Effect of Reaction Rate on Morphological Change of Reactive Blends

The effect of reaction rate on the morphology of reactive blends has been studied using 75/25 (wt/wt) monocarboxylated polystyrene [PS-mCOOH]/poly(methyl methacrylate) [PMMA] with poly(methyl methacrylate-ran-glycidyl methacrylate) [PMMA-GMA] as an in-situ compatibilizer, by varying the amount of PM...

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Veröffentlicht in:Macromolecules 2000-10, Vol.33 (22), p.8200-8210
Hauptverfasser: Jeon, Hyun Kyoung, Kim, Jin Kon
Format: Artikel
Sprache:eng
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Zusammenfassung:The effect of reaction rate on the morphology of reactive blends has been studied using 75/25 (wt/wt) monocarboxylated polystyrene [PS-mCOOH]/poly(methyl methacrylate) [PMMA] with poly(methyl methacrylate-ran-glycidyl methacrylate) [PMMA-GMA] as an in-situ compatibilizer, by varying the amount of PMMA-GMA in the blend, the molar concentration of GMA, C GMA , 0 in PMMA-GMA at fixed molecular weight, and the molecular weight of PMMA-GMA at fixed C GMA , 0. For the blends with PMMA−GMA having lower C GMA , 0, there exists a critical amount of PMMA−GMA above which a sharp decrease in the surface area average domain size (D s) occurs. This amount was shifted to a smaller value with increasing C GMA , 0 in PMMA-GMA. We demonstrated that the interfacial graft reaction between PS-mCOOH and PMMA-GMA at 220 °C was described by the simple second-order reaction kinetics, i.e., mean field reaction kinetics. From the morphological evolution, it is found that the morphological change by an external flow from a pellet size to D s with less than 1 μm occurred within a very short time of ∼30 s. After this transition, coalescence is the main mechanism for determining the final morphology obtained at a mixing time of 20 min. Finally, a master curve is obtained when D s is plotted against C GMA , 0, implying again that the concept of mean field reaction kinetics adequately applies to the blends employed in this study.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma000842i