PVA/PAA-AM共混高吸水纤维的微观结构与吸液能力*

丙烯酸(AA)、丙烯酰胺(AM)为单体,在聚乙烯醇(PVA)溶液中共聚,由聚合物溶液纺丝制备高吸水纤维。用扫描电子显微镜(SEM)观察了纤维微观结构,结果表明,高吸水纤维具有微相分离结构,纤维表面形貌和横截面形状随纤维组成变化。从吸水溶胀后经液氮冷阱干燥的纤维干凝胶的SEM照片,可以观察到纤维内部存在原纤间交联网络和大量各向异性分布的长形孔洞,证实纤维具有三维网络结构并且吸收过大量的水。随AM加入量的增加,纤维的吸液能力先上升后下降, w〔AM/(AA+AM+PVA)〕=3%时,纤维吸蒸馏水倍率为 243,吸ρ(NaCl) =9g/L的盐水溶液倍率为 58。研究表明,较多的AM会导致共混结构不相容性增加,吸水能力下降。

Morphology and Absorbency of PVA/PAA-AM Blend Superabsorbent Fiber

The blend superabsorbent fibers of PVA/PAA-AM were prepared by copolymerization using acrylic acid(AA) and acrylamide(AM) monomers in polyvinyl alcohol(PVA) solution then solution spinning.Structures of the superabsorbent fibers were examined by use of SEM,which indicates that there is a microphase separation in the blend fibers and transverse section figure and superficiality of the fiber change with the composition of the fiber.From the SEM photos of the dry gels,which is dried by liquid nitrogen after absorbing water,we can observe cross-linked networks between the fibrillar structure and many long holes distributing anisotropically.These SEM photos prove the existence of three-dimensional net structure and that the superabsorbent fibers have absorbed a lot of water.The absorbency increased at first and then reduced as the content of AM increased.Wnen w〔AM/(AA+AM+PVA)〕=3%,absorbency of this fiber for distilled water was 243 g/g and 58 g/g for 0.9% NaCl aqueous solution.Overmuch AM resulted in more incompatibility and lower absorbency.