Preparation and Physical Properties of Styrene-butadiene-styrene block copolymer in Different Proportion of Hard and Soft Segments

• Main Authors: Ting-Hsuan Peng, 彭定軒
• Other Authors: Dr. Rong-Hsien Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/18368824586196732924

碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系碩士在職專班 === 101 === Various block lengths of tri-block copolymer, thermoplastic elastomers, have been successfully synthesized by anionic polymerization. Experiments were carried out at 50 ℃using cyclohexane, tetrahydrofuran (THF) and n-butyllithium (NBL) as solvents at a fixed concentrations. The weight ratios of soft segment (butadiene moiety; BD) to hard segment (styrene moiety; SM) in the synthesized copolymer are 3:7, 4:6, 5:5, 6:4 and 7:3. The molecular weights for previously mentioned tri-block copolymer (SBS) were in the range of 63,000 ~ 71,000 g/mole by the GPC measurement. These ratio-values and the values of Vinyl type %, cis/trans, and SM wt % were characterized by 1H-NMR. The results demonstrated that the various SBS at specially designed BD/SM ratios have been successfully synthesized. Mechanical properties, such as tensile strength, storage modulus (G’), loss modulus (G”) and tan δ were also investigated. In addition, the fracture morphology of SBS was investigated using SEM by staining in solution of osmium tetroxide (OsO4) on an unsaturated double bond of the SBS.