炭黑与聚四氟乙烯复配粉体/硅树脂复合涂层的制备及疏水稳定性研究

Preparation and Hydrophobic Stability of Carbon Black/PTFE Composite Powder/Silicone Resin Coatings

采用甲基三乙氧基硅烷和γ-氨丙基三乙氧基硅烷对炭黑与聚四氟乙烯的复配粉体进行改性,并将其添加到硅树脂中,喷涂于镁合金板上,经高温固化制得复合涂层。表征了硅烷改性复配粉体和复合涂层的微观结构,测试了复合涂层的疏水性能、附着力、耐摩擦性能、耐酸碱性能和耐候性能。结果表明:炭黑和聚四氟乙烯复配粉体经硅烷改性后,表面的粗糙度和结构复杂度增加,并连接上了疏水基团;随着改性粉体用量的增加,复合涂层表面的粉体开始出现团聚现象,微纳级二级结构中的孔隙减小;随着改性粉体用量由20%增加到40%,复合涂层的静态水接触角从102°升至152°后降至111°,动态滚动角则从27°降至6.5°后升至16°,附着力由6.32 MPa降至4.17 MPa;当硅烷改性粉体用量为30%时:制得的复合涂层具备超疏水性能;且随着循环摩擦次数由10次增加到50次,静态水接触角由152°降至110°,滚动摩擦角由3.8°升至25°,表面粗糙度降低;在酸性溶液中浸泡48 h后的静态水接触角和动态滚动角分别下降5°和升高1.5°,在碱性溶液中浸泡48 h后的静态水接触角和动态滚动角分别下降20°和升高4°,但均能保持静态水接触角大于130°和动态滚动角低于10°,耐酸碱性能良好;在自然环境下曝露50 d后,静态水接触角和动态滚动角分别为150.14°和4.3°,相比于曝露前无明显降低,耐候性能良好。

The compound powders of carbon black and polytetrafluoroethylene(PTFE)were modified by methyltriethoxysilane andγ-aminopropyltriethoxysilane,and then it was added to silicone resin,sprayed on magnesium alloy plates,and the composite coatings was prepared by curing at high temperature.The microstructure of silane modified composite powders and composite coatings were characterized,and the hydrophobicity,adhesion,friction resistance,acid-base resistance and weatherability of composite coatings were tested.The result show that after the carbon black and PTFE composite powder is modified by silane,the surface roughness and structural complexity increase,and hydrophobic groups are connected,the powder on the surface of the coatings begin to agglomerate,and the pores in the micro-nano secondary structure decreases.When the modified powder increases from 20%to 40%,the static water contact angle of the coatings increases from 102°to 152°and then decreases to 111°,and the dynamic rolling angle decreases from 27°to 6.5°and then increases to 16°,the average tensile strength decreases from 6.32 MPa to 4.17 MPa.When the amount of silane modified powder is 30%,the coating is super-hydrophobic,and the static water contact angle decreases from 152°to 110°with the cycle friction times go from 10 to 50 times,the rolling friction angle goes from 3.8°to 25°,thus a decrease of surface roughness is occurred.The static water contact angle and dynamic rolling angle decreases by 5°and increases by 1.5°respectively after soaking in acidic solution for 48 hours,the static water contact angle and dynamic rolling angle decreases by 20°and increases by 4°respectively after immersion in alkaline solution for 48 h,but the static water contact angle>130°and the dynamic rolling angle<10°,and the acid and alkali resistance is good.In the natural environment,the static water contact angle and dynamic rolling angle are 150.14°and 4.3°respectively after 50 days’exposure,which has no decrease compared with that before exposure.