Study On The Preparation And Performance Of Cellulose-based Water-absorbent And Water-retaining Resin

Superabsorbent polymers are high-performance water absorbent and retention materials withthree-dimensional network structures. They are able to absorb water and other liquids tens tothousands times their own weight in a relatively short time. They can also retain a swollen stateeven under some pressure. Given all these advantages, superabsorbent polymers are widelyapplied in various fields, such asin agriculture, horticulture, hygiene, medicine, petrochemistry.However, most of these superabsorbents are synthetic polymers based on acrylic acid (AA) oracrylamide (AM), which are costly, poorly degradable, and environmentally unfriendly.Cellulose is abundant, renewable, low cost, and biodegradable. To take full advantage ofresources, using flax yarn waste as raw material to prepare cellulose-based superabsorbent is ofgreat significance. This paper studied on the preparation process, morphology and structuralcharacterization and performance testing of the superabsorbentTwo methods, heterogeneous system and homogeneous system, were studied to synthesize thecellulose-based superabsorbent in this paper. The focus research was reflected in thehomogeneous polymerization. Meanwhile, its performance, influencing factors, morphology andstructural characterization were also analyzed in this paper.1. Research of the preparation of acrylic-grafting flax cellulose in heterogeneous system.In the present work, flax cellulose was separated from flax yarn waste by a chemicaldegumming method. A novel cellulose-based superabsorbent was prepared by water solutionpolymerization. The influence of different synthesis condition (reaction temperature, monomeramount, initiator amount and cross-linking amount) on performance of superabsorbent werediscussed respectively through singe factor experiment. The optimum process parameters in thisexperiment system were obtained:70°C reaction temperature,5g/g monomer (AA) to cellulosemass ratio,0.1g/g initiator to cellulose mass ratio,0.04g/g cross-linking to cellulose mass ratioand3h reaction time. The maximum water absorbency was658g/g distilled water,382g/g tapwater, and65g/g0.9wt%aqueous NaCl solution. The grafting percentage and graftingefficiency were129.7%and32.4%. The sample retained81.2wt%and24.6wt%of absorbencyafter being heated for10h at30°C and60°C respectively, and retained74.3%of absorbencyafter being heated for12d at room temperature. The prepared novel superabsorbent composite had excellent water absorption and retention capability.2. Research of the preparation of acrylic/acrylamide-grafting flax cellulose in homogeneoussystem.On the basis of our work1, a new cellulose-based superabsorbent composite washomogeneously synthesized by simultaneously grafting the hydrophilic monomers AA and AMonto a cellulose backbone in low-cost NaOH/urea solution. The influence of different synthesisparameter on performance of superabsorbent were discussed respectively through single factorand ortho-experiment. The water absorption and retention capacity, biodegradability of thesuperabsorbent were also investigated. The optimal synthesis parameters were70°C reactiontemperature,4g/g monomer (AA+AM) to cellulose mass ratio,0.1g/g initiator to cellulose massratio,0.04g/g cross-linking to cellulose mass ratio and3h reaction time. The maximum waterabsorbency was875g/g distilled water,490g/g natural rainwater, and90g/g0.9wt%aqueousNaCl solution. The biodegradability of the superabsorbent prepared in the present work issuperior to synthetic resin, after90days, the sample had a weight loss of47.4%during thecourse of degradation in soil. The release of urea from superabsorbent lasted for a relatively longtime. Therefore, the prepared novel superabsorbent composite had potential applications inmodern agriculture and horticulture. The superabsorbent composite were characterized by FT-IRmeasurements, Thermal analysis and scanning electronic microscopy. It turned out that thethermal stability, decomposition temperature and surface morphological of superabsorbentcomposite were notably influenced by the copolymer component.In this paper, a cellulose-based superabsorbent composite was successfully synthesized bygrafting AA and AM onto flax yarn waste cellulose, achieving the cyclic utilization of industrialwaste resources and conforming with the circular economy policy of China. Meanwhile, theprepared superabsorbent, with great application potential, is hopeful to be promoted toindustrialization in related areas.