Research progress of waterborne polyurethane blending modification!

Although waterborne polyurethane has good environmental advantages, in order to make the PU prepolymer easy to emulsify in water, the molecular chain of waterborne polyurethane contains hydrophilic groups, such as carboxyl groups, hydroxyl groups,

Blending modification, also known as physical modification, is a modification method in which the synthesized water-based polyurethane emulsion is mixed with different nanoparticles and resin materials through high-intensity mechanical stirring in different proportions.

The aqueous polyurethane emulsion was synthesized by the acetone method, and then colloidal SiO2 with a content of 0-50wt% was added to the aqueous polyurethane emulsion, and a series of WPU/SiO2 mixed materials were obtained by vigorous stirring

A waterborne polyurethane (referred to as P) was first synthesized with polydimethylsiloxane (PDMS) as the only soft segment, then P was mixed with different types of waterborne polyurethanes, and a small amount of P was used to study the mixed waterborne polyurethane emulsion Influence of properties, surface structure and properties of membranes

Ethyl orthosilicate (TEOS) was directly added to amino-terminated PU resin to prepare WPU/SiO2 hybrid materials

3 wt% TEOS was added dropwise to the aqueous polyurethane emulsion, and the WPU/SiO2 hybrid material was synthesized by the sol-gel method

Firstly, the surface of fumed SiO2 and nano-SiO2 in silica sol was chemically grafted and modified, and then the modified nano-SiO2 particles were added to the synthesized water-based polyurethane emulsion to prepare a series of nano-SiO2 blends with different contents.

Add the epoxy resin E-51 diluted with acetone into the water-based polyurethane emulsion, and disperse at high speed to make it evenly mixed

The blending modification has the advantages of low cost, easy operation, convenient formula ratio adjustment, and can be used as needed
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However, in the blending modification, the interaction between the modified particles and PU is weak, no substantial chemical bonds are formed, and the degree of phase separation is high
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Moreover, the nanoparticles in the mixed system obtained by the blending method are prone to agglomeration, the product uniformity is not good, and it is difficult to obtain high-performance waterborne polyurethane products
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