Study Of Waterborne Polyurethane / Polyacrylate Composite Latex (styrene)

In this thesis, we focus on the preparation, characterization and utilization of polyacryalte(styrene)/waterborne polyurethane hybrid latex. The main contents embrace three aspects which are summarized as follows:1. Emulsion polymerization of MMA (styrene) using waterborne polyurethane dispersion as seeds or emulsifier.a) The WPU/PMMA composite latex is prepared via ⁶⁰Co-γ ray-induced seeded-emulsion polymerization of methyl methacrylate using waterborne polyurethane seeds. The kinetics of the condensation polymerization was investigated in MMA medium. The grafting percentage of WPU/PMMA composite polymer initiated by γ-ray is larger than that initiated by K₂S₂O₈.b) The waterborne polyurethane was synthesized. The CAC of WPU increased with the increase of pH value. The conversion-time curves were obtained and the polymerization rate of styrene increases with the increase of the content of WPU and the irradiation dose rate. The grafting reaction between the polyurethane and polystyrene was proved by the FT-IR and XPS spectra of extracted PSt/WPU emulsion. When the content of WPU is lower, the grafting percentage of WPU is larger. The grafting percentage of WPU also increases with the increase of the irradiation dose rate. Furthermore, the irradiation induced seeded-emulsion polymerization of styrene in presence of WPU proved to be an effective method to improve the grafting reaction between the polyurethane and polystyrene.c) The carboxylated waterborne polyurethane was synthesized and used as emulsifiers for the emulsion copolymerization of styrene and methyl methacrylate (MMA). The emulsion of styrene and MMA was induced by ⁶⁰Co-γ ray radiation at room temperature. The conversion-time curves show that the polymerization rate improves rapidly with the presence of MMA. TEM images indicated average particles size does not change with the mixture ratio of styrene versus MMA and particle sizes distribution was narrow with the presence of MMA. The copolymerization between MMA and styrene was proved out via ¹H-NMR spectra. Furthermore, the grafting reaction between WPU emulsifiers and polystyrene/PMMA was proved via FT-IR and...