| Summary: | 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.
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