嫁接
过硫酸铵
肿胀 的
高分子化学
化学
壳聚糖
丙烯酸
过硫酸钾
蒸馏水
水溶液
核化学
自愈水凝胶
共聚物
化学工程
单体
有机化学
聚合物
色谱法
工程类
作者
Mehrdad Yazdani‐Pedram,Jaime Retuert,Raúl Quijada
标识
DOI:10.1002/1521-3935(20000601)201:9<923::aid-macp923>3.0.co;2-w
摘要
A large number of carboxylic groups were introduced onto chitosan by grafting with poly(acrylic acid) as an efficient way of modification. The reactions were carried out in a homogeneous aqueous phase by using potassium persulfate and ferrous ammonium sulfate as the combined redox initiator system. The efficiency of grafting was found to depend on monomer, initiator, and ferrous ion concentrations as well as reaction time and -temperature. It was observed that the level of grafting could be controlled to some degree by varying the amount of ferrous ion used as a co-catalyst in the reaction. Evidence of grafting was obtained by comparison of FTIR spectra of chitosan and the graft copolymer as well as solubility characteristics of the products. The swelling behavior of chitosan samples, grafted with 115% and 524% poly(acrylic acid), was studied as function of pH, in distilled water and in aqueous NaCl solution. The sample that has 115% grafting swells considerably more both in distilled water (pH 5.8) as well as higher pH values than the sample with 524% grafting. In contrast, an inverse swelling behavior at pH 2 was observed. An unusual swelling behavior at pH 2 was found for the sample with 524% grafting, which swells to a greater extent than in distilled water. This was attributed to the amphiphilic nature of the modified chitosan from which complex inter- and/or intramolecular interactions could originate.
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