CS-PAA聚电解质络合物的形成及其机理研究

Study on Formation and Mechanism of CS-PAA Polyelectrolyte Complex

壳聚糖 (CS)和聚丙烯酸 (PAA)在不同的 p H值下以不同的比例混合 ,当离子强度在 0 .1～ 0 .3范围内时 ,形成的聚电解质络合物 (PEC)的量通过测定悬浊液在 42 0 nm处的浊度来确定 .在 p H=2时 ,没有 PEC生成 ;在 p H=3～ 6时 ,PEC形成的最大量出现在不同的混合比处 .该范围内离子强度对 PEC的形成影响并不大 .通过对上清液 p H值的测定分析得知在 p H=3～ 5时 ,混合物的 p H值随着 PEC的生成量增大而减少 ,而在 p H≥ 6时 ,混合物的 p H值随着 PEC的生成量增大而增大 .由此可推测 PEC形成的机理是 PAA的羧基和 CS的氨基基团之间发生静电作用 ,这一点亦可通过对不溶的 PEC的红外光谱进行分析来证实 .

Chitin (CS) and polyacrylic acid (PAA) are complexed on the different values of pH with different mixing proportions. When ion strength between 0.1 and 0.3, the polyelectrolyte complex (PEC) will be formed. The mass of PEC was obtained by testing the turbidity of suspension solution which at 420 manometer. When pH=2, the PEC was not produced, when the value of pH from 3 to 6, the maximum mass of formed PEC appeared at different mixture ratio points. Ion strength affect little the formation of the PEC. By testing the value of pH of up\|layer clean solution we could know that when pH value from 3 to 5, the value of pH of mixing solution was decrease followed the rising of the formed PEC mass, and when pH≥6, its rise followed the rising of the PEC mass, too. So we think that there has the electrostatic action between the carboxylic group of PAA and amino group of CS, and it is the mechanism of PEC formation. This was proved by the analysis of FT\|IR spectrum.