多糖类高分子材料海藻酸钠的辐照降解
Radiation-Induced Degradation of Polysaccharide Sodium Alginate
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摘要: 对大分子量海藻酸钠进行了60Coγ辐照降解，并利用多角度激光光散射仪与凝胶渗透色谱仪联接系统（MALLS/GPC）测量了其辐照前后的绝对分子量变化。实验发现，当吸收剂量率为80Gy/min、吸收剂量为0～60 kGy时，随吸收剂量的增大，海藻酸钠的分子量减小，重均分子量（Mw）从321596.5降至10024。同时，随着吸收剂量的增大，海藻酸钠分子量分布宽度变窄，积分分子重量占83.22%的单峰的Mw降为6 000。分子量小于10 000的海藻酸钠因具有优良的理化性质并能被人体很好吸收，在农业、医药和美容等领域有广泛的应用前景。通过对辐照后分子量分布曲线中出现的各峰值的计算，发现在辐照过程中除产生聚合度不等的海藻酸钠外，还产生了少量的新组分，这些新组分需进一步分离纯化，检测其生物毒性。Abstract: The radiation-induced degradation of sodium alginate by 60Coγ-rays was investigated in air at ambient temperature, and the change in their molecular weights was measured by multi-angle laser light scattering detector equipped with gel permeation chromatography (MALLS/GPC). The molecular weight of sodium alginate decreases with the increase of absorbed dose in the range of 0-60 kGy at the dose rate of 80 Gy/min. The dispersion of molecular weight distribution of sodium alginate becomes narrow along with the absorbed dose. The weight-average molecular weight (Mw) changes from 321 596.5 to 10 024 when the absorbed dose increases from 0 kGy to 60 kGy. It is found that the degraded sodium alginate with molecular weight peak of 6 000 is 83.22% of cumulative weight fraction. Anyway, the sodium alginate may have comprehensive application in the fields of agriculture, medicine and cosmetology as it can be absorbed well by biological tissue, if its weight-average molecular weight is below 10 000. It is also found that new components will be contained in the products of sodium alginate degraded by irradiation. The further study dealing with the checking the biological safety and purification shall be performed.
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