Weibin Bai

Poly(1,1'-binaphthol butyl ether) prepared by solid-state oxidative coupling polymerization and their nanospheres via the reprecipitation method

Poly(1,1′-binaphthol butyl ether)s have successfully been synthesized by solid-state oxidative polymerization of 1,1′-binaphthol butyl ether with FeCl3 as oxidant for 35 min at 25 °C. On the basis of FT-IR, 1H NMR and computational calculation results, the intermolecular 1, 4-linked coupling is the main way to extend the polymer chain, accompanied by the formation of intramolecular coupling. The increase of FeCl3 ratio can increase more fused aromatic structures in the polymer backbones to increase the conjugation length and coplanarity. The extended large π-conjugated structures not only improve the thermal stability of the polymers, but also control the emission wavelengths ranging from blue emission to green emission in solutions and blue emission to yellow emission in films. The polymeric spherical nanoparticles with sizes of 100 nm can be obtained by the reprecipitation method, and show a yellow-green emission at around 567 nm.

Bio-inspired electrochemical corrosion coatings derived from graphene/natural lacquer composites

Protective corrosion coatings are preferably composed of available, environmentally friendly, and low-volatility organic compounds. Herein, new excellent corrosion graphene/raw lacquer composite coatings were formed, in which waterborne graphene was modified by taking lignin tripolymer (LT) as an aqueous stabilizer and subsequently adding to raw lacquer (RL). Graphene/lacquer composite coatings were achieved by an eco-friendly fabrication process. The structure and thermostability of the lignin derivative were studied by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TG), respectively, while the composition of the LT was characterized by Raman spectrometry. And the experimental result revealed that LT was an effective graphene dispersant (LTG) up to 60 d without any precipitation. Besides, the SEM of the graphene/lacquer coatings revealed that the excellent protection properties were highly attributable to the formation of a very rough surface, because of the highly dispersed nature of the graphene nanoparticles. Also, the corrosion behavior of the composite coatings on a metal substrate were studied by polarization curve analysis and electrochemical impedance spectroscopy (EIS). According to the electrochemical corrosion tests, the lacquer composite coating with 5 wt% LTG dispersion (RL/LTG-5, containing 0.3 wt% graphene) possessed excellent corrosion resistance, making it suitable for protecting bare metal substrates.

Effect of Silane on the Active Aging Resistance and Anticorrosive Behaviors of Natural Lacquer

Environmentally friendly and renewable hybrid lacquer coatings with excellent aging resistant and anticorrosion properties were studied. The coatings were prepared using raw lacquer coupled with the silane agent 3-aminopropyltriethoxysilane or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane via an eco-friendly sol–gel preparation process. The physical–mechanical properties, thermal stability, aging resistance, and anticorrosion properties of the as-prepared coatings were analyzed. Additionally, the surface of the coatings before and after an accelerated aging treatment was studied by scanning electron microscopy and X-ray photoelectron spectroscopy. The results revealed that the hybrid lacquer coating A (with a raw lacquer-to-APTES mass ratio of 1.8:1) resulted in films with a significantly enhanced antiaging effect (e.g., six times higher than that of lacquer at a gloss loss rate of 30%). Besides, this film revealed an exceptional anticorrosion performance (with the lowest corrosion current Icorr = 2.476 × 10–10 A·cm–2) and a high protection efficiency (99.99 and 94.10%), as demonstrated by its electrochemical characteristics. Furthermore, all films exhibited a good barrier because of their dense structure, which prevents the corrosive medium from penetrating the coating during the salt spray test analysis after 1000 h. And the coating A relatively layered was distributing any significant cancaves, integrity better than all coatings studied, indicating that the based electrolyte was easier to penetrate it after salt spraying 2000 h.