รศ. ดร.ศิริลักษณ์ พุ่มประดับ
E-mail : Sirilux.p@chula.ac.th
Telephone : +66 (0) 2218 7518
Education :
- B.Sc. in Chemistry, Chulalongkorn University, Thailand
- M.Sc. in Chemistry, Chulalongkorn University, Thailand
- D. Eng. in Poly. Chem., Kyoto University, Japan
Major research interests :
- Reinforcement of natural rubber by nanofiller
- In situ silica generated into natural rubber matrix by the sol-gel process
- Strain-induced crystallization in natural and synthetic rubbers
Publications :
2004
Toki, S.; Sics, I.; Ran, S.; Liu, L.; Hsiao, B. S.; Murakami, S.; Tosaka, M.; Kohjiya, S.; Poompradub, S.; Ikeda, Y.; Tsou, A. H.
In: Rubber Chemistry and Technology, vol. 77, no. 2, pp. 317-335, 2004, (cited By 82).
@article{Toki2004317,
title = {Strain-induced molecular orientation and crystallization in natural and synthetic rubbers under uniaxial deformation by in-situ synchrotron X-ray study},
author = {S. Toki and I. Sics and S. Ran and L. Liu and B. S. Hsiao and S. Murakami and M. Tosaka and S. Kohjiya and S. Poompradub and Y. Ikeda and A. H. Tsou},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-4043123898&doi=10.5254%2f1.3547826&partnerID=40&md5=99284c56c2b65864a933694348b58cb4},
doi = {10.5254/1.3547826},
year = {2004},
date = {2004-01-01},
journal = {Rubber Chemistry and Technology},
volume = {77},
number = {2},
pages = {317-335},
abstract = {In-situ synchrotron wide-angle X-ray diffraction (WAXD) studies and simultaneous measurements of stress and strain during uniaxial stretching of various vulcanized rubbers were carried out (at room temperature and 0°C) to reveal the strain-induced molecular orientation and crystallization relationships. Rubbers evaluated included natural rubber (NR), synthetic poly-isoprene rubber (IR), poly-cis-1,4-butadiene rubber (BR) and butyl rubber (IIR). Some universal features were observed in these systems: (i) At high strains (> 5,0), the majority of the chains (up to 50-75%) in natural and synthetic rubbers remained in the un-oriented amorphous state with only a small amount of crystalline fraction formed (10-20%). The rest of the chains were in the oriented amorphous state, (ii) During deformation, the oriented amorphous chains acted as precursors to strain-induced crystallization. A network of micro-fibrillar crystallites is formed within the closely populated vulcanization points, leading to the enhancement of mechanical properties at high strains. Different rubbers exhibited different behaviors during strain-induced crystallization. For example, poly-isoprenes (NR and IR vulcanized with sulfur and peroxide) showed strain-induced crystallization at a low strain of 2.5, resulting in larger crystalline but smaller oriented amorphous fractions. In contrast, BR and IIR crystallized at a higher strain of 4.0 lead to higher molecular orientation, higher oriented amorphous, but smaller crystalline fractions. The relationship between the molecular orientation and crystallization in strained rubber depends on the intrinsic crystallizability of the chains and the topology of the crosslinked network.},
note = {cited By 82},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In-situ synchrotron wide-angle X-ray diffraction (WAXD) studies and simultaneous measurements of stress and strain during uniaxial stretching of various vulcanized rubbers were carried out (at room temperature and 0°C) to reveal the strain-induced molecular orientation and crystallization relationships. Rubbers evaluated included natural rubber (NR), synthetic poly-isoprene rubber (IR), poly-cis-1,4-butadiene rubber (BR) and butyl rubber (IIR). Some universal features were observed in these systems: (i) At high strains (> 5,0), the majority of the chains (up to 50-75%) in natural and synthetic rubbers remained in the un-oriented amorphous state with only a small amount of crystalline fraction formed (10-20%). The rest of the chains were in the oriented amorphous state, (ii) During deformation, the oriented amorphous chains acted as precursors to strain-induced crystallization. A network of micro-fibrillar crystallites is formed within the closely populated vulcanization points, leading to the enhancement of mechanical properties at high strains. Different rubbers exhibited different behaviors during strain-induced crystallization. For example, poly-isoprenes (NR and IR vulcanized with sulfur and peroxide) showed strain-induced crystallization at a low strain of 2.5, resulting in larger crystalline but smaller oriented amorphous fractions. In contrast, BR and IIR crystallized at a higher strain of 4.0 lead to higher molecular orientation, higher oriented amorphous, but smaller crystalline fractions. The relationship between the molecular orientation and crystallization in strained rubber depends on the intrinsic crystallizability of the chains and the topology of the crosslinked network.
