An acrylate-modified aqueous polyurethane copolymer emu […]
An acrylate-modified aqueous polyurethane copolymer emulsion (PUA emulsion) was prepared by emulsion polymerization, and the solvent resistance, thermal properties and mechanical properties of the PUA emulsion were preliminary studied.
1. The main raw material for the experiment
Waterborne polyurethane emulsions; methyl methacrylate, butyl acrylate, acrylic acid; acrylamide; OP-10; sodium lauryl sulfate; K2S2O8, etc.
2. Experimental process
Aqueous polyurethane and emulsifier were added to a four-necked flask and emulsified by rapid stirring for 0.5 h. The acrylate mixed monomer and acrylamide were added dropwise at 80° C. and K2S2O8 was added dropwise. The addition was completed within 3 h. After the reaction was incubated at 80 °C for 2 h, it was cooled and discharged.
3. Performance test
Effect of acrylate modification on thermal stability of waterborne polyurethane film
The initial decomposition temperature of the modified aqueous PUA is about 150°C higher than that of the aqueous PU, and the heat resistance is greatly improved. This may be because PU core, acrylate shell, and core-shell structure formed by grafting enhance the thermal stability of each group, making decomposition more difficult.
Effect of Acrylate Modification on Mechanical Properties of Waterborne Polyurethane Film
After modification, the tensile strength of PUA is larger than that of PU, and the elongation at break decreases, and the film becomes hard.
Effect of Acrylate Modification on Solvent Resistance of Waterborne Polyurethane Film
The solvent resistance of PUA film is obviously better than PU, and the modification effect is remarkable.
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