环氧树脂基近红外吸收涂层的近红外光谱、力学及耐盐水性能研究

Study on Near-Infrared Spectroscopy, Mechanics and Salt Water Resistance of Epoxy Resin-Based Near-Infrared Absorbing Coatings

以环氧树脂为粘合剂,Sm2O3为功能颜料,硅烷偶联剂和石墨烯为改性剂,制备得到了一种同时具有突出力学性能和耐盐水性能的近红外低反射率涂层。系统研究了Sm2O3添加量、硅烷偶联剂种类、硅烷偶联剂添加量和石墨烯添加量对涂层性能的影响。结果表明:Sm2O3添加量的增加可明显降低涂层对1.06μm近红外光的反射率,当Sm2O3添加量为50%,涂层对1.06μm近红外光的反射率可低至31.2%。此时,涂层的附着力和耐冲击强度分别可达到1级和50 kg·cm。用硅烷偶联剂改性涂层,偶联剂上的强极性基团分别可与涂层中的树脂基体和颜料形成共价键结合,从而可发挥桥连作用,进而可明显改善涂层的柔韧性,其中KH560的改性效果最佳。当KH560添加量为5%,涂层的柔韧性可从改性前的9 mm显著改善为改性后的4 mm。石墨烯具有特殊的共平面结构和超长共轭结构特征,使其对入射光的吸收可延伸到近红外区域。石墨烯特殊的片层结构使其具有很高的耐冲击强度和柔韧性,在涂层中添加石墨烯可明显改善涂层的力学性能。研究发现石墨烯的添加可在进一步改善涂层力学性能的前提下显著降低涂层对1.06μm近红外光的反射率。当石墨烯添加量为8%,涂层对1.06μm近红外光的反射率可低至12.6%,此时涂层可具备突出的激光隐身效能。同时,涂层的附着力、柔韧性和耐冲击强度分别可达到1级、2 mm和50 kg·cm,可很好地满足实际工程应用要求。在环氧树脂、硅烷偶联剂和石墨烯的协同界面优化作用下,最佳配方(Sm2O3添加量为50%、KH560添加量为5%、石墨烯添加量为8%)的涂层经盐水腐蚀21 d后,涂层的微结构、近红外低反射率性能和力学性能可保持稳定。此时,涂层对1.06μm近红外光的反射率为12.47%,涂层的附着力、柔韧性和耐冲击强度分别可保持在1级、2 mm和45 kg·cm,表明制备的涂层具有良好的耐盐水性能。

A near-infrared low reflectivity coating with outstanding mechanical properties and salt water resistance was prepared using epoxy resin as a binder,Sm2O3 as a functional pigment,silane coupling agent and graphene as modifiers,respectively.The effects of Sm2O3 addition,silane coupling agent type,silane coupling agent addition and graphene addition on the coating properties were systematically studied.The results show that the increase of the additional amount of Sm2O3 can significantly reduce the reflectivity of the coating to 1.06μm near-infrared light.When the additional amount of Sm2O3 is 50%,the reflectivity of the coating to 1.06μm near-infrared light can be as low as 31.2%.At this time,the adhesion strength and impact strength of the coating can reach greades 1 and 50 kg·cm,respectively.The coating is modified with a silane coupling agent.The strong polar groups on the coupling agent can form covalent bonds with the resin matrix and the pigment in the coating,respectively,to play a bridging role,which can significantly improve the flexibility of the coating.Among which,KH560 has the best modification effect.When the addition amount of KH560 is 5%,the flexibility of the coating can be significantly improved from 9 mm before modification to 4 mm after modification.Graphene has a special coplanar structure and ultra-long conjugated structure characteristics so that its absorption of incident light can extend to the near-infrared region.In addition,the special lamellar structure of graphene makes it have high impact strength and flexibility.Adding graphene to the coating can significantly improve the mechanical properties of the coating.The study found that the addition of graphene can significantly reduce the reflectivity of the coating to 1.06μm near-infrared light to further improve the mechanical properties of the coating.When the additional amount of graphene is 8%,the reflectivity of the coating to 1.06μm near-infrared light can be as low as 12.6%,and the coating can have outstanding laser stealth performance at this time.At the same time,the adhesion strength,flexibility and impact strength of the coating can reach grades 1,2 mm and 50 kg·cm,respectively,which can meet practical engineering application requirements.Under the synergistic interface optimization of epoxy resin,silane coupling agent and graphene,The microstructure,near-infrared low reflectivity properties and mechanical properties of the coating with the best formulation(50%of Sm2O3,5%of KH560,and 8%of graphene)can remain stable after being corroded by salt water for 21 days.At this time,the reflectivity of the coating to 1.06μm near-infrared light was 12.47%,and the adhesion strength,flexibility and impact strength of the coating can be maintained at grade 1,2 mm and 45 kg·cm,respectively,indicating that the prepared coating has good saltwater resistance.