Corrosion behavior of 3wt.% Cr low alloy steel in aqueous CO2‐H2S environment was investigated in comparison with API X60 carbon steel using high temperature and high pressure autoclave. The corrosion performance of 3Cr steel was analyzed by XRD, XPS, SEM, EDS and EIS. In CO2‐H2S environment, the corrosion scale of 3Cr steel possessed a triple structure of the outer layer of FeS, the middle layer of FeCO3 and the inner layer of FeCO3, Cr(OH)3 and Cr2O3. FeS mainly formed through the dissolution and re‐deposition from FeCO3. Hydrolytic action of Cr3+ during corrosion affected the formation process of corrosion scale of 3Cr steel. The Cr‐rich layer of the corrosion scale of 3Cr steel blocked the ions transport through corrosion scale to improve corrosion resistance of 3Cr steel. For H2S‐containg CO2 environment, 3Cr steel still exhibited higher corrosion resistance than X60 carbon steel and would be a promising material option in such environment.
PurposeTo evaluate the competing reaction of isocyanate with cellulose and water which can provide direction for further studies on bonding and curing reactions of isocyanate with wood.Design/methodology/approachTwo modern analytical techniques, Fourier transform infra‐red (FTIR) and X‐ray photoelectron spectroscopy (XPS), were used. The FTIR was used to identify the products of the reaction of phenyl isocyanate (PI) with alcohol, water, and cellulose; while the XPS was used to evaluate the proportions of isocyanate that reacted with water or cellulose when PI reacted with cellulose at different moisture contents (MCs), respectively.FindingsMethods for the IR identifications of reaction results of PI with n‐propanol, water, and cellulose, in which the reactions of PI with water and PI with cellulose resulted in N,N′‐diphenylurea and carbamate, respectively, were developed. It was discovered that the extent of reaction of isocyanate and cellulose decreased with increasing cellulose MC, and 92.98 per cent isocyanate reacted with water when 9.78 per cent MC was reached. It was confirmed that the products of the PI reaction were distributed mainly on the surface of the cellulose particles.Research limitations/implicationsThe study only focused on the reaction of PI. However, the industrial isocyanates, e.g. methylene diphenyl diisocyanate (MDI), polymerized methylene diphenyl diisocyanate (p‐MDI) that have complexities in chemical structures and components, make analyses with FTIR and XPS impossible.Practical implicationsThe paper provides some instructive information about the isocyanate reaction that will help understanding the characteristics of isocyanate and guiding the design of technology bonding isocyanate to fibre, wood, etc.Originality/valueThe application of FTIR and XPS for evaluating the reaction of isocyanate with cellulose having different MCs was novel and may be used as a reference for other relevant studies.
In this study, a reactive hindered phenol antioxidant, 3,5‐di‐tert‐butyl‐4‐hydroxyphenyl methyl isobutylene ester (DBHMIE), was synthesized and used to improve the antioxidant performance of ABS (acrylonitrile‐butadiene‐styrene terpolymer) resin. The chemical structure of DBHMIE was determined with Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), and 13C NMR spectroscopy. Moreover, the effects of the DBHMIE content on the antioxidant capabilities, thermal stabilities, tensile strengths, impact strengths, and morphologies of the ABS/antioxidant systems were investigated. The results indicated that the oxidation induction temperatures of the systems increased from 229.7 to 245.4°C as the DBHMIE content was increased from 0 to 0.5 wt%. The 5% mass loss temperature of the system was increased from 338.4 to 347.8°C by the addition of 0.3 wt% DBHMIE. The impact strengths of the systems increased with increasing DBHMIE content up to 0.1 wt% and then decreased. The addition of DBHMIE did not significantly affect the tensile strength of the ABS resin. SEM images showed that the DBHMIE was uniformly distributed in the ABS resin at low DBHMIE contents and agglomerated at high DBHMIE contents.
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