PASP/PAA互穿网络水凝胶的制备及其作为保水剂的应用

Preparation of PASP/PAA interpenetrate networks hydrogel and its application in water retaining agent

摘要:

采用水相法成功制备了聚天冬氨酸-聚丙烯酸互穿网络水凝胶（PASP/PAA IPN），通过正交设计优化制备工艺，利用红外光谱（FT-IR）、扫描电镜（SEM）和热分析法（TG-DSC）对PASP/PAA互穿水凝胶的结构及性能进行表征，考察了PASP/PAA互穿水凝胶在不同温度及pH条件下的吸水率，最后作为保水剂进行盆栽试验。结果表明，互穿网络组成对水凝胶的稳定性和吸水性具有明显的影响，综合水凝胶稳定性和吸水性，选择最终工艺为丙烯酸加入量2 mL，交联剂EGDE用量1 g，交联剂MBA用量16 mg。所得PASP/PAA互穿水凝胶吸液倍率为266 g/g、吸盐水倍率为63 g/g，具有良好的热性能，pH敏感性和温度敏感性。盆栽试验证明PASP/PAA互穿水凝胶无论正常浇水还是干旱胁迫下，其生长情况、光合速率及叶绿素含量均优于市售PAA保水剂，其中光合速率较PAA保水剂分别高7.82%，53.4%；叶绿素含量较PAA保水剂分别高58.33%，249.7%。

Abstract:

The polyaspartic acid-polyacrylic acid interpenetrating network hydrogel (PASP/PAA IPN) were successfully prepared by solvent-free processes. The preparation process was optimized by orthogonal design. The structure and properties of PASP/PAA IPN hydrogel were characterized by FT-IR, SEM and TG. The water absorption at different temperatures and pH conditions was also investigated. Finally, the prepared hydrogel were used as water retaining agent for pot experiment. The results show that the composition of the interpenetrating network has a significant effect on the stability and water absorption of the hydrogel. Based on the combination of stability and water absorption, the final process was selected to 2 mL of acrylic acid, 1 g of EDGE and 16 mg of MBA. The obtained PASP / PAA IPN hydrogel has a liquid absorption rate of 266 g/g and a saline absorption rate of 63 g/g, and has good thermal properties, pH sensitivity and temperature sensitivity. Pot experiment show that the growth, photosynthetic rate, and chlorophyll content of the PASP/PAA IPN hydrogel were better than those of commercially available PAA water-retaining agents under normal watering or drought stress. The photosynthetic rate was 7.82% (normal watering) and 53.44% (drought stress) higher than PAA water-retaining agent, respectively. The chlorophyll content was 58.33% (normal watering) and 249.7% (drought stress) higher than PAA water-retaining agent, respectively.