| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 100 === Phase behavior of poly(styrene-g-acrylic acid) (PS-g-PAA) with different block copolymers was investigated using small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). In PS-b-PAA/PS-g-PAA blends, the morphology showed a strong of molecular weight of two copolymers. When the molecular weight of PS in PS-b-PAA is small, PS in PS-g-PAA could not be incorporated into PS in PS-b-PAA, causing the assembly of PS-g-PAA in PAA domains of PS-b-PAA. As a result, the domain size of blends increased with the content of PS-g-PAA. When the molecular weight of both domains in PS-b-PAA is larger than that in PS-g-PAA, PS-g-PAA located at the interface between PS and PAA in PS-b-PAA, resulting in the decrease in the domain size of blends.
We also investigated the effect of compatibility of PS-g-PAA and PS based block copolymers on the phase behavior of block/graft copolymer blends. In PS-b-PEO/PS-g-PAA and PS-b-P2VP/PS-g-PAA blends, the present of H-bonding between PAA and PEO, and PAA and P2VP facilitated the incorporation of graft copolymer in block copolymer. This in turn caused PS-g-PAA to locate at the interface between microdomains in PS-b-PEO or PS-b-P2VP. With an increase in the amount of graft copolymer, the domain size decreased and an order-disorder transition occurred at high graft copolymer content. On the contrary, in PS-b-PMMA / PS-g-PAA, poor miscibility of blends prevented PS-g-PAA from incorporating into the microdomains of block copolymers, causing the macrophase separation of blends upon the addition of graft copolymer.
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