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Study On Synthesis And Application Of Super Absorbent Polymer

Posted on:2006-05-17Degree:MasterType:Thesis
Country:ChinaCandidate:Y B NiuFull Text:PDF
GTID:2121360155452616Subject:Materials science
Abstract/Summary:PDF Full Text Request
Super absorbent polymer (SAP) is a kind of cross-linked functional polymer.They are widely used such as absorbents in healthcare, communicationtechnology,building industry,chromatography,water purification,agriculturalapplications and so on. In the thesis P(AA—AM)GB (SAP) was synthesized bymeans of aqueous, using partly neutralized acrylic acid (AA) and acrylamide(AM)as monomers, N, N'—methylenebis—acrylamde as cross-linking agent, andpotassium peroxydisulfate as initiator. The effects of monomers composing,cross-linking agent amount, initiator amount, monomers concentration, AAneutralization and reaction temperature on water or solution absorbency werestudied.When the ratio of AM/(AA+AM)% is 30%,SAP will have the biggest water andsolution absorbency. It is because that the non-ionic group (—CONH2) isintroduced into the SAP and this improves the water and solution absorbency ofSAP.When the weight ratio of cross-linking agent to (AA+AM) is about 0.05%, SAPwill have the biggest water and solution absorbency. If the ratio is below 0.02% thepolymer chains will not be well cross-linked, and this will cause SAP partlydissolved in water, and the water and solution absorbency will decline. If the ratiois above 0.05% , the degree of cross linking will increase and the water andsolution absorbency will also decline.When the amount of initiator is 0.3% of the monomers weight, SAP will havethe biggest water and solution absorbency. Initiator concentration can influence theSAP absorbency by influencing the molecular weight of the polymer. Only themolecular weight of the polymer is big enough, there will form appropriatemolecular network to absorb water. When the concentration of the initiator is toosmall, the conversion of the monomers will reduced, and the molecular weight ofthe polymer will decline, and the polymer will partly dissolved in water. When theamount of the initiator is excessive, according to the kinetic mechanics: γ∝[I]0.5,the molecular weight of the polymer will also declined. This goes against theformation of the appropriate molecular network. When the amount of inorganic filler BG is about 20%—40% of the monomersweight, SAP has the best combination property. From the SEM photos of SAP wecan see the inorganic powder is at the frame of the molecular network, and thisimproves the rigidity of the molecular network and polymer gel. When the degree of neutralization of acrylic acid is 80%, reaction temperation is70℃, SAP will have the biggest water and solution absorbency. The reaction iseasy to control. SAP also has the good properties of temperature resisting and watercontaining. The SAP we synthesized has good water absorbency. The thesis creatively makesSAP as moisture absorption material. The mechanics and the quality of moistureabsorption of SAP under different conditions were studied. By comparison therewas a result that different SAP has different quality of moisture absorption. If SAPhas bigger water absorbency, the velocity of moisture absorption will be faster, andthe capability moisture absorption will be larger. The thesis compares the quality ofmoisture absorption of SAP under different conditions with silicon gel andmolecular screen. It is found that when temperature is below 30℃and relativehumidity is below 50%,the moisture absorption of SAP is equal to silicon gel andmolecular screen. When relative humidity is above 50%, the velocity and thecapability of moisture absorption of SAP are much lager than silicon gel and...
Keywords/Search Tags:super absorbent, water absorbency, reclaim in situ, moisture absorption, graft
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