Study On Preparation And Properties Of Fe₃O₄/polyvinyl Alcohol (PVA) Magnetic Hydrogels

Polyvinyl alcohol(PVA) hydrogel with good biocompatibility and high mechanical properties is an ideal artificial cartilage material,polyvinyl alcohol(PVA) and polyvinyl pyrrolidine(PVP) are naturally degradable biopolymers.Magnetic materials have especial magnetic.The micron Fe₃O₄/ PVA,nano Fe₃O₄/ PVA, micron Fe₃O₄/PVP/PVA magnetic hydrogels were prepared by freezing-thawing techniques.Comparing the properties of different compositions hydrogels,the good swelling,magnetic properties and other properties were showed.The three series of different composition magnetic hydrogels were signed:the micron Fe₃O₄ / PVA magnetic hydrogels was named number 1,the nano Fe₃O₄ / PVA magnetic hydrogels was number 2 and micron Fe₃O₄/PVP/PVA magnetic hydrogels was number 3.Electronic balance,XRD,TG,SEM,tensile testing machine, properties detect system(PPMS),magnetic electromotor were used to investigate the swelling,re-swelling,tensile property,thermal property and magnetic.The results showed that:First,XRD results analysis:the cross-linking density of the three set of magnetic hydrogels increased with the increasing freezing-thawing times.The SEM showed that Fe₃O₄ particles were cross-linked by PVA,it was the basic condition the magnetic hydrogels contain mechanical property and magnetic property together.Secondly,the network cross-linking points have an effect to swelling.The improvement of cross-linking density leaded the swelling rate of magnetic hydrogels reduced with the increasing freezing-thawing times.The swelling rate of number 1 hydrogels were from2 to 7.5,and that of number 2 hydrogels were from 3.5 to 10, that of number 3 hydrogels were from 3 to 11.The swelling rates of Number 2 and number 3 hydrogels were the same almost.The re-swelling rates all of hydrogels reduced with the increasing freezing-thawing times.At the balance points,the re-swelling rate of numberl hydrogels were from 5 to 0.6,that of number 2 were less than 1,and that of number 3 were from 1.8 to 0.7.The third,the bonds force between PVA and Fe₃O₄ particles became stronger and the mechanical property increases with the increasing magnetic particle.And the improvement of cross-linking density leaded mechanical property of magnetic hydrogels increased with the increasing freezing-thawing times.The fourth,The thermal stability was descended by adding Fe₃O₄ magnetic particles,and the thermal stability of magnetic hydrogel containing Fe₃O₄ nano-particles was not as good as the other two groups.The fifthly,the saturation magnetization and residual magnetization of number 1 samples were increased with the increasing magnetic particles concentration and freezing-thawing times;the saturation magnetization of number 2 samples was so,too.But the residual magnetization changed a little with the increasing freezing-thawing times,the number 2 Magnetic hydrogels showed superparamagnetic properties for the low residual magnetization.