Browsing by Author "Shih, Ruey-Sheng"

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Hydrogen Bond-Mediated Self-Assembly of Polyhedral Oligomeric Silsesquioxane-Based Supramolecules
(2010-08-05)
Shih, Ruey-Sheng
;
Lu, Chu-Hua
;
Kuo, Shiao-Wei
;
Chang, Feng-Chih
;
應用化學系
In this study, a functionalized pentaerythritol star polyester compound [tetrakis(nicotinoxymethyl)methane, TNMM] and an octakis[dimethyl(4-hydroxyphenethyl)siloxy]silsesquioxane (OP-POSS) were synthesized and used as tetrahedral and cubic building blocks, respectively, for three-dimensional, hydrogen-bond-mediated, polyhedral oligomeric silsesquioxane- (POSS-) based supramolecular network structures. With noncovalent chain extension of hydrogen bonds between its pyridine and phenol groups, the PUSS-based supramolecular networks exhibited thermally reversible properties. Compared with the glass transition temperature of OP-POSS (ca. 20 degrees C) and the melting temperature of TNMM (ca. 70 degrees C), the hydrogen-bond-mediated miscible blend of 40 wt % TNMM in OP-POSS exhibited a single and higher glass transition temperature (37 degrees C). Because of its strong intermolecular hydrogen bonding, the dewetting pattern of the blend of 40 wt % TNMM in OP-POSS formed ringlike structures rather than the droplets formed by pure OP-POSS. A transparent, brittle, and glassy solid at room temperature, the blend of 40 wt % TNMM in OP-POSS is an explicit and successful example of a PUSS-based hydrogen-bonded supramolecular network.
Thermal and mechanical properties of microcellular thermoplastic SBS/PS/SBR blend: effect of crosslinking
(2011-02-03)
Shih, Ruey-Sheng
;
Kuo, Shiao-Wei
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
This study investigates the effect of peroxide crosslinking on the structure and mechanical properties for SBS/PS/SBR foams composed of polystyrene (PS), poly(styrene-b-butadiene) diblock copolymer (SBR-1502), and poly(styrene-b-butadiene-b-styrene) triblock copolymer (SBS). The cell size and its distribution of SBS/PS/SBR foams were investigated by SEM images, showing the smaller and denser of hollow cells for the SBS/PS/SBR foam containing the higher concentration of DCP (dicumyl peroxide). As expected, the density of the SBS/PS/SBR foams increases with increasing the content of DCP. The high density of polymeric foams exhibits the high mechanical properties such as hardness, shrinkage, tensile strength, tear strength, elongation at break, and compression set. (C) 2010 Elsevier Ltd. All rights reserved.