Effects of Triethylorthoacetate and Diethoxyethane on the preparation and microstructure of the SBS thermoplastic elastomer

• Main Authors: Lin, Yih-Chau, 林義超
• Other Authors: Raymond Chien-Chao Tsiang
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/01065694881130255211

碩士 === 國立中正大學 === 化學工程研究所 === 84 === In this research,we have developed the precursor technology for making saturated Styrenic Block Copolymers. First,we found the relationship between the microstructure of Unsaturated Polystyrene-Polybutadiene-Polystyrene (SBS) block copolymers and the modifiers.The microstructure of SBS copolymer was analyzed using FTIR and NMR.The modifiers changed the microstructure of polybutadiene in the SBS copolymer by increasing the content of vinyl-1,2 butadiene.In the experiments,we used triethylorthoacetate and diethoxyethane as structure modifers. The content of vinyl-1,2 butadiene was increased to about 71.21% with the addition of 10000ppm of triethylorthoacetate and the content of vinyl-1,2 butadiene was increased to about 88.81% with the addition of 10000ppm of diethoxyethane.Since the vinyl content required for making saturated SBS copolymer is about 40%, the optimal concentration of triehtylorthoacetate is suggested to be 300ppm,and diethoxyethane be 50ppm.We chosed two methods to polymerize the SBS block copolymer: one is a sequential process and the other is a coupling process. Using the latter method ,we also found the relationship between the modifers and the coupling efficiency.The coulping efficiency was decreased by increasing the concentration of the modifiers,while molecular weight distribution remains the same.On the other hand,both modifiers are very effective on increaing the butadiene polymerization rate. For SBS copolymer synthesized via a sequential method, the addition of the modifiers minimizes the crossover deficiency which would otherwise result in a skewed molecular weight distribution with a higher polydispersity.