Double-Layer Coating Films Prepared from Water-Borne Latexes of Acrylate鈥揤inylidene Chloride Copolymers: Investigating Their Heavy-Duty Anticorrosive Properties

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• 作者：Ce Fu ; Tong-Xian Zhang ; Fa Cheng ; Wen-Zhu Cui ; Yu Chen
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：March 26, 2014
• 年：2014
• 卷：53
• 期：12
• 页码：4534-4543
• 全文大小：534K
• 年卷期：v.53,no.12(March 26, 2014)
• ISSN：1520-5045

文摘

Aqueous latexes of copolymers of vinylidene chloride (VDC) with an acrylate, namely, methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), or 2-ethylhexyl acrylate (EHA), were employed to form a double-layer coating film for the heavy-duty anticorrosion of metal. Measurements of the water-vapor transmission rate and oxygen-gas transmission rate and electrochemical impedance spectroscopy (EIS) demonstrated that the barrier properties of MA鈥揤DC and EA鈥揤DC films were better than those of BA鈥揤DC and EHA鈥揤DC films. Among the MA鈥揤DC and EA鈥揤DC coatings, EA鈥揤DC85 showed better comprehensive properties and, thus, was selected as the top layer of the designed double-layer coating film. Adhesion tests demonstrated that the BA鈥揤DC and EA鈥揤DC coatings had better adhesion to tinplates than the MA鈥揤DC and EA鈥揤DC coatings and, thus, were suitable for use as the bottom layer of the designed double-layer coating film. The characterizations of the double-layer coating films by adhesion tests and EIS showed that BA鈥揤DC75 was the optimal bottom layer. Under harsh salt-spray corrosion conditions, the optimal double-layer coating film (ca. 50-渭m thickness) with EA鈥揤DC85 as the top layer and BA鈥揤DC75 as the bottom layer could protect tinplate well for at least 800 h, and the adhesion of the coating film to the tinplate was still excellent even after 1000 h of corrosion. Scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy were used to evaluate the corroded double-layer coating films.