多醛基海藻酸钠交联剂的制备及性能

Preparation and Characterization of Crosslinker of Multi-aldehyde Sodium Alginate

采用水/乙醇为反应溶剂,用高碘酸钠氧化海藻酸钠,制备了多醛基海藻酸钠(multi-aldehyde sodium alginate,MASA)。采用费林试剂、盐酸羟胺-NaOH电位滴定法、乌氏粘度计、与明胶的交联反应分别对氧化后的海藻酸钠进行表征。结果发现,氧化的海藻酸钠溶液可与费林试剂反应生成砖红色沉淀;海藻酸钠的氧化度随高碘酸钠用量及反应时间的增加而增加。投料比为80%时,氧化度最高可达约80%,收率约58.7%。MASA的粘度随反应时间、高碘酸钠浓度的增加而急剧下降。氧化度分别为20%、40%、60%的MASA,37℃下可使明胶在5min内生成凝胶。因此,水/乙醇作为反应介质、通过控制氧化剂的用量和反应时间,可以得到产率较高、分子量及氧化度可控的多醛基海藻酸钠多糖交联剂。

Multiple aldehyde groups （MASA） was prepared using sodium metaperiodate as an oxidant to oxidize sodium alginate（SA）, in the mixed solvents of water and ethyl alcohol. The oxidized sodium alginate was characterized by Fehling＇ s reagent, electric titration of hydroxylamine hydrochloride-NaOH, Ubbelohde viscometer and the crosslink reaction with gelatin. Results show that the oxidized sodium alginate reacted with Fehling＇s reagent in solution to form brick-red precipitate. The oxidation degree increased with the increases of the concentration of sodium metaperiodate and reaction time. The maximum of oxidation degree reached about 80% when the molar ratio of sodium periodate to monomer unit of sodium alginate was 80% and the yield was about 58.7%. The viscosity decreased rapidly with the increases of the concentration of sodium metaperiodate and reaction time. MASA with an oxidation degree of 20%, 40% or 60% gelled gelatin within 5 min at 37 ~C. Thereby, polysaccharide crosslinker of multi-aldehyde sodium alginate with controllable molecular mass and oxidation degree could be prepared in a high yield by adjusting the concentration of sodium metaperiodate and reaction time in a water-ethanol medium.