| Lacquer surface polishes are a long-established and diverse range of coating surface treatment agents.In recent years,the use of water-based paint surface polishes has become increasingly widespread due to their environmental advantages.In the field of aeronautical engineering,not only is the basic function of a paint surface polish to effectively reduce the surface roughness of the paint to be polished required,but also a series of special effects such as hydrophobic and anti-dirty,UV shielding ability and delayed ageing.However,as the world-wide research is still in its infancy,the preparation methods,performance parameters and applications of aircraft paint surface polishes have rarely been reported.Based on the research on the current status of lacquer surface polish at home and abroad,this thesis has developed a high-performance water-based siloxane environmental polish with KH550 modified nano-CeO2 as the functional abrasive（referred to as water-based lacquer surface polish later）through the formulation design and preparation process research of aircraft skin lacquer surface polish.The water-based paint finish polish can form a smooth and dense multi-functional film on the surface of the paint layer,which gives the surface of the aircraft paint layer better hydrophobicity,anti-fouling and anti-aging properties.Details of the research are as follows.Firstly,a mature laboratory KH550 modified nano-CeO2 process protocol was explored and the prepared KH550 modified nano-CeO2 functional abrasives were characterised using FTIR,TGA,TEM,XRD and other testing methods.The KH550 modified nano-CeO2 was used as the functional abrasive,sub-micron bentonite as the earth phase filler,aqueous inorganic silica nano-resin（high hardness inorganic nano-material）,polydimethylsiloxane（PDMS）and the laboratory home-made oil phase as the film-forming substances,together with various auxiliaries and deionized water,and the water-in-oil process was used to achieve the synthesis of aqueous lacquer polishes.The performance study of the water-based lacquer polisher shows that when the addition of KH550-CeO2 nanoparticles in the polisher is 10.0 w.t.%,the surface roughness of the aircraft polyurethane lacquer layer sample（a commonly used skin lacquer system for civil airliners）is reduced from 140.20 nm to 33.28 nm after the polisher is applied,and the surface roughness of the aircraft rain-resistant and anti-static lacquer layer sample（a military aircraft skin lacquer system）is reduced from 901.20 nm to 33.28 nm after the polisher is applied.It was found that the home-made water-based lacquer polish had a low viscosity and was stable under high and low temperature conditions.Finally,to further investigate the functionality and suitability of the waterborne paint finish polish,the waterborne paint finish polish was applied to aircraft polyurethane paint samples and aircraft rain resistant anti-static paint samples and polished and filled with the polish,and the treated aircraft paint samples were then characterised for overall performance.The experimental results demonstrate that the waterborne finish polish can effectively improve the hydrophobicity,chemical resistance,surface hardness,abrasion resistance and UV shielding of the paint surface.At the same time,the use of aqueous lacquer polish does not affect the insulation properties of the lacquer and does not affect the gloss of the matt lacquer.In a rain corrosion test on rain resistant anti-static paint samples,the rain corrosion resistance time was doubled when comparing before and after the application of the polish.Through the comprehensive test analysis of weathering resistance,it is confirmed that the home-made water-based paint polish has good ageing resistance,the home-made water-based paint polish can resist the decay of ageing on the hydrophobic contact angle and UV shielding ability of the paint layer,and can achieve the improvement of the three ageing resistance single grade indicators of light loss grade,discolouration grade and tarnish grade by 1 grade under two specific paint conditions,and the spot grade can be improved by 2 grades under the condition of rain corrosion resistant anti-static paint layer.In the case of the rain and corrosion resistant antistatic layer,the spotting level can be increased by 2 levels,and the overall ageing rating can be increased by 1 level in both specific layers.In summary,the waterborne siloxane aircraft skin surface polish has significant advantages over similar products in terms of overall performance. |
