Jinhuo Lin

On the UV-Induced Polymeric Behavior of Chinese Lacquer

To dry Chinese lacquer rapidly for the protection and restoration of archeological findings coated by lacquer or excavated lacquer wares and the development of new application of this lacquer, we carried out UV curing technology to improve its curing rate using a high-pressure mercury lamp as a UV source in the absence of any additional photoinitiator. The effects of mainly specific components in Chinese lacquer sap and the role of each reactive group of urushiol, namely hydroxyl groups, hydrogen on the phenyl ring, and olefins in the side chain, in the course of UV exposure were well-investigated. The UV-cured Chinese lacquer films were also characterized by FT-IR, (1)H NMR, SEM, TGA, and Py-GC/MS. The results showed that urushiol was the main component to form Chinese lacquer films, and decomposed to generate the urushiol semiquinone radicals, which sequentially induced the polymerization of Chinese lacquer by radical polymerization, as well as radical substitution under UV irradiation. In addition, the TG analysis suggested that polysaccharide and glycoproteins were integrated with the UV-cured films by covalent bonding. Furthermore, this method could be suitable to fast cure other phenol bearing long aliphatic unsaturated chain, such as CNSL.

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.

Novel Anisotropic Janus Composite Particles Based on Urushiol-erbium Chelate Polymer/Polystyrene

Janus particles are mainly composed of synthesis polymer. Herein, the natural product of urushiol is used to fabricate Janus particles. The erbium ion absorbed on polystyrene (PS) reacted with urushiol and then the urushiol-erbium chelate polymer (UEr) shell formed. The UEr-PS Janus particles originated from the swelling of UEr/PS core-shell structure. The UEr-PS Janus particles were compartmentalized into two parts with different morphologies and chemical compositions. The thickness of the UEr shell could be controlled by adjusting sulfonated time. The UEr-PS Janus particles possess the characteristics of urushiol and erbium, which can be used in oriented materials.

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.