New Superabsorbents Preparation, Characterization And Anticoagulant Study

Based on the intercalation, composition and nano-modification theories on layered minerals and polymer matrixes, in this paper, montmorillonite has been introduced into superabsorbent to modify its properties, and novel poly (acrylic acid)/ montmorillonite superabsorbent nanocomposites have been synthesized using acrylic acid together with organic-montmorillonite and sodium type montmorillonite respectively. Effects of various main factors on water (saline water) absorbency were systemically investigated. The structure and surface morphology of the superabsorbent nanocomposites have been characterized by Fourier transform infrared spectroscope (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that montmorillonite reacted with acrylic acid monomers during polymerization, and its layers exfoliated and dispersed in the composite at nano size after copolymerization. The introduction of appropriate amount montmorillonite largely increased the water (saline water) absorbency of the superabsorbents.In order to modify the dense of the hydrophilic groups of the superabsorbents, as well as reutilize wast polymer , a rigid and hydrophobic polystyrene chain have been introduced into the superabsorbent, and novel superabsorbent nanocomposites based on partially neutralized acrylic acid, waste polystyrene foam and sodium type montmorillonite powder have been synthesized. The properties of the superabsorbents, effects of various main factors on water (saline water) absorbency have been systemically investigated. The structure, surface morphology and thermal stability of the composites were characterized by FTIR, XRD, SEM and thermo gravimetric analysis (TGA). The results show that montmorillonite reacted with acrylic acid monomers during polymerization and its layers exfoliated and dispersed in the composite at nano size after copolymerization. The addition of montmorillonite not only increased the water absorbency of the composite, but also enhanced its thermal stability and water retention ability. The introduction of rigid hydrophobic PS chain can effectively reduce the 'flour conglomeration effect', thus increase the absorbency rate of the composite.Based on anticoagulation principle of materials and the properties of the superabsorbents, two superabsorbents (PAA, PAA/MMT) are selected to investigate their blood compatibility through three commonly used intuitionistic methods. The results show that PAA/MMT nanocomposite, as well as PAA superabsorbent, has very slight interaction with blood cells. And their hemolysis ratios are less than 5%, which is the international hemolysis standard for biomaterials. The coagulation time of PAA and PAA/MMT are 620s and 766s, which are much longer than that of the blank samples (213s and 359s). The recalcification times of the samples, compared with the blank sample, are obviously prolonged, especially when MMT has been added into the superabsorbent, which means the synthesized superabsorbant can remarkably postpone the activation of coagulation factors and intrinsic coagulation system, and can markedly increase the resistance of intrinsic coagulation route.