Preparation And Study Of Carboxymethyl Cellulose And Starch Based Superabsorbent Resin

Super absorbent polymer（SAP）was a low-density cross-linked polymert that had good water absorption and water retention properties,which had been widely used in life,especially in human physiological hygiene products.In this paper,carboxymethylcellulose（CMC）and starch（St）were used as raw materials,with potassium persulfate（KPS）as initiator and N,N-methylenebisacrylamide（NMBA）as cross-linker.Three kinds of resins were synthesized by aqueous solution polymerization.SAP were characterized by Electron microscopy（SEM）,X-ray diffractometer（XRD）and Fourier infrared spectrometer（FTIR）;at the same time,its comprehensive properties were investigated.The specific content was as follows:1.Preparation and Comprehensive Properties of a Novel CMC-AA-AM/PVA Semi-IPN Superabsorbent Polymer.A new CMC-AA-AM/PVA semi IPN superabsorbent resin was synthesized by aqueoussolutionpolymerizationmethodwithCMC,acrylicacid（AA）,acrylamide（AM）and polyvinyl alcohol（PVA）as the main raw material,KPS as initiator.The structure and morphology were characterized by FTIR,XRD and SEM.Results proved the synthesis of semi IPN resin in product.The optimum conditions were screened by single factor method:65%of the neutralization degree of acrylic acid,70℃of the polymerization temperature and 100%:2.67%:6.67%:0.667%:0.046:33.4%of w（AA）:w（CMC）:w（PVA）:w（KPS）:w（NMBA）:w（AM）.In the optimum conditions,resin water absorbency rate was 494g·g^-11 and salty water（0.9%NaCl）absorbency rate was 96g·g^-1.The temperature-resistance,centrifuge water retention,degree of vacuum water retention,reusability,high-temperature water retention kinetics,and water absorption rate were studied.The results showed that the absorbency rate of the resin in the range of 20°C-70°C was the basically same;the SAP had good water retention and reusability;the SAP had the ability to absorb water quickly and could reach the saturation of water absorption within 20 minutes;the high temperature water retention kinetics of SAP satisfied the Arrhenius equation k=2.673×10⁴e^{（-25025/RT）}.2.Preparation and Comprehensive Properties of a Novel St-AA-AMPS/PVA Semi-IPN Superabsorbent Polymer.A new St-AA-AMPS/PVA semi IPN superabsorbent resin was synthesized by aqueous solution polymerization method with St as substrate,AA,AMPS and PVA as the main raw material,KPS as initiator,NMBA as crosslinking agent.The optimum conditions for synthetic reaction were:60%of the neutralization degree of acrylic acid,70℃of the polymerization temperature and 1:10.67%:9.333%:0.6667%:0.050%:33.33%of w（AA）:w（St）:w（PVA）:w（KPS）:w（NMBA）:w（AMPS）.Under the optimum conditions,resin deionized water absorbency rate was 1214g·g^-1and salty solution absorbency rate was 116.0 g·g^-1.The structure and morphology were characterized by FTIR,XRD and SEM;at the same time,the centrifugal water retention,the degree of vacuum water retention,reusability,the rate of saline absorption and its salt water swelling behavior were studied.The results showed that the SAP had good water retention and reusability;SAP’s physiological saline absorption reached saturation within 25 min;SAP swelled at the initial stage as the Fickian swelling model,and the diffusion swelling conformed to the second-order kinetic model.3.Preparation and Comprehensive Properties of tomite/sodium carboxymethyl cellulose organic-inorganic superabsorbent resin.A diatomite/sodium carboxymethyl cellulose organic-inorganic superabsorbent resin was prepared by aqueous solution polymerization with CMC,AA and AMPS as raw material,the diatomite as inorganic additives.The influences of neutralization degree,the content of diatomite,CMC and AMPS on the absorption performances of synthesised resins were studied by single factor test and orthogonal array design methods,and the optimal conditions was determined.Under the conditions,absorbencys of the resin in distilled water and salty solution was 1695.1g·g^-11 and120.0g·g^-1,respectively.The resin was characterized by FTIR,XRD and SEM.At the same time,the SAP’s water retention rate was studied.The results showed that after centrifugal separation in 6000r·min^-11 centrifugal machine for 60 min,the water retention rate of resin was up to 79%;Compared with commercially available water-retaining agents,the three water-absorbing resins synthesized in the lab had better absorption（salt）water rate,absorption（salt）water rate and water retention performance.4.Adsorption properties of methylene blue on diatomite/sodium carboxymethyl cellulose organic-inorganic superabsorbent resin.The effect of adsorbent dosage,contact time,initial concentration,temperature,and ion concentration on the adsorption of methylene blue was investigated by using diatomaceous/carboxymethyl cellulose sodium organic-inorganic super absorbent resin as an adsorbent,and its adsorption kinetics was investigated.The results showed that when the adsorption temperature was 20℃,pH=7 and the adsorbent was 0.007g,the maximum adsorption capacity was 3775.57mg·g^-1;The adsorbent reached saturation within 45min;The process of adsorbing methylene blue conformed to the second-order kinetic model;adsorption capacity of the adsorbent increased first and then decreased with the increase of pH;When the adsorption temperature was 20°C,the adsorbent was0.007g,and the solution pH was 7,the adsorption capacity of the adsorbent increased with the increase of the initial concentration of methylene blue;When the initial concentration was 300 mg·g^-1,the adsorption reached equilibrium.the adsorption effect of the adsorbent decreased with the increase of the temperature;the adsorption amount of the adsorbent decreased with the increase of the ion concentration.5.Degradation property of diatomite/sodium carboxymethyl cellulose organic-inorganic superabsorbent resin.The three degradation methods of solution impregnation degradation,ultraviolet radiation degradation and soil burial degradation were studied and compared.The results showed that the degradation rate was the highest with ultraviolet irradiation,followed by the impregnation degradation with strong alkali solution,the degradation with hydrochloric acid impregnation,and finally the landfill degradation.The most environmentally friendly and inexpensive degradation was landfill degradation and the six-week degradation rate was 36.6%.