Abstract:

Fluorine groups were integrated into polyurethane main chains using monocarboxyl fluorocarbon chain as fluorinated modifier. Fluorinated waterborne polyurethane(WPU) containing ionic in soft segment（FSPU） was obtained via molecular designing process. The properties such as synthetic method, water assistance, thermal stability and crystallinity of conventional WPU, fluorinated WPU containing ionic in hard segment（FHPU） and FSPU were compared. Among of them, FSPU shows the best performance. The structure of fluorinated WPU was determined and the influence of fluorine groups on hydrogen bond between soft and hard segments was characterized by IR spectra. The water contact angle was increased from 73° to 107° with the increase of fluorine groups. Water absorption was reduced by 66% and water resistance of polyurethane was increased. The themogravimetric analysis results indicated that the max mass loss temperature of polyurethane glue film was increased by 30 ℃ therefore the thermal stability was improved. Wide X-ray diffraction and scanning electron microscope results showed that multiphase structure existed in the fluorinated polyurethane, the crystallinity of fluorinated polyurethane glue film was increased and the crystalline form was slightly changed.

Key words: waterborne polyurethane, organic fluorine, water resistance, heat atability