyapatite biomaterials: Preparation, characterization, and in vitro bioactivity
(2009-02-01)
Siriphannon, Punnama
;
Monvisade, Pathavuth
Poly(ethylene terephthalate)/hydroxyapatite (PET/HAp) composites were prepared by mixing HAp powder with a mixture solution of cyclic oligo(ethylene terephthalate) (C-OET) and dibutyl tinoxide catalyst in dichrolomethane, and then shaping the precomposites in cylindrical pellets. The C-OET in the precomposites was ring-opening polymerized (ROP) to PET under vacuum at 250°C for 24 h. The PET/HAp composites were formulated with HAp to PET ratios of 60:40 (H6P4) and 50:50 (H5P5). The ROP-PET in the composites was present as a thin-layer coating on the HAp grains and evenly distributed throughout the samples. Compressive strength of the PET/HAp composites was significantly increased from 8 MPa of the H10P0 to 17 and 29 MPa for H6P4 and H5P5, respectively. In vitro bioactivity of the PET/HAp composites was studied by soaking in simulated body fluid (SBF) at 36.5°C for 7-28 days. After prolonged soaking, the HAp nanocrystals precipitated from the SBF solution and formed as a layer of globular aggregates, coated on the composite surfaces. The H6P4 composite showed faster formation rate of nano-HAp than the H5P5 composite, indicating that the bioactivity of PET/HAp composites depended on the amount of HAp. © 2008 Wiley Periodicals, Inc.
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Synthesis of poly(ethylene adipate) and poly(ethylene adipate-co-terephthalate) via ring-opening polymerization
(2007-08-01)
Monvisade, Pathavuth
;
Loungvanidprapa, Pittaya
Syntheses of poly(ethylene adipate) (ROP-PEA) and poly(ethylene adipate-co-terephthalate) (ROP-PEA-co-PET) were achieved via ring-opening polymerization of corresponding cyclic oligoesters. In case of ROP-PEA, cyclic oligo(ethylene adipate) (C-OEA) was equilibrated in the presence of di-n-butyltin oxide as a catalyst under high-concentration conditions at 180 and 200 °C for 1-24 h. The polymer products were obtained in yields up to 100% with the over(M, -)<inf>n</inf> and over(M, -)<inf>w</inf> in the ranges of 3000-23 000 g/mol and 5000-60 000 g/mol, respectively. The ROP-PEA-co-PET was prepared by equilibrating an equimolar amount of C-OEA and cyclic oligo(ethylene terephthalate) (C-OET) using di-n-butyltin oxide catalyst under high-concentration conditions at 250 °C for 24 h. The copolyester produced was obtained in yield of 97% with the over(M, -)<inf>n</inf> and over(M, -)<inf>w</inf> of 18 000 and 46 000 g/mol, respectively. 1H NMR spectrum of ROP-PEA-co-PET showed two new proton signals of ethylene unit representing the existence of heterolinkage with different chemical environment in the copolymer. This indicated the random transesterification of C-OEA and C-OET resulting in random structure in copolyester. In addition, the result of ROP-PEA-co-PET from DSC showed the glass transition temperature in the values of -8 °C with no melting temperature indicating thermoplastic elastomeric behavior. © 2007 Elsevier Ltd. All rights reserved.
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Preparation and characterization of hydroxyapatite/poly(ethylene glutarate) biomaterials
(2007-05-01)
Siriphannon, Punnama
;
Monvisade, Pathavuth
;
Jinawath, Supatra
;
Hemachandra, Khemchai
Hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) biomaterial composites were prepared by ring-opening polymerization (ROP) of cyclic oligo(ethylene glutarate) (C-PEG) in porous HAp scaffolds. The HAp/C-PEG pre-composites were prepared by immersing the porous HAp scaffolds in the mixture solution of C-PEG and dibutyl tin-oxide catalyst overnight and polymerizing at 200°C for 24, 48, and 72 h under vacuum. The successful ROP of C-PEG in the porous HAp scaffolds was corroborated by the signals of hydroxyl end-group of PEG shown in the 1H NMR spectrum of the ROP-products extracted from the composites. PEG in the composites was present as a thin layer coating on the HAp grains and was evenly distributed throughout the samples. The PEG content was about 13-16 wt % and decreased with increasing polymerization time. Its molecular weight (M̄<inf>w</inf>, weight average) measured by gel permeation chromatography was in the range of 4300-6800 g/mol. Compressive strength of the HAp/PEG composites was significantly increased from 3 MPa of the porous HAp scaffold to 11-15 MPa, depending on the PEG content in the composites. In vitro bioactivity of the HAp/ PEG composites was studied by soaking in simulated body fluid (SBF) at 36.5°C for 7-28 days. After prolonged soaking, the HAp nanocrystals precipitated from the SBF solution and formed as a layer of globular aggregates, coated on the composite surfaces. This result suggested that the HAp/PEG composite was a bioactive material. © 2006 Wiley Periodicals, Inc.
