两亲性Janus片的制备及提升水性涂料防护性能

Amphiphilic Janus sheets for improving the protective performance of water-based coating

摘要:

∶利用水包油Pickering乳液界面诱导相分离的溶胶-凝胶一步法制备两亲性Janus介孔片,通过改变氨丙基三乙氧基硅烷(APTMS)和苯基三乙氧基硅烷(PETS)的加入量调节Janus片两侧的亲水性氨基基团(—NH₂)和疏水性苯基基团(—Ph)接枝量,制备了系列不同亲/疏水性的Janus片(α-Janus-β)。将α-Janus-β作为功能填料添加至水性环氧(WEP)涂料中,制备Janus/WEP复合涂层。APTMS与PETS质量比为2∶1时制备的Janus片(α₄-Janus-β₂)添加量为WEP 3%质量分数时分散性良好,且疏水侧自取向构筑阻隔保护层,显著提升WEP涂层的疏水性、耐腐蚀性等防护性能。WEP复合涂层的水接触角由59°提升至90°,电化学阻抗值在30天周期后仍可达到3.7×10₇ Ωcm₂^,经过1440 h盐雾测试后仍具有防护能力。

Abstract:

∶ Amphiphilic Janus sheets with mesoporous were synthesized by one-step method of sol-gel reaction via interface-induced phase separation of oil-in-water emulsions. The grafting amounts of hydrophilic amino groups (—NH₂) and hydrophobic phenyl groups (—Ph) on both sides of Janus sheets were adjusted by changing the addition amounts of 3-aminopropyltrimethoxysilane (APTMS) and phenyltriethoxysilane (PETS), respectively. A series of Janus sheets with different hydrophilic/hydrophobic properties (α-Janus-β) have prepared. Using α-Janus-β as functional fillers of the water-based epoxy (WEP) coating to prepare Janus/WEP composite coatings. Hydrophobic and corrosion resistance of WEP coating were significantly improved because of the good dispersion of hydrophilic groups and the barrier protective layer constructed by the self-orientation of the hydrophobic groups when adding the Janus sheets which prepared by setting the mass ratio of APTMS to PETS as 2:1 (α₄-Janus-β₂) with 3% mass fraction of the WEP. The water contact angle of the WEP composite coating is increased from 59° to 90°. The electrochemical impedance value of the coating could reach 3.7×10₇ ^Ωcm₂ ^{after a 30-day}s test cycle. The coating remained protection ability during salt spray test after 1440 h.