笼形聚倍半硅氧烷-六方氮化硼-苯胺三聚体共掺杂的改性环氧树脂防腐涂层

Epoxy resin anticorrosive coating modified by the co-doping of polyhedral silsesquioxane/hexagonal boron nitride/aniline trimer

为了改善环氧树脂(EP)涂层防腐性能,采用笼形聚倍半硅氧烷(POSS)修饰的六方氮化硼(h-BN)和苯胺三聚体(AT)作为填料加入环氧固化体系中进行共掺杂,研究两种POSS分子、两种添加方式以及不同添加量对复合涂层的性能影响。首先通过高温剥离六方氮化硼得到羟基化氮化硼(OH-BN),而后采用硅烷偶联剂KH-560对其表面进行乙氧基功能化修饰,再分别将氨丙基七异丁基POSS(APS)和八氨苯基POSS(OAPPS)与之接枝,经反应合成出两种新型的POSS杂化氮化硼功能助剂APS-BN和OAPPS-BN;进一步将它们和AT通过π-π相互作用共混,以不同的添加比例分散到环氧树脂中制备有机无机杂化的环氧复合防腐涂层材料,最后表征涂层的交流阻抗谱、塔菲尔曲线、盐雾试验、接触角、热性能和力学性能等。结果表明,与纯环氧涂层相比,掺杂0.5wt%OAPPS-BN-AT的环氧复合涂层性能提升幅度最大,阻抗值为1.27×10^(11)Ω·cm^(2);腐蚀电位提高了0.35 V,达到−0.052 V;耐盐雾性能也有明显提高,30天未出现点蚀和起泡。此外,基于POSS杂化氮化硼功能助剂中POSS表面迁移作用和h-BN屏障作用,复合涂层铅笔硬度提高到3H级别;表面疏水性有所提升,接触角从纯环氧涂层的67.1°增大到93.2°,并且还显示出优良的附着力、耐冲击性、柔韧性和耐热性能,说明0.5wt%OAPPS-BN-AT/EP防腐涂层在金属腐蚀与防护领域将具有一定的潜在应用前景。

In order to improve the corrosion resistance of epoxy resin(EP)coatings,both polyhedral oligomeric silsesquioxane(POSS)modified hexagonal boron nitride(h-BN)and aniline trimer(AT)were co-doped into the epoxy curing system using as functional fillers.The hydroxylated boron nitride OH-BN was obtained by peeling off the hexagonal boron nitride at high temperature.The surface of OH-BN was modified with the silane coupling agent KH-560,and then the aminopropyl heptaisobutyl POSS(APS)and octaaminophenyl POSS(OAPPS)were grafted to synthesize APS-BN and OAPPS-BN.The two modified h-BN and aniline trimer were dispersed into EP to prepare organic-inorganic hybrid coatings throughπ-πinteractions.The coating's AC impedance spectroscopy,Tafel curve,salt spray test,and contact angle,thermal and mechanical properties were characterized by some techniques.The results show that,compared with the pure epoxy coating,the composited coating doped with 0.5wt%OAPPS-BN-AT has the largest improvement in performance with an impedance value of 1.27×10^(11)Ω·cm^(2).The corrosion potential is−0.052 V with an increasing of 0.35 V.The salt spray resistance test exhibites that no pitting or blistering occurred for 30 days.Based on the POSS surface migration effect and h-BN barrier effect,the pencil hardness of the composited coating is increased to 3H level.The surface contact angle is changed from 67.1°to 93.2°.In a word,the composited 0.5wt%OAPPS-BN-AT/EP coating has excellent adhesion,impact resistance,flexibility and heat resistance,which showed a promising potential in the field of anti-corrosion.