摘要
采用中性氧化法利用过氧化氢氧化降解羧甲基壳聚糖得到不同分子量梯度的产物。在海水体系中,通过失重试验测定了不同浓度羧甲基壳聚糖及其降解产物对低碳钢的缓蚀效率,并用电化学方法和椭圆偏振法分析了缓蚀机理。结果表明,增加过氧化氢用量有利于降低降解产物分子量;羧甲基壳聚糖及其降解产物的缓蚀效率随其浓度的增加而提高,但分子量大小的改变对缓蚀效率的影响不大;极化曲线分析表明,该类缓蚀剂为抑制阴极过程为主的混合型缓蚀剂;椭圆偏振法分析表明,羧甲基壳聚糖及其降解产物为多层吸附,随着分子量减小,吸附层厚度增厚,而分子量越大,吸附点越多,吸附越牢固。
Hydrogen peroxide was used to oxidize and degrade crboxymethyl chitosan via neutral oxidation route, generating degraded products with different molecular weights. The molecular weights of the degraded products were measured using viscosity analysis method. The inhibitive properties of carboxymethyl chitosan and its degradation products for mild steel in seawater were studied using weight loss method, and the inhibitive mechanisms were analyzed using electrochemical and ellipsometrical method. Results showed that the molecular weight of the degraded products decreased with increasing quantity of hydrogen peroxide, while the inhibitive effect of carboxymethyl chitosan and its degraded products increased with increasing dosage of hydrogen peroxide. The best inhibitive effect was obtained at a hydrogen peroxide dosage of 800 mg/L, but the inhibitive effect kept almost unchanged with varying molecular weight of the degraded products. Analysis of the polarization curve indicated that carboxymethyl chitosan and its degradation products were mixed-type inhibitors dominated by cathodic inhibition. Moreover, as evidenced by ellipsometric analysis, carboxymethyl chitosan and its degraded products experienced multi-layer absorption on carbon steel surface. The thickness of the inhibitive film increased with decreasing molecular weight of the degraded products, while the degraded products with larger molecular weights had more adsorption sites and stronger adsorption as well.
出处
《材料保护》
CAS
CSCD
北大核心
2008年第6期1-4,共4页
Materials Protection
基金
中国科学院知识创新工程(KZCX2-YW210)
青岛市科技发展计划项目(05-1-JC-87)
关键词
羧甲基壳聚糖
降解产物
缓蚀作用
低碳钢
极化曲线
椭圆偏振
carboxymethyl chitosan
degraded product
inhibitive performance
mild carbon steel
polarization curve
ellipsometry