Tosaka, M.; Kohjiya, S.; Murakami, S.; Poompradub, S.; Ikeda, Y.; Toki, S.; Sics, I.; Hsiao, B. S.
Effect of network-chain length on strain-induced crystallization of NR and IR vulcanizates Journal Article
In: Rubber Chemistry and Technology, vol. 77, no. 4, pp. 711-723, 2004, (cited By 86).
@article{Tosaka2004711,
title = {Effect of network-chain length on strain-induced crystallization of NR and IR vulcanizates},
author = {M. Tosaka and S. Kohjiya and S. Murakami and S. Poompradub and Y. Ikeda and S. Toki and I. Sics and B. S. Hsiao},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-10044296365&doi=10.5254%2f1.3547846&partnerID=40&md5=13f04bfcd02f7258be88904cb0628541},
doi = {10.5254/1.3547846},
year = {2004},
date = {2004-01-01},
journal = {Rubber Chemistry and Technology},
volume = {77},
number = {4},
pages = {711-723},
abstract = {Strain-induced crystallization of natural rubber (NR) and synthetic isoprene rubber (IR) with various crosslinking densities was investigated by wide angle X-ray diffraction using a synchrotron radiation and simultaneous tensile measurements. The elongation ratio at the onset of crystallization (αc) was almost independent of crosslinking density. IR samples showed larger αc values than NR because of the lower stereoregularity of IR. These results suggest that the onset of crystallization is determined by increased melting temperature by strain due to an entropic reason. The amount of oriented amorphous component changed approximately linearly with strain, and was a little larger in IR than in NR when compared at the same elongation ratio. At small strain (and stress), crystallinity in IR was lower than in NR. These results indicate that, at small strain region, the more stress is assigned to oriented amorphous in IR than in NR.},
note = {cited By 86},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Strain-induced crystallization of natural rubber (NR) and synthetic isoprene rubber (IR) with various crosslinking densities was investigated by wide angle X-ray diffraction using a synchrotron radiation and simultaneous tensile measurements. The elongation ratio at the onset of crystallization (αc) was almost independent of crosslinking density. IR samples showed larger αc values than NR because of the lower stereoregularity of IR. These results suggest that the onset of crystallization is determined by increased melting temperature by strain due to an entropic reason. The amount of oriented amorphous component changed approximately linearly with strain, and was a little larger in IR than in NR when compared at the same elongation ratio. At small strain (and stress), crystallinity in IR was lower than in NR. These results indicate that, at small strain region, the more stress is assigned to oriented amorphous in IR than in NR.
2002
Tuntulani, T.; Thavornyutikarn, P.; Poompradub, S.; Jaiboon, N.; Ruangpornvisuti, V.; Chaichit, N.; Asfari, Z.; Vicens, J.
Synthesis of tripodal aza crown ether calix[4]arenes and their supramolecular chemistry with transition-, alkali metal ions and anions Journal Article
In: Tetrahedron, vol. 58, no. 52, pp. 10277-10285, 2002, (cited By 78).
