氧化海藻酸钠/聚丙烯酰胺水凝胶的制备与表征

通过水-乙醇和水-正丙醇两种不同的溶剂体系制备高分子量和不同氧化度的氧化海藻酸钠(OSA),然后引入聚丙烯酰胺(PAM)交联网络结构,通过二步法获得OSA/PAM复合水凝胶。探讨了不同反应体系下,HCl体积分数对OSA分子量的影响以及氧化剂(高碘酸钠NaIO_4)添加量、反应时间对OSA氧化度的影响规律。结果表明:在水-正丙醇体系下,HCl体积分数为24vol%时,氧化海藻酸钠的分子量达到170 000;调节NaIO_4的添加量和反应时间可以控制OSA的氧化度在10%~85%范围内变化。在此基础上对OSA/PAM复合水凝胶的溶胀率和力学性能进行了探讨,发现氧化度10%的复合水凝胶48h后的溶胀率达1 777%,断裂强度为0.11MPa,随着OSA氧化度的增大,OSA/PAM复合水凝胶的溶胀率增大,而拉伸强度逐渐减小。

Preparation and characterization of oxidized sodium alginate/polyacrylamide composite hydrogels

Oxidation of sodium alginate (OSA)with high molecular weight and different oxidation degree was pre-pared by water-ethanol and water-n-propanol system,then the poly-acrylamide (PAM)cross-linked network struc-ture was introduced.The OSA/PAM composite hydrogel was obtained by the two-step method.The effects of the volume fraction of HCl on the molecular weight of OSA as well as the influence rules of the amount and reaction time of oxidant (sodium periodate NaIO4 )on the oxidation degree were investigated under different reaction conditions. The results show that the molecular weight of oxidized sodium alginate can reach 170000 when the volume fraction of hydrochloric acid is 24vol% in water-n-propanol system.Adjusting the addition of NaIO4 and the reaction time can control the variety of oxidation degree of OSA in the range of 10%-85%.Based on this,the swelling and me-chanical experiments of OSA/PAM composite hydrogels were studied,showing that the swelling rate of OSA/PAM composite hydrogel with 10% degree of oxidation is 1777% after 48 h and the breaking strength is 0.11 MPa.In addition,with the increase of the degree of oxidation of OSA,the swelling rate of OSA/PAM composite hydrogel increases and the tensile strength decreases.