Swelling Properties In Vitro Experiment Contrast Of Three Kinds Of Super-absorbent Polymer Resin

[Objective] To study three kinds of super-absorbent polymer-polyvinyl alcohol (PVA), polyacrylamide (PAM) and poly (methyl methacrylate and vinyl pyrrolidone)[P (MMA-VP)], in vitro experiments contrast, expecting to find a water gel with high swelling degree, just needing small volume implanted into the organization to get much soft tissue increment.[Methods] Prepared PVA and PAM by high temperature dissolving, freezing and unfreezing cycle, using vacuum dry oven to get the volume for18mm X5mm X4mm dry gel. Compared PVA and PAM dry gel with P (MMA-VP),German Osmed company production, in characterizing the whole first, then water absorption, swelling rate and recorded the swelling degree changes of the three gels in simulated body fluid in3d、18d and25d. And also recorded swelling degree changes in the simulated body fluid under the condition of pressure. Finally sorted data, analyzed statistics, and drew the swelling degree curve, comparing the study of observation of the swelling degree of change.[Results](1) The water swelling rate in15wt%of PVA than20wt%and25wt%was greater; On the contrary, the small water swelling rate in25wt%of PAM than20wt%and15wt%was greater4-5times. (2) In simulated body fluid, the concentration of15wt%PVA hydrogel was minimum of swelling degree, the swelling trend was the most gentle within72h,and the change of volume was the smallest in three; The concentration of25wt%PAM’s swelling degree in42hours got to a maximum size, after42hours the volume decreased, and later fractured; P (MMA-VP) got to maximum volume quickly in36h, and maintained the maximum volume of the swelling degree after36hours, no longer changing; In simulated body fluid the maximum swelling degree of25wt%of PAM and P (MMA-VP) was lager about4-5times than15wt%of polyvinyl alcohol.(3) The volume swelling degree of P (MMA-VP) gel was the largest in three in18d and25d contrast observation, and kept the maximum stable status; The swelling degree of maximum volume25wt%of PAM gel than P (MMA-VP) was a little small, but PAM after the maximum volume decreased rapidly, then fractured; PVA gel swelling degree was the minimum in three.(4) Under the condition of pressure the volume swelling degree of P (MMA-VP) gel was still of the three largest, and mantained the maximum stable status; P (MMA-VP) gel swelt quickly in2d before and after no longer changed, the volume holded stable;The swelling degree maximum volume of25wt%PAM gel was slightly larger than P (MMA-VP), but PAM after the maximum volume changed rapidly to irregular shape, gradually dissolved; Under the condition of pressure PVA gel’s swelling degree was still minimum in three.[Conclusion](1) Stirring could dissolve a small amount of the PVA and PAM in deionized water at room temperature, the higher temperature could completely dissolve them. By freezing and unfreezing cycle PVA could be got solid state structure, after vacuum drying oven the volume shrinkage could be2-3times of the fomer gel.(2) The moisture content of P (MMA-VP) and PAM than PVA were4-5times.(3) In simulated body fluid, whether or not under the condition of the pressure, the maximum swelling degree of P (MMA-VP) and PAM were lager4-5times than PVA.(4) P (MMA-VP) and PAM expansion rates are faster, in2days they could reach maximum expansion degree, by contrast PVA expansion rate was slower, getting maximum expansion degree in10days.(5) In the process of expansion, P (MMA-VP) and PVA were relatively stable.From starting to reaching maximum swelling degree expansion they would not happen dissolve, and kept the balance after the maximum swelling degree without fracture, and dissolution. But the PAM dissolved rappidly after getting into the volume’s largest volume, and fractured later.(6) Under the condition of the pressure, the morphology of P (MMA-VP) and PVA would not change, and not move towards to the low pressure area, but PAM would move from the high stress area to the low pressure area.