@article{Tuntulani200210277,
title = {Synthesis of tripodal aza crown ether calix[4]arenes and their supramolecular chemistry with transition-, alkali metal ions and anions},
author = {T. Tuntulani and P. Thavornyutikarn and S. Poompradub and N. Jaiboon and V. Ruangpornvisuti and N. Chaichit and Z. Asfari and J. Vicens},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037164665&doi=10.1016%2fS0040-4020%2802%2901447-3&partnerID=40&md5=54d142009f28b845e5708de6b622f3d0},
doi = {10.1016/S0040-4020(02)01447-3},
year = {2002},
date = {2002-01-01},
journal = {Tetrahedron},
volume = {58},
number = {52},
pages = {10277-10285},
abstract = {Tripodal aza crown ether calix[4]arenes, 5a, 5b, 6a and 6b, have been synthesized. The structure of protonated 5a was elucidated by X-ray crystallography to be a self-threaded rotaxane. Complexation studies of 5a and 5b towards anions using Na+ as countercation were carried out by 1H NMR titration in dimethylsulfoxide-d6 and the mixture of chloroform-d and methanol-d4, respectively. Ligands 5a and 5b were able to form 1:1 complexes with Br-, I- and NO3- and the complexation stability varied as follows: NO3->I->Br-. The effect of countercation on anion complexation was also investigated. The results showed that the association constants of 5a towards Br- in the presence of various cations varied as K+>Bu4N+>Na+. The enhancement in anion complexation ability of 5a may result from the rearrangement of the tripodal ammonium unit in the presence of K+. The neutral forms, 6a and 6b, were able to form complexes with transition metal ions such as Co2+, Ni2+, Cu2+ and Zn2+. The stability of the complexes followed the sequence: Ni2+
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Tripodal aza crown ether calix[4]arenes, 5a, 5b, 6a and 6b, have been synthesized. The structure of protonated 5a was elucidated by X-ray crystallography to be a self-threaded rotaxane. Complexation studies of 5a and 5b towards anions using Na+ as countercation were carried out by 1H NMR titration in dimethylsulfoxide-d6 and the mixture of chloroform-d and methanol-d4, respectively. Ligands 5a and 5b were able to form 1:1 complexes with Br-, I- and NO3- and the complexation stability varied as follows: NO3->I->Br-. The effect of countercation on anion complexation was also investigated. The results showed that the association constants of 5a towards Br- in the presence of various cations varied as K+>Bu4N+>Na+. The enhancement in anion complexation ability of 5a may result from the rearrangement of the tripodal ammonium unit in the presence of K+. The neutral forms, 6a and 6b, were able to form complexes with transition metal ions such as Co2+, Ni2+, Cu2+ and Zn2+. The stability of the complexes followed the sequence: Ni2+<Co2+≪Cu2+≫Zn2+. Compounds 6a and 6b may, therefore, potentially be used as either transition metal ion or anion receptors that can be controlled by pH of the solution. © 2002 Elsevier Science Ltd. All rights reserved.
2001
Tuntulani, T.; Poompradub, S.; Thavornyutikarn, P.; Jaiboon, N.; Ruangpornvisuti, V.; Chaichit, N.; Asfari, Z.; Vicens, J.
Aza crown ether calix[4]arenes containing cation and anion binding sites: Effects of metal ions towards anion binding ability Journal Article
In: Tetrahedron Letters, vol. 42, no. 32, pp. 5541-5544, 2001, (cited By 50).
@article{Tuntulani20015541,
title = {Aza crown ether calix[4]arenes containing cation and anion binding sites: Effects of metal ions towards anion binding ability},
author = {T. Tuntulani and S. Poompradub and P. Thavornyutikarn and N. Jaiboon and V. Ruangpornvisuti and N. Chaichit and Z. Asfari and J. Vicens},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035817394&doi=10.1016%2fS0040-4039%2801%2901029-2&partnerID=40&md5=2126c3ddd6a5c5ac1c8d4b17e4b1aa8b},
doi = {10.1016/S0040-4039(01)01029-2},
year = {2001},
date = {2001-01-01},
journal = {Tetrahedron Letters},
volume = {42},
number = {32},
pages = {5541-5544},
abstract = {Tripodal aza crown ether calix[4]arenes containing both cation and anion binding sites (5a and 5b) have been synthesized. The X-ray analysis shows that 5a forms a self-threaded rotaxane-like structure in the solid state. 1H NMR titrations of the two ligands with various halide anions indicate that 5a and 5b can form complexes with Br- and I- but not F-. However, both compounds form more stable complexes with I- than with Br- in the presence of Bu4N+. The presence of K+ enhances the binding ability of 5a towards Br-. © 2001 Elsevier Science Ltd. All rights reserved.},
note = {cited By 50},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Tripodal aza crown ether calix[4]arenes containing both cation and anion binding sites (5a and 5b) have been synthesized. The X-ray analysis shows that 5a forms a self-threaded rotaxane-like structure in the solid state. 1H NMR titrations of the two ligands with various halide anions indicate that 5a and 5b can form complexes with Br- and I- but not F-. However, both compounds form more stable complexes with I- than with Br- in the presence of Bu4N+. The presence of K+ enhances the binding ability of 5a towards Br-. © 2001 Elsevier Science Ltd. All rights reserved.