摘要
以过硫酸胺为引发剂 ,在PVA水溶液中原位聚合丙烯酸单体 ,得到的PVA/PAA混合水溶液在凝固浴硫酸胺饱和水溶液中纺丝制备了物理缠结和氢健固定网络形式的PVA/PAA水凝胶纤维。该纤维于NaCl溶液中在直流电场作用下具有电流 -刺激敏感性 ,表现为溶胀、收缩、弯曲行为。纤维的弯曲速度和最大弯曲度随电场强度和凝胶网络中PAA含量的增加而增大 ,随电解质溶液离子强度的变化出现临界最大值。纤维向负极弯曲的过程中 ,在电场作用下自由离子和反离子迁移引起的渗透压起主导作用 ,弯曲过程主要是溶胀弯曲 ;向正极弯曲过程中 ,由于电化学反应和电场作用产生的 pH梯度导致凝胶网络构像变化起主导作用 ,弯曲主要是收缩弯曲 ;弯曲由负极向正极转化过程中 。
Using ammonium peroxodisulfate (APS) as initiator, AA monomer was in situ polymerized in PVA aqueous solution and the transparent PVA/PAA blending solution was get. Then the entanglement and hydrogen bonding crosslinked PVA/PAA hydrogel fiber was prepared by spinning the blending solution in saturated ammonium sulfate aqueous solution. The fiber exhibited electric current sensitive behavior showing swelling, contracting and bending. Bending speed and maximum bending degree of the hydrogel fiber increased with the increasing of electric field density and PAA content within the gel network. And there was a critical maximum value as ionic strength increased in NaCl aqueous solution. For the bending of the fiber toward the negative electrode, the osmotic pressure of the fiber between the positive and the negative electrode side caused by the movement of the free ions toward the counterelectrodes played a dominant role, and the bending is swelling bending. For the bending of the fiber toward the positive electrode, conformation changing of the gel network caused by pH gradient which induced by the electrochemical reactions and the electric field played an important role, and the bending is the contracting bending. In the conversing course, the effects to the bending of the fiber from the two roles are contra balances.
出处
《功能高分子学报》
CAS
CSCD
2001年第2期185-189,共5页
Journal of Functional Polymers
