| This project was commissioned by the Huizhou Petrochemical Company of CNOOC Energy Co.,Ltd.to study how to further improve the properties and capabilities of super absorbent resin based on the research of acrylic superabsorbents in the laboratory.It mainly solves the problem of poor salt resistance and degradability of acrylic resins,and improves the economic and environmental benefits of acrylic superabsorbents.N,N'-methylenebisacrylamide?MBA?wasusedasacross-linking agent,Potassium persulfate?KPS?was used as an initiator,Acrylic acid?AA?,2-acrylamido-2-methylpropanesulfonicacid?AMPS?andmethylallyl polyoxyethylene ether?HPEG-2400?as monomers,Starch?ST?and Medicinal Stone?MS?as raw material.Graft copolymerization and chemical intercalation techniques were applied.The organic/inorganic composite superabsorbent resin was prepared by aqueous solution polymerization method:ST-g-?AA-APMS-HPEG?/MS?SAAHM?.The molecular structure of SAAHM resin was characterized by means of modern physical instruments.The infrared spectrum?FT-IR?showed that constituent containeda carbonyl group of 1736.84 cm-1,a carboxyl group of 1296.45 cm-1,a sulfonic acid group of 1226.22 cm-1,an amide group of 1624.09 cm-1and an ether group of 1110.73 cm-1.X-ray diffraction showed that the particle size of the polymer increased,modified medical stone pore size became larger,the degree of crystallinity decreased after compounding,and the organic-inorganic components dispersed more uniformly in the system.Transmission electron microscopy?TEM?showed that the resin chains cross-linked to each other and distributed in branches.Thermogravimetry?TG?and differential thermal?DSC?indicate that the resin has better thermal stability and the thermal decomposition temperature is 337.6?.The paper has studied the synthesis conditions and control factors that affect SAAHM performance.The types,amounts and proportions of raw materials of acrylic olefinic monomers,the active methods of medical stone and starch,and the share of the total mass of monomer raw materials were systematically discussed.The choice of initiators,crosslinkers,and the share and amount of the total mass of the raw materials,the degree of neutralization of acrylic monomers,the order of addition of these materials,the reaction temperature,the stirring speed,and the reaction time affect the performance of SAAHM,through single-factor,orthogonal test,the synthesis formula and process conditions of the best product were obtained.The test results show that when the mass ratio of AA,AMPS and HPEG-2400 is 10:3:1,the degree of neutralization of acrylic acid is 75%,and the amounts of ST and MS are respectively5%and 10%of the total monomer mass,The KPS and MBA dosages were 0.8%and0.08%of the AA mass respectively,the reaction temperature was 65°C,the stirring speed was 200 r/min,and the reaction time was 1 to 1.5 hours.The target product SAAHM was distilled with distilled water,tap water,The ratios of 0.9%NaCl saline,artificial urine,and artificial blood were 948 g/g,534 g/g,126 g/g,57.14 g/g,and 13.7g/g,respectively.Compared with P?AA-APMS-HPEG?water-absorbing resin,the ratio of distilled water and 0.9%NaCl brine?893g/g,93g/g?increased by 6.15%and35.48%,respectively;The ratio?454 g/g,77 g/g?increased by 108.8%and 63.6%,respectively.At the same time,the salt absorption solution,water retention performance and kinetics,biodegradation rate and mechanism of SAAHM were studied.The results of the experimental study indicate that the introduction of medical stone into the resin is intercalated and the superabsorbent polymer exhibits a strong salt water absorption performance.The process of water-absorption of the composite superabsorbent resin has both the swelling process and the diffusion process of the solution into the interior of the resin.The two processes proceed simultaneously.The swelling process meets the pseudo-second-order kinetic model.The pseudo-second-order kinetic equations are represented as follows:Distilled water:t/Qt=1/0.0003Qe2+t/Qe;Tap water:t/Qt=1/0.00069Qe2+t/Qe;Normal saline:t/Qt=1/0.0021Qe2+t/Qe;Artificial urine:t/Qt=1/0.0051Qe2+t/Qe;Artificial blood:t/Qt=1/0.0279Qe2+t/Qe.In-solution diffusion complies with the Fickian diffusion process.Fickian diffusion rate equation are represented as follows:Distilled water:lnF=0.457lnt-0.97;Tap water:lnF=0.454lnt-0.9238;Normal saline:lnF=0.4678lnt-1.05;Artificial urine:lnF=0.4844lnt-1.07;Artificial blood:lnF=0.45447lnt-0.9238.The introduction of starch and medical stone could enhanced the water retention of the resin.The resin was left at 25?for 12 days,the water retention rate was59.35%;the water retention times at 45?,65?,85?,and 105?were 60h,23h,9h,and 7h,respectively;and the pressure was 196 Pa.Under the conditions,the water retention rate was 94.7%;the water retention rate was 93.37%after centrifugation at2500 r/min for 30 min.Water retention kinetics equation at 25?:R=100%-0.1394t;The thermodynamic equation of the water retention process is,the apparent activation energy Ea=3.8×104 J/mol,and the pre-exponential factor A=3.5×106.Using the soil burying method,the degradation rate of the resin within 30 days under natural conditions on a self-made laboratory bench was 36.2%.By introducing starch and medical stone into it,its degradation performance can be improved,and the degradation kinetic equation is:St=S0-0.1219t.This study provides a scientific basis for the engineering strength of polyacrylate-based superabsorbent resins to solve the problem of gel strength,salt tolerance,biodegradability,and cost reduction.It also expands the application fields of polyacrylic superabsorbents.improve the"three benefits"guiding role. |
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