Preparation And Properties Of Hyperbranched Waterborne Polyurethane/Acrylate Hybrid Emulsions

Polyurethane（PU）is an important organic polymer material with special chemical structure,and its properties can be changed by changing the composition of soft and hard segments.With the improvement in environmental protection awareness,waterborne polyurethanes（WPU）with a little volatile organic solvent or even none have gradually replaced traditional solvent-based PU.As environmentally friendly products,WPU are more and more popular and widely used in the electronic,biological,and coating fields because of its good resistance to cold,excellent flexibility,and unique mechanical properties.However,compared to conventional solvent-based PU,WPU have some shortcomings,including a lower solid content and poor water and weather resistances.Moreover,the type and content of raw materials restrict its properties and applications.However,these problems can be solved by crosslinking modification,polymer acrylate modification,inorganic filling,and so on.In this study,the main research content of this paper includes the following aspects:（1）hyperbranched polyester polyol（HP）with many hydroxy was synthesized by Isophorone diisocyanate（IPDI）,dimethylol propionic acid（DMPA）and diethanol amine（DEOA）.（2）Poly（tertramethylene ether glycol）（PTMG）,1,4-butanediol（BDO）,IPDI,DMPA,HP and triethyl amine（TEA）were used to synthesize hyperbranched polyester polyol modified polyurethane（HWPU）emulsion.Finally,the acrylate monomer,emulsifier and initiator were added,and hyperbranched polyester polyol modified polyurethane/acrylate（HWPUA）composite emulsion was synthesized by seed emulsion polymerization.It was found that the water resistance,mechanical properties and thermal stability of HWPUA composite increased with increasing HP content.When the HP content was 1%,the performance of HWPUA composite was the best.When the HP content was 1.5%,the performance of the composite decreased.Experiment results have proved that the moderate HP content could improve the performance of HWPUA composite,but the excessive HP content had a detrimental impact on the performance of the material.（3）SiO₂ nanoparticles were modified with silane coupling agent（KH-550）,which made amino groups present on the surface of SiO₂.NCO-terminated HPU was synthesized with PTMG,IPDI,DMPA,BDO and HP.The SiO₂ nanoparticles were added to the reactor to synthesize SiO₂ modified hyperbranched waterborne polyurethane（HWPU-SiO₂）.Then,acrylate monomers and initiator were added to the system and the free radical polymerization was initiated to synthesize SiO₂ modified hyperbranched waterborne polyurethane/acrylate（HWPU-SiO₂/PA）composites.It was found that when the SiO₂content was 1%,the performance of HWPU-SiO₂/PA composite was the best.When the SiO₂ content was increased to 3%,the performance of HWPU-SiO₂/PA composite decreased.Experimental results showed that the addention of SiO₂ could improve the performance of the material,but the addition of excessive SiO₂ had a detrimental impact on the performance of films.