In this work, the accelerated weathering test of immersion-wet-dry combined cycles was carried ont. The artificial acid rain of NaHSO3-(NH4)2SO4-H2SO4 solution system was selected as immersion solution. Acidity of art...In this work, the accelerated weathering test of immersion-wet-dry combined cycles was carried ont. The artificial acid rain of NaHSO3-(NH4)2SO4-H2SO4 solution system was selected as immersion solution. Acidity of artificial acid rain affected corrossion weight loss of carbon steel, and pH 4.1 was found to be a critical point. Anodic reaction resistance of the samples during accelerated weathering test increased with exposed time by electrochemical measurement.展开更多
LDPE （low-density polyethylene） photo degraded through various accelerated weathering tests has the molecular weight distribution curves unlike that through outdoor exposure. The authors therefore developed new weat...LDPE （low-density polyethylene） photo degraded through various accelerated weathering tests has the molecular weight distribution curves unlike that through outdoor exposure. The authors therefore developed new weathering test condition based on the existing accelerated weathering test using a xenon arc lamp. Samples of LDPE were photo degraded using various accelerated weathering test conditions and outdoor exposure. The physical properties and chemical structures of the photo degraded samples were studied through a tensile test, infrared spectroscopy, and gel chromatography. The authors found that the molecular weight distribution curve of a sample photo degraded using a xenon lamp at a higher BPT （black panel temperature） （73 ~C） was more similar to that of an outdoor-exposed sample than that of a sample photo degraded at the standard BPT （63 ~C）. It is considered that higher temperature accelerates radical recombination, consequently recreating molecular enlargement similar to the outdoor-exposed sample. Multiple regression analysis using newly introduced Mp （peak-top molecular weight） and Mw （weight-average molecular weight） as explanatory variables was conducted, which successfully enabled the authors to provide a simple explanation for the decrease in polymer tensile strength.展开更多
Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450 EW weathering steel in cyclic immersion test was s...Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450 EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450 EW weathering steel is closely related to chromium content. The addition of chromium significantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m-2·h-1. The rust of S450 EW weathering steel was mainly constituted of Fe OOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-Fe OOH. The fine precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneficial for the cure of original defects and cracks of the rust layer via the enrichment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450 EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.展开更多
文摘In this work, the accelerated weathering test of immersion-wet-dry combined cycles was carried ont. The artificial acid rain of NaHSO3-(NH4)2SO4-H2SO4 solution system was selected as immersion solution. Acidity of artificial acid rain affected corrossion weight loss of carbon steel, and pH 4.1 was found to be a critical point. Anodic reaction resistance of the samples during accelerated weathering test increased with exposed time by electrochemical measurement.
文摘LDPE （low-density polyethylene） photo degraded through various accelerated weathering tests has the molecular weight distribution curves unlike that through outdoor exposure. The authors therefore developed new weathering test condition based on the existing accelerated weathering test using a xenon arc lamp. Samples of LDPE were photo degraded using various accelerated weathering test conditions and outdoor exposure. The physical properties and chemical structures of the photo degraded samples were studied through a tensile test, infrared spectroscopy, and gel chromatography. The authors found that the molecular weight distribution curve of a sample photo degraded using a xenon lamp at a higher BPT （black panel temperature） （73 ~C） was more similar to that of an outdoor-exposed sample than that of a sample photo degraded at the standard BPT （63 ~C）. It is considered that higher temperature accelerates radical recombination, consequently recreating molecular enlargement similar to the outdoor-exposed sample. Multiple regression analysis using newly introduced Mp （peak-top molecular weight） and Mw （weight-average molecular weight） as explanatory variables was conducted, which successfully enabled the authors to provide a simple explanation for the decrease in polymer tensile strength.
基金Item Sponsored by National Natural Science Foundation of China(51104039)Fundamental Research Funds for the National Key Basic Research Program of China(2012CB626812)
文摘Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450 EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450 EW weathering steel is closely related to chromium content. The addition of chromium significantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m-2·h-1. The rust of S450 EW weathering steel was mainly constituted of Fe OOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-Fe OOH. The fine precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneficial for the cure of original defects and cracks of the rust layer via the enrichment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450 EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.
