Preparation And Properties Of Organic-inorganic Composite Environmental-friendly Degradable Superabsorbent Polymers

SAP are polymers with fast and high water absorption capacity,which have wide application.The superabsorbent polymers are absorbing water by the combination of chemical bonds when compared to that of traditional sponge and paper,which make it better water retention performance.Since the common as-superabsorbent polymers are the kind of polyacrylonitrile,polyacrylic acid or polyacrylamide,the polymers with excellent water absorption and water retention performance are difficult to be degraded.At present,due to the large-scale use of non-degradable superabsorbent polymers,the environmental problems are becoming more and more serious,and it has the trend of becoming the next"white pollution".In recent years,the major problems are to improve the low degradation rate of common superabsorbent polymers.Superabsorbent polymers based on starch and other natural macromolecules and their derivatives can be biodegraded,with lower toxicity,but the degradation degree of starch and other natural macromolecules and their derivatives based superabsorbent polymers is not high,there are some residues.Some special inorganic with special properties can overcome this shortcoming,such as adding nano-TiO₂ with good photodegradation performance,to prepare organic/inorganic complex degradable superabsorbent polymers,which can increase the photodegradation performance of superabsorbent polymers and reduce the residues of starch and other natural macromolecules and their derivatives based superabsorbent polymers.In this paper,acrylic acid?AA?and acrylamide?AM?were used as monomers,natural polymers and their derivatives as the main chain,polyacrylic acid and polyacrylamide were grafted on to the main chain,cross-linking agent was then added to form three-dimensional network structure.Furthermore,nano-titanium dioxide was added to synthesis of organic/inorganic composite light/biodegradable materials,the main contents are as follows:?1?Nano-titanium dioxide particles were prepared by hydrothermal method with tetrabutyl titanate as titanium sources.And the preparation scheme of anatase-type nano-titanium dioxide particles with high photodegradation efficiency was selected by studying lots of parameters.Then the nanometer titanium dioxide particles were modified with silane coupling agent?KH 570?,which can make better combination with the superabsorbent polymers;?2?CMC-g-P?AA/AM?/TiO₂ superabsorbent polymer was prepared by inverse suspension polymerization method which AA,AM and carboxymethyl cellulose?CMC?were used raw materials,potassium persulfate?K₂S₂O₈?as initiator,N,N'-methylenebisacrylamide?MBA?as crosslinking agent,cyclohexane as the continuous phase,Span80 as the dispersant.And then the superabsorbent polymer was obtained with adding the nano-titanium dioxide particles modified silane coupling agent.The experimental results showed that when the content of initiator was 0.85%,crosslinking agent was 0.08%and the ratio of oil to water was 4:1,the water absorption capacity of superabsorbent polymer was the best.And the degradation performance of superabsorbent polymer prepared under the selected conditions were also tested.It was found that the degradation rate of the superabsorbent polymer in the soil was 28.72%after 98 days,and the degradation rate was 27.78%in the UV light irradiation condition after 48 hours,which indicated that the superabsorbent polymer had good degradation performance in soil and in UV light environment.?3?CTS-g-P?AA/AM?/TiO₂ superabsorbent polymer was synthesized by inverse suspension polymerization which AA,AM and chitosan?CTS?were selected as raw materials.The orthogonal test design and L₁₆?4⁵?orthogonal table were used to investigate the effect of initiator to monomer ratio,crosslinking agent ratio,neutralization degree,acrylic acid and acrylamide mass ratio and temperature on the absorbent ability of the superabsorbent polymer.The experimental results showed that when the ratio of initiator to monomer was 0.85%,the ratio of crosslinking agent to monomer was 0.12%,the degree of neutralization was 70%,the mass ratio of acrylic acid to acrylamide was 5:1,and the temperature was 75?,the degradable superabsorbent polymer had the highest water absorption rate of 1747 g/g.The degradation rate of the superabsorbent polymer in soil was 35.60%after 98 days in the soil environment,the composite superabsorbent polymer could degrade 28.76%after48 hours under UV irradiation,which showed a good degradation ability.