Siriphannon, Punnama
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Preferred name
Siriphannon, Punnama
Alternative Name
Siriphannon, P.
Main Affiliation
Email
punnama.si@kmitl.ac.th
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Item type:Publication, Mechanical properties and bioactivity of calcium silicate/poly(ethylene terephthalateco-caprolactone) composites(2013-12-01); Calcium silicate/poly(ethylene terephthalate-co-caprolactone) (CS/PET-co-PCL) composites were prepared via ring opening polymerisation (ROP) technique. The CS/PET-co-PCL composites were prepared by mixing 60 wt-% of CS, 40 wt-% of cyclics and dibutyl tinoxide catalyst (3 mol.-% with respect to cyclics). The cyclics consisted of the mixture of cyclic oligo(ethylene terephthalate) (COET) and e-caprolactone (CPL) with varying molar ratio of C-OET/CPL, i.e. 7 : 3, 8 : 2 and 9 : 1. The precomposites were then ring opening polymerised at 200°C for 24 h. The ROP-PET-co-PCL in the composites was present as a continuous phase impregnated with the CS particles. The 1HNMR spectra of ROP-PET-co-PCL extracted from the CS/PET-co-PCL composites showed heterolinkage signals between PET and PCL at d 4·4 and d 4·6 ppm, indicating successful copolymerisation. When the PCL content increased, the ROP-PET-co-PCL changed in the copolymer structure from block to random structure. The presence of CS powders in the CS/PETco- PCL composites resulted in high stiffness of the composites and inhibited heat dissipation during the dynamic mechanical analysis performed between 250 and 200°C. The compressive strengths of all the composites were in the range of 16-21 MPa. The higher the PET content, the stronger the CS/PET-co-PCL composites obtained. Composites containing 9 : 1 of C-OET/CPL polymerised at 200°C possessed the highest compressive strengths of 21·3 MPa, falling in the range of cartilage bone, i.e. 14-59 MPa. Bioactivities of the CS/PET-co-PCL composites were studied by soaking in simulated body fluid for 7 days. All CS/PET-co-PCL composites could induce the formation of hydroxyapatite nanocrystals on the composite surfaces, indicating the bioactivity of the CS/PET-co-PCL composites. © W. S. Maney & Son Ltd. 2013. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Chemical and dielectric study of PMMA/Montmorionite nano-composite films(2010-01-01); ; Louarn, GuyTetrabutylphosphonium intercalated montmorillonite (P-MMT) was dispersed in toluene using sonication technique and a PMMA/toluene solution. The PMMA/P-MMT nano-suspension was then casted as a composite film on a glass plate, using spin coating technique with a rotation of 180 rpm. The composite films were characterized by various analytical techniques such as X-ray diffraction, X-ray fluorescence spectrometry thermo-gravimetric analysis, etc. The montmorillonite interlayer distance, estimated XRD results, was found to be equal to 1.6 nm. The PMMA/3 wt%P-MMT nano-composite film was found to completely decomposed at the temperature Td (PMMA/3 wt%P-MMT) = 370°C which is slightly higher than that of the neat PMMA, i.e. 365°C. It was also found that both plots of ε′<inf>r</inf> and ε″<inf>r</inf> versus frequency display equivalent behaviour. The optical absorption spectra show a rather large domain of transparency between 300 and 2700 nm, with a rather structured absorption band between 1700 and 2700 nm. Dielectric constant ranges near 1 to 3, depending on the frequency. This is very important for some electronic application, as underlined by former Authors. Copyright © 2010 Taylor & Francis Group, LLC.