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Chitosan intercalated montmorillonite: Preparation, characterization and cationic dye adsorption
(2009-01-01)
Monvisade, Pathavuth
;
Siriphannon, Punnama
Chitosan intercalated montmorillonite (Chi-MMT) was prepared by dispersing sodium montmorillonite (Na+-MMT) into chitosan solution at 60 °C for 24 h. The Chi-MMT was characterized by XRD, XRF and FT-IR. The intercalation was accomplished via the ion-exchange of Na+ ions with -NH<inf>3</inf>+ of chitosan, resulting in the expansion of d<inf>001</inf> from 1.42 nm of Na+-MMT to 2.21 nm of Chi-MMT. The chitosan content in the Chi-MMT measured by TGA was about 17 mass%. The adsorption capacity of Chi-MMT was investigated in comparison with the starting Na+-MMT and chitosan using three different cationic dyes, i.e. basic blue 9 (BB9), basic blue 66 (BB66) and basic yellow 1 (BY1). The Chi-MMT showed the highest adsorption capacity in the range of 46-49 mg/g when the initial dye concentration was 500 mg/L, being equivalent to 92-99 wt.% of dye removal. The adsorption capacities of Chi-MMT for all basic dyes increased with an increase of initial dye concentration. An increase of adsorption capability of Chi-MMT was attributed to the existence of intercalate-chitosan. It could enlarge the pore structure of Chi-MMT, facilitating the penetration of macromolecular dyes, and also electrostatically interact with the applied dyes. These results indicated the competency of Chi-MMT adsorbent for basic dye adsorption. © 2008 Elsevier B.V. All rights reserved.
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Effect of ring-opening polymerization condition on the characteristic and mechanical properties of hydroxyapatite/poly(ethylene glutarate) biomaterials.
(2009-01-01)
Monvisade, Pathavuth
;
Siriphannon, Punnama
;
Tapcharoen, Walailak
Preparation of hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) composites was carried out by ring-opening polymerization (ROP) of cyclic oligo(ethylene glutarate) in porous HAp scaffolds using various reaction temperatures and times. The content of ROP-PEG interpenetrated into the porous HAp scaffold was about 13-18 wt % with the values of number average molecular weight (overline_M{n}) and weight average molecular weight (overline_M{W}) of 2120-3630 and 2760-5250 g/mol, respectively. The increase in polymerization time and temperature brought about increase in molecular weight of ROP-PEG, but decrease in its content. Compressive strength and compressive modulus of the HAp/PEG composites were about 5.8-20.1 and 105-208 MPa, respectively. These mechanical properties depend upon the effects of distribution, content, and molecular weight of ROP-PEG in the composites. In vitro bioactivity of the HAp/PEG composites was studied by soaking them in simulated body fluid (SBF) for 28 days. The formation of HAp nanocrystal on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution was observed after soaking, indicating the bioactivity of these HAp/PEG composites.
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Synthesis of poly(ethylene terephthalate-co-isophthalate) via ring-opening polymerization of their cyclic oligomers
(2008-10-01)
Monvisade, Pathavuth
;
Loungvanidprapa, Pittaya
Syntheses of poly(ethylene terephthalate-co-isophthalate) (PET-co-PEI) were achieved via ring-opening copolymerization of corresponding cyclic oligoesters. The ring-opening polymerization (ROP)-PET-co-PEI were prepared by equilibrating an equimolar amount of cyclic oligo(ethylene terephthalate) and cyclic oligo(ethylene isophthalate) using di-n-butyltin oxide catalyst under high concentration conditions at 270 and 290°C for 8 and 12 h. The copolyesters were obtained in yields of up to 91% with the inherent viscosity (η <inf>inh</inf>) of up to 2.89 dl/g indicating the drastically high molecular weight compared with the conventional and ROP routes for the synthesis of PEI. The differential scanning calorimetry data of ROP-PET-co-PEI showed the melting temperatures above 400°C indicated the potential used in high temperature application. © 2008 Springer Science+Business Media B.V.

Monvisade, Pathavuth

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