疏水二氧化硅粒子的制备及超疏水改性聚氨酯树脂

Preparation of Hydrophobic Silica Particles for Superhydrophobic ModifiedWaterborne Polyurethane Resin

为了制备具有稳定超疏水性能的改性水性聚氨酯树脂,受“荷叶效应”的启迪,以十二烷基三乙氧基硅烷(DTES)的碱性水解反应为基础,通过SiO_(2)粒子表面硅羟基的接枝反应,在其表面引入低表面能的长链烷烃结构,制备了微胶囊包覆型的具有疏水效应的二氧化硅粒子。通过红外光谱、X射线衍射、扫描电镜等手段表征其结构,确定了疏水改性粒子的制备方法和规律。将自制改性SiO_(2)粒子与水性聚氨酯树脂(WPU)进行物理共混,制备出具有超疏水性能的水性聚氨酯涂料。采用差示扫描量热分析和热重分析表征涂料的共混性能及耐热性能,采用扫描电镜和原子力显微镜量化分析涂层特征及表面形貌,采用接触角测试表征水性涂层的超疏水性能及表面能的变化。结果显示,自制疏水粒子迁移到环氧树脂表面,通过化学作用和物理缠结形成强烈的界面结合,使其表面微纳结构稳定且持久,结合长链烷烃的低表面能修饰,赋予共混树脂超疏水性能,接触角达到158°,而涂层的均方根粗糙度(Rq)由纯WPU的7.82 nm增大至101 nm,平均粗糙度(Ra)由6.24 nm增大至77.9 nm,表面粗糙度大大提升。将水性树脂的水性化制备与超疏水性能相结合,制备了绿色环保具有自清洁效应的水性聚氨酯,而形成的特殊的树脂涂层表面在苛刻环境中保持了结构的稳定性和持久性,表现出优异的耐磨和耐化学腐蚀性能。

In order to prepare the modified waterborne polyurethane resin with stable superhydrophobic properties,inspired by the“Lotus Effect”and based on the alkaline hydrolysis reaction of dodecyltriethoxysilane(DTES),a long-chain alkane structure with low surface energy was introduced on the surface of SiO_(2) particles through the grafting reaction of hydroxyl groups on the surface.Thus,microcapsule coated silica particles with hydrophobic effect were prepared.To determine the preparation method and law of hydrophobic modified particles,the structures of the particles were characterized by infrared spectroscopy(FT-IR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and other testing methods.Then aqueous polyurethane coatings with superhydrophobic properties were prepared by physical blending of self-made modified SiO_(2) particles and waterborne polyurethane resin(WPU).Using differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)to characterize the blending properties and heat resistance of the coatings,using scanning electron microscopy(SEM)and atomic force test(AFM)to quantitatively analyze the characteristics and surface morphology of the coatings,and using water absorption capacity(WAC)to characterize super hydrophobic properties and surface energy of the waterborne coatings.The results show that the self-made hydrophobic particles migrated to the surface of the epoxy resin and formed a stably rough surface structure through chemical action and physical entangling.Combined with the low surface energy modification of the long chain alkane,the resin is superhydrophobic and the contact angle reaches 158°.Moreover,compared with pure WPU,the root mean square roughness(Rq)of the product coating increases from 7.82 nm to 101 nm,and the average roughness(Ra)increases from 6.24 nm to 77.9 nm,which greatly improves the surface roughness.By combining the water-based resin preparation with superhydrophobic properties,the water-based polyurethane with green environmental protection and self-cleaning effect was prepared.The special resin coating’s surface maintains the stability and durability of the structure in harsh environment,and shows excellent wear and chemical corrosion resistance.